|Wheel building question for big guys||Softrider|
Jan 13, 2004 9:17 AM
|I am trying to help a guy in our group that is having a wheel problem.
He is a big guy, about 275 lbs. and is riding Mavic OP's 32 hole laced 3X. The front is fine, never been trued after about 2K miles. The rear has been a different story. Has broken 5 or 6 Non drive side spokes in the same amount of miles.
We are going to give this one last try, can you give me any suggestions that would make this wheel stronger?
Would a 4 cross lacing pattern help?
Thanks for your help.
|Probably won't work.||Spoke Wrench|
Jan 13, 2004 9:41 AM
|If you try to cross four with a 32 hole hub what will happen is the spokes on one side of each flange will block the holes for the spokes on the other side of the same flange.
As a general rule, breaking non-drive spokes is usually attributed to inadequate spoke tension. Of course, when you increase the non-drive tension, you also have to increase the drive side tension an equal amount and sometimes that's hard to do.
A trick that sometimes works is to loosen all of the non-drive spokes 1/2 turn. Now you'll find it easier to tighten your drive side spokes by 1/2 turn. Finally, tighten all of the non-drive spokes a full turn.
|just have it rebuilt by someone who knows what they are doing.nm||niteschaos|
Jan 13, 2004 9:46 AM
|get a 36 hole and a stronger rim||ColnagoFE|
Jan 13, 2004 10:01 AM
|Something like a CXP33 and 36 hole laced 3x with brass nips should do the trick.|
|Non drive side spokes breaking are often due to||bimini|
Jan 13, 2004 10:06 AM
|those spokes being too "loose". The spokes on that side have to have less tension than the drive side to get the wheel to dish right. The spokes always need to be in tension. As the wheel rotates the load on the spokes goes up and down. If the tension gets to low or gets near or below zero at the bottom of the rotation the spoke can rub at the bend where it goes through the hub and this leads to failure.
A possible solution is to use straight gauge 14 on the drive side and a butted 14/15/14 on the non drive side. This will allow you to put more tension (lbs/in2)in the non-drive side spokes to maintain the same pulling force (lbs) due to the smaller cross section. At 275 lbs I would keep both sides 3x. Your friend may be near the limit of a 32 hole OP.
Adding a LITTLE tension all around may help but be cautious of adding too much. If you get too much tension you will get cracking around the spoke holes in the rim and ruin the rim. Compare the sound to a well built wheel using the same gauge spokes and cross pattern.
|What bimini and ColnagoFE said.||eddie m|
Jan 13, 2004 11:19 AM
|A 275 lbs. rider is nearly double the weight of a typical pro rider that lightweight components are designed for. A heavier 36 hole rim and straight guage spokes on the drive side are both good suggestions for anyone that size.|
|Frame flex, Mavic T series, Ritchey Zeros||Continental|
Jan 13, 2004 1:00 PM
|Spokes can also break because of excessive frame flex with a large rider. A noodly frame with a 275 lb rider can flex enough to have the drive wheel alignment cycle back and forth and put huge stress on the wheel. A 275 lb rider should be on a bike designed for fully loaded touring. Cutting a few pounds from the frame weight for a 275 lb rider is absurd.
I have Ritchey Zero hubs on my bike and I like the idea behind them alot. The Zero hubs greatly reduce or eliminate the need for dishing the rear wheel, making the rear wheel stronger and more reliable. I don't have the Ritchey OCR rims, but if you use the Zero hub and the OCR treking rims you will completely eliminate dish and greatly strenghthen the wheel.
Another option is a Mavic T series rim with 36 or even 40 spokes. They're good for tandems.
|re: Wheel building question for big guys||Fred2000|
Jan 13, 2004 1:01 PM
|Is that guy me? No, I am right at 275 and have had a lot of similar problems with rear wheels. Fronts last forever but I seem to kill spokes on either 32H or 36H.
I ordered a set of wheels from Dave Speedream and told him my size and riding style. I got them in July and have about 2000+ Miles on them without any issues - still true as when I got them which is saying a lot.
So it may be more about who is lacing the wheels then what kind of lacing is done.
|re: Could be the build and not the wheel||jrm|
Jan 13, 2004 1:34 PM
|I'd try a quality built 3x 32H OP using 14/15 DT spokes.|
|half radial lacing?||joe friday|
Jan 13, 2004 1:48 PM
|"With half-radial spoking, the amount of dish is slightly less to begin with if you run the radial spokes up along the inside of its flange. In addition, since there are no "leading" spokes, no amount of torque on the hub can reduce the tension on any of the spokes. In fact, if you have a customer who has been breaking left side spokes, "half rebuilding" the wheel into a half radial will solve the problem once and for all."
I have NO IDEA if this would help or not. I've built my
mtn. bike wheel this way and have had
absolutely no probs at all but i'm under #200.
Hope you find a solution!
|the guy is close to 300 pounds||ColnagoFE|
Jan 13, 2004 2:09 PM
|If ever there was a case for a 36 (or more) rear wheel this is it. Why skimp?|| |