Fixed Gear Conversion

Replies to This Discussion

Permalink Reply by on2wheels on June 30, 2009 at 2:57pm

If you want to do it proper, you will need to get a fixed or flipflop rear hub and re-build your rear wheel, or buy a new/used rear wheel already built.

Next you need to get a proper chainline using either spacers on the rear axle, replacing or flipping the BB, changing the cranks, or any combination there of.

Other parts you will need are -
The proper cog and lockring.
Probably a new chain. may not be necessary, but there is more force than usual on fixed gears
tight pants and a hacksaw for your handlebars, JK

read here for more info http://sheldonbrown.com/fixed/index.html

As far as cost. Rear wheel is going to be your biggest, but shouldn't be too bad. Check Craigslist for biggest deals. If you want new and are willing to spend the $$ try yojimbos for the best stuff.

*Disclaimer - I do not ride fixed gear, but I have converted a bike.

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Permalink Reply by Gecko on June 30, 2009 at 3:15pm

I'm assuming the frame has horizontal dropouts? If not you'll have to get an eccentric hub.

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Permalink Reply by on2wheels on June 30, 2009 at 4:22pm

But you don't want to go cheap putting those on. I am not sure how much a builder would charge you to replace your dropouts with those. (And there are only a few in the city who will attempt it)


grayson said:

These are pretty cheap and very high quality.

$40 a pair.

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Permalink Reply by Daniel Villarreal on June 30, 2009 at 4:36pm

It alreDy has the correct drop outs

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Permalink Reply by on2wheels on June 30, 2009 at 4:39pm

$40 + labor - thats a night out with some friends at charlie trotters :)

Could you elaborate on how the tightness of the axle nut effects the bearings. Isn't that what the locknuts are for? The dropout is clamped in between the outer nut and the locknut, so those two are the only things that have torque on the threads. Am I missing something?


grayson said:

Yeah I wouldn't go to a builder that called themselves "cheap" =) But you can't go wrong with $40 - thats basically a night out to eat and drink with some friends.
But it seems to me that it would be even easier to just find a cheap track frame than to convert a road frame. I would be too paranoid off the wheel popping out of the horiz stays - although I've never heard of that happening. My wheels slip enough with horiz drops with a tugnut. Over-torquing the hub will ruin bearings.

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Permalink Reply by Ed on June 30, 2009 at 5:00pm

If its originally a 10, 12, or 18, speed bike, you will probably have to change the chain as well. The fixed gear and freewheel cogs are a different size chain than a multispeed roadbike.
But new chains can be had for about $10.

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Permalink Reply by David Travis on June 30, 2009 at 5:07pm

If you have been taught correctly in how to build hubs and wheels, you should have been shown that overly tight QR levers or nuts do microscopically stress the threads and cause the bearings to be tighter than ideal. This is rarely noticeable to most mechanics because the angular momentum of the whole wheel masks the overly tight bearings once mounted on forks or rear dropouts. In other words, once the wheel is mounted on the frame, you can't feel if it is a bit too tight or not by turning the wheel. If you release the whole tightening mechanism and feel the bearing by turning the axel between your fingers, they will appear to be fine. This is why you must have loose individual dropouts on each end of the hub when initially tightening bearing cones in hubs. This allows you to feel the bearings while they are stressed after being torqued exactly the way they will be when installed. It's a intelligent trick that Chris Wallace teaches all his students, backing it up with actually microscopic photographs of overly stressed axel/bearings.

The question remains how much over tightening is enough to ruin the bearings and/or the races. It can't help. Note, however, that overly loose bearings, although they feel smoother, do more damage than ones slightly too tight. This is because all the weight of the rider/bike will be only on the two bottom bearings. When the bearings are slight too tight, all bearings make contact. It's counter intuitive, but true.

on2wheels said:

$40 + labor - thats a night out with some friends at charlie trotters :)

Could you elaborate on how the tightness of the axle nut effects the bearings. Isn't that what the locknuts are for? The dropout is clamped in between the outer nut and the locknut, so those two are the only things that have torque on the threads. Am I missing something?


grayson said:

Yeah I wouldn't go to a builder that called themselves "cheap" =) But you can't go wrong with $40 - thats basically a night out to eat and drink with some friends.

But it seems to me that it would be even easier to just find a cheap track frame than to convert a road frame. I would be too paranoid off the wheel popping out of the horiz stays - although I've never heard of that happening. My wheels slip enough with horiz drops with a tugnut. Over-torquing the hub will ruin bearings.

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Permalink Reply by on2wheels on June 30, 2009 at 5:31pm

Thanks for the thorough explanation David,

So one should build their hubs to be a bit loose, so that if they are relying on the outer nuts to hold the wheel on, they can get them tight enough to hold the wheel in the dropouts. Thus bringing the bearings to the correct tightness.

David Travis said:

If you have been taught correctly in how to build hubs and wheels, you should have been shown that overly tight QR levers or nuts do microscopically stress the threads and cause the bearings to be tighter than ideal. This is rarely noticeable to most mechanics because the angular momentum of the whole wheel masks the overly tight bearings once mounted on forks or rear dropouts. In other words, once the wheel is mounted on the frame, you can't feel if it is a bit too tight or not by turning the wheel. If you release the whole tightening mechanism and feel the bearing by turning the axel between your fingers, they will appear to be fine. This is why you must have loose individual dropouts on each end of the hub when initially tightening bearing cones in hubs. This allows you to feel the bearings while they are stressed after being torqued exactly the way they will be when installed. It's a intelligent trick that Chris Wallace teaches all his students, backing it up with actually microscopic photographs of overly stressed axel/bearings.
The question remains how much over tightening is enough to ruin the bearings and/or the races. It can't help. Note, however, that overly loose bearings, although they feel smoother, do more damage than ones slightly too tight. This is because all the weight of the rider/bike will be only on the two bottom bearings. When the bearings are slight too tight, all bearings make contact. It's counter intuitive, but true.
on2wheels said:

$40 + labor - thats a night out with some friends at charlie trotters :)

Could you elaborate on how the tightness of the axle nut effects the bearings. Isn't that what the locknuts are for? The dropout is clamped in between the outer nut and the locknut, so those two are the only things that have torque on the threads. Am I missing something?

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Permalink Reply by David Travis on June 30, 2009 at 5:49pm

Without experience its hard to say to what tightness to adjust your cones (this is for cones and bearings). I would not recommend making them too loose, as you will not know if they are still too loose after they are put in the dropouts and tightened. If the hub is not yet laced to the rims then you can mount them on the frame and feel them when tightened. If you don't have this option and don't have two individual dropouts, then I recommend making them feel just right or even backed off just a degree or two. Remember if they are just right and then tightened onto the frame, they at least will not be too loose, which is to be avoided. Also if you forget to clean and re-grease, none of this will matter.

on2wheels said:

Thanks for the thorough explanation David,

So one should build their hubs to be a bit loose, so that if they are relying on the outer nuts to hold the wheel on, they can get them tight enough to hold the wheel in the dropouts. Thus bringing the bearings to the correct tightness.

David Travis said:

If you have been taught correctly in how to build hubs and wheels, you should have been shown that overly tight QR levers or nuts do microscopically stress the threads and cause the bearings to be tighter than ideal. This is rarely noticeable to most mechanics because the angular momentum of the whole wheel masks the overly tight bearings once mounted on forks or rear dropouts. In other words, once the wheel is mounted on the frame, you can't feel if it is a bit too tight or not by turning the wheel. If you release the whole tightening mechanism and feel the bearing by turning the axel between your fingers, they will appear to be fine. This is why you must have loose individual dropouts on each end of the hub when initially tightening bearing cones in hubs. This allows you to feel the bearings while they are stressed after being torqued exactly the way they will be when installed. It's a intelligent trick that Chris Wallace teaches all his students, backing it up with actually microscopic photographs of overly stressed axel/bearings.
The question remains how much over tightening is enough to ruin the bearings and/or the races. It can't help. Note, however, that overly loose bearings, although they feel smoother, do more damage than ones slightly too tight. This is because all the weight of the rider/bike will be only on the two bottom bearings. When the bearings are slight too tight, all bearings make contact. It's counter intuitive, but true.
on2wheels said:

$40 + labor - thats a night out with some friends at charlie trotters :)

Could you elaborate on how the tightness of the axle nut effects the bearings. Isn't that what the locknuts are for? The dropout is clamped in between the outer nut and the locknut, so those two are the only things that have torque on the threads. Am I missing something?

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