Urgent help - breaking spokes

Help - I am taking part in the 94,7 tomorrow. I have a Trek 7200 FX. The spokes on the rear wheel started breaking two weeks ago. Always the lefthand set and one at a time. I have had the standard spokes replaced with DT spokes a while ago when I had the same problem. Now it is starting all over again. Could it be my weight. I weigh 110 Kg. what solution. I think the rim is 24 spoke. Should I upgrade to a 32 spoke rim???? Please help. I will carry three spare spokes for tomorrows race.

 

hmm that sounds nasty . all i know i from advice from the bloke from my bs. did you install you spokes? they should not be all the same tension some this is to allow for strech. if the spokes where not fited right they might of had too much tension and snaped?. and once one went the the others where weakend.? any whay thats my guess and going to a 32 spoke wheel is not a upgrade its a downgrade

 

Hi H. You don't say where the spokes are actually breaking.
At the hub flange, or at the nipple?
Inside spokes or outside? Or both?
How many spoke crosses on each side?

If at the flange, then there are a number of causes -

1. Spoke elbow too long for the width of the flange.
          Solutions: Use small washers at the elbow
                        Find spokes with the correct elbow length
                        to suit your hub.
 DT did have a change, and some controversy.
 Here's the link:
 http:/www.peterwhitecycles.comDTspokes.htm

2. Spoke tension incorrect. If spokes are not tight enough,
   the wheel flexes (side to side) causing the spokes to flex
   i.e. bend back and forth a little where they exit the hub.
   Spokes are very strong in tension, but don't last long
   under such conditions.

IMHO, the 32 spoke wheel is stronger. Plus you will have 16
spokes pulling, not just 12.  

If you were to hawk your wheel round to different bike shops,
you may get any one of the following responses:-

 1. Just replace the broken spokes.
 2. A full rebuild, same as before.
 3. A full rebuild, using all new spokes, tight, no fancy lacing
     or crossings, and no radial. Cross 3 or 4 both sides.

Number 3 option is the one you need.

<Admin - fixed link>

 

willie obviosly knows all the tech wording

but willy you said that 32 spoke wheels are stronger this is not what i have heard

the bloke from the bs said:

the amount of spokes (eg 32) was used before not only to suppord the hub but also support the rim.

now with the new rims there they are much stronger and do not need the spoke support. the spokes only need to really support the hub. also because of the greator tension and desiging 16 spokes are no weaker than 32. ;D

so what do you think?

 

Here are some links which may be of interest:

http://sheldonbrown.com/wheelbuild.html
http://simon.trinhall.com.ac.uk/bike/wheels.html
http://www.youngwheels.com/index.html
http://www.wheelsmith.com/page5.html
http://www.peterwhitecycles.com/DTspokes.htm

Later.

 

Please accept my apologies for the multiple posts.
The computer was showing Error, etc., so I tried again....
Sincerely,
Willie.

No problem - all fixed - Vo2

 

I had a similar problem on a bike I'd put together for commuting. Tried different types of spokes, lengths, tensions etc. Even tried using different wheels but to no avail. Was getting through one spoke per 40 miles. I can only assume there was something wrong with the frame or it's alignment. Solved it by dirching the bike.

My sympathies are with you.

 

First, the trek 7100 comes with stock with a 32 spoke wheel.

The poster with all the recommendations is correct in all but mentioning that overtighten spokes will also cause breaks. So will uneven tightening around the set.

His recommendation for a total rebuild with all new spokes (you should not reuse spokes once they have been tensed) is the mechnics recommendation but your cost effective option is going to be replacing the wheel entirely. Labor rates on a rebuild plus materials will cost you more than a new wheel. This is your opportunity upgrade to a better wheel.

CapN W

 

went through a phase of breaking spokes every 100km or so on my back wheel until i had it rebuilt with 14G stainless spokes. only had to true it yesterday for the first time after 7000km and have not broken any spokes