How difficult to modify a cheap stationary bike?
09-15-20, 11:44 AM
#1
Junior Member
Thread Starter
How difficult to modify a cheap stationary bike?
Amazon and other places sell stationary bikes for ~$300 that look sturdy, have a monster flywheel, magnetic eddy current resistance, and look ok. Put on your old vector pedals and you've maybe got a machine for winter training.
But how difficult will it be *really* to get such a bike into acceptable shape for serious training? I see a number of issues:
1) Stem/handlebars. Some of them seem to have OK/adjustable handlebars. Of course the geometries are ridiculous, but they do give you a lot more hand positions than a standard road bike. If the stem can move fore and aft, I would think about just leaving it how it is. Otherwise cut a clamp out of an old steel stem and use it to bolt on road handlebars, maybe with dummy brakes.
2) Seat: It looks like you can swap in your favorite seat on most of these no problem.
3) Geometry: The effective seat tube angle seems designed for sitting upright on most of these. It's not clear once you have your own seat on that you can move it far enough forward to get a standard road bike geometry. The pedal axle is going to be way too far foward compared to your hips no matter what you do. Some do seem to have enough forward travel to do the job, others will require some welding.
4) Crank arms: This is a real problem! Most cheap trainers come with 150mm crank arms, and a lot seem to be one-piece cranks. This is a non-starter -- you want to match your crank arm length to your road bike, and most people have 170 or 175 mm cranks. A couple models looked like they had standard crank arms where you could take an old Alu crankset, cut away the spider with an angle grinder and bolt it on. Has anybody tried this?
5) Power. I would go with one of the pedal based power meters. It's going to cost more than the bike if you get it new, but lots of people have a perfectly good old one lying around from the old days.
6) Variable resistance. I don't know any cheap way of retrofitting a resistance unit. You'll just have to reach down and turn the knob when you need to make more power. I would think that some creative welding would be possible to rig a spring and shift lever to control the resistance from the handlebars. The kind of resistance unit you have on a Wahoo kickr where the resistance is controlled by Zwift, I have no idea how to retrofit that. You just have to go into another price category for that.
Has anybody done this?
What brand/model/price?
Was it worth the effort?
Cheers,
Jon.
But how difficult will it be *really* to get such a bike into acceptable shape for serious training? I see a number of issues:
1) Stem/handlebars. Some of them seem to have OK/adjustable handlebars. Of course the geometries are ridiculous, but they do give you a lot more hand positions than a standard road bike. If the stem can move fore and aft, I would think about just leaving it how it is. Otherwise cut a clamp out of an old steel stem and use it to bolt on road handlebars, maybe with dummy brakes.
2) Seat: It looks like you can swap in your favorite seat on most of these no problem.
3) Geometry: The effective seat tube angle seems designed for sitting upright on most of these. It's not clear once you have your own seat on that you can move it far enough forward to get a standard road bike geometry. The pedal axle is going to be way too far foward compared to your hips no matter what you do. Some do seem to have enough forward travel to do the job, others will require some welding.
4) Crank arms: This is a real problem! Most cheap trainers come with 150mm crank arms, and a lot seem to be one-piece cranks. This is a non-starter -- you want to match your crank arm length to your road bike, and most people have 170 or 175 mm cranks. A couple models looked like they had standard crank arms where you could take an old Alu crankset, cut away the spider with an angle grinder and bolt it on. Has anybody tried this?
5) Power. I would go with one of the pedal based power meters. It's going to cost more than the bike if you get it new, but lots of people have a perfectly good old one lying around from the old days.
6) Variable resistance. I don't know any cheap way of retrofitting a resistance unit. You'll just have to reach down and turn the knob when you need to make more power. I would think that some creative welding would be possible to rig a spring and shift lever to control the resistance from the handlebars. The kind of resistance unit you have on a Wahoo kickr where the resistance is controlled by Zwift, I have no idea how to retrofit that. You just have to go into another price category for that.
Has anybody done this?
What brand/model/price?
Was it worth the effort?
Cheers,
Jon.
