Cooling down brakes and rims I recently rode my bike on some steep hills. After descending on a 4 km road with some sections at 21% slope, I realized my rims were pretty hot not only where the brake pads operate, but even up to the sprokes connection.

Though I realize that keeping the bike moving will allow for a more effective cooling, should one let the rims cool down to preserve braking efficiency in such situations?

Your braking technique is probably bad with respect to overheating. Continuing to ride could help, but only if you do periodic breaking, i.e. you don't break at all until you reach max safe speed, then you brake hard to slow maybe by 10km/h, repeat. How much speed to lose depends on slope (how fast you gain speed again) and load (how much energy is dumped into your brakes to slow the same amount). If you brake more in one go, then your brakes have more time to cool in between but your average speed is also slower. In the absolute worst case (heavily overloaded/bad brakes/too steep) you stop almost all the way and your max safe speed is also pretty low. Make sure the periods of braking are much shorter than the periods of free-rolling.

If your rim brakes become too hot you risk melting the tube (or otherwise damaging the rim, but I suspect first to go would be the tube) and at least disc brakes also just stop braking at all once they are properly overheated (I can tell you from experience, this is no fun).

If the above technique doesn't suffice, then it's too steep and/or there is too much load on your bike for this gradient and you must periodically stop and let the brakes cool or just walk your bike down the hill.


Shimano 105 + Shimano Tiagra? I am looking to buy a new high end performance road bike soon along with a power meter. I'm looking at possibly a Shimano 105 or Tiagra groupset. However, stages doesn't make a power meter for Tiagra crank arms. Is it possible to ride with a Tiagra right drive side crank and a Shimano 105 left side crank? I know its a silly question and it probably wont work but all in the name of saving money!

Latest 105 and Tiagra iterations at this moment are 4700 and 5800. Both have same crankset design, so I don't see why left crankarm wouldn't be compatible. I'd figure you would be more concerned about color mismatch. There's also a slight weight difference, but I doubt most riders would notice it.


Tire size conversion from 700 x 23c A tire with the size of 700 x 23c, when changed to inches, what is the diameter and what is the width?

You're asking a question that cannot be answered.  Sorry - the plethora of tyre size measuring systems means there is no good answer.

Diameter could be 29 inches, it could be 28 inches, it could even be 27 inches.  But the bead seat IS 622 millimetres without exception.

The width likewise varies - there are fractional inch measurements that do not line up with the decimal inch of the same size - IE 1 1/2 inches is not the same width of tyre as 1.5 inches.  But 23mm is 23mm without exception.

This is why the ETRTO measurement system is simply superior to all that went before.  Not that its based on metric, but ETRTO is consistent and accurate.

A "700c" tyre in a width of 23 is a ETRTO measurement of 622-23, which is sometimes written as 23-622.

You might glean some more information from How do I know what size tyres can I fit on my rims? and from How do I determine my wheel size

Or consider asking about what you're trying to achieve - this sounds like an XY problem.


How much faster will I be if I lose 10kg (from 100kg, all else equal) All else being equal (power output, weather, wind resistance, etc.), how much faster will I be if I lose 10kg (going from 100kg to 90kg) while riding?

Acceleration and climbing might be much different, but while riding steadily on a flatish road outputting the same power as before, how will my cruising speed change ?

According to BikeCalculator, assuming you drop 10 kg while everything else remains the same (power output, etc.), you would travel 0.3 km/hr faster over a 50 km ride, on the average. In other words, at 100 kg, assuming an average power output of 150 Watts, you'd average 27.54 km/hr over a 50km ride if you weighed 100 kg; doing the same ride at the same 150 Watt average output, you'd average 27.84 km/hr if you weighed 90 kg. That's an increase of very slightly over 1% in speed.

Having just gone from 100 kg to just under 90 kg over the past couple of months, however, I'd say that BikeCalculator understates the practical impact of losing that kind of weight. Since climbing, in particular, is basically all about the power to weight ratio, I have certainly noticed how climbing has gotten easier and how I can go faster up various climbs, and I intend to drop another 9-10 kg. For example, if you ride on a mix of terrain, both flat and climbing, you will gain more than 1% in average speed. Assuming the same average power as above, here is how average speed will increase with a 10 kg weight loss for climbs of different slope.

Best of luck dropping the weight and keeping it off.


Broken pedal on an old french bike I broke the pedal of an old french bike (Peugeut Mixte 70's). The threading doesn't fit the one in modern pedals.

Now I am wondering if I should insist in finding an old french pedal or if I should rethread the pedal support in order to be able to use modern pedals.

Though, I am a bit scared about rethreading. Can it really be done safely? Is the space between threads the same? Has anyone here done this?

To quote Sheldon:

  Older French bicycles used a different, smaller diameter where the
  pedal screws into the crank, 14 mm x 1.25 mm.

  The vast majority of French bicycles imported into the U.S. used
  standard 9/16" x 20 tpi crank threading, but if you find an older
  bicycle that was bought in France, you may run into this problem. The
  French-thread cranks can be tapped out to 9/16". This is much easier
  (and more worth the trouble) with aluminum cranks. Start the taps from
  the inside of the cranks,so any possible thread damage occurs where it
  doesn't matter. French pedals will often be marked "G" (Gauche=left)
  and "D" (Droite=right).


How to remove clear coat drips? I have sanded, applied primer and then spraypainted my bicycle. Then I sprayed clear coat on it. This last step ruined my bike. The clear coat was dripping all over the bicycle frame.

How can I smooth this out? Could I use sandpaper with 1200 grit size and then reapply the clear coat on the sanded areas?

I rather not sand down the entire bike and start all over again starting with primer.

As per Daniels' suggestion try sanding the rough spots.Before repainting try to figure out what went wrong the first time,was it to humid outside,did the nozzle glog during application,did you apply it too thick?Painting round surfaces can be difficult.Try applying several light coats while allowing it to dry between applications,follow the instructions on the can for drying times.Practice your spray technique on some scrap pipe or backyard fence to get your arm movement consistant.Pay particular attention to complex areas like the bottom bracket area where many pieces and angles are involved,it may take several passes at odd angles to get complete coverage without runs and sags.


Bike lock for a Mountain bike with easily removable wheels I have a Trek 3500 that I need to lock up when I ride city trails, but I have been nervous as both of the wheels are incredibly easy to remove (flip a switch, rotate a lever a few times and they detach in seconds.)

I purchased a cable lock assuming it would be sufficient, but the more I read here about how easy cable locks are to remove I'm getting a little nervous as bike theft is a pretty big problem in my area.

Is a combination of a cable and a U-Lock the best? I purchased a decent (but not high end) cable lock, and I reviewed most of the suggestions for locks found in Best bike lock and the other threads. However the cost of a combination of these locks is around $120+.

In the end, its not the money (as having to buy a new bike obviously wouldn't be good), but is it worth it to invest so much into a combination of lock systems?

Perhaps you might swap your current quick-release skewers by one of the many "anti-theft" alternatives (listed in my perceived order of security):

Pitlock (www.pitlock.com): these require a special shaped key to open. You carry the keys with you, and no thief could take the wheel. Neither yourself if you lose the damn key;
Velo Orange anti-theft skewers: a 5mm allen bolt with a pin inside. Need a special 5mm allen key with a drilled tip, to open. VERY clever... No thief in the world would have this drilled key;
Gravity-activated skewers, like this one by Zéfal: there is some moving part inside the skewers acting as a lock on certain bike positions. When your bike is locked to something else, it cannot be turned upside down so it's impossible to take the wheels away;
"Numbered padlock" style skewer: these have those infamous numbered dials. You have to match a secret code to open the skewer. Although one can try to guess the number, there are 1000 combinations on the 3-digit models. Don't know how they react to weather and dirt, though...

There are a number of other alternatives. The main idea is to replace the quick-release skewers for some anti-theft ones, so the wheels (and maybe seatpost) don't need to be locked, only the bike frame.

Hope this helps.


Will a front wheel with 24 spokes be strong enough for a total load of ~100kg? I want to build a wheelset for my Adventure/Gravel Bike based on the DT Swiss GR 531. I want to use my SON Delux Dynamo Hub. Since it is for 24 Spokes I am thinking of mount the rear wheel with 28 straightpull and the front wheel with 24 non-straightpull Spokes. The bike is used during the for asphalt primary but also for bikepacking adventures in Iceland or Norway as well as gravel and forest rides at weekends.
My weight is 73 Kg. The bike will probably around 9.5 and I calculate 15 Kg of luggage and food.
Are 24/28 Spokes enough for what I want to do?

24/28 spoke count wheels with good quality rims and the correct spoke tension should work fine in this application as your total weight is well within spec for most wheels.  With lower spoke count the quality of the spokes and the spoke tension used will be more critical than in a higher spoke count wheel.  In terms of anecdotal experience, I have used good quality 24/24 spoke count wheels in bike packing scenario with little issues (I weigh an additional 5 kg to your quoted weights).

Lower spoke count wheels generally will run slightly higher spoke tensions than higher spoke count wheels.  Getting the exact right tension is a bit of "Goldilocks" scenario and I will often default to more experienced wheel builders for this key build parameter.  The build will be more sensitive to the evenness  in spoke tension as there are fewer overall spokes, so take your time during your build to ensure you have evenly tensioned the spokes.  If this is your first wheel build you may want to seek out a mentor to check your work.  For first builds it is hard to go wrong with 3-cross 32 spoke wheels.

Finally, I hope you consider butted spokes in your build as these tend to result in more robust wheel builds and are worth the extra cost.  As the rim deflects (e.g., hitting a hole), spokes can become de-tensioned which can let the nipple back-off changing the spoke tension and putting the wheel out of true. Butted spokes have more give/stretchiness to them than straight gauge spokes, so they tend to handle bigger rim deflections before de-tensioning the nipple.


Why should I use a mirror? In a comment to an answer about helmet replacement mention was made of a mirror and perhaps suggesting that a helmet was merely a good place to mount a mirror. I, hopefully humorously, suggested that a mirror user might not have much inside to need protection of a helmet ...

As someone who does a lot of miles and most of them in town, where seeing behind you is useful, I've never even considered a mirror. My preconception is that any mirror small enough to not be obtrusive or distracting would not be large enough to provide a decent view behind and, besides, I can look over my shoulder periodically and get a decent grasp for free.

So what am I not seeing; why should I use a mirror?

You should use a rearview mirror because:

It allows you to look behind you by moving just your eyes. This will help you not accidentally swerving into the traffic coming up behind you you're trying to get a look at.
You can (almost) look behind you and in front of you at the same time because it just takes a small eye movement rather than a huge head movement to go from looking ahead to looking behind and back.
It actually shows you a useful part of the road behind you despite the small size (try it)
All the other reasons I don't know about for which they are mandatory on motorized vehicles in (almost?) all countries all over the world.
They actually cost less than a good pair of socks.

You shouldn't use a rearview mirror because:

You'll look like a dork, same as with a helmet.
You're an experienced bicyclist and you know enough to stay out of danger
It'll add extra drag.
It'll add extra weight.
They cost more than a cup of coffee.
They'll screw with the sleek lines of you fixed gear machine.

I bought one after a few days of cycling in new zealand. Narrow roads, wide cattle and log trucks with sleepy drivers, some near misses, and constant warnings to be very afraid of drunk drivers made it an obvious choice. Especially because of the swerving point above, which seems aggravated when riding a bike with 20kg of luggage strapped to it uphill. I've used it on all my cycling holidays since.

Then again, I don't use a rearview mirror in city traffic in my hometown either.


What are the technical differences between a bike for off-road touring and a mountain bike? There are a lot of adventure touring bikes, or bikes designed for bikepacking, off-road touring and the like. But what is the difference between one of these and a standard mountain bike.  E.g. what is the difference between the Salsa Fargo frame and something like the Kona Explosif. Or what is the difference between the Thorn Nomad or Raven and an Orange P7. I understand that the touring frames are more likely to have rack eyelets, but what are the other differences in design?

Aside from touring specific braze-ons (rackss, fenders, spokes, pump, etc), the short answer is that adventure touring bikes are going to be more well suited as an all around machine where as an MTB has a narrower performance mark.

The long answer is frame geometry. Briefly looking at the geometry of some of the bikes you listed shows the Kona having shorter chainstays and a higher bottom bracket. In theory giving the bike better pedal clearance a shorter more responsive wheelbase. The Orange on the other hand has a lower BB and longer chainstays for increased stability and better heal clearance for rear panniers.

Frame geometry, however, is extremely subjective. Builders take a lot of things into account when making decisions. A lower bottom bracket for example decreases frame clearance but increases stability at higher speeds by lowering your center of gravity. One frame builder may value this decision higher than the other.


Chain get stuck on front sprocket during pedalling When pedalling the chain sometimes get stuck on the front sprocket. This happened after I cleaned the gears and replaced the chain. What could cause this?

The purple line is the chain. The circles are front and back sprockets.

You can see the chain in the bottom of the images following the sprocket back up during rotation.

One cause of this is chainring wear. The teeth become slightly hook shaped, which catches the chain rollers and pulls the links up around the chainring.

This will be exacerbated by introduction of a new chain. A worn chain gets slightly (in the order of 0.5 - 0.75%) elongated due to wear between the rivets and plates. The new chain, having slightly less distance between rollers is more prone to getting caught.

Look at you chainrings and look for signs of excessive wear, especially the one you use the most. Also look at the cassette sprockets, if you didn't change the cassette when you got a new chain.


torque wrench warm up procedure? Does anybody have a suggested "warm up" procedure for a small 1/4" drive torque wrench?  I've searched the internet and found surprisingly little on this topic.

Here is how I've been doing it so far:

1) Set the torque wrench to a setting at the bottom of its range, ex. if the torque wrench range is 2 Nm to 20 Nm, set it to, say, 3 Nm (it should go without saying that the wrench should have been stored at the min value on the scale, 2 Nm in our example).

2) Find a bolt that is at least substantially more, for example at least 5 Nm, and gently / smoothly turn the wrench on that bolt until it clicks (without the bolt moving of course, if it moves something is seriously wrong, have your torque wrench recalibrated or use a different one).  Alternatively you can put a bolt in a vise and click it on that.

3) Repeat perhaps 5 to 10 times, waiting a few seconds in-between each to allow the internal lube time to spread out.

Is this an acceptable warm up procedure for a small 1/4" drive torque wrench commonly used on bikes?  Does anybody have a different suggested procedure?

Some people claim that warming up a torque wrench necessary, but I've never seen it actually seen a manufacturer (Park Tool, Snap On, etc.) recommend a warm up procedure (*) so I don't see it as necessary.

I just use torque wrenches/keys directly. As Zinn notes (see for example, Appendix D of Zinn & the Art of Mountain Bike Maintenance 5e), you have a lot of things that can affect a torque reading:

Lubrication (or condition in general) of threads
Position of using the torque wrench, extenders, etc.
Choking up on the torque wrench (your hands will be more sensitive, and on many wrench designs it doesn't affect the reading)
Corrosion
Materials
Bolt turning vs starting from stuck (static vs kinetic friction)
Calibration (which can be thrown if you use it to loosen bolts or drop the wrench repeatedly or just through (ab)use)
Etc.

If you're working with carbon fiber or light weight materials, you have to be careful, but for most parts, its not the end of the world if you over/undertighten by a bit (though of course, its better to be at the right value). Having a sense of what the torques feel like is a good thing to have -- most people do just do these things by feel on normal grade parts. Using torque = arm length * force (assume force is applied perpendicular to the arm), you can get a rough sense of how much force you need. A liter of water has 1 kg mass, so its weight is about 10 Newtons. So, if you apply it at on an arm of about 20 cm (roughly the length of many small torque wrenches), you get a torque of 2 N-m.

(*) Life's full of these sort of things: For example, waiting for your car to warm up in winter before driving, rather than just driving gently after you turn it on.


Mechanical cable-actuated disc brakes started working really badly Currently I have a cyclocross bike with Tektro Lyra mechanical cable actuated disc brakes with 160mm wave rotors.

I have had issues with the brakes for some time now, mainly my fault, I accidently put some oil on the rear brakes so they almost stopped working (it was a while ago now). After properly cleaning them they seem to just slip so I ordered new brake pads.

The current problem is not the pads or oil; it's the actual cable and braking mechanism (in my opinion): when I try to brake, the cable and lever are not tight enough, but when I tighten them it becomes really hard to pull the lever. Then I checked the brakes, and compared to the front brakes, they do not 'restore' to same place - when I brake, the lever is hard to press, but then afterwards the cable does not go back to its initial place for some time. The front brakes are super easy to pull, brake fast and restore to initial position almost instantly.

What could this be? I know it's hard to explain, but it seems like the cable is moving back really slowly, and the mechanism in the rear brakes that is supposed to snap back is not as effective.

Should I just take the bike to be repaired?

My guess would be the cable is old. The inner cable begins to seize or bind with the outer cable. This could be caused by corrosion caused by water ingress over time or dirt ingress over time.

The binding basically causes more friction along the line of the cable - eventually preventing a smooth return to the "Off" position on the brake lever.

You can do a "bodge" and that would be to squirt something like WD40 down the cable line to free it up. But this is only a temporary fix.
The proper fix is to install some quality pre-lubed cables which are also weather sealed.

Incidentally, pads contaminated with oil can be cleaned by removing the pads and heating the pads over a flame to burn off the oil.


Investing into a fixed bike Well, two weeks ago I bought this fixed-gear bike and although it was my first time buying one of its kind, I considered it was cheap.

Problem here is that when I tried to search for any clue of the brand... oh surprise, there's no brand!

I was told that it was a pure cycle fixed bike, but I realized that it was painted over and the only thing that I have is a serial number that throws no information when I search it on the web.

Should I invest my money in add the front brake? And also all of the details that it has? (Bad paint job, change relatively new wheels, fight the rust that is forming in the gear?)

I paid $80 USD. And I bought it mostly because I wanted to have a fixed bike and to start learning to repair bikes. Could I sell it for more than the final price that will cost to me?

Yes, add the brake - as others have said, it might not be 'cool' but you'll end up being much more confident on it knowing you can stop it quickly. I also can't work out if you have foot retention or not from the picture, but even with a brake I'd highly recommend some kind of foot retention, and if you ride brakeless you are pretty much unable to stop at all without it.
If you like it and it fits, keep it. If you don't really like it, or it doesn't fit then it doesn't sound like you'll lose too much by selling it.

I'd get a brake on it and make sure it's serviceable then ride it for a while and see how you like it. Riding fixed takes some getting used to, so get some miles in before making your mind up!


Relative efficiency of different commute bike setups My interest is in long distance commuting (e.g. more than 50 km a day) and the relative efficiencies of different commute bike setups (e.g. drop bars vs flat bars, fenders vs no fenders, panniers vs backpack, etc).

As such, does anyone know if this type of information has been pulled together (e.g. magazine article, web page)?  I am looking for hard hard numbers (e.g. wattage or relative difference in wattage) that document real world differences associated with how one sets up their commute bike.

Why I even care

Background

Last year I had my commute bike stole. When I replaced it, I kept most of the build identical (e.g. drop bars, 2x racks, fenders, dynamo hub, disc brakes), except I also moved to an internal hub. When commuting distances, I notice this bike is slower.  On the top end I think I lose anywhere from 5 - 10 km/hr.  This bothered me so much I ended up building another commute bike, but went in the complete opposite direction (classic steel road, with low profile fenders and one low profile rack).  This second bike is so much faster I typically use it on club rides and put the carbon crew to shame.

While there is no question the second bike is more efficient (32 vs 42 km/hr top flatland cruising speed), the builds are also night and day apart so I am racking my brain to point the finger at the main culprits behind this efficiency difference.

Crazy Plan

If this type of info isn't out there, I would like to run a series of experiments to understand the differences.  I would have a designated time trial, record the power needed to cruise at a given set of speeds.  I would then slowly strip the bikes down and repeat.  The hope would be to determine the relative differences in efficiency different build decisions produce and by extension how much time difference there would be in a 50 km ride.

However before I start this, I would want to make sure this type of experiment hasn't been done before.

NOTE - There may be scepticism over how 'doable' this type of experiment is.  If the type of information I am looking for doesn't already exist and there is sufficient interest, I  am willing to draft up my planned methodology and post online for review (perhaps at a different and more appropriate venue).  I do have expertise in both statistics and experimental design so I believe I would be up to the task.

Jan Heine performed some wind tunnel tests of "Real World Aerodynamics" a few years ago. A link to a blog post (and the results published in Bicycle Quarterly) can be found here. Those tests cover only one component (the aero drag component) of commuter-type bicycles vs. "racing" bikes.

If you want to make your own apples-to-apples comparisons of performance potential between any number of bikes of any type there are five pieces of information you need to know:

how much power you produce on that particular bike;
how much (you and) the bike weighs;
the Crr for that bike;
your CdA on that bike; and
how much of your power is lost in the drivetrain.

With those five bits of information you can compare the performance of a road racer to a TT bike to a penny farthing to a velomobile to a MTB; on a hill, on the flat, on a descent, on a velodrome. Of course, those five variables won't tell you if the bike fits, or if it handles well, or if it has a way to carry your groceries and laptop and change of clothing, but as far as performance goes, that's all you need to know.

A good bathroom scale will help you measure 2). Since you have a power meter, there are field test methods and protocols that will help you determine 3) and 4).

1) explores whether you can produce more power on one bike than another, because of positioning (for example, many riders find they produce lower power in a TT position than in a traditional road racing position) or crank length or gearing (for example, some riders find they produce less power on a single-speed than on a multi-geared bike).

Finally, 5) measures losses in the drive train, such as in a fixed-gear or with an internally-geared hub like the Alfine. In general, measuring losses in the drive train can be expensive because you need a way to measure power at each end of the drive train. See Kyle and Berto here, for an example of a rig used to measure losses. A similar rig was used by Spicer here. However, if you have a crank-based power meter (and, if you're using an Alfine then I suspect you must), it is possible to use the crank-based power meter to measure power at one end of the drive train and then use "virtual elevation" methods to measure the power at the driving wheel. A detailed description of the protocol is long but a quick description is to climb the same hill on a calm day with different configurations. Since the hill is the same and the conditions are calm you know that the "virtual elevation" should match the true elevation profile of the hill; so if you can measure power at the crank then differences in observed VE must be the result of differences in losses in the drive train.


Good type of bike to get for commuting (thinking of road v touring) I'm new to this site but I've been intrigued by the thought of picking up cycling as a means of my new way of transport as well as for recreational purposes.

As a little background, I live in London and as a recent graduate, I do not have the widest of budgets but I would not mind spending at most £1000 for a bike (thank you cycle to work scheme.) I weigh around 63kg and I am a bit of a tiny man sizing up to around 165cm.

I had previously owned a mountain bike when I was younger, but I had recently purchased a second hand road bike for £60, which I have found an absolute joy to ride! My stamina/endurance isn't at the greatest yet, so I plan to stick with my road bike to practice and build up stamina, but I really want to find what might be the best bike for me in the long run. I do know that touring bikes would be great, especially since it can handle extra loads, which would be brilliant for shopping. But I am worried that the extra weight due to being a steel frame would highly impact my speed in the long run.

My current milestone goal is to be able to start cycling to work, though considering it's winter right now, I am aiming for this at around spring/summer. The reason I think the weight might come to play is because I will be traveling around 13 miles one way. Thus, if someone could enlighten me if the weight of a touring would heavily hamper my journey, I'd really appreciate it!

I digressed quite a bit but, in short if anyone could give me some advice on what would be a good choice of bike for commuting for me with drop handlebars (I've fallen in love with this form) I would really appreciate any of the expertise you can provide me!

If I haven't provided enough information, please just give me a shout and I'll get back as quick as I can.

There are a bunch of bikes sold in the UK that are specifically designed for the cycle-to-work scheme: they have good specs for commuting, are priced to come in under the £1000 limit, etc. A number of online vendors stock these. So that would be a good place to start. Or find someone selling one of those bikes used.

The additional weight of a steel bike is not that significant. Less than 1 kg. When you get done fitting mudguards, racks, lights, a toolkit, and whatever you're schlepping to work, you won't really notice the difference. That said, as Argenti points out, you'll probably be shopping for either steel or aluminum. They're both good options.

Also budget for the clothing and accessories you'll need to ride comfortably and safely. That would be a subject for another post entirely.


Sport Hybrids For Commuting and Exercise? Main Question: What should one look for on a sport hybrid if the primary use will be commuting and riding around 10 - 20 miles a day for exercise?

Motivation:  I was a resident of Chicago (which was absolutely beautiful for biking along the shore and such) and I had a 1977 Trek road bike that I loved.  Now I live around the New Orleans area and the roads are absolutely terrible to bike on; I have replaced tires, tubes, and rim tape a number of times, but it never quite works; it's getting to the point where I'm worried about going farther distances because I'd be stuck there if my tube popped (and this has, in fact, happened a few times...).  I went to my LBS and they told me that I should think about getting a sport hybrid --- and if this term is not standard, it seems like a hybrid which doesn't have shocks.

I am reluctant to buy one because I don't know all that much about bikes yet and I'm not sure what to look for in this type of bike; moreover, I am used to drop handlebars which are not standard in sport hybrids.  Does anyone have any experience with these kinds of bikes or from going from a road bike to a sport hybrid?  Are these kinds of bikes good for commuting to work ( < 5 miles) and for longer exercise rides (10 - 20 miles), or would a different bicycle be more fitted for these purposes?

If you're dealing with rough roads, a bike with slightly wider tires will be more comfortable, less likely to throw you with small obstacles/ruts, and probably have a wider selection of puncture-resistant tires.

Most road bikes are designed for very narrow tires and can't accomodate anything much wider. Narrow tires on rough roads are more likely to get caught on small ruts (etc).

You could always put the widest puncture resistant tires possible on your old road bike (maybe also a tire liner, puncture resistant tubes, etc) and pack a decent repair kit (2 tire levers, 1 tube, a few patches) into a seat bag.

I think the definition of a "sport hybrid" is fairly flexible (vague, inconsistent).  "Hybrid" almost always means a bike with flat handlebars (like a mountain bike), but with larger thin wheels like a typical road bike. A "sport" hybrid is one that's a little more geared for speed than comfort (possibly even the same as a "flat bar road bike"), so maybe has you leaned a bit more forward and has some higher end components and probably no suspension stuff.

For a less than 5 mile commute on relatively flat ground, any bike you like will do, as long as it's capable of carrying whatever you want to carry and ride comfortably over the roads. For your longer ride you're more likely to want the drop handlebars, mostly to have more positions for your hands, but also to go faster. You can add extensions or replace the bars on a flat-bar bike to get more hand positions, though.

For the somewhat longer rides, if you want to be able to go relatively fast and you have to deal with bad roads, I'd look at:

Sport hybrids
Cyclocross bikes (made for racing on mixed trails/mud/pavement)
Touring bikes (road bike designed for long trips in possibly terrible conditions. wide tires, tough frame)
"Commuter" bikes (hybrids optimized for commutes).
any number of more basic less specifically named "flat handlebar road bikes" or "hybrids"

For all of those, you're likely to want to replace the stock tires with something more puncture resistant (for the glass you don't see), and maybe have those be wider tires, too.

From your description of liking drop handlebars, I'm thinking a cyclocross bike might be the best option. Cyclocross frames tend to be very similar to road frames, but can handle wider tires. There's other less important differences that could be asked in another question. Probably won't come with handlebars as low as many modern road bikes, but that is likely to be fixable. The cheaper cyclocross bikes often have the stuff to make it easy to mount a rack and/or fenders, too.


Correct wheel size for a vintage Peugot I'm currently upgrading an old Peugot frame and I'm trying to buy the correct wheel size for the bike. This is actually my second attempt after selecting the incorrect size last year. The bike is old and uses cantilever brakes and i'm trying to identify the correct width, I'm 90% confident it will accept a 700c.

The big question I'm struggling to know is the width the wheels should be. I made a massive mistake and brought 700 by 13 - ridiculously thin. I'm know hearing anything between 19 and 27 but I'm not sure what to check so I can determine the correct size.

I'm also looking for a single gear.

Any ideas what the average wheel width should be for a vintage Peugot bike?

Here are some more details on the bike:

Estimated age: 70's
Type of bike: Racer
Photos attached.

A 70s Peugeot sold outside France probably used 27" wheels, not 700c wheels (though aside from the Velo Orange wheelset, you're probably going to have trouble finding 27" wheels and will have to try 700c wheels + a brake that fits it [an extra 4 mm adjustment is needed]).

The bigger issue is finding a wheel set which has hub spacing that fits this frame - likely 120mm in the back and possibly 96 mm in the front (or finding someone who is willing to cold set the frame+fork).


Replace / Repair Diamondback bike stem I have a Diamondback Edgewood 26" hybrid bike.  I believe it is a 2008 model.  Mostly it's a great bike and it certainly serves my needs right now.

However,  the stem has become loose so the handlebars pivot on about a 75° axis.  Thus, the only way to ride it is to tilt it forward so it is flat - definitely not the most comfortable position.

The top and bottom screws are adjustable, but they don't effect this aspect of control.  The side screws are what I need to adjust - 4mm hex screws on both sides - and completely stripped.  If they made a 4.25 - 4.5mm hex bit, I might be able to get it out, but I don't think so.  It's pretty rounded.

So I'm probably gonna have to drill them out, and my question is twofold:

Can I replace just the screws - if so, with what?  How to know correct measurements?
Or failing that, is the stem replaceable and where can I find the right one?  I looked around  online, but I couldn't find anything that I was confident would be an answer to my question.

From the information available your bike uses a 1-1/8" quill style adjustable stem. The only other pertinent  variable is handlebar diameter. While you most likely have 25.4mm (1 inch) bars you could have 31.8mm bars. Locating replacement bolts will likely be difficult as the pinch bolts of pivoting stems are typically brand specific in terms of length of the shoulder and diameter of the head.


What is the difference between Shimano BB71 and BB72 bottom brackets? I often see the Shimano BB71 and BB72 press fit bottom brackets listed on stores alongside one another, like here for example, so what's the difference?

Are they both the same geometrically? Is one a premium version over the other?

Additionally it appears my Giant TCR Advanced 2 2016 has a BB-71, though from an answer below it appears that's an MTB bottom bracket? How does that make sense?

From the very amazon.co.uk page you quoted:

  Hi, what is the difference between these 2 bottom brackets.i have a sm-bb7141 bottom bracket on my giant tcr composite 1 2013,not which 1 to buy

  Answer:
  The SMBB7241B comes with the 86mm sleeve interconnecting the bearing cups - this is suitable for BB86. The XT SMBB7141A has a 93mm sleeve suitable for MTB frames - I'm not entirely sure which standard this is.
  By Chris Gold on 13 February 2018

So, at least the width of the sleeve is different, and one is marketed for road bikes (hence the Ultegra branding), while another one is for MTB (hence the XT sticker).


Choice of spare tyre and tube in Europe for 40-559(ETRTO) or 26"X1.5 I am currently having tyre 40-559(ETRTO) or 26"X1.5 and tube picture. But I recently thought of buying a spare tube and tyre(available on some offer). However, I had a hard time in matching it with my current tyre dimensions.

Tube on offer: HUTCHINSON 650x28-42 A/B (26x1"1/4 / 1"3/8)
(ETRTO 28/42 - 571/584)

And a tyre also on offer:

VTC 37-590 1 26x1-3/8 650x35A HS348

As I am new please forgive me for the obvious or senseless questions. But I didn't seem to get help from the shops or Google search.

40-559 is the number to match. For tubes, the ETRTO number is a range of fitting tire sizes. For complete explanation, see http://www.sheldonbrown.com/tire-sizing.html

EDIT: This answer originally hinted that 37-590 would be correct. It isn't, 559 is the rim diameter and it must match.


How to replace a wheel Spoke One of the spokes of the front wheel of my bicycle is removed and this really affected the alignment, How can I replace it and make the wheel balanced back, or do I have to replace the whole wheel?

Thanks

You don't need a new wheel, and the repair is cheap if you have the correct tools.

Here's a guide if you want to try it yourself, or I reckon it would cost 0.5 - 1hr labour at a bike shop (plus the price of a single spoke).

edit - just read that it's the front wheel, which makes things easier still. No need to remove any cassettes!


I'd like to fit a suspension seatpost but have only 9 cm between saddle and frame - is this enough? I'm 5'3" tall and ride an XS size gravel bike. I have only 9 cm of seatpost between the saddle and the frame, and you can see there's no possibility of extending that! I find the aluminium frame quite harsh and would like to swap my normal seatpost for a suspension one. Is 9 cm enough room for this to work?

As Daniel R Hicks says, it depends on the seatpost.
There are some seatposts that offer "passive" suspension—they have no suspension mechanism, and rely on the flexibility engineered into the seatpost's materials (always carbon fiber, AFAICT). From what I've read, these don't do much good. The suspension effect with these will depend on the amount of seatpost sticking out (more material to flex), so even if they do work, they won't work as well for you.
There are a few "active" seatposts that do have suspension mechanisms. Cane Creek has one where the mechanism occupies 70 mm of seatpost length, so that should fit. Redshift sells one that is bang-on at 90 mm maximum insertion depth.


Passing cars on the right, and later merging into their lane My commute takes me along a fairly busy road, with 4 lanes of traffic and parked cars along most of it. There are no bike lanes, but in some places, it's wide enough that I can easily pass traffic on the right (which is legal in my state, as far as I can tell), and in some places, there's actually a whole extra lane on the right for a block or two. However, the conditions change from block to block. On some of the blocks, there is not enough room to pass safely on the right of cars, and there are some places where the extra lane on the right no longer exists across the intersection or is filled with parked cars.

There are several times when I've passed cars on the right, either in a full lane or in the room between a lane of stopped cars and parked cars, and then realized after crossing through the next intersection that I need to merge back into the next lane. What is the etiquette of merging back into the next lane in such circumstances?

There are a few possibilities that I've tried, and all of them seem unsatisfying in certain ways.

Continue to travel in the lane that will run out until it actually does, then stop and wait for a gap in the traffic before merging in. That can sometimes require stopping and waiting for quite a while, due to busy traffic.
Signal to the left in advance of running out of the lane, check for a reasonable gap in the cars while still moving, and merge into that gap once I've determined it's safe, or fall back to the first option if that doesn't work. The problem is, this requires a good deal of judgement to tell when there's a good enough gap in traffic to merge back in, I can only glance back quickly and not make good eye contact with drivers in the lane I'm merging into since I need to be paying attention to what's ahead of me as well, and I'm not sure if I'm cutting people off too closely.
Pass the cars on the right, then pull up in front of them at a stop light so I can take the lane when it turns green. This makes me feel like a jerk, like I'm cutting in line.
Simply stay in, and take, the lane that doesn't keep disappearing. This is what I would do if I were driving a car. The problems are that I get stuck in stop-and-go traffic which slows me down, I have to breathe in the smog of trucks and busses in front of me as I wait, and I hold up somewhat more traffic as I don't take several of the block-long opportunities to make it easy for cars to pass me.
Run red lights. This way, I can actually get into the lane I need to before I have to contend with cars. The disadvantage is, of course, that I'm running red lights.

Seems to me that your best option is choice 2: Signal to the left in advance of running out of the lane, check for a reasonable gap in the cars while still moving, and merge into that gap once you've determined that it's safe.

In that option you are essentially behaving like exactly what you are - a slow moving vehicle.  Your behavior is like what you would expect if you were operating a tractor, or a horse-drawn carriage.  You operate in the lane when neccessary, move over to the right to allow others to pass when safe and convenient, and carefully merge back into the traffic lane when the shoulder is no longer safe.

While doing this you want to avoid weaving in and out of traffic every few feet.

This is also similar and predictable behavior much like what you need to do when the shoulder runs out as a right-turn only lane blocks your path.

Option 1 is unsatisfactory because you lose momentum and will have a difficult time merging.

Option 3 is a poor choice, not from the issue of passing cars on the right (which while legal in many areas, is dangerous), but because it's rude and then forces cars to pass you later - playing leapfrog.

Option 4 is a possibility, but then again, think about operating a 'slow moving vehicle.'  If you are consistently the same speed as motorists, you may stay in the lane, particularly if the shoulder is unsafe, otherwise, move over and let them pass.

Option 5 is the poorest choice.  You may be able to cross against the light safely, but not only is it risky, it makes you a poor ambassador of cycling, causing motorists to be angry at other cyclist, and frequently puts you back in the leapfrog situation.  Plus, you could get a ticket, at least in my town.


How long will I survive? 5 wheel spokes missing What do you think, guys? Or should not I try it at all?

Nope. Don't ride it. It's hosed. You risk catastrophic failure riding this wheel, Other spokes will snap soon due to more load put on them and uneven tension. That is if it's even true enough to not rub the brakes or chainstays.

You could replace the broken spokes and have a working wheel if your rim wasn't damaged severly like it appears to be. If you've rode on this for a while, there is a chance that the existing spokes are over stressed and should be replaced as well. I would rebuild the wheel with new spokes and rim if it was my bike.


Looking for a good mountain bike for my daugher. Want disc brakes and Fork lockout My daughter is a teenager and we love going biking, either on trails or during camping trips.  We are not hard core bikers, but she is ready for a bike upgrade as she is using a 20" wheel bike right now.
I am looking to buy her a bike that will last her a long time.
Looking for
a) Aluminum frame for someone 5' 5"
b) 26 or 27.5 inch wheels
c) disc brakes,
d) fork lockouts
e) women geometry (she likes girl colors like pink, teal, purple etc)
Can you recommend a decent brand/bike that won't be above $600 ?  I've seen Motobecane and Liv online, but am not sure these are good brands.
Thanks so much.

We generally don't do shopping questions as they get outdated quickly, but I'll post some general guidelines for shopping.
Just about any major brand sold by your local bike store will be of comparable quality within the same price range. Trek, Specialized, Cannondale, Scott, etc. Be careful of online brands as they can be fine but are much more willing to skimp out on certain components to meet a price that they don't think people will notice like lower end brakes or derailleurs.
Don't buy a big box store bike from Walmart etc. Especially because your budget is higher, no user even looking at these bikes.
For tire size I would recommend 26 inch at your price. I recently got a 650b bike and they are still kind of niche, making even things like tubes difficult to find. Maybe that's just the pandemic and lower supplies overall though.
At her height she is definitely ready for an adult size bike, but one of the smaller sizes available.
I would recommend going down to the local bike shops, or calling them up if they aren't open for in person shopping, and explaining what you are looking for. They will be able to ensure that you get a bike of the right size that suits your riding. Call up a bunch of different places just to make sure you aren't getting a bad deal.
Supplies are quite low right now, so I would suggest you get shopping if you want something in time for the spring.


How worn is this chainring? I have the chainring shown below. It's the front sprocket of an ebike. Does this chainring need replacing or are the teeth still OK?

Shows some wear, but looks OK.

All teeth look symmetrical and so do the spaces between them. Really worn teeth look like a swept back shark dorsal fin or develop a visible burr.

Do a Google image search for 'worn chainring teeth' and you'll get plenty of examples.


Puncture in tube with sealant Had a thorn in my tyre last night, the tube has sealant in it, which worked.
How long is it likely to last, or should I change/repair the tube as soon as possible.
28 mm almost slick tyres running with 110 psi.

To clarify, the tyre has an innertube that came with sealant already inside the tube. I removed the thorn and the hole sealed, it is still holding pressure. The recommended pressure for the tyre is up to 120 psi.

Hypothetically yes, it will last a while - if a sealant is used in a tube and the tire subsequently gets a puncture, you must remove the penetrating object or it will flex in the tire, continually un-sealing the hole and shredding the tube.

If you believe you completely removed whatever caused the puncture and the sealant plugged the hole and you were able to continue your ride, that's great!

Some steps to further make sure the sealant will hold for future use:

If significant sealant was lost during the puncture and you have a removable valve core, add more sealant.
If you are truly concerned if the tube will stay plugged you can add glitter through the valve core. This helps plug holes, especially depending on the type of sealant you are using.
Reattach the valve core and inflate the tire.
Spin the wheel to mimic the motion of rolling down the road.

Given enough time, most sealants cease to be active and should be cleaned out; if they solidify, they unbalance the tire with useless weight concentrated in a single spot. On a tire with an inner tube, including a tubular, you’ll need to remove the sealant through the valve, which requires removing the valve core, and ideally rinsing and sucking it out. That is a lot of work if it is a tube in a clincher wheel. So you could always deflate the tire, remove the tube and insert a brand new tube and repeat the steps listed above.


Broken bearing cover near stem I have a small issue with a bearing cover/seal (not sure how it's called properly) that I would like to fix.
I'm attaching the picture for clarity.
I imagine I should just replace the part but I have no idea how to go about looking for it. It's an old Bianchi racing bike.

You have the sort of headset where the adjustable race consists of a plastic shield fixed to a steel piece that has the bearing surface and the wrench flats. I think it might be a Shimano Exage Sport.

If you have access to the sort of used bike/parts shop that has bins of old stray headset parts, you might be able to find a replacement. But what you've got has never been super common and even then it's only one model, so you might be looking for a while. On the plus side, uppers tend to die last, so you might be able to find an orphaned one someone squirreled away.

Printing a replacement would be pretty reasonable here too, if you're into that kind of thing. You could saw it in half through the the middle to get the cross section and then lay that on a scanner, and from there make up a new plastic seal part in Fusion 360 or whatever you like and snap it onto the existing bearing race part.

Probably the most reasonable thing is to just replace the headset, or even just the upper.


Niner Biocnetric Compatibility Have an older Niner Air 9 Carbon that has the original Biocentric eccentric hub.
Does anyone know if the Biocentric II is compatible?

I stopped by the local Niner shop and they told me the II is compatible


Crankshaft snags and loses resistance while cycling I have a hybrid (18+ years old) that I use for daily commuting which has developed a problem with the cranks. Every so often (perhaps 10% of the time) when I push down on either crank arm after free-wheeling, there is the sound of the cranks snagging/grinding on something internally, which can sometimes be felt through the pedals. The cranks then momentarily lose resistance and stop driving. This usually corrects itself within another complete 1-2 revolutions of the cranks (leading to further sounds of grinding metal), after which resistance is restored.

I'm not sure whether it's relevant but I recently had the pedals replaced on the bike, and the mechanic mentioned they were hard to remove. The cranks seemed to be fine before having the pedals replaced (no problems or noises). The bike also used to make a quiet "tick-tick-tick" sound when free-wheeled, but I've noticed this has stopped completely.

I suspect the bottom bracket needs replacing (the last time would be years ago, if ever), and we've had lots of rain recently so maybe some water found its way in.  Everything else (chain, gears, pedals, etc.) are fine.

Are these symptoms consistent with bottom bracket failure, or something else?  Does this explain why the "tick-tick-tick" sound has stopped?

Thanks.

It's not the cranks or bottom bracket (though it sounds like the BB might need replacing anyway) if the chain is moving normally.  The crank is fixed to the chain rings with bolts, so that can't slip.

It's much more likely that the ratchet mechanism in the rear hub is broken.  Older ones work on 2-4 small spring loaded "palls" that engage a ramped gear.  If the springs or the palls themselves rust and break, then the hub will no longer engage and you'll get that "no resistance" feeling.  The grinding you are feeling is probably bits of pall, spring, freehub body and possibly bearing moving around in the rear hub.  The lack of "tick-tick-tick" is because those palls are not being clicked into the gear by their springs.

Unfortunately, this probably means a new rear wheel.  The freehub body is probably ground down into pieces, and those pieces will have damaged the inside of the hub itself.   Technically, you could buy a new hub, and get your bike shop to lace that onto the existing rim, but it will probably be cheaper to just buy a whole rear wheel.


Is the KMC X8 a better quality option for an 8 speeds chain? I sell a lot of SRAM PC830 chains that I buy in bulk.
The KMC X8 has, I think, nickel plated outer links.
Other than that, it claims to have mushroomed rivets and the X-Bridge outer plate.
Does that make it a better quality or more durable chain?
I'm looking for a better or more durable 8 speeds option for my customers, but even the KMC websites won't confirm if the outer links are nickel plated or not.
Thank you.

The KMC X8 has, I think, nickel plated outer links.

Doesn't matter except for looks. The plating of outer links is not what wears in chains.

Other than that, it claims to have mushroomed rivets

Every chain today has "mushroomed" rivets. These rivets prevent joining the chain again with its own rivets, a clear drawback. However, they make shifting possible under load. You don't need to shift under load on bikes powered by human power only, but for e-bikes the mid-drive doesn't turn off the torque quickly enough when you stop pedaling, so shifting under load is something that is unavoidable. So you want "mushroomed" rivets on e-bikes. On non-e-bikes, you probably won't want "mushroomed" rivets so you can re-join the chain again using its own rivets, but oops, "mushroomed" rivets are only type of rivets you can find.
Fortunately, Shimano has solved the rivet issue with reinforced rivets that are single use only. They allow you to break and re-connect the chain over 100 times (assuming the chain is over 100 links long). It costs some amount of money to buy enough of these reinforced rivets for your emergency toolkit, but they weigh next to nothing.
With other makes than Shimano, you can only use "quick" links, a misnomer since they should be called "slow" links instead. The reason is that although a joining link of this type is quick to be installed, and quick to be removed from a chain that is clean, if you go out and actually ride your bike the chain becomes dirty and the dirt makes joining link removal so difficult that it's almost impossible without special pliers.
Because Shimano allows you to use reinforced rivets, whereas other makes demand you to use these "slow" links, I recommend Shimano chains. A mini chain tool is smaller and lighter weight than joining link pliers. Besides, a chain tool is something you in every case need because you need to shorten the chain to its proper length prior to installation, so you can't omit owning a chain tool. But you can omit owning joining link pliers.

and the X-Bridge outer plate.

Nothing in the outer plate affects the property of interest, how fast the chain wears. Only the half-bushings that are integral to the inner plates, and the chain rivet, affect chain durability. So you are definitely interested in the quality of steel used in inner plates and rivets, but the quality of steel used in outer plates doesn't matter.

Does that make it a better quality or more durable chain?

No, not any more durable.
Focus on the quality of steel on rivets and inner plates. The steel should be chrome hardened. That makes the chain much more wear resistant.


What weather conditions are slicks suitable for? I currently use 700x25 slicks on my commuting bike, to get the easiest ride possible.

I also own:

700x28 with some tread
700x35 metal studded snow tires (Purchased last year for UK snow)

Ideally I'd prefer to keep the slicks on all year round, as they give the easiest ride. However when conditions require it, I'll change tires.

So my question revolves around what weather conditions slicks are acceptable in:

Heavy rain?
Snow?
Ice?
Other...

Bike tires are treaded to grab on customers rather than the road. Obviously, different tread patterns will perform differently off road, that is: on earth, mud, gravel, sand, roots..

BUT - contrary to popular belief - on the road, whether it is concrete, tarmac or asphalt, treads will do nothing except offer a slightly slower ride and at the same time, less grip on the surface.

On car tires treads have one main function, and that is to channel away water to allow most rubber possible to be in contact with the road. Because of the broad square profile of the car tire, at higher speeds water is 'caught' by the tire too fast for it to escape to the sides, causing the tire to'float' on the water - hydroplaning. Good tread patterns can reduce this effect dramatically.
A secondary function of treaded tires - at least for most of us who seldom leave the tarmac/concrete - is of(f) course better traction on soft surfaces.
On dry tarmac/concrete treads have no effect at all, other than reducing the contact with the surface. In other words, treading will increase contact with surface driving through a puddle of rainwater, but decrease contact under dry conditions. The treaded tire is a compromise.

If you only own one bike with one set of wheels and you ride this bike year in and out, both on and off the road, then you would need to compromise too. But many of us sports more than one bike; we grab our MTB for trekking and reach for our roadbike/hybrid/city commuter when we're on those hard, smoother surfaces. In the latter case a treaded tire has no positive effect what so ever - even if it rains. Here's why:

Hydroplaning on a bike is virtually impossible. Because of the bike tires narrow rounded profile, water is lead to the sides (like a boat cutting through water), ensuring sufficient contact with the ground.

Then what about the wet surfaces? Those slippery curbstones, road paint, manhole covers? Won't treaded tires help at all? Apart from the placebo effect for some riders, the simple answer - backed by physics - is no. Basically, if the treaded pattern don't leave an impression on the surface, it cannot have any effect in regards to traction. You might add water or oil, still those treads will not help you. The same goes for ice. In fact, the only situation where a (heavily) treaded tire will give you better traction within the city limits might be on some types of snow.

All experiments on traction supports this fact and all tire developers know this, yet when you enter a bike store to buy a set of new tires for your hybrid, you are offered treaded tires over slicks in a ratio of 20:1. Why?
1. because the customer believes in treaded traction
2. the shop owner also believes this
3. the customer wants to chose between different products, and choosing between 20 different types of slicks doesn't seem to be much of a choice.
4. the customer wants something new and improved, and 'hey, you had 20 different types of slicks when I was here last'
5. the tire producers know their customers and to keep them buying their stuff - they offer  "something new and improved". They of course know that less costy than actually researching and developing new stuff, is making slight cosmetic changes to existing designs. Thread patterns in road bike tires most definitely belongs to the department of cosmetics.

So, does that mean that any (no-)treaded tire will do? Well, certainly not! Tire profile, thick vs. thin walls, type of rubber compound - there are many factors that will affect grip and traction, tread not being one of them. Also how much air you pump into a tire will affect this.

For those below zero winter days with ice and snow, however, a set of slicks is not recommended. But that also goes for the other regular threaded tires. The only remedy for icy roads are tires with steel/metal spikes. Unfortunately - these tires suck at anything other than icy/snowy conditions. If you live in a part of the world with cold winters, the best thing to do is loading a second pair of wheels with spiked tires, like Schwalbe Ice Spiker or Nokian Extreme, and swapping wheels when the conditions call for it.

I ride my bike(s) to work and for fun. I have a cheap, old "winter bike" for those to-and-from-work snowy days, but my other two tarmac/concrete/asphalt bikes - an old Colnago and a C.dale Bad Boy never wear anything but slicks. Infact, within city limits, I have used slicks only since the mid '90s. Yesterday I received a new pair of Schwalbe Kojak's (26/fat) for my Bad Boy = full control, come rain or shine.


Is it difficult to do a post-break-in wheel tune-up? I've heard that when you get new wheels you should put a couple hundred miles on them to let everything get set in and get an initial stretch, then do a tune up.

Can I just go by feel and tighten the spokes that seem a litte lose?  I don't think the wheels are untrue, they're heavy duty wheels.  Are there any tricks to this initial tune up?

As has been mentioned in the comments, you should take it to a shop. You're likely to do more harm than good if you're not already experienced in at least truing and preferably building wheels.

It also might not even take a couple hundred miles. I'd probably check on it once a week or even every couple days. Feel the spokes. Once it gets to a point where there are notable differences in tension, go ahead and take it in.


Huffy cranbrook popping I have the huffy cranbrook bike I just bought for my daughter she loves the bike but it makes that popping sound. How can I fix it??

I have tried tightening the chain.

Going out on a limb, my guess is that the chain is too tight.

I've seen (heard) this issue on many bikes like this. On about 98% of big box store bicycles are sold with all the bearings and the chain too tight and the tires too low on air.

How tight should it be?:

  The chain slack on a bicycle ... is quite critical, and is regulated by moving the rear axle back and forth in the forkends. ... The chain should be tight as it can be without binding. If the chain is too loose, it can fall off

Later in the article:

  When adjusting the chain, you need to be able to turn the cranks. With a fixed gear or coaster brake, the rear wheel has to be off the ground. Keep your fingers away from the sprockets: the momentum of the rear wheel can crush a finger caught between a sprocket and the chain.
  Sheldon Brown, Minimizing Chain Slack

Assuming the chain is too tight you'll want to loosen the chain just enough to make the popping stop.

Loosen the chain side axle nut and push the tire to the side so that the chain is gains a little slack.
Snug the chain side axle nut up enough to hold (it does not have to be fully tightened yet) and test chain tension by pedaling (watch your fingers!) and listen for popping.

If the popping is gone tighten the chain side axle nut fully. If not repeat steps 1 and 2

After adjusting chain tension the wheel may not be in the center of the frame.

Loosen the non-chain side axle nut and center the wheel in the frame.
Tighten the non-chain side axle nut fully.

If the chain is not the cause of the popping sound no amount of loosening will make the popping go away.
What ever it turns out to be riding enjoyment and bike lifespan will be maximized if you have someone with some knowledge of bikes check it over from end to end.


What parameters are important when replacing a rear hub? My rear hub is damaged. I have not yet inspected the source of the damage, but the wheel is moving sideways when rotating (a LOT), plus I rode it like this for about 35km. Therefore, I find it probable to soon need to replace the hub.

The rim and spokes are new (couple of months of commuting). I suppose I wouldn't be running in the "old spokes new hub" problem.

The old hub has 24 spokes. The disc rotor is attacked via 6 bolts.

What else should I know in order to judge if a specific hub will be a compatible swap (beyond that getting the exact same hub should work okay).

You need the:

right width to match the dropouts you are fitting the wheel to (135 mm for rear hubs, 100mm for front typically).
same number of spokes as the rim you intend to use.
the right brake rotor mounting (center lock or 6 bolt).
the right axle width, diameter and fastening for the dropout (bolt thru, butted axle, quick release or thru axle (eg. maxle / maxle lite).

Putting the wheel together is a whole different matter, and there are tons of questions on wheel building here as well as entire books (like Brandt's The Bicycle Wheel).

As for 24 spokes, I'm not sure I'd be comfortable with a 24 spoke wheel in most cases.


How do you protect your bike from scratches? Anyone here use protective tape to protect a new frame? To which areas do you apply the tape?  I have a new frame and I am worried that other bikes sharing bike racks will scratch my ride.

I use helicopter tape. You can find it on Amazon or from most any race car supply shop. It's a little pricey but well worth it. It's very sticky and thick enough to absorb impacts from rocks. I use it on the bottom side of my downtube, on the drive side chain stay, and anywhere a cable is close to the frame.


Should I use lights in foggy conditions? Today it was foggy, visibility was only slightly reduced, I already wear a high-vis on my bike but I am wondering if it is still worth me using my lights or is that overkill?

I definitely recommend this. Running lights will make you more readily visible as the light will penetrate the fog to an extent.  Reflectors and high-viz clothing will be somewhat less effective during foggy conditions.  Use caution riding in foggy conditions as drivers may not see you until they are very close.


Replacing Bontrager Race Lite Freehub I had excessive play between my cassette cogs, taking the cassette off revealed that the splines are quite chattered up and I believe this is the source of the play.

I've ordered a new freehub from the Trek dealer (W431450), but for the life of me I can't seem to get the old one off. If I understand correctly, there's "cap" that should come off first (that the thru axle goes through) and then the freehub should pull off easily.

I can't get the cap off and I can't pull the freehub off.

I've tried tapping lightly on the outside of the cap to try and provide a little percussion to break it free, and I've also tried that on the freehub, but no luck. I also (maybe stupidly) tried to use some pliers with a bit of rubber tubing to keep the pliers from scoring the cap, but that also didn't work.

Any suggestions? Thanks in advance!!

Side rant: Why is it so hard to figure out these part numbers? I can't find a comprehensive part listing for my bike (2019 model). The part number on the hub takes me to random cookie-cutter webpages from different bike stores that look like they're all using the same Trek backend? To figure out this freehub part number, I had to call the Trek store and have them look at some system they have. If I look up the wheels, the wheel info page doesn't have any information on the freehub either. Very frustrating.

It's hard to know exactly why that cap is so well stuck on, but you are right, it should pop of with a good firm tug. I believe there is a rubber O-ring that keeps it on. I have a DT-Swiss wheel that uses a similar cap, and when mine was stuck on like this,
soapy water helped me. I diluted some dish soap and poured a tad all around the cap and it popped right off. If you have an axle vise or a large drill chuck that might help you grab onto that thing to give it a good pull.


Rear hub bearing replacement Bike noob here.

I have a Quando rear hub with a busted cap?  By cap I mean the cap covering the bearings beneath the cone.

This cap is separate from the bearings.  It hold the balls in place.  Is it possible to replace this with a Sealed Bearing.  If not, am I able to purchase just the cap or must I replace the entire hub?

I can post some pictures if this isn't descriptive enough.

Summary: buying just the dust-cap is unlikely, normally you buy new cones and often a new axle, but that's because new cones are cheap. You'd only buy a new hub if something else is damaged (rare). You won't be able to fit sealed bearings.

I the picture below from the Park site is the bearing cone and cap. I assume that's the cap you're talking about?

That cap is just a dust/dirt shield and you can run without it (as you possibly have been doing) but that will shorten the life of the bearings.

Normally a bike shop will replace the bearings and cones shown at the same time, leaving the cups in the hub alone (except for cleaning). Few hubs have replaceable cups. Some shops will only stock complete axles with cones as the axle is a cheap part and it's easier to have a known-good axle every time (they sometimes bend just a little, enough to wear out bearings fast but not enough to see unless you roll the axle on a dead flat surface). Other shops stock a bunch of cones separately, but have to keep them carefully arranged in pairs since you almost never replace just one cone, and it's annoying to have to sort through the pile looking for an exact match. Another reason to use axles to hold them together :)

You won't be able to put sealed bearings into a hub not designed for them, the recess that the bearings sit is is different (one has a bearing cup, the other a cylindrical recess for a sealed bearing). If you had a lathe you might be able to cut the cups out... but it'd still be cheaper to just buy a new hub. You could possible bodge in sealed bearings buy just sliding them along the axle until they hit the cups and buying the right size to fit inside the recess in the hub, but you wouldn't get much overlap there so you'd probably break the hub in short order.


Does inseam of pants convert to stand over height of a bike? If I know my jeans size, for instance 32", 32", can I convert this into an estimate for standover height on a bike?

This might not be a very good place to start from when sizing a bicycle.  Your inseam measurement is from the top of the crotch (top inseam point) to the BOTTOM SIDE OF THE ANKLE (lowest inseam point).  Your feet go all the way to the floor.

Inseam is specifically to determine what pants you wear.  I might point out that pants and bicycles are made and sized quite differently.

As @darkcanuck suggested, you're better served to stop by a local bike shop (LBS) and have them size you.  Most LBS sales people will be more than happy to put you on a couple of bikes and let you take a test ride, even if you say, "I don't plan to buy anything today, I'm just starting to shop around."  It won't cost you anything and you'll start to get a feel for how different styles of bikes feel in different sizes.

Note also that standover is not the only measure you need to size your bike.  The TOP TUBE length will also come into play--depending on how long your arms and torso are.  Different manufacturers build different bikes with different ratios of top-tube-to-stand-over.

Depending on the bike, you will also want to consider handle-bar width, crank-arm length, etc.  Don't plan to buy a bike off of the internet because it has the right stand-over!  At least, don't be surprised if you do so and then it doesn't feel right.

Try out several actual bikes--even if they aren't ones you plan to actually buy--so you know how those different geometries feel when you're riding.

AND IF YOU'RE LOOKING AT A USED BIKE... it still pays to try out some new ones and know what geometry suits you.  When you are negotiating with a seller of a used bike, show up with tape measure in hand!


Are these Giant bikes fake? There's a second hand bike I'm looking at. Photos are here: Giant defy 1 2017.
The seller says it's a giant defy 1 2017, purchased last year. I noticed the stem says something like raceface which suggests to me that it's been replaced.
I found another similar looking one where the seller says it's a Giant defy 1 2016 model. Photos are at: Giant defy 1 2016
I haven't been able to find the exact same model on the giant website.
Can anyone identify  what model is this bike? Or is it a fake?

The paint scheme looks like that of the 2009 Giant Defy Advanced 1
Check out https://www.bicyclebluebook.com/value-guide/product/3050124/
bikepedia.com and bicylebluebook.com have lots of info on bikes by year and model.
Here's the 2010 Giant Defy 1, which again looks very similar, with a few minor differences in the paint scheme: https://www.bicyclebluebook.com/value-guide/product/19422/


Experience biking with child trailer during winter? What's your experience biking with child trailer during winter in the city?

I live in Cracow, Poland. Recent winters were almost snow-less, but it's <0°C cold and slippery anyway.

I am used to biking alone but never hauled 60kg behind me on a slippery road. Here are few things I am interested in:

Tires on bike and trailer. I have Croozer 2 seater with whatever funky tires it came with. My bike is a folding electric city bike with nice Schwalbe Big Apple 20" tires.
Mud/dirt. My Croozer came without any fenders. It get's dirty even during summer.
Kids' clothes. It was 15°C recently and I closed the translucent "window" in the front of the trailer. When I put my hand inside after few minutes of biking it was really nice inside. Boys confirmed but they have a history of lying.
(bonus) Electric 20" wheel in the back. This will be interesting :)

Updated with bike details. It’s chinesium bike branded EcoBike in Poland. They probably sell under a different brand in other countries.

I strongly suggest you put a studded tyre on the bike (ideally 2, but certainly the back in your case).  I run Schwalbe winters for occasional icy patches (overkill round here, except when they aren't).  This will be important for stopping as well as going. Spinning the back wheel with a trailer is no fun.  The trailer tyres don't matter nearly so much.  They don't really need traction (though side-slipping isn't good). You can get marathon winter tyres in 20×1.6" which will fit both your bike and your trailer.

The trailer will get cold inside in sub-zero temperatures.  But it will do a good job of keeping the wind off, so your kids should be fine wrapped up warm.  Makes sure the to start with short journeys, as you won't be able to hear the kids easily (especially if you fit studded tyres) and you want to know before too long if they get cold. I know on a rear seat even above 0°C kids can get quite cold despite gloves and warm clothes, but that's only sheltered by my body.  Some form of hat or even a (thin) balaclava under their helmets would be a good idea.  Lining the seat with a blanket you can tuck round them might also be good if you've got room.

Visibility is important, including visual signs of the width of the trailer. Drivers need all the help they can get to see your trailer in dirty, dark conditions.  Little blinking LEDs as wide as possible on the trailer frame show up well.  I've got 2 of those plus a big steady rear light, as well as extra reflectors and lights on the wheels.  And that's just on the trailer.

Bikes and accessories get dirty in winter.  Mudguards won't help much on somethign so low to the ground, and every trailer is different when it comes to fitting accessories (as I found when fitting parking brakes to mine).  Folding makes accessories really tricky. Overall you'd almost certainly have to make mudguard brackets of some sort, and remove them for folding.  A rear mudguard on the bike would be a very good idea though, and one with a low, soft mudflap on the bottom.


How can I undo the locknut on this Shimano 105 hub I'm having trouble working out how to properly service this Shimano 105 rear hub. I've watched some videos, read Leonard Zinn's book and following Park Tools' instructions, but it doesn't help.

I've got a 15mm cone spanner around the cone (I think that's the part in the picture), but there are no flats of any size on the locknut.

I got some vise-grip pliers and managed to get it undone, but there must be an easier way!

OK, I eventually worked out the easier way.

The locknut has a hole in the end which, in addition to taking the skewer when fitted, has a hex socket for a 5mm allen key. Turn the hex/allen key anti-clockwise relative to the cone spanner to undo.


Can i use a thinner standard mtb chain (SRAM 971) or does the chain need to be specific (SRAM PC-1) for coaster brake single speed Time for a replacement chain, and i have a sram 971 sitting around, don't want to spend the money on a new chain, if i can get away with using a mountain bike chain. Hopefully it won't pop off with standard tension?

Your cog is probably 1/8" like that PC-1 chain, so that 3/32" chain isn't going to work. Let's say you could even get it to fit in the first place, it would probably pop off at the least convenient moment, like when you're trying to stop with that coaster brake.


how to chose the right frame size for touring bike? I am going on a two week bike trip with a friend and I can only afford a second hand bike. My concern is that I will wind up buying a bike that I later discover was the wrong size for me.

I know that in an ideal situation I would try out a bunch of bikes at a shop and pick the one that fits the best, but if I am buying one second hand it's going to be more of a, 'ride it around the block and then make a decision' scenario.

Given that, are there some tips / things to keep in mind that would help to lower my chances of buying an ill-fitting bike?

How:

The low tech way:

Measuring tape Simply take it with you and measure five bikes that are comfy, and five that are not.
Digital camera Ask someone take a picture of you sitting on the bike, then review the picture to analyse yourself the sitting positions, both those that feel comfortable, and those that feel uncomfortable.

Geometry:

Chainstay. You need long enough chainstay for panniers. My recommendation is 45 cm. Below 42 cm your feet can hit the panniers even with small feet.
Comfort. You can select the ideal frame size based on different criteria: aerodynamics, efficiency, comfort, resulting speed, etc. For touring, the comfort is 10x more important then speed or anything else. This is because you sit 3-6h a day, for many days. On a tour, you get further by pedaling more and less by pedaling faster. Example: you can be 30-50% faster in an uncomfortable, but speedy position, but you can maintain that only for 1-2h. However, in a comfortable position, you can stay even 6-7h in the saddle.

I'd rather select a slightly smaller bike vs. a slightly bigger bike.

By buying a second hand bike, what you risk is hidden failures vs. the gain of lower cost.

Steel frames: check for "bents" and corrosion
Alu frames: check for cracks.

Bents usually come from accidents (falling with the bike), and cannot be corrected. You feel it only in the first moments of the riding, after a couple of minutes the feeling can go away. This cannot be repaired. I do have a steel bike that is bent.

Cracks come from big impacts and overload. This can be corrected by welding the alu frame, you need to find an alu-welder. I do have an alu bike with a crack (high quality brand, I didn't take yet the time to find a welder and get it repaired.

For more details, see my response here:
How do you distinguish a touring bike...


Will microSHIFT ADVENT 9 speed handle 46t, 50t large sprockets? Title says it all.

As we have 11-50t 9 speed cassetes available now, I was curious if anyone tried to use them with microSHIFT advent? or I have to be the first one to try it out?

That would be great wide range and inexpensive setup.

They do not officially support it.
Even on the long cage version the maximum supported sprocket size is 42t.

https://www.microshift.com/en/product/rd-m6195l/


Removing an unusual freewheel Could someone tell me which tool I can use to remove the freewheel in the attached picture please. I do have a couple of freewheel tools but they don't fit this particular freewheel.

Thanks

Chris

The Park Tool FR-3 should fit that.

https://www.parktool.com/product/freewheel-remover-fr-3


Buying mudguard and pannier together vs separately I need to get new fenders/mudguards, and I also need to get a pannier rack.

As I understand it, these can sometimes be bought as one unit, they can obviously be bought separately, and I am not sure if one can buy them as a pair that are desgined to go together, but not actually welded together (i.e. could be used separately)

Between these 2/3 options, is there any general advice as to which is better.

Bike will be used pretty much just on road/paths, most for commuting, very old standard frame.

If your bicycle and riding style will permit it, I would certainly recommend getting "proper" fenders / mudguards which are close to the wheel and cover it a good portion of the way round.  These will do the best job at keeping spray away from you and from the rest of the bike.

You say old standard frame - so that sounds like it may well have the right attachments for fenders / mudguards.

I spent many years commuting year round in London - 12 miles each way, and spent a great deal of time and bitter experience optimizing my set up.  I tried different bike set ups and a variety of fenders / mudguards and by far the most effective were the SKS thermoplastic ones which sit very close to the wheel.  They stop the most spray going up your back / butt and over the bike.

If the weather is reasonably inclement the difference between ok and good fenders is a lot…in my experience of riding through driving rain, sleet and snow!


What does "11-25" mean in the cassette description? I need to replace the chain and cassette on my bike soon but I don't know what teeth to count.

The Shimano Ultegra 6800 11 Speed Road Cassette - has 11 gears on the back so I know to go for the 11- bit but I don't know the second part -

e.g 11-23t 11-25t 11-28t 11-32t

I think its 25 but what am I meant to count ?

https://www.dropbox.com/home/Photos?preview=DSC_0115.JPG

The first is then number of teeth on the smallest and the second is the number of teeth on the largest cog.

If you like the current gearing then stay with that.  Or you can adjust.  If you stay with the same then match the number of chain links.

The count is also typically also stamped on the cogs.  On the bike and dirty it is typically easier to just count them.


Shimano RD-5800 and 7 speed cassette Is Shimano RD-5800 rear derailleur compatible with a 7 speed cassette?

Nope. The RD-5800 is the previous generation 105 level derailleur that works with 11 speed shifters and cassette.

You need a derailleur intended specifically for 7 speeds. The only 7 speed models Shimano makes are in the Tourney range.

Apparently, at least for 7-9 speeds, Shimano road derailleurs are compatible with 7-9 speed shifters as the combination of shifter cable pull and derailleur ratio will index the cage correctly. This does not work for 11 speed though.


can I use my road bike off road? I have several bikes. I noticed that 90% of times I go on road  so I got myself a road bike. But, can I use it for off road? Nothing extreme maybe some dirt roads or with small stones or poorly maintained roads. There is a really small amount of rains here so mud it is not a danger. The idea is that I can lend it to a friend to make some soft off road routes or use it myself and lend a more off road bike.

There's a whole sport - cyclocross - that involves riding road bikes off road. Typically the gearing is a little lower than a stock road bike, and these days a lot of them have disk brakes. Most will take fairly wide tyres, 38mm is not out of the question.

For riding a stock road bike off road, I'd look mostly at tyres. If you can find some that will clear your frame that have a bit of tread that will help a lot. Puncture resistance may also be worth while, you're more likely to find thorns off road. I would also experiment with lower tyre pressures, as that may improve traction.

Other than that, I'd just ride and see what happens.


Hand numb during sleep after training ride After a hard training ride, I am more likely to wake in the night with my hand numb. This does happen at other times, but more often after a tough ride. I drag it around on the mattress to wake it up. Is there a nutrient I am missing?

Could be a number of things causing this, as others have mentioned in the comments just moving your hands around during the ride might be the fix.
You didn't mention what type of riding you're doing, but as someone who had similar concerns after a decent MTB ride (around 50km), here's a few things I did and was advised to try

Worked on using my core to hold me up rather than putting all that weight through my arms and hands
Got a set of ergo grips with a little "shelf" for the heal of my hand and take the weight off my palms
Got some small bar ends.  In the long haul part of the ride gave me more places to put my hands
Raise the handle bar.  Puts you into a more of an upright position so weight further back
Narrower bar, again as per above
Shorter Stem, as number 4

I did 2 & 3 while training myself to use my core.  Now I'm back on normal grips and as long as I remember to move my hands around, problem gone


Giant Rack-It Front Rack experience + bow vs. "bow-free" front racks I'm looking at getting a front rack for my Kona Dewey 2015, which has two sets of mounting points on the forks. Specifically looking at getting the Giant Rack It front rack (https://www.giant-bicycles.com/gb/giant-rack-it-front-rack-black) mainly because it's cheap (~£20) and looks okay. Does anyone have any experience with this particular rack?

Giant Rack It Front
Also, unsure what the benefits/disadvantages of bow vs. bow-free racks are (ie that arch of metal that connects the two sides of the rack) as seen in comparing the Tubus Tara vs Tubus Duo for instance. What is the benefit of the bow? Examples here: http://bikeshed.johnhoogstrate.nl/bicycle/rack/low_rider_comparison/

Tubus Tara, with bow

Tubus Duo, bow-free

Stability of load will likely be quite different between the Tubus and giant racks.

For the Tubus racks the Tara had a cross brace to help stabilize the load.  The Tubus duo does not, but if you look carefully it mounts to both the inside and the outside of the mid fork eyelets, while the Tara mounts only to the outside.  This adds stability lost by not having a cross brace.  Note however that most forks today only have the outside midpoint eyelet (cost), so the Tubus Duo is not compatible with many bikes, which is why the Tara is their most popular model.

So why does the Dou even exist?  Tire clearance.  You can run massive tires without worrying about rubbing the cross brace.  In terms of performance I have used both racks and couldn't tell any difference between Tubus models in terms of stability.

Now this gets us to the Giant rack.  From the picture it appears to only mounts to the outside of the fork and has no cross bracing.  As such, it will have worse load stability compared to the Tubus models. If you are only running a light load, then it probably won't matter.  If you want to run a heavier load, but want to try and maintain steering responsiveness, then look for a low rider with cross bracing.  Note however that both manufacturers rate their racks as having the same max capacity.


Leak in my disc brakes I had a small crash and the other day I checked my bike for damage. I found that there is very small leak on my brake hose where it meets the lever.

I tried pushing the lever but nothing came out so can it leak only for one day and then it stops?

My brakes are Shimano BR-MT200.

Thanks in advance

You definitely do not want to ignore this. Loss of brake function is obviously dangerous.

At the very least, check regularly for further leaks in this area, before and after you ride. You mat find that the leak re-occurs after a while even though you cannot replicate it by squeezing the lever a few times.

You can of course have a repair shop look at it. Checking the hose for damage and replacing the bolt, olive and insert is probably a good idea.


30 lb Geared Bicycle vs 20 lb Single Speed, Which Is Faster for Commuting? This is not a literal question so I'm not looking at / for specific models, but more a theoretical one. Let's assume I could choose between two bikes for commuting, one with a modern 22 speed drivetrain setup and another with a single speed. The geared bike weighs 30 lbs, and the single speed bike weighs 20 lbs. They cost around the same (not that it makes any difference in this particular scenario). My commute would be about 8 miles each way, so 16 miles round trip, in a major U.S. city with normal traffic and not too much elevation gain (say around 150-200 ft or so, also round trip). Let's assume the city has 4 seasons and I would commute every day. Let's say I weigh around 140 lbs. I've tried to outline both the pro's and con's below, but I'd like to figure out if I'm missing something.

Geared Bike

Gears may allow for a faster overall speed if there are long uphill or downhill sections, or long open flat stretches with no traffic

Single Speed Bike

There is a weight reduction vs the geared bike (in this scenario about 6%) which may result in an increase in acceleration, especially when accelerating from frequent stops in traffic or going uphill
There is a slight increase in drivetrain efficiency due to a lack of derailleurs and a "perfect" chainline

If the rider regularly encounters traffic or does not ride over any substantial hills, I believe the single speed may actually be the better choice in most urban commuting scenarios. Given all of the following information, which one do you think would be faster and why? Any real world experiences and results would be welcome as well. Please disregard any other benefits not related to speed, such as the single speed having less parts = less maintenance and more reliability, generally more quality for the same amount of money spent on a single speed, etc.

Edit: I feel like everyone is missing the point of this question, so I thought I'd clarify. I own a modern 22 speed bike, a fixed gear, a single speed, a single speed mountain bike, and a relatively light 3 speed IGH. As I mentioned before, I do not want to hear about the pro's and con's of actually using each one for commuting in terms of cost, maintenance, etc.: I know about these already having owned them. I just want to know, given my particular scenario, which one you think would be faster and the technical reasons why you came to that decision. I'm not interested in discussing anything other than implications on commuting speed for this particular question.

To answer this question you have to factor in all the specifics of your commute. In particular those are (including yours for completeness):

Length of your commute (in time - distance is less relevant).
Steepness of ascends (and descents if you accelerate down-hill).
Overall 'windiness' of your city.
Number of full stops and slow-downs you have to do (due to corners, crossings and traffic lights).
Your physical strength and general fitness.
Amount of time you are willing and able to spend maintaining your bike.

Number (1)2-5 need to be considered when choosing your gearing. If the ascends are steep (or you have expect strong headwinds often) you'd need to run a smaller gearing. That would enable you to power through the ascends and accelerate quickly - but it would also limit your top-speed. Also your long-time endurance would be worse on a high-cadence gear-setup.

Meaning: in such conditions it would probably be better to ride a couple of gears. 200%-300% difference should suffice - a range that you cat get out of a small road-race cassette.

If in turn your commute consists of shallow ascends and descends, and you pack enough strength to decently accelerate the gear-ratio you'd want to be running during your average commuting speed - then you can do just fine on a single-speed bike. I rode a commute of 27km (~17mi) on a single-speed bike for years without trouble.

If you're still undecided you might want to consider my point 6. Maintenance can be a hassle, costing time and money. But it is not necessarily much more expensive on a geared bike. On a single-speed bike you have much higher wear on your chain ring and the sprocket, due to the higher torque you put into your drive-train. On a geared bike that wear is considerably lower, since you can down-shift to accelerate, and it is spread over a number of sprockets instead of just one.

My personal choice for commuting: Internaly geared hubs

You can combine both of those upsides by running an internally geared hub. Something like the Shimano Alfine 8 should be more than enough for all commutes, and doesn’t cost more than most other geared drive-trains. It’s insanely durable and needs very little maintenance. I rode one for approximately 25-30000 km (including a technical trans-Alps tour with 20000 vertical meters) and it’s still going strong in my daily-driver commuting MTB. Of course those upsides are bought with a little lower transmission efficiency and a  higher weight. But that shouldn’t be to bad for a commuter. Plus you get instant-shifting capabilities – even without pedaling! This is something I grew quite fond of, because it enables me to brake and shift later – makes it easier to keep the speed high.