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Building Wheels for Disc Brakes vs Rim Brakes

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Building Wheels for Disc Brakes vs Rim Brakes

Old 07-23-13, 07:31 PM
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Bicycle365
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Building Wheels for Disc Brakes vs Rim Brakes

Just a question for those that know more about wheel building than I (i.e. everyone).
Now I had my wheels built by a professional wheel builder (Peter White in New Hampshire) as I do not want to be my own guinea pig and try and learn the art.

I have conventional cantilever brakes so when I'm flying down a hill and apply the binders I am slowing the rim while the hub is trying to keep going and tear itself free from the spokes that are holding it back.
On a DISC brake bike the forces are reversed, the hub is trying to stop and the rim has all the energy and force.

Do you have to build the wheel differently to account for this? I understand that the total forces needed to stop x pounds moving y mph are the same in either case but my gut feeling is that the loads and stresses are distributed differently throughout.

Joe B
Front: Velocity Chukker 40 hole w/ Son28 hub
Rear: Velocity Chukker 40 hole w/ Phil Wood Touring hub
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Old 07-23-13, 08:07 PM
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Counter balancing tensions of wheels with any cross pattern to them, act as a whole..

radial spoked wheels are unsuitable for hub brakes, but OK with rim brakes..
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Old 07-23-13, 11:33 PM
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The rim has to be stronger obviously, but modern alloys can easily alleviate this. Stronger spokes (butted, double butted, triple butted), and nipples as well. Modern technology can solve most of the stresses put on a wheel from disc brakes. A wheel built in the 30's would explode if you tried to put a disc brake on it.
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Old 07-24-13, 06:53 AM
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A bicycle is a simple machine but the devil is in the details.

On a bike with rim brakes the front hub doesn't do much more than hold up it's end of the bike. That's why radial spokes work for front wheels. Brakeing forces are transferred around the rim from the brake caliper to the contact patch with the road.

On a bike with disc brakes when you apply the brake the wheel tries to rotate around the disc pad rather than the hub. It's actually possible for the wheel to completely eject itself if the conditions are right. It's important to have a good gripping front QR skewer and to keep those little "lawyer lips" that we all like so much on your fork.
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Old 07-24-13, 08:57 AM
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A wheel built in the 30's would explode if you tried to put a disc brake on it.


the hub brakes 30 years ago were Drum brakes , 1930's like you were even born then ..
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Old 07-24-13, 11:41 AM
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Originally Posted by fietsbob View Post


the hub brakes 30 years ago were Drum brakes , 1930's like you were even born then ..
I wasn't implying I was born 80 years ago, but rather that technology has drastically improved since and one needn't worry about extremely catastrophic events as such.

Retro Grouch is right about the wheel possibly flipping out of the dropouts. That being said, I think that we can all say that a wheel exploding is the least of our worries.
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Old 07-24-13, 11:50 AM
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wise frame designers have changed front forks , the physics has the torque center, rotate around ,

where the brake pad grips the disc.

so some forks now open at the front , not the Bottom..

most bikes have not changed , they rely on the bumps on the fork tip, AKA Lawyer's lips,

after a liability suit got a payout from bike manufacturer's insurance company.

so make sure that QR stays Tight enough.
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