Seatpost clamp sizing issues? I have a carbon bike frame that has a seat post with diameter of 31.6mm and i got a clamp that said  34.9mm but it doesn't fit on the frame (too small). There is no manufacturer details outside of the below geometry. The frame was bought secondhand and it looks like its model number FR 905 from a Chinese company called FLYXii.

I am helping friend build it.

I measured it with a ruler and it not perfect but it looks like its 35.5mm plus or minus .2mm

First double check that it's not a simple case of it just being tight, which is actually pretty common. Remove the bolt completely and gently wedge it open just a little bit with a screwdriver, and see if it will fit on then. Do not force it - you're checking to see if it fits correctly albeit a bit snugly.

If that doesn't work, and/or if it's just clearly the wrong size completely, you need to measure both the clamp you've got and the outside diameter of the seat tube. Ideally use a caliper. You could almost get away with just using a ruler to see what size the frame is actually "trying to be", but the problem is that frames do exist just .5mm larger than 34.9, even though 34.9 (aka 35mm) is much more common.

There are some weird, semi-proprietary diameters in the 35-36mm range that have given rise to clamps like this and this. 36.4mm is also a standard size, but as far as I've observed it's not common for carbon road bikes.


Choosing frame size when still growing I am about to purchase a 2018 Kona Sutra touring bicycle but I need some advice on how to know which is the right size for me.

My measurements are 174cm tall with a 79cm inseam. I was advised that a 52cm size frame was the right size but I am 18 years old and I still have the potential to grow.

On a 54cm frame the top tube almost touches my crotch but I was told that if I were to grow anymore that a 54cm frame would be perfect and now I am left with the decision on which size to buy.

I would go for the bike that fits well today. You can allways increase the saddle height a bit should you grow a bit more. A good fit is very important when it comes to your enjoyment of the bike.

If you do grow, you can get a new bike in a couple of years, if you don't grow you're not stuck with a too large bike.


How to fix braking problem My Shimano BR-Z57 front side pull brakes. Don't brake smoothly and jerks under braking. Does anyone have any suggestions on why & how to fix this problem?

Possible issues (probably not a complete list - things I've seen)

Dirty rims - if the rim does not provide a consistent friction surface (there is dirt that makes one part too sticky or too slick - brake pad residue etc.) you will not get smooth braking.
Dents or blips in the rim - if the rim is wider or dented in some places it will affect braking smoothness.
Dirty brake pads - may not affect smooth braking but clean pads will improve general braking.

I'm sure others will have suggestions.


Can't reassemble Shimano bar-end shifters I have a Shimano (I think Dura Ace) 10-speed rear shifter from around 2008, it came on the aero bars of a Cervelo P2-SL.  Like a genius I took it apart today and I cannot for the life of me work out how it goes back together.  Not much on the web though many people refer to a '105' bar end shifter though mine says '10S' (10 speed), it looks a lot like '105' so I think that is the cause of the confusion.
Here are the constituent parts:

And with the four rightmost parts turned around:

I haven't found the exact part on Shimano tech docs.  The closest I find is the SL-BS78, but the exploded view PDF makes no mention of the two irregularly-shaped washers in the centre of my pictures, and they're my problem.  I did find what seems to be the same mechanism in the SL-7900 downtube shifter, relevant bit shown here:

It's the two washers that are killing me.  The rightmost one (part 5 'Stopper washer' in the EV) fits in the lever nicely, but the leftmost one (part 6, 'Spacer for rear'), while it does sit over the mounting stud, freely rotates when it seems it should engage on something.  It has 6 tabs that correspond to the mount, and seem to correspond to the 6 lugs on the SIS unit (lower photo, right), but it doesn't fit over or inside any part during assembly.  It slides around and it seems it needs to line up with the SIS unit somehow.
My washer 6 has a tab (lower photo) that goes toward the mount.  The 7900 EV doesn't show that, but the Service Instructions show its orientation, which I'm following.  It's just that I can't get it to line up with or over the SIS unit.

Help me, wise interwebs.
EDIT: November 2020
Short answer: I kept fiddling with it, and eventually it all snapped together nicely.  So there is no magic orientation, you'll know when everything is correctly assembled.  The answers below are much more methodical, and helpful.

You have probably resolved your problem, but others may encounter it; I did.
Number the 6 parts in your photographs from left to right so they correspond to the exploded sketch: 8--the nut; 7 and 7a (7 is the mount that enters the bar; 7a is the notched, cylindrical disk that is a separate piece from the mount.);  6--the single tabbed notched washer; 5--the double tabbed washer; 4--the lever; and 321-- the pronged ratchet mech, conical plastic cover, and bolt.
Washer 5 rests with the tabs against either end of the raised segment of 4 (lower photo).  Insert 321 into the back side of 4.  Place 6 on top of 5 with the tab up and notches aligned with the prongs of 321.  Place 7a on top.  The tab shown at the top of 7 in the sketch fits between the single tab and the raised segment.  All the parts are “fiddly” but will fit together only one way; if any parts are canted even slightly, try again.
I found it helpful to put a dot of nail polish on 321 and 7a in way of the single tab of 6.
Install the parts on the mount, tighten the bolt, and check the function.


How should a bicycle helmet fit? I see enough folks wearing helmets in such a manner that they might as well not be.  What is the proper way to fit & wear a bicycle helmet?

This image has kicked around the net for a while - IDK what the original source was:

Otherwise, I second the guidance and link provided by @fady.


Clicking while pedaling I recently purchased a 2nd hand bike, and I am facing a clicking noise when I pedal (under slightly higher than normal load). I feel it almost as a pair of clicks in both pedals, and I feel one click when one pedal is ahead and another click when the other one is ahead (1 click when each pedal is at 5'o'clock position and I add weight on it)

What I tried.
1) I noticed this first after changing the pedals, so i changed it back, tightened the pedals multiple times but it persists.
2) I tightened the screws on the cranks/chain rings (spider to chain ring) (they were quite quite loose) but it didnt seem to help (Are both the chain rings held with the same screws? I use the little chainring only)
3) I tightened the 8mm hex holding the crank arms itself. Also didnt seem to help.

2) and 3) Seemed to get loosened after the ride, so I wonder if they are indeed the problem. I have tightened them tighter now, hope to see in the next ride.

I have not done anything with the BB yet.

What else to look at, what can I do/try? Makes my bike feel very cheap :P I want to fix this.

If the click is felt in both pedals the problem is likely to be the bottom bracket bearings.

You should be able to feel bearing stiffness, roughness or 'notchiness' be turning the crank manually. It helps if you can get the chain off the rings to do this so the crank turns freely. Also check for any play of the crank axle in the bearings.

If the crank axle is not turning smoothly in the bearings or there is excessive play you likely need a new cartridge bottom bracket unit. These are not expensive but require special tools to take off the cranks and extract/install a new BB unit.

It's a bit worrying that you are finding loose bolts all over your drive train. You should probably do a complete drive train checkup to make sure there are no other lurking problems.

The cranks bolts are of special concern. If the alloy crank arms come loose on the steel axle taper they can be terminally damaged in short order. The bolts can be removed (the crank will stay on the axle), the bolt and internal thread in the axle should be cleaned and de-greased then the bolts -re-installed with non-permanent thread locker (e.g., blue Loctite) and torqued to proper specification. (This will of course all get done if you replace your bottom bracket cartridge.)


Is the head angle on full suspension bikes given with or without sag? Is the head angle on a full suspension mountain bike measured with our without sag? I would imagine that the rear shock sagging would give a slacker head angle than what is measured without sag.

Generally they are measured unsagged. Usually, as @alex said, it doesn't matter, since they are full suspension bikes, but some setup (e.g setup for super steep races) where you want your rear end softer, it would matter.

Some hardcore hardtails (e.g the blue pig of http://www.ragleybikes.com/) measure the head angle in a sagged situation. Because they are hardtails they only nose dive under the rider's weight.


Tire popping out of rim when inflating tube This is very similar to this question.

When I fill my tubes up to about 85 psi the tire pops off the rim and the tub gets caught on the rim and blows up.  I have gone through 4 tubes in two days at this point and the only thing that seems to help is to inflate them to about 60 psi.  Even putting pressure on the tires so they seat correctly (not sure if that is the correct term, I am quite new to cycling) only works until I put weight on the bike, and then the tubes blow.

For some info, I frankensteined a bike together out of used/old parts so my rims are quite old (although relatively true after ~8 hours of work) but the tires are falling apart.  The rims are 27's (inches?) and there were really no options for newer ones at the place I put my bike together at, only 700's.

Could replacing the tires fix this?  I would like to get the tubes to around 90 psi since at 60 they are quite flat when riding.

Edit:  Some details on the tire, tube and rim.

Rim:  ~1 Inch wide at the top, ~25 1/2 inches in diameter
I couldn't really figure out how to check the bead.
Rim tape looks fine, it is some hardish plastic covering the spoke screws.

Tire:  See these images of the tire.
Supposedly a 27 x 1 1/8 tire that holds 90psi.  Not sure what else is helpful info other than the pictures of the deteriorating side walls (and the lip at the bottom that catches the bead)

Tube:  700x18-23 27x1 48 mm presta valve.  I can't find max pressure, but I am sure it is in excess of 90 psi.

Three things to check:

1, Is the bead seated correctly. It's pretty common to get tyres blowing off the rim if they're not seated correctly. That said, this usually leads to an exploding tube rather than the tyre just coming off
2, As Daniel R Hicks said, are the rims so worn they're expanding?
3, Check the rim for dings and warping as Malarky sort of says, but not just the area for the bead. You may have a bent rim

Chances are, though, that the tyres are done. The pictures would make me think they're on their last legs. I had a pair of 20+ year old ones recently that ended up in the bin as they just weren't reliable enough for me. Some things aren't worth saving a few euros/pounds/dollars over, and the contact points on a bike are some of those things for me. If the rims seem fine new tyres are where I'd go.


Feeling of click/slip when pedalling This is very hard to explain, but I will try my best.

I recently got a Shimano Ultegra cassette, crankset, front and back  derailleurs, chain, and cables installed on my Giant TCX SLR1 2015 bike.

Every time I pedal, I feel a subtle click or slip on my left foot at a specific interval (when the left arm is going down). However, there is no sounds, I can only feel it in my feet. It’s very subtle.

However, I do not feel it when I put a lot of pressure or when off the seat. I really cannot pin it down to anything, hence I would be grateful for any opinion.

You state in the comments that the (pinch) bolts on the left crank had come loose (Ultegra Hollowtech 2). So you’ve solved the problem by tightening the bolts.

I saw another bike (I think Ultegra cranks) do this yesterday, again it was a very new bike, it was on its first serious outing and the left arm had worked loose.

I found the question with a relevant Shimano publication extract: How to tighten the Hollowtech II (on R2000 Claris) cranks?

In short, any time you install these bolts, tighten/torque check them again after 20 km, much like checking the wheel nuts on a car, a short time after it’s been in for a service.


trueing front bicycle wheel Just got a brand new mountain bike and the front wheel is so out off true spin it looks undesirable. But I know it can be fixed. I have the tools for it . my question is, can I just remove the front wheel off of my bike and lay on a flat table , lose in all the spokes and start from scratch to repair the wobble. I mean it really sounds like a logistical technique. Any opions would be very welcomed. Thank you all. Tye

On a brand new bike I would expect the seller to take responsibility for this and sort it out.

If this is not an option, the usual way to true a wheel without a stand is to turn the bike upside down, or remove the fork and hold in a vice, attach a zip-tie to one of the fork legs and use that as a guide.

The procedure is spin, find largest deviation, pull/push that towards the centre, repeat ad nauseam. There are guides all over the internet on the actual process of truing.

Do not just loosen the whole wheel. Getting a slightly wobbly one straight is easier than building one straight from scratch.


Crank Arm Compatibility - Shimano Ultegra 6800 and R8000 Does anyone know if an Ultegra 6800 left crank arm will work on an Ultegra R8000 crank? I'm looking at upgrading my road bike, and I'd like to move my current crank-arm power meter over to the new bike rather than spending even more money. Thanks!

Yes

The website for the Stages Power Meter mounted to a Shimano Dura-Ace R9100 non-drive-side crank arm says:

  Crank Compatibility: All Shimano Hollowtech II road cranks

This also agrees with Rider_X’s comment and my own guess that they should all be compatible.


How often should I check rear derailleur adjustments? If I remove the (rattling)plastic disc  -

How often should I check the limit screws on rear derailleur?
If the shifter cable tension is less than optimal, would this be a possible cause to drive the chain in between the spokes and the rear cog-set?
Excluding the case of debris getting stuck in drive-train; are there any other adjustments besides above two and true-ness of rear wheel that may cause the problem of getting chain between cogs and spokes?

Derailleur in question is a Shimano Deore.

Update: Details- For mileage, I commute about 110 miles/week.

It's really up to you how often to check your adjustments, but I'd say it's not an "every ride" kind of check, unless you're giving your drivetrain a workout! If there's any damage to the derailleur, hanger, or rear wheel, you may want to start there as well.

To specifically address your questions:

You should check your limits any time you have a drivetrain issue. That could be poor shifting, dropped chain, or inability to shift.
Shifter cable tension should only affect how easily/quickly the derailleur moves. However, there could be a case where too much tension could cause the derailleur to move through the last shift enough to stress past the limit screw, but I think this is unlikely.
The rear wheel could be out of dish (centered from side-to-side) which might have moved the cassette further in. Readjusting the limit screws should take care of that, but you might still have shifting issues. (I had the same problem this spring)


Clear glasses without "ghost" double images? I've been looking for a good pair of glasses for low-light or nighttime cycling.  I've tried a few pairs but all have the same issue: a "ghost" double image of any bright lights.  It can be a bit disorienting. It seems to be due to some sort of internal reflection.

I've tried the Oakley Fast Jacket and Smith Pivlock V2, and the clear and orange lenses that go with both have the same issue.  Are there any glasses that don't have this problem?

Anti-reflective coating is the first solution that comes to mind.  No brand of clear-lens safety glasses occurs to me, but you might try a trick I used many years ago when I commuted by motorcycle in less than optimal lighting or weather: Car-wax the lenses.  Keeps softer plastics from scratching as badly, and changes the surface characteristics of the more modern and harder plastics.  Give the wax plenty of drying time or the fumes will make your eyes burn.  You might want to have an eye exam as well.  Second surface reflection could be a symptom of something a professional could correct.


Using wrong speed/size cassette on trainer I have a 10-speed bike and my wife an 11-speed. I have burnt enough old tyres on my indoor trainer so decided to try a trainer specific tyre on an old wheel.

The old wheel currently has an 8-speed cassette on it. What would be the effect of using that with my bike and my wife's bike? I'm guessing this would be pretty horrible.

What if I change the wheel to a 10 speed cassette (which is what I will probably do) will my wife's bike work?

My current rear cassette is 11-23 if I put a bigger cassette on say 11-28 I expect my chain would normally need to be lengthened. If I don't lengthen my chain will I just lose the use of the largest cogs or would there be worse consequences?

I have no concerns about poor shifting or missing gears because it's only on the trainer. As long as I can get in one gear that's enough, the trainer has its own difficulty adjuster. Wear on the chain or damage to other parts would be a concern.

As you suspect, you cannot use the 8 speed cassette with either bike. The indexing will be completely wrong.

8, 9 and 10 speed cassettes use the same freehub body so you can put a 10 speed cassette on the wheel. The sprocket spacing on the 11 speed cassette is different from the 10 speed, so that isn't going to work, at least not very well. Maybe you could get a few gears to work.

If your derailleur capacity and chain length don't allow the use of a 11-28 cassette, you will be OK as long as you stay off the sprockets that are too large. If you can't use a 11-28 cassette, why fit one? I guess you happen to have a spare lying around?


Late 90s mtb with shimano ig chain, trouble buying cassette So I have really difficult time finding parts. I need to swap the rear cassette to a new one because the chain and some sprockets are worn out. However I can't find ig cassettes anywhere and I don't understand any of the numbers.
The bike was bought 1999 or so and has 7 sprockets rear and 3 in front. So 21 speed. It's been well maintained so I don't want to get rid of it now. I recently bought 2 ig chains (kmc z8.1) for spares and did maintenance and replaced other bits. So I have a bit of sunk cost fallacy going on here too. I think the front sprockets need replacements soon too.
Is there a 7 speed cassette out there that is compatible with my ig chains(kmc z8.1)? Some sram, kmc or cassette maybe? Could I use hg 7 speed cassette with my ig chains? Or do I need to just suck it up and swap to hg parts? And what all hg parts would I need? Or just buy new bike?

Every currently produced 7-speed cassette you can buy, which all have Hyperglide-style ramping, will be fine with your KMC Z8.1 and all the other currently produced Shimano, SRAM, and KMC 7/8-speed chains. You should buy whatever appropriate range 7-speed cassette you can get your hands on.
Shimano called out various incompatibilities involving HG vs IG chains. The third-party makers just say their chains work with both. (You can probably find some exception to this if you look back far enough). I've never had an issue dealing with the HG vs IG question by just putting a SRAM or KMC chain on.


Using a ski helmet for winter biking I am curious if anyone uses a skiing helmet for winter biking? Would this be safe? Are skiing helmets designed to protect you from the same kind of accidents that you would have on a bike?

My thinking is that a ski helmet would:

Help to keep your ears warm
Would fit well with ski goggles (which fit poorly with my bike helmet)
Not have air vents in it which make you cold in the winter

I wear a Bern Brentwood with a winter liner in cold weather. It's a certified bike helmet, but designed more like a ski helmet. The winter liner does a great job of keeping my ears warm without wearing any other protection, but doesn't block traffic noise. It is vented, but not well enough that it makes my head cold. It also has a clip in the back for ski goggles if you're using them. With the summer liner it works well for fall and spring, too.


Resources for bicycle compatibility I'm looking to build my own bicycle. The main thing I care about is compatibility. I've been researching around and have found various gold nuggets along the way:

YouTube - How To Build A Bike From Scratch

insight: There are a lot of different bicycle standards and parts.

YouTube - Bottom Bracket Standards Explained

insight: Threaded bottom brackets do not require special tools.

Nomad Trails Blog Post

insight: Friction shifters are compatible with more cassettes.

Shimano Wikipedia Article

insight: Shimano has a huge market share. Does Shimano set the standard?

Shimano vs SRAM Blog Post

insight: Shimano and SRAM are the two dominant parts manufacturers.

International Organization for Standardization ISO 4210

insight: There is a collection of standards for bicycles but you have to pay hundreds of some kind of currency to read it.

It seems like building your own bicycle with reliable interchangeable parts is a trade secret with tiny insights hidden in places across the internet. I've found people who care about things being light or new. The main thing I care about is compatibility because I want to build my own bicycle, maintain it, and swap out parts. I haven't found reliable coherent source that cares about that.
Intuitively I'd rather figure out what the most reliable standards are and then buy parts that follow the standard instead of only by parts from one manufacturer. I want reliable parts that are maintainable with regular tools instead of a high performance special things that require special tools. I'm not sure how to describe what I'm looking for bicycle parts.
To use an analogy: I'm looking for a ThinkPad not a MacBook. There are a bunch of well defined standards that different Original Equipment Manufacturers can follow to make various components of a ThinkPad. If I want to swap out the DVD drive and stick a Hard Drive Caddy in there I can because the measurements for that slot are clearly defined. Further, I can buy the Hard Drive Caddy from dozens of manufacturers. The same goes for the battery. Also, if I want to change the thermal paste I only need a Phillips screwdriver to open up the ThinkPad. The MacBook on the other hand requires special tools and the battery is a proprietary technology that is glued into the machine because it's thinner or for some other performance reason. When measured by some performance metric the MacBook might be better but from the standpoint of compatibility the ThinkPad is better. So when talking about brands it's better to go with IBM Lenovo if you care about compatibility. I want to develop a similar intuition with bicycles but I'm not finding a coherent source of information.

What are good sources of information to learn about bicycle compatibility ideas?
If there aren't any brands that care about compatibility and standards is the idea to just use Shimano parts because they have the biggest market share?
What guidelines do you follow if you care about compatibility and maintainability?

If you want something utilitarian and practical leaning, the closest thing to your "Thinkpad and not a Macbook" analogy is going to be something from one of the spare-parts-bin-oriented frameset companies like Surly, Soma, etc.
If you want something more mainstream and performance-oriented, you'll just want to avoid bikes with proprietary gimmick type features and proprietary standards. There are more companies doing that kind of thing than there used to be, but it's not ubiquitous. What is fairy ubiquitous now is brands adopting new standards at a rate fast enough to cause confusion because things have been changing relatively quickly in the era we're in, but they're still standards.

20 years ago, there were a few resources that did a decent job at being all-inclusive compatibility references. Sutherland's Handbook and Barnett's Manual were what shops used, and sheldonbrown.com was available for free and also could answer most compatibility questions. Sutherland's was the big kahuna of these. In the time since then, the speed of change in the industry has outstripped any such efforts on seemingly anyone's part, free or not. There are no singular and definitive resources for bicycle technical information anymore. Those who used to be in that game have quit. If you're into old bikes or want to learn about some of the foundational ideas, these are still good sources however.
You have it pretty close; in many cases choosing the Shimano offering will keep you out of trouble as well as be solid value, but it really depends on what kind of bike you're talking about.
Steel bikes lend themselves the most to someone that even cares about long-term maintainability and parts interchangeability. Avoid cranks with proprietary bolt patterns unless you have good reason not to. Figure out what high gear and low gear numbers you need access to and let your component decisions flow from there. Use friction front shifting if you value the ability to do what you want with your components.


My local bike shop owner said to me "I would never use tubeless tires for a Gravel Bike" My local bike shop owner said to me "I would never use tubeless tires for a Gravel Bike".
Where I ride in central Iowa, we only seem to have the large clunky gravel with fairly sharp edges. I have been getting the pinch type flats, like a snake bite. So I started reading and have viewed a number of "experts" who swear by tubeless, especially GCN presenters I follow. I am a fit Superclydesdale rider, so not a featherweight person, and all my bikes must be very sturdy.
Who to believe?

Who to believe?

You can believe that the shop owner believes that tubeless is not for him/her.
But that does not mean that you are in exactly the same situation or have the same needs.
Here are some high level steps for arriving at a solution that works for you.

Read and listen to what others say
Look for information that matches what you intend to do and what you value / care about.
Make your best guess at what will work best for you and try it out
Evaluate your experience and make changes based on what did / didn't work

The answer to almost any "What's better?" question is "It depends"
It depends because what works best depends on your situation and what is important to you.
The shop owner who won't ride tubeless has made a decision based on his/her preferences. Is he/she wrong? No, it's not wrong if it works for him.
Google "tubeless bicycle tires pros and cons" and you will get a variety of results with a variety of lists for and against.
Just two examples:
TUBE VS TUBELESS BIKE TIRES: PROS AND CONS
Pros and Cons of Tubeless Mountain Bike Tires
At the end of the day you can believe your own experience.


Matching Rando bag and seat-attached saddle bag? What companies make matching sets of rando bags (with a clear map pocket and opens toward the rider) and seat mount saddle bags (not panniers) made from waxed canvas, duck cloth, or other non-synthetic material?

I've found only one http://www.acornbags.com that seems to have completely matching sets that meet my requirements. Are there other companies?  I've checked out velo orange but their offerings are poorly matched as they have 3-4 different brands which don't look great together and no larger saddle bags that match the one rando bag they offer. Zimbale bags looked promising, except their front rack bag doesn't have a map pocket and opens away from the rider...

I do have front and rear racks with a platform, I'd prefer not to have to rely on having the rear rack installed unless I plan on touring. So, I'd prefer that the saddle bag be seat/seatpost attached only.

The Brooks Cornwall handlebar bag matches your needs, in leather, and in multiple colors.

Matched with the Glenbrook Saddle bag,

or the Brooks Challenge Roll-up Tool bag,

it would be pretty nice.

All of these, along with a multitude of other brands and styles can be found on the Wallbike.com site, or your LBS can order them for you.


Can I replace my Shimano outer chain ring with a SRAM? I need to replace my outer chain ring.

I am currently running a 50t, I'm pretty sure it's a 130 BCD.

I am considering a SRAM Outer chain ring as a replacement. I assume as long as measurements are the same I Should be OK. The description says (not for 2012+ 'New-Red' cranks with hidden-bolt spider) so that's positive I think for my purpose.
Here's the info on the SRAM ring I'm looking at: http://prntscr.com/8fwk1u

You can use the chainring, but each brand (Shimano, SRAM, etc...) aligns the shifting ramps and pins to work best with their own brands inner rings. So the indexed shifting will not be as fast/smooth as when you would use the same brand of rings together.

Inner rings frequently have individual teeth shaped so that the chain will lift off and drop down faster in certain positions. These teeth are lined up with the ramps and pins on the outer ring, to facilitate faster/smoother shifting. If you pair a SRAM outer with your Shimano inner, these teeth will not line up correctly. It won't make the shifting not work, but it will just not work as well. The X-Glide road rings are also designed for 11-speed, Yaw front shifting; your're paying for tech/features that your bike can't fully utilize.

Also, you are right, X-glide rings do not come in 50T, 130BCD combinations. You'd have to go with a 53 or larger size.

chainringsramyawcompatibility


What do the conical springs in quick releases actually do? What is the purpose of the conical springs in quick releases?

For centering? For anti-rotation? For dropping on the garage floor and rolling under the table? A legacy of the great spring controversy of 1913?

The springs help you center the skewer in the dropout which makes the wheel easier to install. You don't need them for the QR skewer to work, but they're nice to have -- if they're damaged or lost, don't worry about it.

Once the wheel is on the bike, they don't do anything.


Minimum tire width to avoid snake bite I have a road bike with 22mm tires. They are super fast, but I get them punctured a lot.

I have decided to switch to wider tires to avoid snake bites, and I was wondering what would be the minimum recommended width of the tires.

I am fully aware that I may not be able to fit just about any 622 ETRTO tire (700c) due to cantilever brake clearance; which is why I am asking about the minimum.

UPDATE: In the end, I went for Continental Grand Prix 4-Season, 25-622, and never looked back - these are (expensive, but) AWESOME!

I doubt you're getting snake bites in a 22mm tyre unless it's very low on air. Even then it's not likely.

Snake bites have a distinctive two-hole pattern so you can check. It's more likely that you're getting ordinary punctures. There may be tough 22mm tyres, but most this thin are designed to be light. There are certainly anti-puncture options at 25mm which should fit, but may be a touch slower.


Is there anything special about rotor bolts? I fitted a new rotor to a new wheel yesterday (6-bolt) and didn't have any spare bolts so borrowed them from another bike.  As I go to buy replacements, is there anything special about such bolts?  I know they're generally Torx button heads, but  I can buy them in steel, titanium or even aluminium.

They're not expensive, and they'd be useful elsewhere on the bike (I'd get stainless) but I prefer socket head screws in general because I don't always have a T25 on me, depending on which tools I'm carrying.

So is there anything special about the material or shape?

The Torx heads are generally lower in profile than equivalent bolts with a hex socket. This solves clearance problems in some fork-wheel-disk setups.

Torx heads can be made shorter because the star pattern of the hole provides more contact points with a screwing tool, thus allowing reaching the same torque values without risk of stripping the bolt head. An equivalent sexagon head would have to be higher to reach the same torque value.


Creaking when in the saddle I know there are about a million questions on here about creaking while pedaling, but I haven't seen one that relates...apologies if I missed one. I bought a 2011 BMC Streetracer SR02 last year; shortly after I got it I removed the Shimano 105 it had previously, and replaced them with a mix of SRAM Rival and Red (Rival shifters and derailleurs, 2012 Red GXP crank). Since I got the bike last February, I've put about 6k miles on it (both the chain and cassette were replaced ~2 weeks ago).

A little over a month ago, I started noticing a creaking/clicking when pedaling, typically beginning when I was about 3 miles into a ride. Nothing was changed on the bike before it started. The creaking occurs about once per pedal revolution (around 6 o'clock on both sides) and stops when I get out of the saddle. It occurs regardless whether my hands are on the bars. I've worked on the bike myself and taken it to my LBS, but we're both running low on ideas.

All the chainring bolts were replaced.
BB was swapped out with a new one.
Red crankset was removed, regreased and re-installed.
Red crankset was swapped out for a non-creaky 105 crankset.
Pedals were swapped out.
Chain and cassette were replaced.
Saddle was swapped out.
Seatpost was cleaned/greased.
Seatpost was swapped out.
Wheelset was swapped out for a newer one.
Headset was removed, inspected and cleaned.
Bottle cage bolts tightened.
Front derailleur braze-on bolt checked/torqued.
Rear derailleur hanger screws checked/torqued.
Wheel skewers swapped out.
Replaced the headset cartridges.

And yet, the creaking continues. At this point, I feel like I'm pretty much out of ideas (short of calling a priest...). I'm almost positive it's coming from the BB area, but I also know the sound could be coming from anywhere in the bike, given all the tubes.

Is it the frame? How would I check to see if it's the frame, rather than one of the components? Any thing else I could be missing?

Update:
I had a chance to play around with the creakiness when I rode last night (with different skewers in the wheels). It seems like the source of the issue is somewhere in the cockpit area. If I don't have my hands on the bars, the creaking is no different than when I have both hands on the bars. However, it seems that if I put one hand on the bars and shift my weight to that side, the creaking seems shift to that side as well. When I got back from the ride, I put a layer of grease on the part of the stem that attaches to the bars, and I'll check if that made a difference on a ride later today. I'm not sure that will be it, but that would make it easier.

Update:
Finally fixed! Following a group ride last week, we looked over the bike in a last ditch effort to solve the creaking. Things seemed in order, but the mechanic greased the seatpost clamp and the bolt attaching the front brake to the frame. He also noticed that the stem bolts (where it attaches to the fork) were stripped. Following the greasing, I briefly rode the bike, with no change in creaking. The next day I replaced the stem with a newer one and went for a ride. The creaking persisted at the beginning of the ride, but disappeared partway through the ride after an extended climb out of the saddle. >170 miles later and the creaking hasn't returned. I'm not sure which of the last three solutions finally did it (greasing the seatpost clamp, the front brake bolt or the stem) or whether the grease just needed more time to filter in, but I'll take it.

Hopefully no one runs into this issue in the future, but if they do, I hope this saves them the trip down the rabbit hole.

Creaking when only in the saddle - I would check the saddle? A drop of oil into the where the saddle rails fix to the seat can alleviate.
But if you are sure it is not this - then perhaps try isolating the noise by using the bike on a static trainer and pedalling. If you remove the chain from engaging with the chainset - it would isolate the noise to the chainset / BB only.


Map of water taps to fill bottles Are there any maps of taps where I can fill my water bottles (bidons) on long rides. I live in Scotland, but would be glad to learn of the existence of such resources worldwide.

Openstreetmap with the cycle layer certainly shows some. Here's one
I was very grateful for in the French Alps.  OSM is not complete but it's open source so you can improve it (I haven't added any taps, but I have added bike parking).  This is a good approach, as it also shows cafes and shops where you should be able to buy water if there's no tap (flipping between the "standard" and "cycling" layers can show more facilities).
In the UK, the cafes on Cafe Network will almost all be very willing to fill bottles for customers - I normally plan on a cafe stop every few hours and take the opportunity then.  Pubs and coffee shops generally will too. Some chain fast food places won't - they say they can't. This is problematic late at night when nowhere else is open.
A possible fallback in the UK is churchyards - there's generally a tap outside, but no guarantee the pipes aren't lead.
It's possible to query OpenStreetMap for drinking water by modifying the following link to give an appropriate bounding box (the last 4 comma-separated numbers):
https://tools.wmflabs.org/query2map/featurelist.php?key=amenity&value=drinking_water&types=points-areas-infos&BBOX=-2.9914,51.5871,-1.32,50.81
changing value=drinking_water to value=water_point returns some more (e.g. next to canals, for filling boat tanks).
Of course some are on private land.  I've seen campsites and schools showing all their water points.  But that's fairly obvious from zooming in.  The bigger downside is that many are missing.


Is it possible to get a light that is too bright? This question is related to this recent question: Best ways to avoid getting hit by cars?

I have a 750 lumens front head light - it's bright! Some of my riding buddies say it is too bright for the streets as it blinds drivers. I disagree that it is truly blinding drivers and think that means it is just doing a better job of making me visible. Is it possible for a light to be too bright?

Another consideration for this is bike paths at night. Obviously a light doesn't need to be as bright on a bike path as a busy city street, but I do feel bad for the oncoming pedestrians that seem to be wincing when I approach. What is the proper etiquette for approaching in these situations. Turning off my light doesn't seem like a good idea. Also, I'm not really interested in jimmy rigging a lens-guard on my light, or purchasing a new one (Bike lights with beam cut-off to avoid dazzling drivers?).

As a side note, on a couple occasions, drivers at intersections have complimented my lights noting how easy it was to see me! I assume they are referring to my tail light, though.

Blinding road users will be the result of the following factors:

Total light output
Mirror design (how is the light shaped)
How you aimed your light

Most trail lights (and high output battery powered lights) use a mirror that casts the light in a symmetrical shape.  This means light is cast up, down, left and right.  Light cast above the horizon is what binds other road users.  Light above the horizon is however great for trail riding as it lets you see overhanging branches and other impediments.

Car running lights (i.e. not high beams) are designed with a horizontal cut-off, where light does not shine above the horizon (actually a low percentage does, this called spill light). If the car light is aimed correctly, the the horizontal cut-off falls below oncoming road users line of vision.  This is why you are typically not horribly blinded by oncoming cars, if they are a) using their running lights and b) have their lights aimed correctly.  High beams do not have a horizontal cut-off, which is the primary reason you get blinded so badly.

Some bike lights (those that are approved for German roads) will have a mirror that has this sharp horizontal cut-off.  They usually will usually be indicated by the some statement on StVZO compliance. Most dynamo lights (e.g., B & M, Schmidt, etc) will have this mirror design. There are also a few battery powered lights (e.g., some B & M models), but they are few and far between.

If you have a light with a symmetrical beam, you can lessen the blinding effect by pointing the light down (as suggested in @Batman's answer), however due to the symmetrical nature of the beam you will still blind road users more than if you had a light with a horizontal cutoff and was aimed correctly as there will still be more spill light above the horizon. This effect is also confounded by how narrowly or wide the symmetrical beam is focused.  Wide flood lights will almost always blind, despite how much you aim them down, spot lights will blind less when pointed down.

Finally, total output does have some impact too, but it is also confounded with mirror design (e.g., high output with a horizontal cut-off may blind less than a low output symmetrical beam).  What really determines whether or not you blind other users is the total amount of light shining above the horizon at their eyes.

In your case your 750 lumen lights are likely trail lights with a wide symmetrical beam.  If you run them at full output you will likely blind others unless you severely aim it downwards.


Can somebody identify my bike for me? I got it as a sort of hand me down a couple of years ago.  I think that it is from the late 90s or early 2000s.  It is definitely a mountain bike and it is red and silver/gray.  It is hard to pick out any defining characteristics because the seat and shocks are aftermarket and there are stickers all over the frame...any ideas?

If you remove the stickers it might help show you any branding.

It LOOKS like a reasonably decent, slightly old school mountain bike. The kind worth handing down. People are debating if its a BSO. This means Bike Shaped Object, which is derogatory term for rubbish bikes sold in supermarkets etc.

It looks better than that, branded forks and decent derailleurs, good headset, but should be easier to ride than you commented. Pick up the bike and spin the wheels. If they stop quickly there's a problem, with the brakes and/or with the bearings.

If you take it to a bike shop, they can help identify it and tell you what it's worth. They can get it rolling like new again. I would recommend some slicker tyres if you want to ride on the road - but keep the suspension for rough roads and potholes!


Which wheels are faster? I look at the different wheels online (road bikes).

What makes a wheel faster than another wheel?

Often they have the same number of spokes, size, weight etc..

What I'm trying to get at is, how do you know which one will be faster or better?

Thanks.

The short but not really useful answer is stiffness, aerodynamics and mass.

Light wheels will allow better acceleration and climbing, because the rider has to put energy into the increasing angular momentum and lifting the mass against gravity.

Aerodynamic deeper section but heavier wheels are faster on the flat at a constant speed. Once the wheels are spun up mass does not need energy to keep spinning, and the aerodynamic losses predominate.

Generally a 'better' wheel will be one designed for the particular conditions you want to use them for, and there is a good correlation between quality and cost.

If you want to figure out which is the better wheel from similar designs from different manufacturers at the same price point, you'd need a testing lab to distinguish the differences.


Are narrow-wide single chainrings compatible between 9, 10, 11 and 12 speed? I am planning to convert my bike to 1x12 setup. Since it is an old bike I want to keep it as low budget as possible. I am looking to keep my existing BB an crank. I have read multiple posts about people just dropping high and low chainrings from 3x ring chainset and replacing middle ring with specific narrow-wide chainring suitable for 1x by setup. It does not look very slick, but there is no reason why it would not work.

So far so good. But now I am in the market for a narrow wide chainring. I can get BCD and number of tooth that I want, but some of these chainrings are advertised as 10speed compatible, others say 9x, 10x, 11x etc.

So the question is: what exactly is so specific in narrow-wide chainring that makes it compatible with say x10 but not x12? Any advice appreciated.

I would have thought that most narrow-wide rings would work with 9 through 12 speed chains. as they all have the same internal (roller) width.

Chains from 5 to 8 have an inner width of 3/32″ (2.38 mm), chains from 9 to 12 speeds have an inner width of 11/128″ (2.18 mm).

Looking at a Blackspire ring:

  For use with 9, 10, 11, or 12 speed drivetrains

  For 9 speed drivetrains you must use a 10 speed chain.

Same for Wolf Tooth:

  Compatible with all 10-, 11-, and 12-speed chains except Shimano 12-speed chains.

  If using a 9-speed drivetrain use a 10-speed chain( shifts and works well on a 9-speed drivetrain and fits the ring tighter for better chain retention)

They obviously think there is something about 9 speed chains that does not work with their rings as well as a 10 speed chain.


Why bother changing a chain? I have heard often that you should replace a worn chain, that a chain lasts somewhere between 800-1200 miles, and that if you don't replace the chain on time, you'll need to replace the cassette when you get a new chain.

My question is this: instead of going through 4 or 5 chains between cassette replacement, what is the downside of riding the same chain until the cog needs replacement? And, if you do that, how long would you be able to do so?

The cost of replacing worn parts is one part of the issue with excessive chain stretch, safety is another component.

Safety

This type of problem will take a while to emerge, but if you are going to run the drivetrain into the ground, at some point your safety may be compromised. Excessively worn chains may break, or skip over excessively worn gears.  At some point you can wear the gears so much you can shear the teeth right off.

If this happens when riding out of the saddle (e.g., accelerating hard or climbing) you can actually be thrown off the bike and into traffic, crash and hit your head, crash your sensitive bits into the stem, or otherwise be embarrassed.  The list goes on.

Will this actually happen to you? Who knows, but you should know that it is a risk.

Total Cost of Ownership

If you let the chain wear excessively you will at some point have to replace:

Chain;
Cassette;
Chain Rings; and
Derailleur pulley wheels.

Chain rings alone can be the cost of 2-3 chains depending on the quality of rings you go for (more if you have a triple chainring).  Cassettes usually cost the price of about 2 chains. Let's put the price of derailleur pulleys at 1 chain (this is up for debate). And a chain costs the price of 1 chain.

That brings the total cost of a drive train to 7 chains.  You would therefore need to get about 6000-8400 miles out of your single chain before the economics start to be in your favour.  Do you think you can do it or will the chain break and become a mangled unusable mess?  When that happens you are stuck replacing everything. Even if you hit 6000-8400 mark, how far beyond it will you get?  Only after 8400 miles are you starting to save.

Also don't forget that a really worn drivetrains shift horribly so you will also need to factor that into the cost somehow.  Is a louse experience worth saving a few dollars?  Only you can answer that question.

The only place where this strategy might work is for single speeds as cogs and rings are relatively cheaper and shifting is a non-issue.


Explanation on the lineup of SRAM Derailleurs @thelawnet has given a very descriptive answer to my previous question which seeks an Explanation on the lineup of Shimano Derailleurs. I am pretty sure that there are people who confuse about the SRAM lineup too and I cannot find a similar question that addresses their complicated lineup. It would be really nice if someone could provide a proper explanation of their MTB and Road lineup. Thank you!

SRAM's road hierarchy is essentially extremely simple:

Red eTap AXS cf. Shimano Dura-Ace Di2 (1/2 x 12 electronic vs 2 x 11 electronic)
Force eTap AXS cf. Shimano  Ultegra Di2 (1/2 x 12 electronic vs 2 x 11 electronic)
Force cf. Shimano  Ultegra (both 2 x 11 mechanical)
Rival cf. Shimano  105  (both 2 x 11)
Apex cf. Shimano  Tiagra (both 2 x 10)

That's it. Five levels, no more, no less.
Other things mentioned:

eTap without the AXS, is simply old 11-speed Etap. It's not a separate level.
Red without the eTap is obsolete - SRAM deem their top kit is all-electronic. They don't make 12-speed road gear that's not electronic. Red is the former top-of-the-line mechanical, but is now outside the hierarchy. Formerly it would have been above Force mechanical, and below Red Etap.
S is not a groupset. It refers to odd parts (e.g., flat bar shifters for road groupsets, or triathlon levers) that are different quality levels. 900 = Red, 700 = Force, 500 = Rival/Apex.
the '1' designation is not a different quality level per se, but for example 'Apex 1' refers to a 1 x 11 system, which is of 'Apex' quality level but more expensive as it had hydrualic disc brakes, which is a feature, not a groupset level per se.

Other designations:

HRD - hydraulic disc brake
HRR - hydraulic rim brake

Note that SRAM offer discounts on their Rockshox suspension for MTB kit if specifying their drivetrain, but for road they are not as attractive as Shimano except at the 'eTap AXS' level, as that is wireless whereas Di2 is not. In addition, their 1 x 11 drivetrain is sometime specified as it may offer gear/brake combinations that Shimano do not.
Sram's MTB hierarchy is more complicated.
Previously:

XX - 2x 10-speed (hence XX) - renamed to XX1 after switch to 11-speed, 10-42t 1x
X.0 - 9-speed, later 10-speed - renamed to X01 after switch to 11-speed https://www.pinkbike.com/news/sram-x01-drivetrain-explained.html
X.9 - 9-speed - upgraded to 10-speed
X.7 - 9/8-speed - upgraded to 10-speed
X.5 - 9-8-speed - later also upgraded to 10-speed
X.4 - 8-speed
X.3 - 7-speed

X1 was a much cheaper 11-speed system:
https://www.pinkbike.com/news/sram-x1-drivetrain-first-ride.html
then GX below that
https://www.pinkbike.com/news/sram-gx-drivetrain-review-2015.html
So you had:

XX1
X01 - only slightly cheaper
X1
GX

then NX below that, with the major cost saving of not using a 10t cassette, only an 11t one.
https://www.pinkbike.com/news/sram-announces-nx-1x11-drivetrain-2016.html
When Shimano moved to 12-speed it didn't change much, but they called everything Eagle.
This results in this hierarchy:

XX1 Eagle (with or without AXS), formerly XX1 and XX
X01 Eagle (with or without AXS), formerly X01 and X.0. Also X01 DH.
GX Eagle formerly GX and X.9. Also GX DH.
NX Eagle, formerly NX, and X.7
SX Eagle, formerly X.5
X.4
X.3

Note that that is 5 12-speed groupsets, where 3 use SRAM's 10t freehub, and 2 do not.
There is also EX1, which is priced between X01 and GX, but is 8-speed specifically designed for e-bikes.
By comparison, Shimano:

XTR
Deore XT
SLX
Deore

are four levels of 12-speed with a 10t cassette/freehub
Shimano's 11-speed Deore probably maps closely to NX & SX Eagle, in that it has an 11-51t cassette, whereas those use 11-50t.
Shimano sell both lighter and heavier components for XTR, depending on your goals (e.g. 4-piston and 2-piston brakes).
So XX1 AND X01 both roughly map to XTR, while GX Eagle is doing the work of THREE Shimano groupsets (XT, SLX, Deore-12 speed). GX Eagle corresponds to Shimano Deore/SLX (which aren't very far apart)
Note that Shimano have dumped Di2 for MTBs, so they have nothing to match AXS for MTBs.
Because SRAM released 12-speed before Shimano and grabbed lots of market share, they have milked their 'Eagle' brand by releasing steadily lower quality/cheaper 12-speed groupsets. SX Eagle is probably around Shimano's Alivio/Acera quality levels. Shimano don't need to make cheap 12-speed kit, as their 9-speed kit is very popular on new bikes, whereas SRAM is not. People looking for an alternative to Shimano for 9-speed bikes tend to spec Microshift.


Chainring rubbing frame after replacing I replaced my Ultegra R8000 inner chainring from 36T to 34T. After installing, I made sure there was enough clearance between the inner chainring and the chainstay and spun it to make sure all is good. However, after today's ride, I realized that the chainring has gotten closer and scratched the paint off the frame. The components are fairly new, so there shouldn't be anything wearing out yet.

What could be the problem and what did I do wrong?

Thanks in advance.

Okay, thanks for everyone's time for commenting but I solved the problem.
After getting home, I immediately rechecked the bolts and disassembled the crank and boy oh boy, found out that I put the inner chainring the other way around. In my excitement when installing the new chainring, I didn't realize that I'd put it the wrong way and also didn't realize anything weird during my ride because I haven't actually used the 34T ring yet.

So, my stupidity costed me a bit of paint on my chainstay that I ended up covering with electrical tape, but all good now.


Does tire need immediate replacement? I have received a hand-down bike from a friend that had a punctured inner tube which I have since patched, however during my fix I noticed that the tyre is not in the best condition when looking at the sidewall, and would like to know if the tyre is dire need of a replacement.
Thanks in advance for any response!

Yes, you do need to replace the tyre. It can burst any time. You just leave the bike somewhere, hear a loud bang and that's it. If you are lucky. If you are unlucky, it happens when you are riding it and you crash because the bike is no longer controllable.


What type of bike is this? this is the bike

This is a bike I purchased and loved. I moved out of the country for a while so I sold it. I regret doing that and now I want to purchase it again but I have no idea what kind of bike it was and these are the only pictures I have of it. I also don't own any documents and the place where I bought it shut down.

If I were to describe this bike to someone, I'd say this is a city commuter bike with a semi-step through frame and windswept (or cruiser style) handlebars.

It looks like the Linus Roadster is very similar looking to this, or the Linus Mixte. Also the Public M7 or C7 is like this but more upright/chill.

You can probably mention these details to a local bike shop and they can help you with something similar. Note that the handlebars and seat are at about the same level, so something to look for to get a similar feel as your old bicycle.


When is a child ready to switch from scooting to pedaling? Last year, we bought a child-sized bike and removed the pedals. My three-year-old has been using it as a push bike (a.k.a. balance bike, run bike, or scooter) and learning how to balance. The plan is that once she's ready, I'll put the pedals back on, but I won't be adding training wheels. However, I don't want to put the pedals back on before she's really ready because it would be a pain to take them back off again.

She's now at the point where she can coast for about five seconds at a time, but she doesn't ride in a particularly straight line. She often asks for pedals, though I'm sure she doesn't appreciate the effort that will be required.

How do I know when she's ready and it's time to put the pedals back on the bike? What specific goal can I give her to work towards (i.e., "When you can do XYZ, then you can have pedals")?

Related question: What is the best method to teach a young child to ride?

I did the same thing for my son when he was 2. After a year and a half, he just "looked" ready. I knew he could ride so I had him try pedaling. I have a short hill in the front yard and put him near the bottom. He was determined to NOT ride properly, so after about 25 feet he "fell" off and said "SEE!! I can't do it!" I laughed and said, "You did it almost all the way across the yard!" Just then his mom came out and asked him to show her, and he jumped up and rode for a few minuets all by himself.

I made sure that the seat was set so that he could easily touch the ground with both feet at the same time so that if he got nervous he could just stand up, but it never got to that point. He was 3.5 years and my girl was 3.75 years when they both learned to ride (I was a few weeks short of being 8 when I learned)

I don't think there is any magic rule to guide yourself with, just look at her confidence and let that be your guide. Make sure she can touch both feet on the ground at the same time, and it really shouldn't be much different than what she is doing now.

(PS: If you do put the cranks on and she just can not do it, you can always just take the pedals off rather than the whole crank set, that will save a lot of time!)

You can see the video of him a few months after he learned to ride at youtube here: http://youtube.com/watch?v=fnb7uhC1J2Q

A few months BEFORE he learned to ride: http://youtube.com/watch?v=jfrz0Q6I_rw

at age 8 when he learned a "Nothing": http://youtube.com/watch?v=CdOfmWYt9FQ

My girl when she learned: http://youtube.com/watch?v=vP6qio6LS78


How do I fix U brakes? I found an old bmx in my shed and I'm just doing it up a little as a good muck around bike. It's not very good, I don't even know the brand but i cut the front brake off, because it didn't even work but the back brake is a U brake but I've found that when biking I'll pull the lever all the way back (as far and the grip) but it's like the brake isn't even working.. I know it's working but it's just not strong enough. So I have 2 questions.

How do I make the brake lever harder to pull so I don't pull it all the way to the grip?
How do I adjust the actual U brake to be a little closer to the rim?

Any help is appreciated! Just trying to get it working. Feel free to ask any questions too.
Cheers!

There are 2 screws you can see at right side of the brake. the bottom one is just above the pad screw - it's one that holding the cable. Open it a little.
Check if the cable is going smooth (if not, you should oil the cable or even replace the cable, and maybe the housing too). Check the pads, that they are not wear, nor dried on sun.
Then pull the cable (be sure that the cable going well at the lever), push the pads up to the wheel from both sides (to add tension), and tighten the bolt. The upper screw is to add more tension if needed.


52/15 fixed gear ratio - what should I change to? I have a 52/15 gear ratio and I find it sort of difficult to pedal.

I'm wondering what I'd need to switch the chainring/cog sizes to that would allow for me to not remove any chain links.

I'm assuming I'd just make up for the difference, for example: if I switched the chainring to 48 the cog would need to be 19 in order to match??

I don't want a drastic difference because I like the control I have when going down hills.

With the current setup the wheel sits in the drops, with the chain is completely tight, and leaves about 5/8" of room I could move the wheel back to (if I were to change the sizes and needed to use the extra real estate)

The area I ride is mostly flat with some moderate hills (none i'd consider steep)
I have a 40 tooth chainring lying around that I could use if that'd be a good fit.

I'm new to swapping out ratios and I'm going to order the parts online, so i want to make sure it works.

Different from the other answer, I read the question as OP wanting to change to lower gear ratio without changing chain length. 52/15 is an extremely high ratio.

For all practical purposes, if you want to keep the chain length same, the sum of numbers of teeth in cog and ring should stay the same.

The changing geometry does affect the result a bit, but the difference it will make is less than a half link's length. The exact math is a bit hairy, since you have to take into account that the part of chain that wraps around cog is not actually part of circle, but N-gon that has its angles at chain pins.

My recommendation would be to bite the bullet and get a chain tool and not try to optimize cog sizes. You will need one anyway later, and if the old cogs and chain were worn, it's best to replace the chain at the same time. A normal sized chainring will give you more options to play with ratios later, and prime numbers 41, 43 and 47 would let you use any cog without thinking about skid patches.

With lower ratio you might need to take the skid points into account.


Lifespan chain and gear wheels on e-bike If is possible to give an indication of the  average lifespan of the chain and gear wheels of an E-bike?
Assuming: Cycling in all weather conditions (commute); Western European climate (10% of time rainy, snow is rare). Average monthly temperature ranges from 0 to 20. No Cycling off road. Open chain/gear (no case).
Lifespan may be in km, or in years/months assuming about 3000 km/y.

It’s impossible to give an answer because chain and sprocket wear is dependent on load as well as distance. Stronger or heavier riders apply more force. Riding lots of hills will do the same.

The best approach is to get a chain wear gauge and record how long a chain lasts for you and your riding.

Conventional wisdom is 2 or 3 chains per cassette. Inspect the cassette when you replace the chain.


Seatpost mounted luggage rack on carbon frame Planning on taking my carbon Ribble to Wales to go play in the valleys.  Need to carry limited luggage from point to point.  Looking at a seatpost mounted rack like the Topeak RX beam, but wanted thoughts on whether this is a good idea on a carbon bike?  Have an alloy seat post but don't want to damage the carbon seat tube.

For the sake of argument, let's suppose you weigh 70 kg, and 60% of your weight is being carried directly over the seatpost (the rest being on your hands). Let's further suppose that you have 10 kg of gear cantilevered out behind the seatpost, with its center of mass being 30 cm away.
In terms of what the frame "sees," the seatpost rack would move your combined center of mass backward by 58 mm. This would be about the same as if you started with your seat fully forward on the rails, and moved it fully rearward and carried the additional load on your back. My guess is the frame can handle that kind of loading.


Upgrade disc-brake wheels Just bought new bike with disc brakes.  If I buy an upgrade wheelset do brake discs (rotors) come with?  Or do you have to buy them separately?

Normally the rotors will be separate. Also, there are two kinds of rotor mounts: 6-bolt and centerlock. You can get an adapter to put a 6-bolt rotor on a centerlock hub (I don't think you can go the other way), so it's something to be aware of.


my bike pedals but the back tire will not move I have a mountain bike and it was working well.then I started to pedal and the back wheel isn't moving.could someone tell me what it could be?

One possibility is that the hub's freewheel mechanism has broken. Maybe it's fixable with some spare parts or you may need a new freewheel hub body or a new hub altogether. Your LBS will be able to assess the situation.

It looks like this: https://www.google.gr/search?q=mtb+freewheel+hub+body&tbm=isch


Why does a tire patch leak near the lip, and how to properly patch the flat? I had a flat in my back wheel because the tire was worn out. I removed it and patched it as in these directions, except for the abrasion with sandpaper, which I never do. I put the tire back in and mounted the wheel, but it deflated again overnight. The leak is under the lip of the patch, which didn't completely seal, as in these pictures:

The hole was around 0.5mm so it is well covered by the rubber cement and the black area of the patch. I have patched many dozens of flats without this problem.

Why does the flat still leak? Is the orange area different from the black area, and does it have to be perfectly glued to the tire?

The edges of patches tend to come unstuck because you are attaching a stiff flat patch to a curved surface. To avoid this, make sure that the vulcanizing solution covers the entire area of the patch, apply pressure to the entire patch while it is curing, and wait a sufficient amount of time before reinflating the tube.
And as others have commented, abrading the tube before patching does also help get a good seal. Sometimes you’ll get a secure patch without it, but your chances are much better if you do it.


Disk brake and wheel is moving: is my fork too long? In the  links I gave below, the website is in French but you can change the language.
Following this thread
I bought new bike components to build my own bike. In particular I bought Surly Steamroller frame and a this Surly fork. I have a QR system to attach this wheel because I wanted to install a disk brake system: disc, brakes.
When I am braking, the front wheel is moving on the left of the fork.
I tried to change the QR attach, tighten it very hard but same problem.
Is it possible I have an incompatibility issue especially between the fork and the frame?

edit: I followed the remarks from here and I tightened the QR even more but same effect.
Could it be my fork that is moving and not my wheel?
I notice that the spacers on top of my headset may be too long (4.5 cm of spacer) and could cause the fork to move, is it relevant? I think I will shorten my fork removing spacers.

The front wheel (of wheel set you linked to) has a 12x100 mm front axle (road thru-axle) but comes with an adaptor for 9x100 quick release axle, and the fork is made for 9x100 quick release axles. Did you install the adaptor kit correctly on the front wheel hub?
If you grab the front wheel by the tire close to the top of the fork and push/pull the wheel from side to side, do you notice the wheel moving at the quick release?
If it moves, there must be something wrong with how the quick release holds the wheel to the fork. Do the end of the axle of the wheel hub protrude out of the fork so the quick release can't make correct contact with the fork?
Minor notice:
The brake disc and brake caliper is not 100% compatible. The RT70 disk is ment for calipers using narrower brake pads, and the MT 200 uses wider brake pads. This means the brake pads is slightly larger than the brake area of the discs, but I'm not sure what the actual consequences will be in this case. Shimano has a document that state compatibility of their products:
https://productinfo.shimano.com/download/pdf/com/2.6/en


What's the purpose of the boot on a v-brake? Just that, what's the purpose of the rubber boot on a v-brake?  How does it do its job?

The idea is that it keeps the dirt and water that would otherwise get kicked on to the cable from getting worked into the noodle, contaminating the cable system and causing friction, corrosion, and poor brake feel.


How to fix this saddle for my road bike? I have this bike:
https://www.boc24.de/p/compel-rr-100/213327/#itemId=213327-1
I disassembled my bike and have Problems putting my saddle back together.

What i tried:
Putting from both sides:

What i expected:
Having only one screw. (Maybe i also confuse having two,..)
(different bike)

I think you have a mixup somewhere.  Those bolts look wrong - given there's a clearance hole in one cylinder and a threaded hole in the other, one bolt should pass through the first and thread into the second.
    +-+   +-+
[]===========>
    +-+   +-+
   slip   threaded

As yours is pictured, the two bolts would push the ends of the clamp apart, if they could both get a grip.
Look around for the missing bolt.   Those two look like water bottle cage bolts, or possibly stem bolts.  What else did you take apart that may have become mixed ?


Do Pros use compact cranksets? Do pro riders use compact cranksets for hilly races? I'm trying to determine if switching to a compact double will mean I don't have the top end speed to be competitive in higher levels of racing (I'm not a pro racer) and unfortunatly I haven't been able to find information on the setup of top racers.

While pro riders often change gearing or whole bikes depending on the nature of the race or the stage, you do sometimes see compact cranksets, particularly among domestiques in mountain stages or races.

A big-name example is Tyler Hamilton in the 2003 Tour De France. After crashing and breaking  his collarbone before the huge mountain stages he was unable to climb out of the saddle. FSA who makes compact cranksets and was a team sponsor set up his bike with a 52/36 crank; allowing him to climb seated.  FSA did a couple of releases and maybe ads about it - and I started to see a lot more compact doubles in local rides.

Just note - a lot of times you can accomplish the same goal (bigger and smaller gearing) by switching the typical 12-23 racing cassette for one that is 11-25 or 11-27 at a lower cost.

You can play around with Mike Sherman's Bicycle Gear Calculator to help you make a decision.


Gipiemme Parade Wheels Strange Noise I have a set of Gipiemme Parade Wheels that look like this:

The other day I was getting my bike out of the garage, and I lightly bumped my rear wheel with my foot. The wheel made a strange rattling noise, as if a nipple or some other metallic item was running around in the wheel. My front wheel doesn't do this, and I haven't noticed it before. Should I be worried, and what's making that sound?

It could well be a nipple. Or some other bit of metal junk. Removing it is a good idea, just because you never want your bike to make metallic rattling noises as part of normal operation. Over a long time, and lots of wheeling your bike, the repeated banging of that object against the rim will damage it somewhat, but I expect you'd have to wheel it thousands of kilometres to cause any real problems.

Getting it out is straightforward, but annoying. Take the tyre and tube off the wheel, remove the rim tape or plugs, rotate the wheel until the object falls out. You may need a bit of shaking and wiggling, and it pays to work out where the loose thing is, hold the wheel up and look into the spoke holes to find the object. Spoke nipples will almost always sit on the hole, they rarely fall through it without you poking them.


Why are license plates for bicycles no longer used? Bicycle license plates were quite common in many countries before, during, and, depending on the region, also after WWII. In Poland, for instance, it was obligatory until the late 60s. I've found that in Switzerland some kind of license plates (Velovignette) were still in use until 2011.

I'm curious why countries retired such regulations, and what are the pros and cons of that situation. I'd like also ask if there are still some countries that require cyclists to register their bikes with some authority and/or are obliged to have insurance etc.

Example license plate below:

In the Netherlands at least:

The license plates for bikes were tied to the taxation of bikes. You needed to get a new plate every year.
The taxation lasted until WWII. The Germans abandoned the tax.

After the war the tax wasn't introduced again so the plates were no longer needed.

It was speculated that after the war the taxing of cars more then made up for the not taxing of bicycles.


cannondale cadd10 105 crankset replacement I had a terrible crash on my Cannondale CADD10 105 (11spd) and wrecked the crankset (the bigger ring bent). It is FSA Gossamer Pro, BB30, 52/36 from the website. Is there an identical one available for replacement? I couldn't find any on Amazon or online store.

And what does BB30 mean?

Thanks

BB30 is Cannondale's (now open) standard for how the crankset fits into the frame.

Cannondale invented the BB30 bottom bracket in 2000 and debuted it at the Tour De France (I couldn't find any information about how they faired) in 2006 the BB30 became an free international standard allowing any cycle manufacturer to use it.

  The BB30 International Standard provides the specifications for an oversized bottom bracket shell for a bike frame. This standard allows for Direct-fit, pressed-in bearings and a 30 mm spindle. The system saves weight by accepting a 30mm aluminum spindle and eliminating cups that would normally hold the bearings.

The claimed advantage of BB30 is an increase in stiffness and a 4% increase in drivetrain efficiency, achieved through an increase in size allowing larger diameter frame tubes. (according to Cannondale - I don't have the rep to comment!)

The Caad10 uses 110 BCD 5 arm chainring, if you put that into your favourite search engine there are a large selection of chainrings that will be compatible. You don't specifically need to replace them with the same size chainring, you can change them depending on your requirements.

The Shimano 105 chainrings should be a direct replacement, and are relatively inexpensive. Personally I wouldn't try to straighten an old chainring, as the metal would have stretched and you are unlikely to get it back to being entirely flat.


Is commuting 10 km on an empty stomach harmful? I recently moved to a new place and I started taking my bike to work. It is a ride of 10-15km, depending on how fancy I feel about taking detours. I wake up at 7:45, and 15 minutes later I am already on the bike. I eat breakfast at work, after 30-40 minutes of biking. My question is: does it have health ramifications if I do it every day? I did some looking around on the internet, but everything I find relates to high-intensity sports cycling, not a leisurely commute.

Some facts that might be helpful:

I maintain a steady pace, enough to get sweaty, but this is more from the length of the ride than from the intensity. I stay dry for the first part of the ride.
I feel strong and capable most days. Rarely I will feel worn out on the last kilometer or two, but this is pretty rare and I guess indicative of bad sleep.
The ride is 100% flat. The biggest climbs are speed bumps.

As far as I can tell, no. I've been riding 30 minutes or more every workday before breakfast for more than 10 years with no detectable ill effects. When I was riding an hour to work I'd sometimes have a small snack before riding, but only rarely. When I'm cycle touring I'll often ride for an hour before I have breakfast, as that wakes me up and gets me warm, then I can stop and eat somewhere pleasant (I usually stealth camp so I'm not always sleeping in a nice place to hang round during the day). But an hour isn't an unreasonable ride before breakfast. For me!

What matters is being aware of your body. If you're feeling bad, stop and work out why. If you're hungover... what did you expect? But if you normally feel fine and one day your stomach hurts, or you feel weak, or something else changes, worry. Stop, work out what the problem is. Eat, drink, pee, whatever. It's the same as if your bike feels funny or starts making a weird noise.

Normally I carry breakfast to work, so I have it with me if I need to stop and eat. I also have money, which is surprisingly useful for solving problems :) If I need to I can get a taxi to work, buy food, whatever.

FWIW I was vegetarian for most of that time, of late I've gone back to eating meat every couple of weeks (I'm getting older and meat seems to help me maintain muscle mass). I don't know if being vegetarian helps, but it doesn't seem to hinder the ride before breakfast.

(ok, I've been doing this for more than 15 years, possibly more than 20)


Can I make this bike fit me? There are two questions here really though they both have to do with fit.

Today I tried a Baad Raad electric fat bike.
This question isn't about batteries or fatties.
I just wanted you to know this bike will be used on rough trails,
snow and whatnot.

The question is about fit.
This is a one size fits all bike.
The frame is said to be a large one.
It seems to be about ninteen inches.
I am six foot two. I tried the bike out and
was pleasantly surprised as far as performance is concerned.
When in pedal assist it does exactly what I want it to do and more.

Do some bikes have shorter cranks on them?
I could still put up the seat more no problem.
The cranks feel short to me. Is that because the seat should be raised?
Is there more to it than that?

What about the handle bars?
My mechanic says they can be raised as well.
Will that affect how the bike fits as far as legs are concerned?

The price is more than right if I can tweak the fit a bit.

Years ago, the US Airforce commissioned the design of a 'perfect cockpit' for a new fighter, spending millions measuring and testing pilots and coming up with the right cockpit for the perfectly average pilot. Only to find there was no perfectly average pilots to fly plane. After that, they made planes with cockpits adjustable to the actual pilots that was flying the plane.

Bikes take this further - the frame is not adjustable without making it heavy and unreliable, and unlike an aircraft, frames are relatively cheap compared to the the rest of the kit. Its cheaper and gives better bikes to make different frames.

All that aid, the bike might fit you - The US Airforce never found their perfectly average pilot, maybe the manufacturer of that E-bike has found there perfectly average rider in you.


Chain rubs against frame when in smallest rear cog I've set up a 12-speed SRAM Force groupset with an XDR cassette. When in the smallest rear cog, the chain rubs against the frame:
Does anyone know what causes this and how to fix it?
The frame is a Dolan Titanium ADX and the wheels have QR axles.

Sometimes things like this happen when newer generation components are put on older frames. When Campy 10 first came out, I remember some frames doing it. However, that was usually from hitting the end of a chainstay or seatstay that wasn't offset flat enough with the inside face of the dropout.
Your picture shows the chain rubbing against the flat surface of the dropout, or what would normally be made as a flat surface, which is odd. Three things that come to mind are the dropout is trying to be flat but isn't, the locknut contact area got worn down or made badly somehow, or the hub and/or cassette is put together wrong. Those are the first things to check.
There are QR and thru axle versions of the frame, and you don't say which you have. There's no QR nut visible AFAIC so I'll assume thru.
It's not clear from the image whether knocking down the relevant dropout surfaces a bit would do it, but that could be one approach. I would let a ti framebuilder or the manufacturer evaluate that unless you're feeling daring. There's also the notion of slightly building up the axle contact surfaces (you'd want to do it symmetrically), i.e. if it were a QR frame and you were okay with the judgment call of increasing the OLD by the needed amount, probably like 1mm total, you could bond in some .5mm ground stainless round M10 shims and then trim them down once set to become part of the dropout. Doing the same would likely not be as straightforward with a thru axle, and you can't easily check the dropout alignment before you start, which is not ideal, but it may be possible.
Edit in response to comment:
Personally, the first thing I would do to evaluate a solution based on adding a spacer or spacers is measure the current rear end spacing and the dropout alignment. While at it you could get an exact measure of the hub OLD, which is less relevant because wheels get switched, but you may have an idea of how long/often it's going to be run with the wheel you've got.
Adding spacer(s) and then putting the wheel back in splays open the frame. What happens when you close the QR is it then squashes the dropouts and axle together to be in line anyway. This creates flexion (I think I'm using the term right) in the dropouts and/or axle. Depending on how stiff, strong, and ductile those parts are, the result can be fatigue cracking in the dropout or axle, or flex in the axle that can cause bearing misalignment and resultant drag, or harmless flex in the dropouts.
A lot bikes in the world have, for example, thin dropouts made of a high-ductility steel like 1020, which is fancy talk for melted Chevys. Do something like this on a bike like that and the dropouts will flex to accommodate and you'll almost certainly never see an ill effect. A recent ti frame with what look like thick dropouts, plus presumably some kind of modern, stiff, oversized aluminum axle will be different. I'd be more concerned about fatigue failure in the dropouts. And if you do wind up with axle flex, that can be pretty bad too.
That is not all to say it couldn't be reasonable under any circumstance. But you need to judge it in light of the existing spacing and dropout alignment as well as how much gap you intend to add. It's common for spacing and dropout alignment to be imperfect as-is. So you want to know it if for example you're taking the dropout alignment in the direction you'll be adding splay from iffy to worse or perfect to iffy or whatever. And same with the spacing. Say it happens to be 136mm with perfect dropout alignment now; if you add 1mm you're actually making it better, because you're presently adding the same sort of misalignment and flex in reverse when you clamp down on your 135. (I'm assuming it's a 135 rear end, substitute 131 and 130 for the above numbers if not.) But if it were 133 with perfect dropout alignment now, the 1mm added means something different. The point is that the state it's in now is really what the whole conversation is about in terms of whether this is a good idea.
Note that driveside dropouts or dropout-chainstay connections are a major place that frames naturally fatigue out even if everything about their construction is great.
As for what to actually do, I, again personally, would never add a free-floating spacer there. Yes it could be a way to make the bike physically work. To me it would feel like janking up a nice bike. It would also feel like janking up a nice bike to only add a drive side spacer and thus either accept the wheel being misaligned in the frame or having to run a wheel that's custom-dished for the frame in the direction that gives up non-drive-side spoke tension. But say you get your M10 ground SS 0.5mm round shims and determine that one is all it takes, which appears likely. There are spacing and dropout alignment situations where bonding on one per side could then be either totally fine or a compromise that never amounts to anything. You could then test before doing it by putting them on and penduluming the wheel with the chain disconnected, and getting a feel for what's happening with the dropouts by tactile observation when you close the QR. (What I found doing this would inform by answer to the question of whether I'd do it if the dropout alignment and spacing were both perfect.)
I would personally be far more curious about first seeing if a ti builder might be into knocking down the rubby areas with a dynafile or whatever.


What model of bike does Alicia Vikander use in Tomb Raider (2018)? Does anyone recognise this model of bike? It has some stickers/decals with fictional logos, but I couldn't find any brands/marks on the bike itself (more images):

Note: The fox tail and paint can are from a 'fox hunt' game/race in the film. See here.

Details original Bike used in the Tomb Raider movie 2018:  SE Bikes Tripel, Saddle Books Champion Standard B17, Vera Citywide tire - SE Bikes logo on the front of the frame -  handle grips purple - red pedal - Rear tire is possibly Kenda K-152. Kenda road tire in yellow.

details of bike

[![][9]][9]


GRX Di2 front derailleur compatibility with Ultegra 2x crankset Researching an upgrade to GRX Di2, am aware from this forum (as well as Shimano) that the GRX 2x crankset is pushed 2.5 mm outboard and thus requires a GRX FD. However, what about the opposite: using a GRX (Di2) front derailleur with an existing Ultegra 2x crankset that came stock on a 2020 Trek Checkpoint SL6?

Is there any particular reason you want to mix FC-R8000 cranks with a GRX Di2 FD-RX815-F front derailleur? the Ultegra Di2 FD-R8050 will get along just fine with GRX Di2 rear derailleur as Di2 sees it all as part of the road family.
the GRX front derailleur, including the Di2 FD, is shifted +2.5mm outboard to match the GRX cranks. I would not count on it working with your Ultegra crankset. that being said, depending on where the frame manufacturer's actual braze-ons lie relative to Shimano spec, the chainline issue may or may not work. unless you've bought smaller chainrings for your FC-R8000, however, your large chainring is too large for the FD-RX815-f, which is designed for a 48T max. if you have purchased the Ultegra 46-36 chainrings for cyclocross, you'll be even further from the 17T capacity of the GRX front derailleur, so I'd treat the front drivetrain as a package deal, and if you must buy one before the other, maybe buy the crankset first.
There was a post on the S-Tec (Shimano bike shop employee site) community forum where a user said that on his Di2 equipped Trek Boone, he was able to get the GRX crankset to work with his old (non-GRX) front derailleur. I wouldn't expect it to work as well in the opposite direction, but the location of the FD braze-on on the Checkpoint might be slightly different one way or the other.
According to a post from 9 months ago on the S-Tec forum, you could even use the RD-RX-817 with a front derailleur, albeit with some limitations, and no official word on "whether or not that will be 'fixed' in a later patch."


(How) should I wax my cassette along with my chains? A while back I got myself a 5kg block of paraffin (this being the smallest the candlemaking supplies store had to offer) to wax my chains. Then it hit me that the cassettes I have been using are definitely of the non-stainless variety, and tend to end up with rust spots on the occasions I have parked my bike outside, and using oil to protect the cassette would defeat part of the purpose of waxing the chain.

So, I started wondering, could a cassette be waxed along with the chains to protect it from rust?

The point of waxing is not to rustproof but to lubricate the chain's internals where they articulate. The rest of the wax flakes off quickly. So this wouldn't have the desired effect.


Front drum (was disc) brake only works when going backwards (!) I am restoring my old bike that hasn't been used for quite a while. The rear brake works fine, however, the front brake has an issue: It only brakes when the bicycle is going backwards, not forwards!

I have no idea how that is even possible - but it shows that at least it can't be the handle or the wire. Something broken inside the brake perhaps?

I attached a picture of the brake for clarity. Any suggestions on how this is possible and if it can be fixed?

There are two possibilities:

1.) The roller brake mechanism and internals are completely seized. Based on the level of rust on the outside of the brake, there is a strong possibility that there is rust inside as well.

Shimano roller brakes do need to be in fairly good condition, and have the correct Shimano grease in them to work well. If the brake had a very thick type of grease injected into it, it may have gummed up the brake completely.

The Shimano Nexave roller brakes, are technically serviceable, but are not warrantied by Shimano if opened up. They are designed as a complete unit; replacement internals are not available, and must be scavenged from other brakes. Most shops will typically not service the internals; know that if a shop is willing to, there are no new parts going into the brake.

Nexave brakes are fairly inexpensive, and any good shop should be able to supply you with a replacement, and install it as well. Despite my normal recommendations to overhaul existing equipment, this is one instance where replacement is the best route.

2.) You are possibly missing a spacer/locknut between the brake drum and the frame.

While this is not your exact brake, the parts are similar. You may be missing item #2.

It looks as though the end of the fork blade may be contacting the drum, and exerting pressure on the drum, preventing it from springing back. Be sure that there is the appropriate locknut holding the brake unit in place, and the over-locknut dimension is 100mm.

This is only likely if the hub has been overhauled, and the brake was put on incorrectly, with the locknut missing.

The reason the brake works while rolling backwards is that the drum is being pushed in the "open" direction, loosening the internals (from whatever is making them stick), and allowing the brake to operate normally.


Which standalone head units would work with Tacx i.Flow T2270? I'd like to be able to use my Tacx i.Flow T2270 trainer without a PC.

Apart from the T2202, which current or older standalone head units would be compatible? Would T1682 work? What about head units from other Tacx models?

(I am looking to buy secondhand, so would like to understand my options.)

The Tacx i-Flow is only compatible with the T2202 head unit for standalone use.

The T1982 Bushido head unit does not connect in my experience, although I have had Tacx support tell me it should work.

The T1962 Flow head unit firmware is not compatible withe I-Flow.

Your best guaranteed option is the T2022.


Do I need to face my new frame? I just purchased a new aluminum MTB frame. The headset is a standard "NECO, 142, 1-1/8” AHEAD". The BB is ... I'm not sure, but is internal and threaded.

How do I determine if I need to face or ream my new frame, before pressing in headset cups and installing the BB?

If your bottom bracket is a sealed cartridge unit it's less important.  If you're using a bottom bracket that has loose ball bearings and a spindle it's very important.  Mostly the same advice goes for headsets.  All this is less important than back in the day when all BBs and headsets had exposed and floating bearings inside.


Bottom bracket spacers I'm installing a Sram GXP English-threaded bearing set in my 68mm bottom bracket.  It is replacing a Shimano Ultegra-level HollowTech II bearing set.  The crank set I'm installing is a Sram  XX 42/28, replacing an XTR 44/32/22.

I would like to center my chainline on the big ring and reserve the small ring for climbing the steeps.  The Shimano bearing set had three spacers (usually two on the DS and one on the NDS but I was reverse of that for derailleur reach reasons).  The Sram bearings come with two spacers and the instructions say one on each side.  The Shimano bearings have fewer threads on each cup so if I put both Sram spacers on one side I still have more threads available to insert into the BB than were available on the properly installed Shimano.

I asked Sram tech support about making the spacer adjustment (without referencing to the competitors set-up).  I received the pat answer of non-liability "don't think outside the box with our products."

Considering the observations I've laid out, it seems reasonable to go ahead an use the two spacers on one side without worrying about stressing the bearing and/or bottom bracket, unless, for instance, the Sram cup material is of substantially inferior material.  Any opinions?

If you know you are doing this and accept the risk there is not really any reason not to do it.

At the least you may get increased bearing wear. However, what I would be worried about is cracking the bottom bracket shell because you are moving the bearing and therefore the leverage point further outboard. That is going to increase the stress on the edge of the shell, even though the GXP cups are longer and have more threaded area than the Hollowtech units.


Please help me identify the specifics on my older Giant Sedona? I was generously given this working, older Giant Sedona. I have searched and searched, high and low to find out specifics on the bike, to no avail. I've been to Giant Bicycles website, there's no info available about older bikes and you can't register an older bike either. I have been to Bikepedia, again no specifics about my bike. bikeindex.org, it was never registered there as stolen. I have google searched "giant sedona" and have looked at images for hours trying to identify specifics on my bike. I have spent hours reading links and pages and pages of posts about identifying bikes. It would be neat if Giant or someone would create a site that one could plug in the serial number and find info about a specific bike. I'm surprised no one has done that yet. Nonetheless, if anyone has any useful tips I'd appreciate it. Thank you.

This is a 1996 Giant Sedona. I had this exact bike, right down to the color.
The frame is 4130 cro mo and the tubes are 'triple butted'. If you notice the top tube and down tube are flared at the joints.  The was the 'external butting' and they were also butted for tube wall thickness internally.
The groupset was entirely shimano STX, which, at the price point (about $600 CAD at the time) represented an amazing value.  7 speed rapid-fire shifters, panaracer smoke and dart tires, non descript black quill stem, giant branded aluminum bar, saddle and grips (which were thin and hard, but after a while I got so used to them that any other grips felt mushy).
I can't recall the rim manufacturer and model, but they were 36 spoke....a great bike, and if you still have it, I'd be tempted to offer to buy it, strictly for nostalgic purposes....


Identify this Gitane road bike I yesterday bought this bike from Offer up for $100 and want to know more about the bicycle. Can someone please help me get the model, type and year of this bicycle from the picture below.

As @Paparazzi said it appears to be a Gitane bike, from looking through the product catalogues on the Gitane USA site I suspect it's a 1984 Gran Tour (from page 5 of the french catalogue) as this style of logo appears to have only been used for the early 80s and this model is the only model that has the bar end shifters/is advertised in the same colour.


Cycling into tunnels with claustrophobic person you are cycling in pair
you may need to travel through tunnels (lenght can vary from few hundreds meter to about 7 kilometers)
your travelmate is claustrophobic, therefore tunnels are a challenge for him
avoiding the tunnel is not always a practical option (it may need a 50 km detour)

Under these conditions, which would be the best approach to prevent as much as possible issues like panic attack, irrational behaviours etc.?

This is how we did it, for all tunnels longer than 150 meters (ranging from 200 meters to 4 km):

before the entrance of the tunnel, the leader slows down or even stop, allowing the follower to get closer
after entering the tunnel with lights on, regardless if there is a cyclable sidewalk or not, every once in a while the leader ring once his bell
if the follower feels ok with the leader's distance/pace, he rings back once. Else, he rings back twice. The follower can also ring twice whenever he feels he should get closer.

The benefit we got:

no need for the leader to turn his head and look back
the follower feels actually in control and not left alone


How to wheelie without hands? I have seen videos of people riding wheelies and letting go of the handlebars.
I have tried doing the same but I have no idea how to do it.

I can ride wheelies easily on my mountain bike.
I am well in balance and not accelerating but everytime I try to let go of the handlebars, the front wheel just goes back down. To keep the wheelie up, I am constantly pulling the handlebar towards me to keep the balance.

So how is possible to ride a wheelie without pulling the handlebars?

You need something else to prop your weight against. Artistic cycling practitioners usually use saddles with high rear edge that can be leaned at. And of course you can use other parts of your body, such as shown here (check the rest of the video for the saddle).


What sort of bike will suit both offroading and onroading I live in an area which is connected to main road by a small lane(worse than mountainous region, I mean it's condition) and the main road is just like a new tarmac surface, the speed breakers are something like road blocks half feet in height and half feet in width with triangular surface. My old bike is an mtb and serves both well but it is heavy any suggestions what I should look for in my new bike.

Check out cyclocross style bicycle.
It does well on the road and light trails.
You can put touring tires on it.

wiki Cyclo-cross