Can trainers cause damage to your bike?

[amgenpharm]

Im relatively new to cycling and have quickly found that a trainer is great when I cant go out for a ride. I've recently noticed that my rear wheel rubs a little bit on the right side of the rear brake every now and then..... is this a problem? Could this possibly be from mounting the bike slightly crooked? Thanks.

 

[lokstah]

Im relatively new to cycling and have quickly found that a trainer is great when I cant go out for a ride. I've recently noticed that my rear wheel rubs a little bit on the right side of the rear brake every now and then..... is this a problem? Could this possibly be from mounting the bike slightly crooked? Thanks.

A lot of things can result in brake-rubbing. First things first: are you confident that your wheel rubs only when you're in a trainer? Any time a wheel is installed via quick-release skewers (whether for trainer-use, or for going out on the road), there's a chance it's not sitting straight in the dropouts, causing it to wobble and rub. Getting a knack for popping that thing in just right can take a little practice.

An out-of-true wheel is naturally skewed, whether you install it evenly or not; sometimes brake rub is the first sign that you need to examine a wheel for true-ness.

Brake calipers can loosen on their mounting bolts and pivot a few degrees off, creating contact with the rim, or exaccerbating one of the problems above.

That said, some weird stuff can happen when you're bolted into a trainer. There's not an obvious place for the natural heave and sway of your body to be displaced, so much of it is absorbed by the frame as flex. This might be evidenced by the chainline visibly moving with your pedal stroke, or as the rear wheel wobbling (or the seat/chainstay assemblies wobbling around a more stationary wheel).

Any of this consistent with what you're noticing? It's likely not a flex/stress issue unless it's something you notice while you're actually on the bike (as opposed to spinning the crank in a repair stand). And assuming your wheel is true, your calipers are straight, and everything is mounted and installed correctly, you probably shouldn't be getting brake rubbing on the trainer even if your frame is flexing. If that's really the case, I wonder if you're on a bike that's suited to your body weight.

Anyways, my bet is that something is just a little crooked. What do the rest of you think?

 

[drewski]

A lot of things can result in brake-rubbing. First things first: are you confident that your wheel rubs only when you're in a trainer? Any time a wheel is installed via quick-release skewers (whether for trainer-use, or for going out on the road), there's a chance it's not sitting straight in the dropouts, causing it to wobble and rub. Getting a knack for popping that thing in just right can take a little practice.

An out-of-true wheel is naturally skewed, whether you install it evenly or not; sometimes brake rub is the first sign that you need to examine a wheel for true-ness.

Brake calipers can loosen on their mounting bolts and pivot a few degrees off, creating contact with the rim, or exaccerbating one of the problems above.

That said, some weird stuff can happen when you're bolted into a trainer. There's not an obvious place for the natural heave and sway of your body to be displaced, so much of it is absorbed by the frame as flex. This might be evidenced by the chainline visibly moving with your pedal stroke, or as the rear wheel wobbling (or the seat/chainstay assemblies wobbling around a more stationary wheel).

Any of this consistent with what you're noticing? It's likely not a flex/stress issue unless it's something you notice while you're actually on the bike (as opposed to spinning the crank in a repair stand). And assuming your wheel is true, your calipers are straight, and everything is mounted and installed correctly, you probably shouldn't be getting brake rubbing on the trainer even if your frame is flexing. If that's really the case, I wonder if you're on a bike that's suited to your body weight.

Anyways, my bet is that something is just a little crooked. What do the rest of you think?

i concur.

as to whether, in general, a trainer can damage a bike, it can wear out the tires faster so i'd use a cheapie tire.

also, trainers where you lock in the front fork can add some greater stresses (IMHO) vs. the purely rear-axle mounted ones.

 

[Randybaker99]

A lot of things can result in brake-rubbing. First things first: are you confident that your wheel rubs only when you're in a trainer? Any time a wheel is installed via quick-release skewers (whether for trainer-use, or for going out on the road), there's a chance it's not sitting straight in the dropouts, causing it to wobble and rub. Getting a knack for popping that thing in just right can take a little practice.

An out-of-true wheel is naturally skewed, whether you install it evenly or not; sometimes brake rub is the first sign that you need to examine a wheel for true-ness.

Brake calipers can loosen on their mounting bolts and pivot a few degrees off, creating contact with the rim, or exaccerbating one of the problems above.

That said, some weird stuff can happen when you're bolted into a trainer. There's not an obvious place for the natural heave and sway of your body to be displaced, so much of it is absorbed by the frame as flex. This might be evidenced by the chainline visibly moving with your pedal stroke, or as the rear wheel wobbling (or the seat/chainstay assemblies wobbling around a more stationary wheel).

Any of this consistent with what you're noticing? It's likely not a flex/stress issue unless it's something you notice while you're actually on the bike (as opposed to spinning the crank in a repair stand). And assuming your wheel is true, your calipers are straight, and everything is mounted and installed correctly, you probably shouldn't be getting brake rubbing on the trainer even if your frame is flexing. If that's really the case, I wonder if you're on a bike that's suited to your body weight.

Anyways, my bet is that something is just a little crooked. What do the rest of you think?

I agree, damage seems unlikely, probably a crooked skewer - and BTW lokstah, that was a really well written post!

I am doubtful that a decent trainer will cause problems with a decent bike, although I suppose a really big person, hammering on a trainer could do some damage. Anyone have a horror story to share?

 

[amgenpharm]

lokstah et al, thank you very much for all of the useful information. The rear wheel just kind of sticks every few times the wheel spins around, on or off the trainer. I just thought that the use of the trainer may have led to this. I will definitely have it checked out.

 

[lokstah]

Thanks Randy, and no problem, amgenpharm.

If you're getting rythmic rub on and off the trainer, there are two obvious things to consider (pardon the rehash). One is that your wheel and/or brakes are simply sitting out of alignment. Even if they're only a bit out of alignment, the uneven-ness can be magnified by frame flex as you pedal. Unclamp the quick-release, and re-clamp it, taking care to see that the rim is centered between the brake pads as you push the skewer lever down. Eyeball the brakes and make sure they aren't sitting crooked either; sometimes re-centering the brakes makes all the difference.

Looking good? Now spin the wheel, and take note of whether the rim wobbles in relation to the pads as it goes around.

If that's the case, either your skewer is tweaked (drop $7 and buy a new pretty one), or your wheel has, in fact, gone out of true.

In case you're not sure what it means, wheel true-ness denotes that the hub, spokes, and rim are aligned and tensioned such that the hub is at the precise center of the wheel, the rim is a near-perfect circle, and that the whole assembly spins on a plane perpendicular to the axis. Most wheels lose their true-ness from time to time. Sometimes it's just general wear, and other times, it's a particular event -- a nasty encounter with a pothole, for instance.

Truing most wheels is something you can learn to do yourself, though it's a project which takes lots of practice, a chunk of time if you're not an ace at it, and some tools. Your local shop can probably do it in a mater of minutes (I take my untrue wheels to the shop). The process involves different techniques, but usually is accomplished by adjusting spoke tension here and there.

Ok, good luck. Take it to a shop and see what they say.

 

[JohnO]

Thanks Randy, and no problem, amgenpharm.

If you're getting rythmic rub on and off the trainer, there are two obvious things to consider (pardon the rehash). One is that your wheel and/or brakes are simply sitting out of alignment. Even if they're only a bit out of alignment, the uneven-ness can be magnified by frame flex as you pedal. Unclamp the quick-release, and re-clamp it, taking care to see that the rim is centered between the brake pads as you push the skewer lever down. Eyeball the brakes and make sure they aren't sitting crooked either; sometimes re-centering the brakes makes all the difference.

Looking good? Now spin the wheel, and take note of whether the rim wobbles in relation to the pads as it goes around.

If that's the case, either your skewer is tweaked (drop $7 and buy a new pretty one), or your wheel has, in fact, gone out of true.

In case you're not sure what it means, wheel true-ness denotes that the hub, spokes, and rim are aligned and tensioned such that the hub is at the precise center of the wheel, the rim is a near-perfect circle, and that the whole assembly spins on a plane perpendicular to the axis. Most wheels lose their true-ness from time to time. Sometimes it's just general wear, and other times, it's a particular event -- a nasty encounter with a pothole, for instance.

Truing most wheels is something you can learn to do yourself, though it's a project which takes lots of practice, a chunk of time if you're not an ace at it, and some tools. Your local shop can probably do it in a mater of minutes (I take my untrue wheels to the shop). The process involves different techniques, but usually is accomplished by adjusting spoke tension here and there.

Ok, good luck. Take it to a shop and see what they say.

One rider I know cracked the bottom bracket on a beautiful CF Trek Y-Foil frameset, after sprinting on it a lot in a trainer. In a trainer, all stress goes straight through the BB. The bike can't move around in response to torque the way it can on the road.

I use an old hardtail MTB in trainers. There is no point in stressing an expensive road bike in a trainer - you won't get any better of a workout, and you certainly won't get to your destination any faster.

 

[tafi]

One rider I know cracked the bottom bracket on a beautiful CF Trek Y-Foil frameset, after sprinting on it a lot in a trainer. In a trainer, all stress goes straight through the BB. The bike can't move around in response to torque the way it can on the road.

I use an old hardtail MTB in trainers. There is no point in stressing an expensive road bike in a trainer - you won't get any better of a workout, and you certainly won't get to your destination any faster.

There is no way for a bike to move with your pedal forces when you're on a trainer (by this I meen side to side). It is not uncommon to see the BB area actually deflecting under load. Clamping a bike in place into the trainer will lessen the life of the frame. Particularly aluminium which cycles to fatigue faster than Steel or Ti. Some manufacturers will not garuantee bikes which ar used in trainers. Be carefull with this. Using rollers avoids this hapening all together.