Originally Posted by dwightonabike
Lever vs. cantilever brakes aside, lots of new "touring" bikes are coming with disc brakes. I have heard that with disc brakes, the stopping force must be transmitted from the hub, through the spokes to the rim and wheel, creating lots of tourqe. I've heard that this is hard on spokes for touring, especially for big guys. Anyone else heard this?
I keep my eye on the touring bike market and I can't think of a single model that has discs. That's real touring bikes, not the cross bikes/urban bikes that are being sold as "touring" bikes. The disc equiped bikes I've seen don't have the proper geometry nor the proper braze-ons to qualify them as bikes for loaded touring. Trek, Cannondale, Fuji, Surly, etc don't use discs on any of their touring bikes. Discs add a lot of expense and complexity without adding durability and ease of repair.
I have not heard of any problems with breaking spokes due to torque. A properly built wheel should be able to handle that kind of stress. That being said, the other problems I can see with a disc is that the front wheel - the strongest one - is now dished to for the disc. This weakens the wheel. The rear wheel is also made weaker by the increased angle of the spokes leaving the wheel, making the wheel less strong laterally.
There have been some people saying that disc and wheels with quick releases on the front wheel are not a good thing. Vector analysis of the forces involved indicate that the quick release can be loosen and come open. It's highly contested by some and just as strongly defended by others.
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