Bicycle Mechanics - Wheel rim fatigue cracks
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08-29-02, 10:54 AM
I'd be interested to hear from anyone with similar experiences or insight on this one.
Just over a year ago I bought new wheels for my road bike, At the weekend I noticed that the rear was running out of true, as if a spoke had failed in on the chain side. In fact the wheel rim was developing cracks, initiating at spoke holes in about 6 places. Some of the larger cracks were accompanied by others in the shoulder of the rim either side of the spoke hole. Sorry, I have no pictures.
There is some corrosion around the spoke holes which could (possibly) have contributed to the start of fatigue.
The rims are only just over a year old, perhaps with 3000 miles. Front and rear were bought together, appear identical, are made by Rigida and are the "Excel" model. I shall be asking the advice of my (very friendly) LBS, but they are not really obliged to do anything. They have been very good in the past though.
I am disappointed that a wheel has gone bad in so short a time - this should not happen!
08-29-02, 11:16 AM
Agreed, that doesn't sound right. Looking at Rigida's page (http://www.rigida.com/anglais/race.asp), I see it's not an exceptionally light model, at 500 grams, so it's not as if it were some featherweight race-only rim, either. Best of luck, perhaps the LBS will make the Rigida rep warranty them :)
Given the fact that I have wheels that are at least
10 years old, and show no signs of cracking and or
rusting I'd be talking to the Rigida people.
I'd agree that the rust around eyelets was the starting
point. However a one year old rim should not be failing.
08-29-02, 12:55 PM
I had this happen on a set of Bontrager rims, they warrantied them.
Early this year I built a set of wheels using Mavic T-519 rims, I had the rim joint separate on the rear wheel after only 500 miles. After investigating the problem I learned the rims were only rated for 105 psi tire pressure, I had been running Contiental 700-28C at 120 psi. I built a new rear wheel and now run my tires at 90 psi, I now have over 3000 miles on the new wheel and it's still running true. I have another bike that I built the same set of wheels for, I used to have to re-true the wheels every 500 miles or so. I started running 95 psi in those tires also and haven't had to touch the wheels in over 4500 miles. So I guess when the manufacturer puts a pressure limit on a rim, they mean it. Check to see what your max pressure recommendation is for your wheels, you may have your answer.
08-29-02, 09:34 PM
Well hate to be the bearer of bad news but the Weinamann factory in Ill. has been closed for a awhile now. Typically though rims cracking at the spoke eyelets, or holes is from too much spoke tension. Rim fatigue when coupled with this can cause failure. I would suggest a rim swap.
I had this happen with a Mavic GL 330 but it took over 15,000kms on a back wheel to happen. The rim sidewalls had become paper thin and the wheel was ready to be retired. That's about normal for a lightweight rim like the GL 330's.
Unless you ride huge miles, though, this sort of thing just shouldn't happen to a heavy rim like the Excel. I agree with Precision Pedal that the wheel may have been built or re-trued with too much tension. I also notice from Rigidafs home page that Rigida rims seem to have the eyelets anchored in the outer rim wall rather then both the inner and outer walls. That would make them susceptible to this sort of problem.
08-30-02, 02:38 AM
Thanks to everyone for their posts, there is a lot of knowledge and experience out there.
To follow up on some points that have been raised:
I checked the Rigida website before posting, to identify the rim type and see if there was much info. There was nothing on recommended tire pressures. I had been running my tires at 90 to 100 psi (the max. rating for Hutchinson Excels)
Until the gross failure at one spoke hole, the wheel had run true without needing any alignment, so it is nothing that I have done to it through inexperienced maintenance. The wheels were a quite inexpensive, off the peg set so they may have been built with too much spoke tension in the first place.
There is also a galvanic action at work , because of the different metals in contact: galvanised spoke, plated brass eylet, and aluminum alloy rim. This is likely to be the cause of the corrosion at the spoke holes.
I will definitely not be riding on this wheel again, and will see if the bike shop are willing to help. I'll let you know how it goes.
Thanks again to all,
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