Calculate rolling resistance for foam filled tire Let us consider a bike wheel. Does anybody know a way to calculate how much does rolling resistance changes if the inner tire volume is filled with foam instead of air? Let's assume a foam hardness which equals a 2 bar inflation.

Even with a finite-element tool kit you would need a lot of physical data in order to be able to calculate the RR. In addition to data for the tyre casing and rubber you would need the visco-elastic properties of the foam. Deformation of a foam will certainly absorb more energy than deformation of an air chamber, hence result in higher RR.

There is a kind of foam tyre made of closed-cell polyurethane foam sold under the trademark name Amerityre Flatfree. You can find on the internet an investigation of this tyre by Thierry Larose Chevalier et al from the University of Ottawa.
http://www.flatfreetire.ca/Ottawa%20U.pdf

The results of this study are a bit ambiguous. Based on in-shoe force measurements from cycling on training rollers the authors state that there is no significant difference in RR with a traditional clincher road tyre. However, the participant cyclists subjectively commented that they felt more resistance.


Should I stick with my Stolen (brand) BMX or should I build my own bike? I live in Greece and I am 13 years old. Recently I found a Flatland frame and thought about building my own bike. Should I build my own bike or should I stick with the Stolen BMX I already have?
I haven't tried to build one before so if you can give me some advice that would be nice. The frame looks like this:

Gianis.

I'm an old man, but I used to ride BMX street and flatland years (decades) ago.

Because of their very specific geometry, Flatland frames are not great for anything but doing tricks.  If you need a general purpose bike for transportation and whatnot, stick with your Stolen (brand) BMX.

For those wondering, "Stolen" is the name of a BMX equipment manufacturer.
http://www.stolenbmx.com/


Are aluminum anti-seize and silver anti-seize different? I asked someone to pick up some silver anti-seize (which I'd seen recommended) and they came back with aluminum anti-seize.  Is there a difference?

I could imagine that, when used between aluminum and steel, you wouldn't want aluminum in the anti-seize.

Anti-seize compound exists to prevent galling, which according to Wikipedia is a problem with metal parts in sliding contact, particularly parts under high pressure with stationary or slow-speed contact.  Some metals, such as aluminum and stainless steel, are more prone to galling than other materials, like hardened steel.

Loctite make a brand of anti-seize compound, Loctite 37565, that is marketed as "Silver Anti-Seize", that they say is "fortified with graphite and metallic flake"; they don't say anything about the product actually containing silver, so I think "silver" is a marketing term.  The metallic flake in it might well be aluminum (copper also seems to be popular).  I couldn't tell you whether aluminum or "silver" anti-seize is better, but I do know from personal experience that if you're using stainless steel fasteners, any kind of anti-seize compound is much better than none.


Old thumb shifter slips - can it be mended? This bike is over 17 years old and not particularly high quality, but it does not make sense to replace the whole thing over one shifter. So I am looking to repair it if possible. I'm confident with most aspects of maintenance, but I've no idea what goes on inside these things.

When changing 'down' to an easier gear with the thumb, the lever slips and the gears do not change. The lever moves further than is expected, with no resistance. By simultaneously applying lots of upwards pressure with the thumb, you can sometimes get it to shift. Once it does shift, the rear functions happily. I've had no other derallier issues.

There's an allen key fitting on the top, and a screw on the bottom. I have not opened it up, worrying that springs will ping out and all will be lost!

I've no idea if it needs more lubrication... or all the gunk cleaning out. Go tighter... or looser?

Thank you.

These shifters are not really supposed to be repaired. Sometimes contamination interferes with the mechanism and can be cleaned out, but if the ratchets have worn out you just need to replace them.

Shimano makes 8 speed shifters that are compatible with older derailleurs. The current Acera/Altus range includes 3x8 and 2x8 shifters for 2 and 3 front chainrings.

Here's the Shimano range line-up page for Acera/Altus: https://productinfo.shimano.com/#/lc/acera_altus/3x8


SON 28 Hub Dynamo "Rotation Lock"? I have bought and successfully installed a SON 28 Dynamo Hub and a Supernova The Plug III on my bicycle.

However, when the wheel spins, the Hub Dynamo connectors will spin together with the wheel.

Is there a specific way to install the wheel packing the SON 28 so that the Hub's electric connectors will remain in place as the wheel spins?

Start by checking that the axle is clamped firmly in place. The connectors are part of the axle assembly and shouldn't be able to turn with the hub unless the axle is loose.

Note that the comment above about having the connections on the right hand side of the hub applies to older versions of the SON28. The newest versions (the 2015 40/48-hole tandem hubs as well as the 2012 and later versions with the smaller flange permit the connections to be on either side, http://www.nabendynamo.de/produkte/pdf/english/son282013e.pdf).


Cartridge equivalent spindle length for Shimano BB-6207 116 mm Cup and Cone Bottom Bracket? I'm building up an old Terry bike and will likely pick up a NOS Shimano 600EX FC-6207 crankset. The corresponding bottom bracket for this crankset is the 116 mm BB-6207 cup and cone. However, given the ease of finding a new UN54 cartridge compared to sourcing a BB-6207, would I be able to use the crankset with a 115 mm cartridge? My bike has 68 mm diameter English threads.

Yes. Remember that 1mm of difference is 0.5mm difference on each side and you will not have to adjust your derailleur or gears to accommodate that. Sounds like you have done your homework already.


How do I correctly set the angle of my drop bars Are there any tricks to setting the correct angle for the drop bars on my road bike, when adjusting my handlebars in the stem?

Is it just a matter of personal preference or is there a general consensus on what angle you should use?

I will post my "non-specialist" way to do this setup, considering:

I have no current bicycle with drop bars;
I've been bred on bicycles riding flat-bar mountain bikes, no tape;
I have more than one bicycle, and the following method is the only one I use for any bike (currently use a lot of riser bars, have used some albatross-style bars).

The method:

With your chosen stem already tight in place, and your saddle the height you usually ride, install only the naked bar(bare metal), and don't tighten it too much.
Install the brake levers in a "starting position" (but not the bar tape) and attach them to the brakes so they actually brake.
On an empty parking lot or the like, ride the bike while trying a lot of handlebar positions, rotating the dropbars forwards and backwards until you can grab a good and comfortable grip either in the drops, or in the upper parts. Don't overemphasize the brake lever position for now. Instead, focus on the bar position itself. Let the clamping bolts a bit loose, so you can get the "sweet spot" with precision and without too much effort. When done, tighten the stem bolts.
Repeat previous step for the levers, clamping them lower or higher. Find the ideal balance between comfortable "in the hoods" position, both for hand rest and brake reach, and a good brake reach in the drops. You can use the "classic position" (whatever it might be) as a reference, but not as a measure of quality. Your comfort, functionality and safety should always be the measuring rule. When done, tighten the brake levers clamping bolts.
After tightening everything in position, go out for a short ride "in the field", perhaps in light traffic, or in the road (a rolling terrain with crossings would be perfect), and perform some final adjustments;
Get back home and wrap the tape.

Of course, these steps might be adapted freely.

Hope it helps.


Is 25 km/h average speed good? What speed should I aim for? So, I recently got into road cycling and have been riding for a few weeks. My average speed for most of my rides is around 25 km/h for the first 40 km and drops to 15 or 20 km/h for the next 20 or 30 km. I want to know if the speed that I'm riding at is considered as "slow" or "walking pace" or is the speed that I'm going at pretty good. I'm not sure what speed I should be aiming at.

Note:

I am preparing for long distance rides, mostly flats more than 80 km. So I want to know what speed I should be aiming for, not to win, but the speed that one should ideally be at.

There is no such thing as an ideal speed you should be aiming for.  It doesn't matter how fast you ride, there will always be faster riders, and there will also be slower riders.  The main thing is that you give it your best and try to enjoy your ride.

At events here in the UK it is typical to see riders averaging from 16-35km/h and everything between.

Edit: Advice above is for a typical sportive ride - if you have intentions to race things are a bit different and you should expect to need to be able to hold a bunch travelling at 35-40km/h for 2hrs for entry level road racing.


Fitting 1.5" tapered fork in a 42mm head tube? TL;DR: is there an IS42 bottom headset for a 1.5" tapered steerer tube?

I have a 2013 Giant Defy 3 road bike with a broken fork.  It's very hard to find used forks for this because the steerer tube needs to be 298mm long.  The inner diameter of the head tube is 42mm top and bottom and it has an integrated headset.  The original fork was 1.25" top and 1.25" bottom.  I found a good deal on a tapered carbon fork which is 1.25" top and 1.5" bottom.  Is there any headset bottom that will make this work?  All the IS42 headsets I have found are for 30mm bottom.

Crane Creek makes a headset that will solve this problem. I've used it on my MTB and it works well. It does slightly increase the stack height.

Do I need a tapered head tube to use a tapered fork on my bike


Why does my non-drive side crank arm come loose? I tighten the bolt super hard. Ride for a while. Then it comes loose again. I don't know if its my BB or the bolts. How can this be fixed??

By "non-drive" I assume you mean the left side.  This is more apt to come loose than the right because of "precession" -- most crank bolts are right-hand thread on both sides, but the motion of the crank arm relative to the shaft tends to loosen the bolt on the left side, whereas it tends to tighten the bolt on the right side.

But if this is occurring it's because there IS motion between the crank arm and the shaft.  This should not be, as the two should fit together so tightly as to prevent any motion.  What has no doubt happened is that the bolt was installed too loosely at one point, the crank arm worked loose, and now the socket of the arm is misshapened so the two tend to move relative to each other all the time.

Using some Loctite (the "removable" variety) on the bolt will help temporarily, but ultimately something must be done about the misfit between the two parts.  Basically either the arm must be replaced (and the shaft, if the situation goes on for too long), or (if this is a square shaft) you must carefully fashion a shim (perhaps out of aluminum pop can material) to create a better fit.  (If it's a splined shaft you're probably SOL.)  And regularly re-tighten the bolt -- don't wait for it to get loose.


Should the bike or the rider take the jolt from a bump, and how? The last part of my commute to work has some significant bumps in the road which are really quite jarring, since I'm on a road bike that, of course, has no shocks (but has a carbon fork).

Most of the bumps are caused by cracks in the asphalt that have separated or curb corners that don't totally flatten to the road level at the crosswalk... or tree roots that have started to push up from beneath the pavement.

Should the bike take most of the concussion from hitting bumps? If I lift myself off the seat only barely and just for a moment, I don't have to feel the brunt of the force, and my bike has more freedom to take the hit instead of me. (These aren't so large that I am at much risk of totally flying off the bike if I stand up slightly for those moments. I'm still holding on, but maybe more lightly.)

Will the bike last longer if I kind of use my legs as springs, or should I stay firmly planted and take the jolt from the bump? What's the tradeoff, if any, between my health/safety and the longevity of the bike?

This is not an either-or proposition. Your bike is hitting the bumps and supporting your full weight (minus the very small proportion of weight that might be falling at that exact moment) regardless of how you stand when you hit the bumps.

The difference is whether you're going to let the additional damping effects of the down tube, seat tube, bottom bracket, cranks, and pedals absorb some of the shock before hitting your body, and whether you take that shock on your feet (which are protected by hard soles and socks and are connected to your springy ankles) or just take it right on the sit bones (which are hard and part of your skeleton). Obviously one of those is going to feel a lot worse than the other.

It's helpful to imagine an analogous system: a very light car carrying a heavy load. Our choice is whether the load is supported on a suspension system or not. If we rigidly attach the load to the frame of the car, the load isn't "taking the hit" when the car hits a bump -- rather, the shock is worsened because there's nothing to absorb some of the energy of the shock. If we suspend the load, the total weight the car is carrying remains the same (it has to), but we let the suspension system absorb some of the energy.

You and your bike are both better off if you get off the seat a bit and let your legs (and the frame, to some extent) act as a suspension system.


How do I fix movement in headset I have bought a second hand bike and generally it's going well. However, there is a small amount of play in the headset that I've been trying to diagnose and resolve.

It's a threadless fork.

I've adjusted the tension by loosening the headstem bolts and tightening the top cap. I tighten it up a lot and this reduces the play a little, but when I brake hard or hit a bump I still get the 'clonk' as it moves to the limit of it's adjustability.

I've used this article on Sheldon Brown for the terminology I use below, particularly this photo:

I've taken some photos and have an idea of what the problem is. In this photo I've laid out from left to right the dust ring, followed by the compression ring.

When the compression ring is placed on the steerer tube, there is slight gap between them. It's maybe a millimeter, although I don't have anything to measure that with here. Watching the movement carefully I'm quite confident that it's this gap that's causing the steerer tube to clonk around.

I've measured the steerer and it's 28.6mm which is 1 1/8" according to Sheldon's site linked above.

So why is there a space around the compression ring? What's the best way to resolve this? Do I just need to find a smaller compression ring somehow? Or is there something I'm missing?

Updated: Added text to photo

Update

I think I'm missing a part. If you look closely at the exploded graphic from Sheldon, the compression ring has a gap in it, allowing it to shrink onto the steerer tube and hold it firmly. My compression ring is solid, so nothing can shrink and grip. Kudos to Zen as well, since he mentions that it's a wedge. I'm going to have a look around at home to see if I can find the missing bits. Otherwise a new headset should sort it. Thanks all!

The compression ring is a wedge.  There will always be space and movement here, until the headset is assembled and adjusted.

It looks like you're missing a part. There should be another hoop with a wedge shape and a split. It's the split ring on the upper left in the image below. This part is what grips the steerer tube tight and will eliminate the clonking you're experiencing.

If you are confident that all the parts are there, and assembled in the correct order, then you have 3 likely reasons for movement:

The first is that there is damage to the bearing cartridges.  This can show as movement when adjusted correctly, although usually on a headset it will fail first by being rough or crunchy feeling.
Secondly, there may be movement between the frame and the headset cup, which can mean that the frame is in need of replacement.  This can't be fixed via adjustment.  There are ways to attempt a fix, but it is best looked at by a qualified mechanic, first.
Last, there may be no movement in the headset, but you could be feeling movement in the brakes, depending on how you are checking for movement.  Try checking for movement by standing the bike on the rear wheel, turning the handlebar all the way to the left or right, and checking for movement with your hand around the headset.  That way if it is in the headset, you will feel it directly.

I hope that is helpful.


Ordering in the right size, and making sure it fits I'm fairly tall (6'4" or 195cm), and the bike I'm looking for is fairly specialised these days (a tourer, presumably steel, possibly with a sideline as a gravel bike/off-road tourer but no need for full-on CX specs and I need heel clearance).  I ride a hybrid.  My total road bike miles add up to about the same as a decent ride on my hybrid (42 miles) and those were on a too-small bike. So I'm not familiar with road bike fit.  I do know that if I can get the saddle high enough I'll be OK for easily an hour in the saddle of anything.

Nowhere stocks a range of tourers in my size. Even finding one single tourer in stock in my size is rare (tourers don't sell fast).

Of course many places can get one in, try to fit it, fail, send it back, try again...  But how do I maximise my chances of getting it right first time?  I don't see that a rough fit on a typical road bike or even a CX bike would be very informative, as I'm after the long wheelbase, relaxed geometry of a tourer.  It feels like I could extrapolate as well from flat bars. I'd almost be glad if these assumptions were wrong, but I might take a little convincing.

The next step of course is testing it to make sure it fits -- with everything set nominally right it will feel a bit odd as I'm used to flat bars.  How can I tell whether this is bad-odd or OK-odd in a short test ride?

Part of my concern is that I'm looking at the Genesis Tour de Fer, and I'm at the top end of the largest size -- by some shops' size guides I should be OK, but not according to others (including the one I may buy it from)

The answer for a rider who's capable of doing the math themselves is use either the bikes that are available to you or help from a pro with a fit machine to establish these numbers:

Target bar height relative to saddle
Target saddle to bar horizontal distance
Target saddle setback (relative to cranks)
Saddle height

There are somewhat more granular approaches and many more parameters on top of these, but these are the big ones to pay attention to know you're getting into the right ballpark, and will in almost all cases be enough to get you to the right size in a given model's size run.

Once you have a good idea of your target numbers, or the range of each parameter that you want to have access to in getting the fit dialed in, you can model each size of each bike you're looking at in a simple 2d CAD program. I use QCad, which is free, and getting the frame geometry of a bike into it from a manufacturer's specs only takes maybe 2-3 minutes once you know your way around.

To emulate what a touring bike would give you using more test-rideable road bikes, you will have to fiddle with swapping stems and potentially even adding a riser for the purpose of a test ride. Some shops would happily do that for the sake of a sale, and many would not.

A bike fitter with a proper fit machine who has some sensitivity and awareness to riding styles other than racing is also an easy path to handling this. Then you're just dialing the geometries of whatever bikes and sizes you're looking at into the machine and test riding to your heart's content. There is a lot you won't learn about the bikes from doing this, but it is a very good way to learn about one's fit needs, and again it's a reliable way of knowing you're getting the right size of a given model.

One of the stumbling blocks with this on touring bikes in particular is whether the steerer comes chopped or not. The norm in the industry is for all steerers to come cut to size to minimize assembly time. On touring bikes where it's more common for people to want high positions, that causes a lot of problems. Some companies, Surly and Salsa for example, who send out a higher than normal proportion of special ordered bikes, send uncut forks with all or almost all their bikes. The important point here is that, especially being tall, you have to know how much steerer you have to work with to get your target bar height. This is true even if you were willing to put a steerer extender on your new bike, which is unfortunate when it winds up being necessary.


Problem with internal gear routing cable and bottom bracket I have a problem where I got a frame made I asked for internal cable routing and it has arrived but there is no provision for the cable to pass through the bottom bracket.

It is a titanium frame and I'm trying to pass the hydraulic cables through but there seems no way of doing so without going under the shell leaving the cable exposed.

No doubt it's a little disappointing to have this hydraulic hose outside the BB shell if you were expecting fully concealed routing but what you have is the norm in a titanium frame. It looks like a lovely bike, I'm sure this small detail won't stop you enjoying the bike to the full!

Looks to me like SRAM Force AXS chainset, with a threaded bottom bracket shell. The crank spindle has a pretty large diameter and basically fills the whole of the bottom bracket shell. See below bottom bracket image, the plastic sleeve is nearly the same diameter as the threading. There isn't any room in the BB shell for hydraulic lines or gear cable routing. This is how metal frames are built, the down tube, seat tube and chain stays are attached to the cylindrical bb shell which is a very standardised dimension, while BB and crank standards have developed to make maximal use of the available space.

If there is room, perhaps in a larger spec shell like T47 or some other modification, the task is still difficult and would add cost to the build with no real benefit. Some builders do offer fully internal, but they are in the minority. The hose would be forced into a tight space with very tight bends which isn't ideal and the routing would make maintenance even more of a chore.

When you have bikes with cables and hoses which pass around the crank spindle inside the frame with plenty of room, these are carbon fibre bikes where the designers have the option to create space in the frame for the lines to pass through and even gear cable routing with removable covers.

image sram.com


handling and steering difference for stem/bar reach combinations? I was wondering what the steering/handling differences would be (if any) between the two combinations below?  Assume rider's hands are on bar hoods.
Combo 1 = 90 stem and bar with 80mm reach.
Combo 2 = 90 stem and new bar with 70mm reach.

My current setup is Combo 1 but I feel I am slightly stretched out.  I would also consider a Combo 3 of new 80 stem and bar with 80mm reach (would be cheaper than #2).

I have had a Retul fit done for my older bike. The new bike I got (2 weeks ago) was fitted by the sales person. I am having a painful adaptation to the new bike fit.

I roughly measured the difference in diagonal reach from mid-saddle to the bar (center) near the hoods. The old bike is 11mm less reach than the new bike. But the old bike is also 17mm lower than the new bike ... this is the saddle to bar drop.

In terms of handling ... isn't a 100 stem with a 70 reach bar roughly the same as a 90 stem with a 80 reach bar?

I understand how a shorter stem can affect the steering but ... I usually steer when my hands are near the hoods, not when my hands are on the top of the bars. So when my hands are near the hoods, then the stem length PLUS the bar reach must be considered together. Or am I missing something?

The exact difference can't be easily quantified in terms of how short is too short. The closer in you get, the more amplified an effect your steering inputs will have, creating a feeling of touchiness. It's not optimal, but it's a pretty subtle downside and well worth it if it's what it takes to get comfortable.

Comparing bars with different amounts of reach (and drop, especially since most bars with smaller reach numbers will also be shallow drop), a major consideration is that the smaller the number, the less variance is created between the different hand/body positions. That's why it makes sense for the size of the reach/drop numbers to scale with the size of the person.


SPD PD-M520 Pedals, replacing the Body Cover I have taken the body cover off my Shimano PD-M520 pedals and am unable to get it back on due to a little nodule having to be behind the bit of metal where the tightness ajustment is. That part is very stiff to move the correct amount! I was wondering if theres a knack to it or if brute force has to prevail here? First Picture shows the body cover not on properly, (I never knew it was called a body cover until I checked out Shimano's schematic for the pedal!) the second picture shows the nodule thing im talking about (Im full of technical terms)

Thanks!

I remember doing this last year. You need a way to keep the spring-loaded part (on the left in your pictures) out of the way while you move the other part into the correct position where you can attach the screw. If I remember correctly, I did this by sticking a long screwdriver between the axle and the spring-loaded part and holding it with one hand while using the other hand to position the loose part and putting at least one screw in to hold it.


I just bought a frame off this kid in my neighborhood but don't know who makes it? I bought this frame off a kid in my neighborhood for 100$. I looked like a cool freestyle frame. I built the bike up and just wanted to know if anybody had a clue to what company makes this frame?
this was on bottom bracket case opposite side of serial # GRREA21
thanks for any and all help.
SG

This one is the closest I could find. It has similar head tube and seat tube cut outs. It's titanium though. Is yours titanium? This is the current, steel version. As far as I can tell, this frame is identical, with the same brake bosses on the wrong side of the seat stays. Also has cable stops in the same place for the rear brake. Seat tube clamp is under the seat stays as well, which is another uncommon similarity.

If this isn't the same frame, your frame is almost definitely manufactured by Eastern. The cut-outs on the seat tube and head tube are very common on their bikes, and many of their models seem to have a similar brake placement. The frame I linked to is the only one I could find that had the exact same head tube cut-out.  All the rest had a logo cut out of the head tube.


Specialized Allez Sprint Fork I have a 2019 Specialized Allez Sprint Frame. I need a replacement fork, but specialized does not stock them. Are there any aftermarket forks that will fit this frame? If so, do they require a new headset?

Here is a photo of the OEM fork illustrating the integrated race and gap below the race, which I believe will make it challenging to find an aftermarket fork that will fit.

Aftermarket forks are available for pretty much any bike frame.

To fit the frame there are three things to consider, length, steerer diameter and taper, and brake mounting.

The length is usually measured 'axle to crown', which means the center of the axle to where the fork meets the frame head tube.

The steerer diameter and taper (larger size bottom bearing) have to match the headset bearings in the frame. I believe the 2019 Allez Sprint has a 1-1/8" to 1-1/2" taper steerer.

Obviously you need either a rim or disc brake fork.


longer seatpost for a folding bike I bought a Hopper 20" Folding Electric bike. This is basically a white-branded Viking E-Go bike when sold via Tesco UK.

But I am quite tall so I need a longer seatpost for it to be comfortable to ride. How can I go about finding a replacement seat that would go higher than the default one?

If you can't get something recommended by the manufacturer, you may be able to find something suitable by taking measurements or reading the size off the existing seat post. Sheldon brown has a database of seatpost sizes, but sadly it doesn't seem to include Viking or Hopper.

I guess there are three things you should look for:

Tube diammeter: Must either match your existing post or you can sometimes use a plastic shim to make up the difference.
Layback/Setback: How much the bracket at the top of the post is offset behind the tube. Larger numbers put your saddle a bit further from the handlebars.
Strength: I'm guessing really long seat posts for folders have to be pretty strong compared to those on standard bikes, so make sure it is specific to a folder and up to the job.

You may be best to take the old one into your local bike shop and ask if they can find something for you.


Can I use slider dropouts on my track dropouts? My bike's dropout/fork-end basically look like this:

and I wonder if I could use something like this to convert it into a vertical dropout with a hanger and disc caliper mount:

I'll only be using the bike for road purposes. I suppose there shouldn't be any stress-related problems, right?

If your rear spacing measures 115mm it might actually be designed as 110mm or 120mm. See here for standard hub spacings.

120mm freewheel hubs should be available, but you will only be able to fit a 5 speed freewheel onto it. If the frame is 100mm and steel you can probably expand the spacing to 120mm - see the page linked above for how that is done.

You will not be able to buy a 120mm hub with a disc rotor attachment. Disc rotors take up space, so hubs and frames had to get wider to accommodate them and keep the spoke flanges separated enough to maintain wheel strength.

Personally, I wouldn't trust a disc brake conversion kit period, especially one that relies on a couple of tabs in the slot dropout to resist braking torque like the one you included a picture of. A decent set of rim brakes should be plenty powerful enough.

Also, the kit pictured moves the rear wheel attachment out of the actual frame dropouts. Again, I wouldn't trust that particular kit. There are slot dropout derailleur hangers available that keep the axle bolted in the frame.


Forcing myself to run a heavier gear 1 mile of elevation gain over 20 miles. This takes me 4 hours. It takes the pros 1.5 hours.

We're riding at roughly the same cadence (if anything I'm a bit faster), but they're turning over a much heavier gear.

(I know these things because I did this route on the day of a race)

I'm on a repurposed mountain bike, so I have a proper granny gear.

If I want to get faster at this climb, should I ride at the cadence that feels right (granny gear), or should I limit myself to using my middle ring of my triple, closer to the gear that the pros use?

(Not sure if this changes anything, but my bike weighs about 35 pounds, 20 more than a race-grade road bike)

Basically what you want to do is to get stronger – you want to be able to ride in a higher gear at the same cadence. There are a number of ways to work on this, one is to push yourself hard(er) on hills.

What has worked for me is to find a hill that feels relatively easy in a low gear (for me this means that I can comfortably ride the hill at around 80 rpm). Then I'll try the hill in a higher gear (a cog or two higher in the rear, still using the small ring in front), pushing myself to keep my cadence up. I'll do this until my legs and/or lungs hurt, then I'll coast down the hill and recover. Then I'll do it again. Maybe four or five times. Then I'll go for a nice ride :-)

I think the formal name for it is something like interval training or hill repeats. The idea is to work yourself hard enough to get your heart rate high and trigger release of growth hormone. The growth hormone tells your body that it needs more muscle. It must figure out somehow that the tired muscles are the ones to grow…

The weight of your bike, is a mixed blessing – for absolute performance it definitely hurts – it's more weight that you have to carry up the hill, but on the other hand that same extra weight is helping you get stronger. I'm sure someone knows how to do the calculations, but my gut sense is that it is not a huge difference.


How should I negotiate price with bicycle salespeople? Aside from just knowing the best time to make the purchase of your bike, what other specific tactics can I make use of in negotiating price on a bike? For instance, what devalues a bike aside from just wear and tear, and how can I use these to get a better price on a bike?

Note:
I appreciate all the comments about LBS and local patronage of merchants is something we can all support. However, like going to buy a car, there are always things to know about a product that (when negotiating) play in the favor of merchants (overvalues the car: like when you had to get on a waiting list to get a Prius) and in the favor of buyers (devalues: when you had to be wary of your gas pedal buying a Prius). This is a question to benefit buyers of bikes.

Don't expect much until you know the guys that work at a bike shop. I bought my first road bike (a single speed) from my not-so-local LBS because it was on sale (45 miles from my house, with several bike shops in between). In the process, I discovered that I got along well with the guys that work there. In return for our growing relationship, they started giving me pointers about maintenance, and discounts on accessories (computer, bar tape, etc).

When I referred my father-in-law to them to get a bike (he's a doctor and doesn't have the same price constraints that I do) they gave him a pretty good deal because I sent him. I have no doubt that when I've saved my pennies enough to budget for a new bike I'll get as good a deal as they can offer me, without having to ask for a deal.

Most bike shop employees and owners could make a lot more money doing something else, but own/work at a bike shop because they love cycling. I appreciated the desire to stretch your dollars as far as they'll go, but nobody is entitled to special deals without earning them.


Bent spokes after lacing It's the first time I build a wheel (3 cross) and I would like to use these components:

DT Swiss H522 29" rim 36H
DT Swiss Hybrid 350 Hub 36H
DT Swiss Champion 2.0/1.8 J spokes

When I insert the spokes they go in easily, but when they reach the end of the "J" part, they get almost stuck (they can be moved by hand, but they stay in place instead of falling). I laced them anyways and the spokes are quite bent.
Should I choose a type of spoke with a longer "J" part?

It sounds as if the holes in your hub are close to the 2mm size of the spoke. This is fairly common, and the way I deal with it is to slightly bend the spoke while I'm lacing it. The goal is to get the J bend to be slightly more than 90 degrees, but normally what you actually get is a slight bend about 5mm past that. It will be hard to do that once you have the spokes attached to the nipples.
One possibility that doesn't apply in your case is the hub being finished with alternate holes countersunk on opposite sides, but the picture I found online of your hub does not have this.
Since you have managed to lace the wheel anyone the spokes should pull straight when you tighen them up (assuming you have laced the wheel correctly).
I highly recommend Jobst Brandt's book on the subject. It's short, dense, and has a good index. It should cover your concern, it's slightly old so has little on disk brakes and motors but the basics are there in detail.
https://www.goodreads.com/book/show/733514.The_Bicycle_Wheel


Change the angle of the arc of downtube / stem shifter lever to make it an alternative thumb shifter? I want to mount the following SunRace clamp-on shifter set horizontally as a "thumb" shifter on a straight MTB handlebar (22.2mm).  I will remove the left lever and only use the right with the clamp.

The problem is that the lever is not easy to reach because it swings from parallel with the handlebar to straight forward.  I would like to have the angle of the full swing of the lever go from a little towards me to a little forward.

Is there an easy way to change the angle of these stem-mount shift levers (which are almost the same as downtube shift levers) by about 45 deg?

Note (in second pic) that these are meant for stem mount, so there is a cable housing stop for the part of the shift cable housing that goes from the handlebar to a downtube stop.

Note that there are different levers, depends of the final position. For downtube, head tube or steam, see the ilustration in the bottom of the page:

Some of them have the cable stop vertically, equal as the tube hanger, and other at 90 degrees of it.


Is there a work around to a presta valve not engaging a tire inflater pin? I believe that either the schrader adapter I'm using is too long or the pin for the presta core isn't long enough for me to be able to use an air compressor. It works fine with a floor pump since a pin doesn't need to be engaged for air to come out. But in my situation of trying to seat a new tire, a pump won't work. I've been searches to see if there are other valve stem adapters that allow this.

You're using the wrong inflator valve on your compressor.

You're likely using this type of inflator valve (aka chuck). It requires the inner pin of the schrader valve of the tire to depress the inner pin of the chuck for the chuck to release air:

Instead you need one of these types of inflator valves which have a manually activated release mechanism (the lever or trigger). The advantage of these types is that they often have a built-in pressure gauge, such as the model on the right. The gauges are not very accurate but are sufficient for eyeballing pressure.

If the valve on your compressor is not replaceable (because it's not your compressor, for example) then you can fill up a portable air tank with the compressor (these tanks have schrader valves) and then hook up your manual-style shrader valve inflator to them. This is also a way to use a tiny little 12VDC electric tire inflator (such as in emergency kits) to build up enough pressure and air reserves to set tubeless tires. It might take an hour to build up 5 gallons at 135psi (and you might burn out a tiny compressor, so you'd take it in chunks) but
you'd have enough air to certainly set even a car tire.

[

Note that this tank has the type of schrader valve outlet that you don't want, but you can easily swap it out.


Pedal thread gone SRAM 150/100 chainset - what can be done? I recently bought an Eastway FB3.0 road bike (http://www.wiggle.co.uk/eastway-fb30-2014/) for commuting and the pedal thread has gone on the right hand pedal.

Am I right in thinking the only solution is to buy another crankset?

The problem is the crankset (SRAM 150) on the bike doesn't seem to on sale anymore. Ideally I'd like to go to a shop in the morning and buy something similar in price and fit it.

If I was to get a Shimano cranset, I assume I would also need to replace the bottom bracket. Is this possible? And is it an easy thing to replace?

Cheers

You can try to helicoil the crankset. This is an insert which can be used to repair threading, though you need some special tools to do it. Your bike shop may or may not have this as an option. They may charge you as much as dropping in a new SRAM S100 crankset for this.

The crankset uses a Powerspline BB (which means if you to keep the BB, you're going to have to use a SRAM crankset and it seems like your only option is the SRAM S100).

You can replace the bottom bracket (BB) with any conventional threaded type and use correspondingly compatible crank. For Shimano, you'll get a Hollowtech II bottom bracket for most mid range or higher cranks and a square taper or octalink for the lower end. Note there are other companies which you might want to look for cranks as well (e.g. FSA).

Your bike shop will be able to guide you on this depending on what they have in stock and your price range. It's an easy job to replace the crank or put in a new bottom bracket, but you need the right BB tool, a large crescent wrench and a crank puller.


Seat Post Binder - Fuji CF1 - circa 2008 I'm looking for a replacement seat binder for a 2008 Fuji Aloha CF1 - The one I had cracked and will no longer work.

I have contacted Fuji but they politely laughed at us!

Most shops looked through their "junk" cabinets with no luck.

What can I do to replace the seat clamp?

Here is the photo of the seat clamp.

The Fuji Aloha is a Tri-bike with a aero shaped seat tube, therefore a generic replacement binder for a regular circular seat post will not work,

You will probably have to contact a bike store that carries Fuji products (at the time of writing that is Performance Bikes) or Fuji Bikes directly to order a replacement.

Update - because apparently neither Fuji nor Performance can help.

If a replacement really cannot be found, you could try finding a machine shop that will do custom small orders. A competent shop with a small CNC machine should be able to create a binder using the damaged one as a pattern.


Can a Garmin Touring charging port be repaired The charging port on my Garmin Touring has become wobbly and will no longer charge. It is about 3 years old.

Looking around on line it appears the solder may have weakened and the charging port has disconnected from the circuit board.

What I haven't been able to find is if this is a repairable issue, either at home, via Garmin or somewhere else.

Does anyone know if this is possible to repair or do I need to start saving for a new one?

As long as the unit is not fully sealed and the port is accessible then yes, the port can be changed. Changing the port is not a job just anybody can do, as in a lot of cases these days just like with mobile phone repairs experience in micro-soldering may be required especially where the ports contacts are soldered to the PCB.

Hot air stations are normally used on this sort of job as the port is usually soldered to a PCB ground plane which makes removal with an iron alone virtually impossible.

A mobile phone repair specialist will likely be able to replace the port for you.


What factors to take into account when choosing a hybrid bike? I've decided I'd like to start commuting to work, but I'm not sure what factors I need to take into account when choosing a bike. I figured a hybrid bike suits my needs best, since I will be riding on the pavement mostly. So far, I'm taking the following into account:

Brakes - My understanding is that hydraulic brakes are the best, especially for where I live (Vancouver, which is a very rainy city)
Fork - I've been told carbon forks are expensive, but worth it for the shock absorption.
Cost - I've limited my budget at $850 CAD (about $650 USD)

What other things should I be looking into? The materials of the bikes I'm looking at are usually a brand name of aluminum alloy. Are there any notorious wheel manufacturers that I should stay away fromDoes the handlebar and derailleurs really matter?

Thanks.

A couple of things I would advice on.

Firstly, from my understanding hybrid bikes tend to be very upright and commonly with front suspension. Have you looked at any touring bikes?

Hydrauclic brakes: Yes, they are usually better than mechanical ones. Although there are some very good mechanical ones too, look at TRP's Spyre or Hy-Rd for example. Hyraulic brakes come with their own problems too, which you should also consider. They are usually more expensive to maintain (liquid and tools cost more than cables). They are also not great with sub-zero climates.

Carbon forks usually have better shock absorb than aluminium, but steel forks are cheaper, have arguably the same shock absorb and can easily load them with pannier if needed.

You should be able to get a good entry ridgid steel bike for that price, if I were you, I'd buy the cheapest second hand steel rigid bike and use it for a while. You should then learn enough to be able to buy a suitable bike for yourself in the future, using your experience with the cheap bike as a guide.

You should read this article Best commuting bikes as it gives a detailed description of the different choices for commuting bikes. By looking at the bikes they recommend, you should look at what you might like from them, flat bars vs drop etc.


Coaster Brake for kids I bought my 3 y/o son a new BMX bike and found out only after that they do not have a coaster brake. They do have two hand brakes, one for the front wheel and one for the rear.

I would like to know the pros and cons of coaster brake vs hand-brake?

One of the advantages of a coaster brake is young children typically have stronger legs than hands. They can apply more brake pressure with the legs than the hands. Many children however have difficulty squeezing the lever with enough force to stop the bike confidently. In my experience the lower the bike quality the more effort required to actuate the hand brake. Some of this can be alleviated by proper adjustment of the lever movement by use of the lever stop screw. This adjustment brings the lever closer to the grip so smaller hands can get a stronger pull on the lever. Many entry level brake levers lack this feature. The disadvantage to the coaster brake is it requires that the crank be rotated backwards to actuate the brake. Most people have a dominant leg similar to be left or right handed. In a panic situation the pedal may be out of braking position delaying braking. Another disadvantage of coater brakes is they are totally ineffective if the chain falls off or breaks. I would teach your son to ride using the hand brakes. Practice stopping drills on a level surface. Perhaps draw a chalk in the drive-way and see how close he can come to line without going over it. With my children as we rode along the local rail-trail I would occasionally tell them to "Stop Now" so they would gain confidence in stopping quickly.


Single Speed vs Multi Speed When coasting (not pedaling) downhill, do single speed bikes tend to be faster than multi speed bikes? Assume that both types are road bikes with similar frame, tires, etc.

The two differences will be that the multispeed bike has more air resistance from the drivetrain and the comparison of resistance between the ratchet in the single speed bike and the freewheel or freehub on the multispeed.  Both effects are rather small.  The rider/bike aerodynamics will dominate.


Upgrading crankset on a 2001 Bianchi Grizzly So, I managed to pick up a Bianchi Grizzly frame for pretty cheap, with nearly all components included to build up. Included was nearly a full XTR groupset that has seen better days. I installed it all, but the cranks quickly gave out on me (they came somewhat stripped).

As far as replacing them, new XTR parts seem a bit expensive, and I had to use a shim for the front derailleur anyway, so the spacing for front shifting was a little weird. Any recommendations on where to start looking for a new crank/what specs I need to keep in mind to have the right spacing?

OG crankset on this bike was 110mm spindle BB, Raceface Progidy LP crank, and maybe Shimano Deore XT Rapidfire SL derailleurs? Should I base crankset spacing off of that? I'm also not sure if it is worth upgrading both the front derailleur and the crankset at the same time, to make sure the spacing works out?

I looked at the Bicycle Blue Book page on the 2001 Bianchi Grizzly, and what you included in your question matches up - 110mm spindle BB, Raceface Progidy LP triple crank.

The important thing to get right with a new crank is the chainline. If that's correct the front derailleur range or movement should cover the chainrings properly.

Standard MTB triple chainline was 47.5mm (see this Sheldon Brown Page) and I think it's safe to assume that's what the Bianchi has (you can check it of course). Presumably you also have a rear dropout spacing of 135mm.

You can get a new crank that will fit on the existing bottom bracket, but different model cranks require a different length BB axle to get the right chainline, so you are probably better off replacing the bottom bracket along with the crank. I'm not sure if you have a square taper or one of the splined types, if the later a BB would probably be hard to find. Also, a 18 year old BB probably should be replaced.

If you are going with a Shimano crank, you just need to look up in the Shimano specifications what chainline potential candidates provide (and the intended rear dropout spacing). The Shimano specs typically tell you what BB and axle length you need also In current Shimano products believe only Tourney level cranks are available in 8/9 speed triple and will give you the right chainline, so you might need to look at older used cranks. Fortunately Shimano provides an archive of specification documents.


SRAM chain with Shimano cassette and crankset? When new my bike had all Shimano components.

When it was time to replace the chain, the LBS installed an SRAM chain.

Was that a mistake on their part (if so, was it a bad mistake)?

I had a problem subsequently, and wonder whether the parts are quite compatible/interchangeable.

Edit -- I thought I remembered someone's saying on this forum that chain and cogs are specially shaped, to help the chain jump from one cog to the next when you change gears; and that this shaping is somewhat manufacturer-specific: so mixing them makes it harder to shift gears.

I run SRAM chains on my bike that has Shimano cogs.  It's by choice, as I prefer the SRAM "Powerlink" to the Shimano scheme.


Will 180mm rotors fit my Carrera Vengeance Ltd. Edition bike? So I would like to get Clarks M3 hydraulic disc brake set but the only size available is 180mm but i am not sure what to measure to see if this will fit my carrera vengeance ltd edition 16 inch frame bike. Many thanks.

As long as the kit includes the correct caliper mount adaptors, it will be fine. You can buy them separately if you need to.
It looks like bike has post mount fork and IS on the frame so it's likely you will need to buy at least one of those in addition to the kit.


How to increase range of disc brake pistons? Recently swapped over my disc brake pads, but discovered that the pistons lightly scrape the rotor when not braking, and when I am braking it doesn't make much of a difference and it allows me to pull my lever all the way to the handlebar. Shimano Deore brakes btw

If you can pull the lever all the way to the handlebar while not getting much braking force, then it is very likely that you somehow got air into the system somewhere, and you need to bleed the entire brake system.
Perhaps when you were changing the pads, you pulled the brake lever while the pads were removed, which would allow the pistons to come out too far ?  That would let air into the caliper, which would lead to the symptom you described.


Is it possible to add another chainring to Cannondale Trail SL 3? I recently bought a Cannondale Trail SL 3 2021, and quickly realized that I need heavier gears for riding comfortably down hill and on flat ground.
Is it possible to add a second, larger chain ring and front derailleur to this bicycle?

There seems to be a place to mount a front derailleur on the seat tube of the bicycle. It also seems to have unused ports in the down tube for routing of another cable.

Picture source: https://www.cannondale.com/en/bikes/mountain/trail-bikes/trail/29-m-trail-sl-3
It is possible that the same frame design is used in different bicycle configurations which come with 2 front chainrings.
Given that your bicycle currently has a drivetrain with quite large rear 12-speed cassette range (from 11 to 51 teeth), there is a better solution.
Replace the front chainring with one that has bigger number of teeth. Currently the bike comes with 30 teeth at the front, so you should go with 32 or 34 teeth. There seems to be enough clearance between the ring and the chainstay to fit a slightly larger chainring.
Replacing just the chainring is definitely easier and cheaper than adding a front derailleur, front shifter, routing all the cables, another chainring and possibly swapping the crankset as the current one may be single-ring-specific.


Setting chain length My chain broke and in a moment of silliness (I was cold wet and slightly annoyed)  I threw the broken one away before thinking about measuring the new one.

Is there a guide to getting the chain length/tension correct ?

It's an 8 speed road bike (Shimano Sora back, double ring front)

Put the chain around the big-big gears without threading it through the derailleur. Have the chain overlap by one link. Now with that length thread it through the derailleur.

http://sheldonbrown.com/derailer-adjustment.html#chain


11-42t cassette with a 9 speed derailleur, will it work? I'm trying to figure out if my 9 speed derailleur (Shimano Deore) will work with a 11-42t cassette (note that it is a specific 9 speed cassette).

It is for a MTB 1× setup

I previously had a 3×9 setup which had a the same Shimano Deore rear shifter.

A 9 speed Deore groupset is presumably a 590, 530 or 510 series. Assume you have a 590 series which was made up to 2009 (the Shimano Wikipedia page has a nice table of group series and years), you can pull the Shimano 2009-2010 specifications from this page

Search in the PDF doc for 'RD-M59' and you'll find the RD-M592 model has a max sprocket size of 32 teeth and the RD-M591 model max sprocket of 28.

So technically no, your derailleur will not work with a 42 tooth cassette, however, many people seem to have had success with a derailleur hanger extension that drops the derailleur down so it clears the largest sprockets. The derailleur has enough total capacity (45 teeth difference for both models) to take up the chain slack if you will be running this with a single front ring.


Do all 10-speed chains fit 3x10? I'm wondering if all 10-speed chains fit to 3x10. A lot of webshops say that the chain is "for road bikes 2x10" or something like that. Or nothing at all.
The chain I have right now (Shinano CN HG-54) is "ultra narrow", but I'm not sure if that's because it's a 10-speed, or if there are sizing issues between 1x10, 2x10, and 3x10.

I appreciate any input!

10 speed works with 10 speed. You will be fine with the chain you have. The major difference being that the one that is made for 3x10 will be a couple links longer generally. Usually this is designated by a number such as 116L where the L stands for links.

Width wise you should be fine with any 10 speed chain. 10sp chains are slightly more narrow than a 9sp so that they could pack that extra cog on the cassette. Although when you look at the difference it is minuscule.


Best long distance padded shorts for tall man sorry if this has been asked million times already...

I need an padded shorts that actually work for making my but stand 150km+ (around 95 miles) a day without hurting as hell after 2 days of riding.

Have in mind that:

I do not expect magic, just the best quality
I am 2 meters tall (that is around 6.6 foot)
I am willing to pay for this

My last longride was 335km in 2 days and I managed to stand it but it was not a pleassure for my ass, since it really hurted afterwards...

Thank you for help :)

I assume given the distance, that you're doing this journey on a road and on a road bike?

You'll be pleased to learn that, as Criggie says, your height is pretty much irrelevant.

You will need to decide between shorts and bibshorts (which come up over your shoulders). Many riders prefer bibshorts because they dispense with the line of elastic around your waist, leaving your stomach "unpressured". But it does really boil down to personal preference.

You also need to remember that there's no silver bullet here. Many experienced cyclists will choose a particular brand of clothing because they tried it in the past and it worked for them. And, not all brands of clothing work for all riders.

Having said that, if you are looking for high-end kit and are prepared to pay for it, I would suggest you could do a lot worse than to look at the kit that the professional teams are using. Not the replica kit, but the team issue kit. You'll pay for it - I'm guessing a ballpark of €200 for a pair of bibshorts - but you are at least getting kit that has been designed to be worn for 5-6 hours over a few hundred kilometers.

Alternatively, you could go to a good (online?) cycle shop, and to start looking at the most expensive kit they stock.

It is a bit of a crass argument to say "best == most expensive", but really until you develop a taste where you can say "such-and-such a  brand works well for me", you have to make a punt of some kind.


Front Derailleur stays on smallest chain ring I am trying to get an old mountain bike working.

I have read and watched numerous videos on the front derailleur but have yet to find anyone having this same issues except for someone who had something caught in the bike chain.

When I shift the chain will move to the middle chain ring but when I release the shift lever the derailleur moves back to the smallest chain ring.  I can move the derailleur by hand and it will lift the chain all the way to the biggest chain ring but again as soon as I let go of the derailleur it moves back to the smallest chain ring again.

So the best I can tell is the spring brings the derailleur back in towards the bike and the cable pulls the derailleur out away from the bike.  I am curious what is suppose to hold the derailleur out away from the bike once you shift?

Is the derailleur broken or is this just a tuning issue?

I am new to bike maintenance so hopefully I have worded everything correctly and you can understand what I am asking.

Update 7/23/2016

Thanks for all of the input.  The issue does appear to be in the shift lever, I believe mine are called index shifters.  The info stamped on the shift/brake levers say Shimano ST-MO50L Japan 22.2  I unhooked the derailleur cable and removed the shift lever from the bike and was able to spray WD40 into the shifter and get it clicking again.  I would like to remove the cover from the shifter to give it a better cleaning but it is not clear how to do this.  i have searched for diagrams/instructions on line but have not come up with anything.

Update 7/25/2015

Found the below diagram on line:

Uh Oh, guess I am not suppose to take the cover off of the shift lever.  I already took the screw out but have put it back and still seems to be working.

If this is an older bike with a standard friction shifter, you need to adjust the friction.

On the shaft where the lever pivots is an adjustment knob of some sort.  Simply tighten that knob until the lever is "stiff" operating but can still be moved with reasonable ease.

If, on the other hand, you have an indexed shifter then the procedure to correct this problem depends on the specific type you have (and how repairable that particular type is).  A picture of your shifter would be most helpful if it is not the standard friction style.


Oil/Anti-seize on outside of nipple when building a wheel? I just took apart my old wheelset which let some delightful snaps out as I loosened the nipples that were seized to the rims. I'm wondering what the benefits would be of a small amount of anti-seize or lithium/dry graphite lubricant on the outside of the nipples where they contact the eyelets of the rims. I realize I wouldn't want it on the spoke threads, because I don't want them to come loose, so I'll be using Wheelsmith spoke prep which acts as loctite on the spoke threads.

So, would it be of any consequence to have some anti-seize / lubricant around the nipples? It would prevent any corrosion between the metals, and also allow easier truing, and the nipples can slide past the eyelets better before the loctite sets.

It could be that the added friction between the nipple and eyelets is beneficial, though, and this might help the nipples loosen even with the spoke prep / loctite solution. Anyone tried it, or have some wisdom???

Threads are a locking mechanism. The issue is simply the threads are easily damaged and do not properly tighten. They can distort from over tightening, crack ect. To say anti seize does not lubricate is nonsense, that's exactly what it does. It allows the threads slip, tightening properly. The pops you hear removing the nipples are the threads gripping each other and your torque is wasted twisting the spoke instead of loosening the threads. This happens when tightening them as well to a lesser degree as they have not had time to corrode together. The nipple is hard to turn but part of the force is wasted on friction and not all the torque is spent on tightening the spoke. To over come you need to waste a lot of energy and again, risk damaging the threads. Not every lubricant is gooey or slippery in your fingers. Ever heard of brass?


Air transport of a MTB with hydraulic brakes I would like to transport my MTB on an airliner's cargo hold.
What are the requirements concerning hydraulic brakes, do they need to be flushed?

Tires on planes are a problem because they are pressurized above sea level atmospheric pressure. The pressure on a commercial airliner drops below that at sea level, so the pressure difference increases which can exceed the pressure the tire can handle.

Hydraulic brake fluid is not pressurized above sea level atmospheric pressure and the brake system is designed to withstand high internal pressure when the levers are squeezed anyway.


Is this normal for my new Cannondale Synapse Alloy 6? I purchased a new Cannondale Synapse Alloy 6 in early March. I have roughly 250 miles on it. After the first 100 miles I took it back to my LBS to have it adjusted and tightened up. Before I did this, it would creak a fair amount when pedaling hard or shifting my weight around on the bike. The 100 mile adjustment didn't seem to help this. I know my LBS actually did what they were supposed to do because I watched them. I can't really tell where the creaks are coming from, but it's in multiple places. One place it seems to be a bit noisy is in the crank.

I would think that for the $1100 I paid for this bike, it should be absolutely silent. Is this normal for my type of bike?

No bike, no matter how good, is absolutely silent. It's possible that this bike needs to be tuned better, but more likely, it's simply the fact that it is Shimano's most basic 10 speed components and what is for Cannondale a more basic alloy frame.

I would suggest taking it to a different LBS for an opinion on what the real problem is, or if there is one.

It could be a loose or dry bottom bracket, headset, hubs, chain, chain ring bolts, saddle, seat post or pretty much any  other moving part on the bike.

I hope that is helpful.


do all diamondback bmx bikes have a serial number on them? I have a diamondback bmx and am sure it is authentic however it doesn't have a serial number anywhere on the frame and certainly not where you would expect it to be ( between where the arm and the crankshaft attach.

Almost all bikes have a serial number on them.
Exceptions might be

A home made bike
A small bespoke framebuilder (rare)
A repaired bike where the part that had the number was replaced
A stolen bike, where someone has ground-off the number to inhibit identification.

A serial number is not overly useful, since you know the brand, hopefully the manufacturer has a system, or has records still, and lets you look them up.  More on serials: What is the purpose of a serial number?


Chain length differences between 1X and multi-chainring setups When determining correct chain size, one common technique is to install the chain (without passing it through any derailleur) onto the largest front and rear sprockets. Then, determine the shortest length that the chain could be cut to, and then add 1 complete link to that length. One complete link corresponds to one inner and one outer pair, which corresponds to 1 inches.
I have noticed that in recent times, some resources recommend adding 2 links (2 inches) instead of only 1, specifically when the bicycle is set up with a single chainring in the front. This seems to be a "tribal knowledge" practice, but fairly common in my area.
Is there any evidence or data to support this practice of adding an additional link to 1X systems, and are any major component manufacturers recommending the practice?
See for example :

https://bike.bikegremlin.com/614/chain-length-sizing-for-bicycles-with-derailleurs/

Regardless of the derailleur or drivetrain type in question, the purpose of a chain sizing procedure based on large/large plus one link is to find the chain size where the rear derailleur is so extended that if it were one link shorter, the frame, hanger, and/or derailleur would be destroyed.
Using that as your target chain length has different amounts of merit on 2x and 3x depending on the specifics or your application and the parts used. There is little reason to use that length with a 1x-specific RD if you have the option of making it some amount longer, which you do in most cases.
If ridden in the large/large combo, bikes tend to shift badly and operate with increased resistance from the rear derailleur if the chain is sized this way. The advantages are minimizing chain slap/derailment and saving weight, and marginally better shifting throughout the more useful part of the range (on a 2x/3x) than if the chain was a link or two longer.
Bikes with 1x specific RDs need their large cog combo to be a fully functional gear. And, extant 1x RDs all or mostly all have clutches, so chain length anywhere within the possible lengths that could work will have next to no effect on slap. Chain sizing instructions for 1x-specific RDs tend to target the length to be around the point where in the lowest gear, the center of the tension pulley is modestly ahead of directly below the guide pulley. There is some variance in that, but it will be some positioning of the lower cage that the manufacturer has chosen to perform as intended.
Bikes with non-1x RDs that are being set up 1x start to ask some questions of the mechanic, and the answer will be different depending on the parts and application in question. That could be either someone setting up a parts-minimal 1x commuter or it could be a cyclocross or DH/freeride bike from before clutches and the mainstreaming of 1x. Generally speaking, aside from slap/derailment concerns, that kind of drivetrain is set up to have the longest chain possible that still allows the chain to be tensioned in small/small, but slap/derailment can and often will cause you to shorten it from there depending on the application, to the point where more rough stuff bikes with that kind of drivetrain would often have the RD extend pretty far forward in large/large, i.e. something pretty close to the large/large +1 method. Chain length sometimes requires tuning on that sort of bike in real life regardless of what any manufacturer instructions say.


Why do peope think the upright postion is comfortable? Since my dad bought my first bike when I was a kid I tended towards a leaned forward position. I don't mean hands on the drops position, just a more leaned forward one. Skip forwards for almost 30 years and I feel the same. Yet I keep hearing that the upright postion is supposed to be the more comfortable one. What am I missing here?

In general terms, a more forward position will mean that more body weight is supported by the arms, and that the back/spine is rotated forwards to a greater angle. The neck will also need to support the weight of the head at a more strenuous angle.

This will put more stress through joints in all of these areas and lead to faster fatigue of the supportive muscles, some people will find this less comfortable if they aren’t used to it.

Perhaps you have grown accustomed to your position because it’s how you’ve always ridden. Maybe your arms are used to supporting your body weight for example. This conditioning means you can be comfortable in a forward position for longer than average.

Riding out of your normal position probably means certain muscles have to work in unusual ways to support your body weight in a new position and they just aren’t used to it, so for you it is less comfortable.

Meanwhile, there will be other riders don’t have the same conditioning and experience things the other way around.


Shifters and internal gears I have an Airnimal Joey with 8 (internal, Shimano Inter 8) rear gears. I wanted to install drops handlebars  and the shifters. I got the Shimano Sora ST-3300-8 Right / Rear 8 Speed Shifter, which I thought will be perfect since there are 8 gears in my bicycle.

Unfortunately my local bike shop told me that the these shifters are not going to work with the internal gears. What are my options in this case? I can always change the gears to the external ones but that would probably be quite expensive as I think I would have to replace the wheels. What are the other options?

Are there any other shifters than can work with these internal gears? I have heard something about the electronic shifters (or perhaps converters) that can make it work? Or perhaps there is some other (preferably not too expensive) way to fix it?

The typical way of using a Shimano IGH with a dropbar is using a device called a Hubbub. It is essentially a little handlebar that plugs into the right hand side of the drops and gives you a mount for the usual twist shifter which comes with the IGH (This is what I would recommend). Another alternative is mounting it on the center of the bar with an extender like the Minoura space grip (though this is more annoying and less robust than the former option). JTek also makes a bar end shifter designed for drop bars as well. I have seen Walmart bikes with gripshifts in the center of dropbars, but these have bars that have essentially been cut in half, gripshifts installed and then bolted together according to the internet (google GMC Denali bicycle).

If you can look up (or measure) the cable pull for your IGH system, depending on if its roughly equally spaced, you may be able to rig a pulley system like a Problem Solvers Travel Agent to change the cable pull to work with the brifters okay. I think I read somewhere this works with some nexus hubs, but I could just be imagining. EDIT: http://www.flickr.com/photos/hiawathacyclery/2348490318/in/set-72157604007257815/ indicates some bike shop has managed to use a travel agent to get it to work: "That silver gizmo on the downtube shifter boss is a travel agent, intended to make short-pull brake levers work with v-brakes (aka linear pull). Coincidentally, it also amplifies the cable pull the correct amount to make an 8sp bar-end shifter index for the Alfine/Nexus 8sp hub. It works surprisingly well in the friction mode, too. ... It's as simple as that. However, I make no promises that this is a safe configuration or that it won't shorten the hub's lifespan. There is a small hesitation between gears 4 and 5, but it clicks into gear when the pressure on the pedal is relaxed slightly. Of course, anybody who's ever ridden an old 3-speed knows this already.... I should add that I believe the Alfine is a better choice than the Nexus. The reason is that the Alfine is more or less silent - any noise you hear is probably the result of a misplaced shift. ... Oh yeah, and we used an extra inline barrel adjuster on the outbound end of the travel agent. This is where the cable tension is adjusted to tune the shifting. The travel agent's barrel adjuster really just tensions the cable between the travel agent and the shifter." It looks like the travel agent mount is a custom one from Hiawatha Cyclery though (but shouldn't be hard to rig one up yourself).

Another thread on bicycles.SE (Is it possible to use road-style brifters with an internal gear hub?) says the Versa VRS-8 shifters are designed for this application, but I've never heard of them before. They also mention Sturmey-Archer hubs have brifters.

Switching to a derailleur and getting the wheel rebuilt may be possible, but you still have the expense of a derailleur, wheel rebuild, and possibly the purchase of an adaptor claw.

Also, not directly related: Installing drops changes the riding geometry of a bike - make sure you can still ride the bike with drops before buying something like a Hubbub since they're not cheap (though it shouldn't be hard to rig up something like that on your own).

Also, it seems your bike is fitted with V-brakes which have different cable pull than other brakes. You need to either get the Tektro RL540 (or equivalent) brake levers and use bar end / hubbub/ some other shifter mount, or use travel agents with STI shifters if you're able to get them to work.

Finally, some companies like Origin8 make bar ends with drops (http://www.origin-8.com/product-description/?prod_model_uid=1596). Not ideal, but might be something to look at.


What is a good gents' hat to wear while cycling in formalwear? As a natty man-about-town, I don't like to go out without a hat. As I always go out by bike, this limits my hat selection considerably to those that will stay attached to my head in any wind, but not using a chin strap or similar which might risk strangling me if the hat gets caught in low overhanging branches.

My everyday solution to this problem is the flat cap. It's smarter than a cycling cap or baseball cap, and its modest peak doesn't generate enough lift to carry it aloft except in the strongest head winds. It also helps that flat caps have been fashionable for the last few years.

Flat caps really don't go with formalwear, though. If I'm cycling to a job interview or a formal dinner, and I'm wearing a suit or a dress suit, I can't wear a flat cap, a sports cap, or a beanie over that. My hair isn't long enough to support a hat pin of the kind you'd see in a ladies' hat. Is there a style of hat that would satisfy both the practical and sartorial constraints of that situation?

N.B. I don't wear polystyrene hats, so please don't post a comment or answer trying to convince me to wear them.

My instant reaction to this is the Deerstalker. Paired with an appropriate cravat this should be able to carry you through the majority of social functions. Tweed being an obvious material for the outdoors.

Depending on how formal you need to go, you might consider a collapsible top hat, which can be changed into on arrival.

Finally, if feeling quirky, a Coke hat would be a viable alternative with the benefit of providing a conversation piece.


non-steel frames and longevity Until recently, I had a late 80's Schwinn aluminum frame bike (now a thief has a 80's Schwinn aluminum frame bike, but that's another story). I had heard a number of horror stories about early aluminum frames--that the welds weren't properly done, or that the technology hadn't been perfected yet, that one should expect the frame to come apart any day, etc. I assume these kinds of rumors are being spread about carbon frames as well. Is there any hard evidence here? I know this is very hard to quantify because there were dozens of manufacturers, and there are/were lots of technologies being used. But is there any evidence, or is it just a cloud of Fear Uncertainty and Doubt?

I ride aluminum frames almost exclusively and have had no problem with them.

The welds are what tend to break first on most bike you hear these horror stories about, but this can happen with any sort of weld (though some forms of welding are more effective than others), so if a bike seems to be too good of a deal to have an aluminum frame, make sure to check out the welds, for those could very well be the deal breaker.


Is a folding bike's chain more likely to slip? I have recently purchased a Raleigh folding bike second hand.  I had to take it back for servicing (within warranty) when there were problems with the gears and derailleur.  The dealers have replaced the chain and the cassette, but when I tested it hard up a gentle hill in top gear, the chain was still prone to slipping.  The dealers were happy to take it back and look at it further, but also suggested that I had tested it too hard (e.g. standing up).

Are my expectations unrealistic - should I accept that a folding bike is less suited to high intensity riding than other bikes?  Or am I sensible to test it so vigorously before accepting it?

Its largely comes down to quality of the bike, which comes down to price, and your size and strength. A well build bike with quality gear set should not do this. A cheap bike, especially a folder, with entry level gears its not entirely unexpected. If you big or strong (or both) the problem is worse

The problem comes from frame flex. The gear spacing on the rear cluster is about 5mm, and the chain is around 8mm wide, the amount of movement needed to initiate a gear change onto the next cog can be as small as a millimeter. When a rider cranks hard on a flexible frame, its easy to get enough flex to cause a gear shift to initiate.

This is flexing not normally considered a big problem - high cadence (pedal revolutions) with lower force is much better riding style than 'mushing' at low cadence. Flexing is not desirable for a number of reasons, so experienced cyclists tend to ride bikes with stiffer frames.

Folding bikes are always going to be compromise as its hard to make a folder stiff.  It may be that a folder is not for you and you would be better with a non folding bike, or you may decide to change your riding style to suit the limits of the bike.

Ultimately any modern derailleur type bike is a finely tuned, precision machine. While they are reliable and can last a very long time, they are far from being indestructible. When poorly ridden they are almost certainly going to fall apart.


Can I replace chainrings without replacing the rest of the drive train? I now ride a 60cm SurlyLHT with chain rings at 26/36/48t. Can I replace with a smaller set at 22/32/46t (or similar combination) without having to replace the entire drive train - cassette, rear derailleur, front deraileur etc.?

The simple answer is yes, you can just change the crankset without replacing the entire drive train however there are other considerations. Depends on if your changing rings out or replacing the set and cranks. Other considerations if doing a full replacement are:

Chain line

When selecting a new crank set you need to ensure it aligns with the current chainline of your bike. If you change the chain line you may not be able to use all of the gears on your rear cassette in all gears up front.

Bottom bracket

You need to ensure that a new crankset will be compatible with your current BB spindle length and interface. (square, octo, isis, hollowtech etc.) If your BB has a lot of wear once you have the cranks off its not a bad idea to change the BB at the same time as they're not that big a cost. Also it's sometimes if you get a good deal on a crankset to get a matching BB as they're the cheaper item.

Chain length

You may need to shorten the chain going to smaller rings if the derailleur doesn't  provide enough tension.

Rear derailleur capacity

Not a problem when shifting to a smaller crankset but if going larger you would need to ensure that the rear derailleur would handle the additional cogs. There are tools online to help calculate this.

Wear

If the chain and rear cassette are showing signs of wear it's often wise to replace these at the same time as they will wear a new crankset faster.

Chain width

If you are buying a new crankset it has to be appropriate for the number of gears on your bike, this is because chains are different widths to accommodate more gears on the rear cassette. The rest of the drive train is sized to fit the chain width.


What do RL and OG mean on a bike chain? While changing my bike chain, I noticed letters stamped on some of the links. The old chain (Shimano CN-HG53) has »OG« stamped on some links, while the new one (Shimano CN-HG93) has »RL«. Google doesn't find anything useful. Anyone knows what it means?

The RL and OG might be date codes. Assuming these are 2 different chains, RL would denote 1993-December and and OG would denote 1990-July. If you think they are newer than that, the chart isn't up to date, but if you follow the pattern, RL could be 2019-December and OG could be 2016-July. The second set of dates makes a lot more sense based on what I can see visually from picture.


What's causing this puncture? This puncture is on the inside face of the tube. One day I got a big piece of glass in my tire. I patched it up and then I got a puncture on the inside face of the tube. I patched that and then I got another puncture on the inside within a few blocks. I patched that and then I got a third puncture on the inside within another few blocks. The punctures are not in the same place so I'm pretty sure the rim is not the issue. Do I have a piece of glass inside the tube, rolling around and puncturing in random places? Why are the holes only on the inside face of the tube? Will any new tube fall to the same fate?

It looks like a glass cut to me.

It is common for glass to lurk in the tire case, so this is unusual.

Take the tire and tube off completely and inspect the inside of the rim and the tire carefully. If you can't see anything, run your fingers around the rim and the tire.

If you still haven't found anything, take the rim tape off and check it and the rim again.

If you still haven't found anything, reassemble, sigh deeply, and hope for the best.


What height should drop handlebars be - relative to my saddle? I've done most of my cycling with flat handle bars on a mountain bike. I'd like to start commuting to work though and am considering getting a road bike with drop handle bars.

The thing is though, I tried a bike in the past that had drops and didn't really find them comfortable. I hardly used the drops because it felt uncomfortable. This meant I usually kept my hands on the tops of the bars, and then that has the problem that I couldn't get to the brakes as quickly as I could with the flat bar bike I had.

Perhaps I had the drops set up at the wrong height when I tried them. What height should the drops be relative to the saddle?

There is no single official accepted guidance. Typically the more you ride, the lower you will tolerate your bars, drops or straights. Pro cyclists have them as low as 10-15 cm below saddle, while amateurs tend to have them level or slightly higher than the saddle.

Don't worry that you cannot spend all your time in drops. Even pro cyclists prefer the more upright position with hands on top of the bars, and will typically go to drops only in critical moments (when in the front, in a breakaway etc.)

The thing with the brakes -- well, that's just the way it is with road bikes and drop handlebars. For giving up immediate access to brakes you gain more hand positions on the bars, which helps immensely on long rides. With your hands in the convenient "on the horns" position, typically you will be able to apply enough pressure to the brakes to slow down, though for emergency braking you'll need to get down to the drops.

You can get an adjustable stem to experiment with handlebar height. Just change it for a normal stem once you decide, or other road cyclists will look down on you -- an adjustable stem is pretty much the mark of a "Fred" :-)


Which master links for 1/8 inch aka BMX chains? It was very easy to find master links for 3/32inch (aka 9-speed chain) but I cannot find them for 1/8 inch (aka BMX chain). My chain is the Nexus CN-NX10. Cannot understand the odd observation that the master links are much more popular with the 9-speed category, I can find only one seller selling "BMX master links" in eBay. I need the master links to easily clean my chains in a fixie that has a lot of dirt in the internal of the chain. Currently, I use a multitool to remove the pin very carefully so not to damage the chain but it is not that fast. So which master links would you recommend for the 1/8 inch chains? If it is a poor idea to use master links with BMX chain, please, explain why.

Resources

perhaps an alternative way to take chains off easily: replacement pins

I suggest asking your local bike shop (LBS) because I've never seen a bike shop that doesn't have them, and they're only a couple of bucks. I found the three piece master links easily enough (on eBay and Amazon). You might prefer the two piece style in silver (Amazon)

I searched for "bicycle master link" rather than BMX to get those results.

For single speed chain I'd always use a master link, but with the narrower chains I often don't bother. But I rarely take the chain off the bike, preferring to run it through the chain cleaner on the bike (but I don't get my chains very dirty). For a single-speed it's possible that a really dirty chain would be easier to clean off the bike, but I still try on the bike first because itś so much easier.


How to install brakes with clamps that are too tight I recently picked up a set of Avid DB1's and put them on my bike, but it was a bear to get them on. For background, they've got a split clamp that is similar to a seat tube where simple compression keeps it in place versus a two-piece clamp that requires more than one screw to tighten.

What I found was that the clamp, even when loosened all the way, would not slide down the handlebar and I had to shimmy it back and forth to move them further in, which ended up scratching and removing a large amount of paint (it's ok, that part goes under the grips). But this doesn't seem right to me. Is there:

a better way to install them?
different handlebar diameters that would complicate installation?
something else I totally missed?

A general procedure with too tight clamps: Put in the screw or a longer one of the same diameter from the opposite side. Fit a piece of (hard, like a small coin) metal into the slot. Tighten the screw carefully. It should open the clamp enough to fit it over the bar


Why would anyone use DOT fluid and vacuum-based brakes? Mineral oil is much less toxic than DOT, does not absorb water, has higher boiling point.

Bleeding Shimano brakes is almost as easy as unscrewing the caliper bolt and pouring oil into the lever system. On the other hand, for Avid-s one needs to observe strict vacuum.

Why would so many companies bother with an American-specific oil and vacuum-reliant system?

Mineral Oil
Shimano
Magura
Tektro
Gatorbrake

DOT
Hayes
Avid
Formula
Hope

Advantages of DOT over Mineral Oil:

DOT has a standard - product that meets the minimum standards is readily available at low cost
Compatibility with cheap materials used for seals
Hygroscopic, so water will not collect in a single part of the system

Disadvantages of DOT over Mineral Oil:

Corrosive despite inhibiting additives, damages paint, skin, metals etc.
Hygroscopic, so water is absorbed and the boiling point drops over time. Limited shelf life and operating life.


How can I tell if my bike has a freewheel or a cassette? I bought a Frankenbike off Craigslist.

It's a Specialized Rockhopper of unknown year, converted to a commuter, with shocks up front and V-brakes.

I love this weird little bike and want to put a Copenhagen wheel on it when they come out, to make it into the ultimate commuter frankenbike.

To install the wheel I'll need to know whether I'm dealing with a freewheel or a cassette. How can I find out without taking the bike apart or knowing the year it was built?

If you take the back wheel off you should be able to examine the freewheel/cassette to determine which it is. Here is a picture of some common types. If yours doesn't look like one in the picture, post a close up and I'm sure someone here can identify it.


What causes the rear hanger to snap off? I have a Specialized Allez Elite road bike, purchased brand new in June this year. So far I've covered around 300 miles in total on it.

During my ride yesterday, as I was going up a slight hill, I switched to the smaller front chain ring. As I did this, I heard a sickening crunch, pedals jammed, looked down to find one of the gear changing parts is jammed into the back chain rings and chain has come off. Luckily I managed to get onto the footpath and dismount without any problems.

I don't know much about bikes so have provided an image of the damage:

Can anyone advise on what parts will need replacing? Also, how can I prevent this from happening again?

Thanks

The derailleur is not a particularly strong part, and in fact when it/its hanger breaks it can often save your frame.

Some common reasons for it breaking are:

Hitting an obstacle (e.g. tree branch)
Going into the spokes (badly set low limit screw or the derailleur was wobbling enough for some reason to get caught in the spokes)
Chain too short.

What you need to do is buy a new compatible derailleur [e.g. whatever was spec'd on it before] (and possibly a derailleur hanger as well). Then you need to get the hanger alignment checked out (using something like the Park Tool DAG-2). Then, get the spokes checked to see if they have taken any damage and have adequate tension (you will likely want to ask a bike shop about this).

It looks like the protector disc (plastic) is still in tact without any damage.


Best type of tire for bikepacking I am going to build a bikepacking bike and was thinking about what type of tires to use, tubulars, clinchers, or tubeless.

I own a road bike with clinchers and a cross bike with tubulars, but have no experience with tubeless.

In the context of bikepacking and riding long  distances in the great outdoors, often far away from any type of help, I'm wondering which tire choice is best suited for reliability and ease of service?

I'm kind of assuming gluing on new tubulars and carrying them, is a bad option, although I love the comfort and grip that come with low inflation pressure.

Clinchers are great but I might want to run low pressure without worrying about pinch flats.

I don't know much about how tubeless tires ride or how easy they are too service.

Is there a preferred setup for bikepacking?

Tubulars would be a bad idea, because you need to glue new ones on and most shops don't handle tubulars so getting spare parts when necessary is hard.

Most people will run a standard clincher for touring on roads, since there isn't much benefit for running a tubeless system for riding on the road and most wheels for road bikes are not tubeless ready (especially for high spoke strong wheels you'd fit on a touring bike). Everyone knows how to handle tubes and the tubes+tires are available almost everywhere if you choose an appropriate wheel size (you'll be able to find 26" wheels almost everywhere, 700c many places, 650b less so in the US, for example).

If you want to run tubeless, you can (which would be a preferable starting point for off road touring) since you can always throw a tube in a tire or put a tube+new tire on if necessary (if you find a shop, note that it might not be equipped for tubeless). Note that you are carrying some extra kit with tubeless such as an extra valve, sealant, less tubes than you would carry with a tube system, plugs, and what not versus say a patch kit, some boots, some tubes.


What would be the modern equivalent for 2001 Specialized RockHopper? My beloved and dependable 2001 Specialized RockHopper A1 were stolen by some lowlife about two weeks ago. After filing a complaint with the local police dept. I filed a claim with my insurance company. They ask for a valuation of a replacement bikes.
Looking at the Specialized website I was kind of amazed to see how the variety of bicycle types and models grew with the years. It is a whole zoo, and it really is hard to tell the differences between models in different but similar categories (but that's probably for another question).
My stolen RockHopper had aluminum frame, 26" wheels, Shimano Deore / Deore-LX derailleur, RockShox Judy front suspension, V-brakes, thin metallic pedals, and that's what I remember in terms of components.
The current entry level RockHoppers offer SR Suntour fork, Altus & Tourney derailleurs and more entry level components.
What model would be considered the equivalent to my old RockHoppers?

RockHopper had aluminum frame, 26" wheels, Shimano Deore / Deore-LX
derailleur, RockShox Judy front suspension, V-brakes, thin metallic
pedals.

I would consider this as mid-range from that era.
Judy forks have remained consistant in their pecking order (give or take) for all this time.
Similarly for Deore / LX. Could argue that LX is closer to modern SLX or even XT. But given that it was a mix before, it would be a mix now. IE not soley high-end.
I personally think that a modern replacement (like for new) would be either the Rockhopper Comp or maybe the Elite. (Deffo not the Expert).
Whether you choose the Comp or the Elite, is up to you. There really isn't much between them in terms of components, and there are arguments for either to be a match for your old one.


What and where is the weeping port on Shimano MTB brake levers? I understand that when you overfill some models of Shimano hydraulic brakes with oil, the excess will flow out of a one-way valve called weeping port, but cannot find any technical documents, pictures or videos that point out where this valve actually is. I suspect it is the conspicuous, but rarely mentioned, cannon-resembling big round ending on top of many Shimano brake lever models, which I highlight in the picture below.

The reason I am asking is because when I pushed back my caliper pistons to install new brake pads today,  a lot of oil suddenly squirted from this part of the lever. The lever became very soft of course, so I bled it and it felt fine, but the oil continued to seep (or, well, weep) slightly as I rode the bike later.
So, is this indeed the weeping port and how exactly should it operate? Does it just let the excess oil out after which the brake functions normally - as mine does so far, but with oil still flowing out very slightly - or should it be repaired?

From my understanding, that port is a pressure compensation port. When the oil level changes because of pad wear, temperature, or a leak, air will enter through that port to balance the reservoir’s pressure. The oil is kept sealed by the membrane, which you might have torn due to overfilling.
There’s a small port in the side of the master cylinder that connects the reservoir to the cylinder. When you actuate the lever, the piston travels past the port, allowing the system to build up pressure. When you release the lever, the port opens up again and does any necessary compensation.


Brifter won't downshift I've got a bike with a Dura Ace R9100 drivetrain. About 800 miles on it. Until my most recent ride, no problems.
On my last ride, the rear derailleur would occasionally upshift spontaneously, and the drivetrain sound was a bit noisy. I assume that I needed to tweak the barrel adjuster.
I've got my bike on the stand right now for a cleaning and to make that adjustment. I removed the rear wheel, upshifted so the derailleur would land on the smallest sprocket when I remounted the wheel, and then remounted the wheel. Now the rear derailleur will not downshift--it feels like if I push on it any harder, something will break.
I can get some slack in the cable at the bottom and move it in its housing, so I don't think the cable is stuck, and subjectively, it feels like the sticking point is in the lever mechanism.

Following up on Andrew's suggestion, I found that the cable head was not frayed, but had become dislodged from its seat, and was preventing the mechanism from rotating.
Putting some slack in the cable and getting it reseated solved the problem.


what features do I give up if I buy the mechanical disc brake caliper costing one fourth that of another manufacturer? I've always had rim-brakes on my bikes but now I'm assembling a bike with a frame that has disc mounts only. What features or qualities am I sacrificing if I opt for the $40 mechanical disc brake caliper over the $160 one?  Reliability?  Longevity?  Lightness? Shorter stopping distances? Easier installation and adjustment?

It depends a lot which specific brakes you are comparing.
If you are looking at $100+ brakes they are probably hydraulic. The high-end market for cable disc brakes is limited because hydraulic seems to be taking over. You can still find boutique brakes like Paul brakes, and there is the Hy/Rd brakes from TRP which cost slightly more. The question of whether to use hydraulic brakes is a discussion unto itself. Hydraulic is favored for low lever effort and not having to be adjusted under heavy use. However hydraulic is also more expensive and has disadvantages of more complicated setup and requiring more special tools and parts.
Within cable disc brakes, the biggest disadvantage of very cheap (generic) cable disc calipers is that sometimes they don't work well, and you may have a hard time finding pads that fit once your current pads wear out. I'm talking about truly generic calipers here, meaning they came with a bike, or they are $10-20. The low end offerings from Shimano and Tektro are in the $40 range, and they work fine. Then again some types of cheap calipers use common (i.e. Shimano) pads, so it really depends on your specific brakes.
Anecdotally, I bought a cargo bike with unbranded mechanical disc brakes. The brakes required too much lever effort for my taste, so trying to improve them, I first replaced the cables with compressionless cables. Then I upgraded to oversized rotors. The brakes were better, but then I installed Shimano cable disc calipers, BR-M375. The brakes became immediately much better and I am very happy with them several hundred miles later.
I bought a different bike with Tektro mechanical discs and the brakes are great. I would say equal to the Shimano. Neither the Tektro nor Shimano calipers are very expensive..$40-50 each. For $60 each you can get TRP Spyre or Spyke brakes which have some nice features but won't really work better than the $40 Shimano.