Bicycle Mechanics - Breaking Spokes

I have had my bike since October or so of last year. It is a Jamis Nova with the typical double butted spokes (14/15). I am not a big guy, 6'2, 165lbs, and not super strong, but I keep breaking spokes. This is #4 for me and I think it is become quite silly now. I got one replaced the last time I road and then broke one again this morning. I am breaking these on my commute, over a nice smooth bike trail, nothing that I would even call hard on a bike.

I have broke three during uphill sprinting. The other one was during a short sprint interval on flat ground. All of them have broke on the drive side right near the hub.

I have spoke to the manager and he is replacing the spokes I break with straight 14s. He also said if it continues to happen he will replace the wheel possibly.

Why am I breaking spokes? I can barely put out 800watts during uphill sprints.

I can virtually guarantee that the spokes are breaking because it's a machine built wheel that wasn't properly prepared by the shop before your bike was delivered.

Any machine built wheel requires:

1. Stress relief of all the spokes on a new wheel (to "untwist" them);
2. Tensioning with a tension meter (the majority of machine-built wheels are undertensioned);
3. Truing and additional stress relief as needed.

If the shop didn't do these things when the bike was assembled, the wheel will continue to break spokes and they should rebuild the wheel with all new spokes now.

Further, if they don't know how to do these things, the rebuilt wheel will have the same problems. So make sure a competent wheelbuilder is doing the work.

Replacing 14/15's with straight 14's is ignorant. 14/15's are stronger than straight gauge spokes. See this Usenet thread: http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&oe=UTF-8&th=b25319ef1f6ea018&rnum=1

RichC

My guess is exactly what Rich Clark is suggesting. I began breaking multiple spokes every ride, and finally figured out that it was a result of ill-built factory wheels that were not properly tensioned. This allowed for a rub spot to form on the affected spokes, weakening them until they finally broke, mostly while just riding along. I got a new, LBS-built wheel and have not had problems since.

-Moab

I pretty much agree with Righ Clark.

More than one or two broken spokes on a wheel is adequate reason to disassemble the whole thing and start over. Also, if the spokes are breaking at the elbow that is already 14 gauge, what can possibly be gained by making the middle part of the spoke, where they aren't breaking, heavier? That's like putting Volkswagen sparkplugs in a Ferrari because they're cheaper and easier to find.

A wire bicycle wheel has four components: Hub, rim, spokes, and assembly skill. Sometimes guys try to overcome lack of knowledge and assembly skill by using more spokes, and heavier components. I think that your LBS' "Heavier must be stronger" theory is proving to be counter-productive. By replacing your butted spokes with heavier, mis-matched spokes, he is making it impossible for the spokes to share the load equally. I'm betting that he hasn't made an adequate effort to balance the spoke tension either. No wonder they continue to break.

I think that you need a complete wheel rebuild, but I don't think that your current LBS is the right guy to do it.

Make sure that the spokes are actually 14/15. I have had quite a few wheels with 15 guage spokes and the J-hook is to small to fit properly in the flange hole, creates a stress point and they snap often. Also if the spokes are not branded (No logo on the spoke head) they seem to break more often.
14/15 butted is the way to go. I have some MTB wheels I built in '94 that are butted and still in great shape, second and third wheels I ever built. Use DT (MY favorite) or WheelSmith( Good also) and you will have no problems.

Make sure that a past overshift of the chain into the spokes has not damaged your outside drive side spokes.

Dave

Double butted spokes are actually STRONGER due to better ablity to share the load as Spoke Wrench put it, than straight gauge! I think someone did not prep the wheel properly as others have mentioned. But questions come to mind: where are the spokes breaking; I am assuming they all broke in the rear and if so how many spokes are on the rear rim?

Actually, DB spokes are not stronger, but they make a more durable wheel. Please, don't confuse the two concepts.

Originally posted by D*Alex
Actually, DB spokes are not stronger, but they make a more durable wheel. Please, don't confuse the two concepts.

You're right, that's a useful distinction. The thinner, springier mid section of the db spoke allows the wheel to absorb sudden shocks better, which means it's not the rim or the hub that take the hit.

Another good reason not to replace individual db spokes with straight gauge ones.

RichC

Spoke strength: The willow versus the oak

I checked the specs on your bike, and, if I am not mistaken, you have Mavic MA3 rims. CXP 21s were stock on my bike and I was a spoke breaker, too. We are the same weight. CXP 21s are unwelded and are weak at the seam. Added to that, all these wheels come from the same machine wheel building shop in Japan. Machine built wheels do not have any compound on the spoke threads. They tend to get loose fast, and dangerously fast near the seam. If you keep a record of it, you will probably find that most of your breaks occur near the seem.

Cheap Mavic rims will give you lots of heartache and lots of experience in learning how to true your wheels yourself. About 6,000 miles ago, I upgraded to handbuilt CXP 33s on Ultegra hubs. They are as true as they were the day I got them. My truing stand has collected a nice layer of dust. :)

Rich

Thank you all for your help.

I am breaking the spokes at the hub.

The spokes that are being replaced are doubled butted, I checked this last weekend. It was the first one that was replaced that was straightgauge and that was from a new guy working there.

I will be building another set of wheels for commuting it seems in the near future. Probably just cut out the hubs and buy a set of decent rims off ebay.

When I threw my chain at Sea Otter it did not hit the spokes. I was in the middle of the cassette during the change (both times).

Lucky for me I have a teammate to borrow wheels from for Wildflower this weekend. I have Jet2000 sewups, but those like to drink water when it is wet out :(

Don't mix straight-gauge and double-butted spokes on the same wheel. If the shop you go to doesn't know the difference, run!!!

This doesn't answer anyone's questions, necessarily, but I thought I'd contribute it.

Years ago, just before a bike tour in the Canadian Rockies, I rebuilt my wife's wheels, the rear one at least, using name brand, double-butted 14/15/14 spokes.

During the tour, my wife kept popping spokes on the freewheel side (these were 5 speed freewheels. Modern cassettes has yet to be developed). This drove me batty as I thought _I_ had goofed somehow in my wheel building.

It wasn't until after we got home that I discovered the reason for the spoke breakage. With a hand lens (on some left over spokes, I could see that instead of a nice radius in the INSIDE of the elbow bend at the hub, there was a sharp corner in each of the spokes I installed on the freewheel side. (I used a different spoke length on the non-=freewheel side that did not suffer this defect). This sharp bend concentrated the forces and resulted in spoke breakage. So, name brand spokes CAN be defective.

I had this problem and discovered the tension in my wheel was extremely low. After raising the tension on the whole wheel twice (tightening each spoke a half turn) (about a week apart as the wheel lost tension over the week). It seems to have stabilized finally and I haven't broken a spoke in 300 miles where I used to average one every 60. I think the loose tension was allowing the weaker spokes to wear faster at the hub. Just a theory as I am not a wheelbuilder and am still trying to learn how to do all my own repairs. That seems to have worked for me though.

BTW- the wheel is under warrantee I just work at the same time that the bike shop is open, hence, I have to fix my own problems. I often wonder if a bike shop opened late in the evening would do better business?

I agree also with Rich clark the wheel must of been not dialed in from the word go.If you bought it at a real bike shop this should not of happened cause they would make sure that your bicycle works properly before you would be allowed to take it home...they have reputations to look after?Years ago I can remember checking all the dept. store bicycles for wheel true...none were dialed in.So when somebody buys what happens is he ruins the wheel for gets offended when he has to take to a real mechanic and pay.Dept store are making progress thou things are improving on some models.The manufacturer should dial them in before there boxed

When spokes are breaking in a wheel under normal usage the problem is that the wheel has not been tensioned properly. Cheap spokes don't last as long as 'quality' spokes, it's true, but if the wheel is properly tensioned even 'cheap' spokes will last at least 5000mi.

Almost all (maybe ALL) machine built wheels are not tensioned correctly.

Sakarias' point on the 'sharp' corner on the spokes he looked at is exactly what you will find when you remove spokes from a badly tensioned wheel. This is caused by the flexing of the spoke in the hub flange as the wheel rotates.

I can't tell you what proper tension is; I don't use a tensioner myself, I just check 'em by pulling on them with my fingers. But if you pull on the spokes of a wheel that's been riden for years, (it's probably tensioned correctly) you can 'feel' what good tension is. Keep practising and you'll get good at it.

I can't take the time right now, I have to run, but Mike Walden from Detroit City once showed me how to build a wheel that was bullet-proof. One of these days I'll share it here.

Ride on!

Originally posted by OB1knobe
When spokes are breaking in a wheel under normal usage the problem is that the wheel has not been tensioned properly.


Actually, if this were the case, it would be much more likely that he'd be breaking non-drive leading spokes.

Dave

Originally posted by chip
I agree also with Rich clark the wheel must of been not dialed in from the word go.If you bought it at a real bike shop this should not of happened cause they would make sure that your bicycle works properly before you would be allowed to take it home...they have reputations to look after?Years ago I can remember checking all the dept. store bicycles for wheel true...none were dialed in.So when somebody buys what happens is he ruins the wheel for gets offended when he has to take to a real mechanic and pay.Dept store are making progress thou things are improving on some models.The manufacturer should dial them in before there boxed
Buying from a bike shop is no guarantee that you won't have wheel problems unless you have them built up the wheels for you, and even then you might have problems if they give the job to the new guy. I've ridden cheap bikes and I've ridden nice ones bought new from two different bike shops, and for some reason it's the latter that's always giving me trouble and breaking things.

As I continue to break spokes on a daily basis, I am looking to build a new rear wheel. It will be a nice 36 spoke, double butted, triple laced rear wheel.

I am glad I planned to ride my bike for a few years before going cross country with 60-100lbs of gear on my bike. I could only imagine how many would break every day with a big load like that.

Thank you all for your help.

Originally posted by Grendel
Buying from a bike shop is no guarantee that you won't have wheel problems.

Amen to that. Especially during busy periods, even a normally decent shop may be guilty of hiring inexperienced help and assembling new bikes and getting them out the door as fast as possible. There are *plenty* of bike shops that don't prepare wheels but just slap them on the bike right out of the box.

I sometimes to wonder whether the era of MTBs with their heavy, high-spoke-count wheels and fat cushiony tires contributed to many shops becoming lazy about wheel preparation.

*Good* bike shops go over every wheel, tensioning and stress-relieving them. Personally, I consider this, along with fitting, to be the real acid test of a good shop.

RichC