Bicycle Mechanics - How much lateral rim deflection is normal for zipp flashpoints?
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07-13-09, 04:38 PM
I had a set of zipp flashpoint wheels, fp60 front and fp80 rear, custom built for me earlier this season [from wheelbuilder.com]. These wheels always seemed to have excessive lateral deflection You can easily deflect the rims a good 1 or 2 mm, all the way into the brake pads just by pushing the rim with your hand, or by leaning the bike on its side during a sprint. The wheels are true and cut through the wind like butter, and seem to perform well, except for the occasional and extreemly counter-productive rubbing on the brake pads. I'm about 175 lbs and no power house.
How much deflection is normal for these wheels?
I ordered a spoke tension meter, but won't have it for a few more days. I'm used to doing all of my own work, but these deep dish wheels are new to me.
Any suggestions or links on proper tensioning and stress relief would be welcome.
07-17-09, 04:53 PM
UPDATE: The builder states it is probably not the spoke tension, and wants to sell me a stiffer axle for the rear. I'm using a 12 mm aluminum, he has a 15 mm steel axel. I'll proabably do the axle upgrade, but don't think that is the root cause of my problem.
The spoke tension meter arrived. The spoke tension is on the non-drive side of the rear wheel, averaging about 55 Kfg; The drive side, seems ok at 122 Kfg. The front has uneven tension rangeing form 70 to 100 Kfg.
Does anyone know what the proper spoke tension would be fore these wheels? I asked the builder, but they just stated its not the spoke tension causing the problem. There is no play in the bearings.
I'm planning to even out the spoke tension myself.
07-17-09, 05:43 PM
Spoke to Builder again. Builder states spoke tensions are correct, if a bit low. I'll try steel axel before turning up spoke tension. New axle will be here early next week and I will report on results.
07-17-09, 07:00 PM
If you don`t have experience truing or building a wheel, i`m goign to advise you right now not to **** with the wheel. Professional handbuilt wheels should not have to be touched up in the way you are planning.
07-27-09, 12:42 PM
OK, got the new axle in and it doesn't solve the problem Big suprise. I can understand a little bit of lateral deflection because of the low spoke count, 24, but in a hard out of the seat sprint, the rear wheel moves enough to not only rub on the the rear brake pads, but to actually move the caliper out of center. The only solution is to run the brakes wide enough to stay out of range of the deflection.
I'll repeat, I'm getting tesion readings as low as 50 Kfg on the non-drive side. This must be way low. I've got free life time truing from the builder, so it may just be time to bit the bullet and send the wheel back to CA.
By the way, I've trued many ordinaly bicycle wheels and worked in a bike shop a good 25 years ago. The idea of retensioning the wheel myself is a very stong temptation.
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