Originally Posted by derath
Hey all,
Just trying to get some ideas. My dad has become a habitual spoke breaker. He has had his rear wheel replaced 3 times and has broken probably 6-10 spokes total.
The wheel has been tested, trued, tensioned etc.
He rides a comfort bike (2005 Jamis Aragon) and is not a small guy, about 250-260lbs. He has lost over 100 riding though
The bike shop was telling him it is due to torque because he cross chains too much. He spends almost all of his time in the big chainring, even down to the biggest cog and can mash the pedals pretty hard. So the LBS was saying that when he is crosschained like that and pedalling hard he is causing too much lateral torque on the hub which is causing spokes to break.
Does that sound like a feasible answer? His wheels seem sturdy enough (36 spoke count). And I know he is getting frustrated by this problem.
-D
Are most of the spokes he breaks on the left side? These tend to fatigue quickly on 3X-laced rear wheels because they become unloaded and re-loaded as the rider pedals... this is exacerbated by hard mashing and maybe cross-chaining, although that last part sorta sounds like BS to me.
A 36-spoke wheel properly built is really very strong. Strong enough to hold a small pyramid of circus clowns. Definitely strong enough to hold your dad! A few suggestions:
* Try another shop. Maybe the wheelbuilders at the shop you've beesn using aren't very good or do the job too hurriedly.
* Try double-butted 14/15/14 spokes rather than straight 14-gauge spokes if you don't have them already. They're more elastic and thus resist jolts better. (See here for why:
http://sheldonbrown.com/wheelbuild.html#spokes)
* Try having the rear wheel laced half-radial: this tends to reduce fatiguing of the left-side spokes. (read this:
http://sheldonbrown.com/wheelbuild.html#half-radial)