Bicycle Mechanics - 'rims are going bad' BS or bad news?

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purple hayes
08-14-02, 12:00 PM
I just got back from the LBS where I took my rear wheel in to have them put on a new spoke. That's the 3rd spoke I've broken in the past month and a half. I paid to have the first one replaced, did the 2nd one myself (it was my first time doing that job) but I decided that since the 3rd one broke so quickly that maybe I screwed up the 1st time I did it.
I asked the LBS guy why I was breaking so many spoke and he said that my rims were probably about shot. I ride a Trek 1000 that I just got in Jan. of this year and it probably has >4,000 miles on it so far.
Was the LBS guy trying to feed me some bull to get me to upgrade my wheels or are my wheels really going bad?
VegasCyclist
08-14-02, 12:11 PM
well if the rims are bent then the LBS guy could be correct, however I doubt it is the case since your bike is so new. unless you have had a serious wreck since you have had it. how exactly are you breaking the spoke? is it under normal street riding or are you doing trails (is the trek 1000 a mtb?)
It also is a good idea to go to or call another LBS and see what they think the problem might be.
purple hayes
08-14-02, 12:15 PM
The Trek 1000 is a road bike. All three of the spoke have broken near the hub.
I plan on calling another LBS, but I wanted to post the question here since no one is trying to sell me anything.
It's either bad facatory wheel building,defective cheap spokes,you are abusing them or you are too heavy for them.The LBS guy is full of it.
Guillermo
08-14-02, 01:36 PM
I have some junk bontrager rims that came stock on my mtb, and after about 2k miles in 3 months (75 % road), they are almost toast. I find them out of true more often than not. They have been trued by several different LBS, and keep wobbling on me. I am not super heavy (175 lbs), but do mash on my gear I guess.
mechBgon
08-14-02, 06:05 PM
IMHO, over 4000 miles is quite a bit for cheap OEM spokes in a rear wheel. It sounds like they're hitting the wall on their fatigue life, one by one. I'd say you got your money's worth and it's time for a rebuild with Wheelsmith or DT spokes, and possibly a new rear rim if the rim no longer wants to be true as a result of the spoke breakages warping it.
dprayvd
08-14-02, 06:20 PM
aaaaa
mechBgon
08-14-02, 06:23 PM
DT rocks :) They've been making stuff out of wire for over 350 years, I understand :eek:
If you decide to replace all of the spokes, strongly consider replacing the rim at the same time.
Over time, spoke tension will cause a hub's spoke holes will elongate, potentially triggering spoke breakage.
Double-butted spokes are a good idea, since spokes generally break at the ends, rather than in the middle.
Always use DT, Wheelsmith, or other high-quality spokes. Anything less is false economy.
Well, you aren't the first person I've run across with this problem. My shop sells Trek and the problem with the 1000 wheelset ain't the rims! It's the 1.8mm straight gauge spokes matched with a 2.6mm hole in the hub! I've had some big riders on these bikes and they all turned into spoke breakin' machines in no time.
I rebuilt them all using 2.0-1.8 double butted spokes with brass washers at the heads. This takes all the slop out the spoke/hub interface and results in a nice strong and stable wheel.
We did these as complimentary rebuilds and upgraded the spokes at no charge. See if your LBS will do the same.
Good luck!
Spoke breakage is due to metal fatigue. Overloading one side with excessive tension will shorten the life of spokes quickly. Hub and rim distorsion can occur but is rare. It is more likely with highly dished wheels and narrow rims. Of course I am a firm believer in traditional spoke counts.
http://www.sheldonbrown.com/symspoke.html
http://yarchive.net/bike/spokes.html
Brian Ratliff
08-20-02, 05:42 PM
I have just recently had this problem with my wheels that I built myself. I have broken spokes on both my bikes now.
The cause of broken spokes involve many factors. Even spoke tension is probably the biggest. Too little spoke tension can be a cause of fatigue because of slop between the spoke head and the hub hole. I have found that most broken spokes happen on the drive side pulling spokes of the rear wheel, though I have had one on the non drive side of the rear wheel. I think that one was from riding with panniers and building the wheel out of 14 gauge spokes.
In all cases, a broken spoke indicates the wheel has something wrong with it. In both recent cases I have broken spokes in the rear wheel, I have rebuilt the wheel with double butted spokes, taking extra care to make sure the spoke tension is correct.
I can belive breaking a low end rim, but not wearing one out after only 4,000 miles.
I just wore out a Mavic GL330 real wheel. That is a really thin walled rim and it still took 15,000kms.
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