Keep breaking spokes
 

Hi,

Have a 2008 Trek 7.3 FX that I use for commuting and recreational riding. I ride exclusively on the streets with the ocassional sidewalk. I try to avoid potholes particuaraly after the frist broken spoke. For the first 4 months (700 miles) no problems but in the last 3 months I have broken 4 spokes on the rear wheel, always on the middle of the wheel. It seems to be random areas on the wheel. After the last break (the 3rd one) the LBS replaced all the spokes as they thought it might be a bad set of spokes but another one broke after 70 miles. I am about 230lbs so am I not the lightest cyclist so I am wondering if weight is an issue. Is this going to be a constant problem and should I consider a new rim or are there thicker spokes available for these wheels? All the components on the bike are stock standard. Any input would be appreciated.

Weight may be an issue. My guess is that it was a poorly assembled wheel to begin with, coupled with your weight, made for a bad combination. You might want to have somebody really sharp with wheels rebuild both. Just because the guy works at your LBS does not mean he is good with wheels.
There's lots of good wheel info over in the heavy people forum.

230 is hardly a heavy clyde. There are folks on the clydesdale forum that are over 100lbs more, riding thousands of miles. Having said that, you need a better wheel, built by hand. Look for one that has 36 spokes, and is a deep V. Once spokes start to break, you are chasing a dream by replacing them.

Here's something to consider:
http://www.peterwhitecycles.com/DTspokes.htm

Not sure on the hardware, but a riding style that might help...I'm 220lbs and when I know I'm about to hit a rough spot I'll rise off the seat and try to take some of the weight off the back so the bike won't take such a hit.

I'll leave it to the hardware experts to offer that advice.

Here's a great thread, extremely helpful, that I started in the Mechanics Forum when I had a similar problem. Some of the material is over my head, but I had the wheel rebuilt by the LBS and haven't had a problem since.

I've had to deal with this as well. After a couple of months on my bike, I broke a spoke, then another every three or four weeks it seemed like. After paying the LBS to fix the first two, I figured I'd better learn how to fix them myself. I've probably replaced almost half the spokes in my rear wheel by now, but spoke breakage has dropped down considerably. I'm surprised that a full respoking by the LBS didn't address it, which makes me wonder if the spokes where not the only bad component, so I'd be inclined to consider a new wheel, hand built, with quality spokes.

I broke a spoke recently and after talking with the mechanic about commuting with two loaded panniers we decided to go with a stronger wheel. It wasn't all that expensive, but it was a double walled wheel designed for touring.

I am about 250, started breaking spokes on my Trek 1000 around 800 miles (a couple years ago). I bought a nice pair of Mavics that have been solid since 04.

My bike was breaking tons of spokes with the stock wheel. After about 20 breaks, I rebuilt it with a good rim (double-walled, about $25, an Alex Adventurer) and DT butted spokes.
My spokes were all breaking at the elbow, which I guess is indicative of load/unload repetitive stress from pedalling, NOT from load.
When I built it, a friend advised me on how tight to make it; his advice was "Crank the nipples on the drive side down until you think you're about to strip something, while keeping the dish and true correct." What you DON'T want to happen is for the spokes to be loose enough that the trailing spokes can unload when you're powering up a hill or something, because unloading then loading up again causes them to crack eventually. You want enough tension on the spokes that even when you're pushing as hard as you can up as big a hill with a full load that you ever get, the trailing spokes still have some tension on them.

FYI, the factory wheel broke its first spoke at about 500 miles, I gave up around 1500 miles, the replacement I built now has over 13000 miles on it and I never touched it after finishing it, and it's still dead true and no broken spokes.

I agree here; I am 240 lbs and was breaking spokes regularly on my rear wheel. Bike shop guy said to rebuild the wheel if it kept happening, and it did so I did--rebuild the wheel. No problems since.

I think if you break on or two but catch them quick and get them repaired quick, the other spokes are ok, but if you miss a spoke breaking and keep riding unawares it creates stress on the other whole spokes and weakens them, and so the break later. Try a wheel rebuild using decent spokes, done by someone who knows what he/she is doing

I was having the same problem. As others have said if the spokes are breaking at the elbow it's not because of load stress, it's because there is something wrong with the wheel. I broke 3 spokes in my rear wheel and my LBS eventually got me a new wheel. Another shop with an experienced wheelsmith told me that because it was a cheaper machine built wheel, the hub has bigger holes so the machine can lace it easily. That can cause the tension to continually increase and decrease at that spot as the wheel turns and cause the spokes to break from fatigue. I'm keeping my fingers crossed with this new wheel, but I may eventually need to go for a quality hand built wheel.

I only broke spokes ever when my wife had solid tires installed on the bike. What are you riding on?

If you keep breaking spokes even when the wheel is true, the usual problem is that the rim is going.
Check the rim around each spoke hole. Look for very small cracks around one of the holes.

If you see anything that looks odd around the spoke holes show you LBS. You probably need a new wheel.

Yep - rebuild the wheel. I also had a one spoke break, fix, another spoke break, fix, two spoke break, complained and it seemed fine. Rode about 40 miles out only to have 4 spokes go - what an effed up ride home that was!!!!! -- Took it to another shop I work with and it was noted that the one side was over tightened. I had the wheel rebuilt and learned to do my own spokes.

True your wheel.

That shop's a keeper. Make him your new mechanic, he knows his stuff....

I agree with having the wheel rebuilt by a wheel builder or bike shop. Then, make sure your wheel is true (though a well made hand built wheel will last a long time before going out of true.)

If your rims are low cost, single wall rims then a box section rim would be a lot stronger and less likely to flex and stress the spokes. A good LBS can show you the two types, it'll be pretty obvious when you look at them which is stronger.

There are different thickness spokes available, and there are also butted spokes, which are thicker at the ends and thinner in the middle. The idea is that the thinner middle section will stretch and give under an impact, absorbing some of the shock.

Cheap spokes are made of galvanized steel, and they don't last long. Better spokes are made of stainless steel, which lasts much longer. When your LBS rebuilt the wheel, which did they use?

How many spokes does your current rear wheel have? 32 is normal, but wheels with 36, 40 and 48 spokes are also available. You'll need a new hub and rim if you want a wheel with more spokes.

Wheels not only have to be true, the spoke tension has to be evenly matched between all the spokes. Otherwise the stresses of riding will not be spread evenly among the spokes, and some will be overloaded and fail.

Spoke tension has to be high enough to keep the loads spread out evenly around the wheel as the wheel rolls with a bike and rider weighing it down. If spoke tension is too high you'll break spokes, though. Good wheelbuilders will use a tensiometer to measure spoke tension, and ensure that all the spokes are tensioned evenly and according to the rim manufacturer's recommendations. Really good wheelbuilders (pro race team mechanics) can do this by feel, but not many LBS mechanics get a chance to build enough wheels to do this.

If they'll fit in your frame, wider tires will cushion the wheel (and your butt) from impacts and reduce the strain on the spokes.

I'm 250lbs and I hgaven't broken spokes since I learned how to keep my wheels trued up. As a heavy guy riding over crappy roads my wheels tend to need truing at least once a month. A quick 5-10minutes on the truing stand and everyting is good.

i am 200 and at least 20 pounds of random gear on my bag.

I have low count bladed krysium something or another in one of my bikes and i am yet to break a spoke.

better wheels are the solution.

I find a lot of Trek's come with wheels that have significantly lower tension than is acceptable. This accelerates spoke fatigue. At this point I'd buy all new spokes, relace them and build them up to maximum recommended tension. If you're not a wheel builder the most economical solution would be to buy some new wheels. 36 spoke with good rims mavic, velocity, heck even I have had good luck with Sun CR18's and for $30 a rim a pretty good deal.