Breaking Spokes on Road Wheel

[RShea]

I have been experiencing a number of broken spokes on my rear wheel on the road bike. Last year a few broke and the shop that did the repair stated that a few more broke while they were fixing it. Then at the beginning of this riding season another broke on the same wheel. They snap right up at the hub at the angle. Talking to another cyclist today he stated the hub may be causing this- his claim is it is common for the holes to start shearing off the spokes.

Any comments on the issue and recommended repair, replacing the hub and the spokes or just the spokes?

[sfotex]

If you have descent quality spokes (DT or wheelsmith), you probably just need to get the wheel retensioned...

[BLOOD SWEAT STEEL]

What kind of hub and spokes? What gauge? Has the hub been built up in another wheel previous to this one?

[mntlion]

shounds like time to repace the spokes and rim/

how many miles/year on it?

[El Chupacabra]

Lots of questions to determine what's really wrong with your wheel... hard to diagnose over the internet too, without looking at the wheel and rim, and feeling the tension by hand.

The elbow where a traditional spoke enters the hub is the spot where breaks most commonly occur. This could be fatigue, could be poor tension, could be poor build... hard to tell from here. Know any good local mechanics you can bring it to?

[rideit]

I think the faulty hub diagnosis is suspect. Like BSS asked, what are the specifics? Sounds to me like it was ridden too hard, and/or too long, with improper tension. I would bet that a rebuild with a new spokes (and rim) would nip it.

[mntlion]

like El C said, local bike store and a 6 pack go a long way....

[Vinman]

the one other thing to consider here is how heavy you are in relation to the rim and spoke guage. If you are a clydesdale riding an x lite race rim for everyday riding, stuff is going to break. If this is the case its possible that no amount of rebuilding and retensioning is going to fix your problem. The only things that fix that problem are either losing weight or getting a beefier rim.

[CantDog]

Are your thighs the size of Erik Zabel's? I think thats your problem. You are simply putting too much power down to the pavement.

[1wsguy]

I'm gonna guess that most or all the spokes that broke are on the drive side.
The drive side spokes are the ones that are subjected to the most amount of torque, like when you stand up and sprint, or just really put the hammer down.

This leads to a constant spoke tension, build up, and release. The elbow of the spoke is the point on the spoke where the stress riser occurs.

If the elbows were not properly "set" at the time of the wheel build, then the stress riser is increased to a point beyond the yield strength of the spoke, and they begin to break.

If the spoke holes on the hub are deformed or elongated, from a couple of rebuilds, or, from Erik Zabel size thighs, then this allows the spoke a little room to move which also creates a stress riser at the elbows.

The guy that replaced the spokes and had some break while trueing should have been able to predict more breakage. Once they start breaking like you described more will continue to break.Just retensioning/trueing will not cure this.

What ever the case, its time for a rebuild (from an experienced wheel guy), with all new spokes/nips, properly set and tensioned, or, a complete wheel replacement if the hub holes are bad.

[BLOOD SWEAT STEEL]

They make these little things called "spoke washers" They are an absolute must with rebuilt hubs, as are 2.0mm spokes [at the head end] ONLY. Anything else, especially when built by an inexperienced wheelbuilder, sooner or later, will lead to breakage.

In my 12-odd years wheelbuilding, I would have to say DT/Hugi, Dura Ace/early XTR and King hubs have the best spoke hole fit. A high quality hub will actually almost make you force a 14ga spoke into the hole. This becomes critical down the road in the life of the wheel, because as you have seen this is the most vulnerable failure point, even in a quality handbuilt wheel. The more miles on the wheel - the bigger the hole gets, the more sloppy the spoke head gets, and pretty soon shit starts breaking. It is important to find a hub that has a canted flange as well [angles toward the rim,] especially in the case of wheels that are going to see a lot of abuse. [DJ, DH, crit, trials]

[RShea]

Thanks for all the comments, I'll try and address most of the questions or unknowns.

First I am not a heavy rider- 170 pounds max. It has been a number of years since I've raced with this bike (and when I did race more often it had tubulars on it). Just local road miles, tours etc.

The hub is the original that came on the bike- Fuji with mostly Suntour componets (not the highest end stuff like Shimano)- the rim is an Araya and the hub has an SR logo. But the bike is probably getting to be 20 years old. I have also run tubulars on this so the same wheel has not had all the miles on the bike. The spokes are the original too so it very well could just be the age and needing a rebuild or possibly retentioned. The spoke diameter is something I do not know what they are- standard if there is such a thing. (do not have callipers either to measure the diamater.

I know a few good mechanics in the area including most of the local shop owners from my involvement with the local cycling club. Just want to know what to expect before walking in, since the spokes seem to be fatiguing and breaking.

Many recommend the rim be replaced too when the spokes are in the thread, is there a particular reason for this, I would understand this more if the problem was down at the rim area. Yes most of the breaks have been on the cassette side as suggested.

Thanks for the feedback so far. I'll probably take it into one of the shops and see what they think it will take and cost.

[BLOOD SWEAT STEEL]

20 year old cheapie spokes [possibly galvanized, too] machine built on an araya rim and Sakae hub. I'd definitely say you've gotten your money's worth.

Fo sho time to treat yourself to a new wheelset.

[rideit]

Fo sho time to treat yourself to a new wheelset.

Absoshitly. they have done superb service. Give em' the gold watch.

[1wsguy]

More possible issues to deal with: A new wheel is gonna lead to some other issues. A 20 year old wheel probably has a freewheel on it and not a cassette. I'll guess that the freewheel is either 6 or 7 speed.
All new hubs are made for cassettes that are 8,9,or 10 speed. The spaceing is different on cassettes and freewheels (narrower on cassette),

so...if you want to replace the wheel with something current,, then your chain will probably be too wide. If you replace the chain, then it may be to narrow for the chainring spacing of the crank, and might jam or slide between the chain rings.

Then there's the shifter question; Index or friction?.........................

You could dump a lot $ into this bike and get something that's just ok.

IMHO if the hub checks out ok:rebuild with new spokes/nips new rim if needed, and call it good for now.

Use Blood Sweat's suggestion:
They make these little things called "spoke washers" They are an absolute must with rebuilt hubs, as are 2.0mm spokes [at the head end] ONLY. Anything else, especially when built by an inexperienced wheelbuilder, sooner or later, will lead to breakage

And start looking for a new ride: the new roadies are soo sweeet!

[ShawnB]

More possible issues to deal with: A new wheel is gonna lead to some other issues. A 20 year old wheel probably has a freewheel on it and not a cassette. I'll guess that the freewheel is either 6 or 7 speed.
All new hubs are made for cassettes that are 8,9,or 10 speed. The spaceing is different on cassettes and freewheels (narrower on cassette),

RShea's getting dope info from everyone on this one; some very astute mags, that's for sure. One thing: The above isn't quite correct; I had the same problem, and worked a sweet fix (and upgrade) by just looking for older high-end wheelsets being sold on craigslist. I suppose you could do eBay too, but w/ CL, you can see the stuff you're buying before you spend. Anyway, about a hundred bucks got me a newish and damn light wheelset, far better than what I had before--with the possibility of adding a cog if I want, later.

Had a 20yr-old (pretty nice) 7spd freewheel setup. New wheelset was 8spd cassette. No difficult compatibility probs. That era's (late 80's) chains/cog spacing are fully compatible w/ 8sp Shimano--spacing is the same, just the hub dish changes on 8-9spd-plus.

Yes, the 8-spd-plus hubs are wider, but my alu frame accommodated them with very little struggle--it didn't seem like a big deal despite all the tsk-tsking you'll find online on that subject. Carbon? Mebbe not, but I doubt that's what you're dealing w/ if you've got Suntour/SR stuff spec'd.

THE ONLY ISSUE: My derailleur couldn't handle traveling the extra inward distance--and I may switch it out in the future--but 7 cogs is good enough, so for now all I did was lose the innermost cog and substitute a spacer instead on the cassette (which I disassembled anyway to switch the cogs to be the range I wanted using only 7 instead of 8 provided. Easy.

So anyway, that's one solution. Cheap, and wheels are a sweet place to upgrade. If you're gonna spend a hunny only, I recommend spending it on New-ish Old Stock wheels from CL instead of on rebuilding shit wheels.

Peace,
Shawn

[RShea]

Craigs List is not a local option- none in my city, so it would be Ebay or more likely something that a local shop had around from a upgrade or trade. Not sure if I would know enough to buy on Ebay either since the issues discussed are valid on the cassette, 8 or 9 speed would be an issue on the existing ride and derailure.

[ShawnB]

Sympathize with you on the lack of Craigslist thing. Sux.

But as for the following...

...the issues discussed are valid on the cassette, 8 or 9 speed would be an issue on the existing ride and derailure.

...I don't read you. What issues do you mean? In my post, I tried to go over the major issues and how I dealt w/ them in just this kind of switch-out. In short: There weren't very many actual issues. Did I miss something, or did I just shorthand it too much and lost comprehensibility?

[1wsguy]

I'm glad that worked for you, Shawn, its been a while since i've converted some old stuff.

Sometimes, though, it's not always that lucky. I've done some conversions (back in the day) where things almost worked, but were just off enough to cause issues.

Most 7 and 8 speed freewheels and cassettes used 3mm spacing, or 3.1 or 3.2 or something close enough to work. Some 5/6 speed freewheels used 3.5.
9 speed is mostly 2.5ish. 10 speed is 2.3 or 2.4 There are also some 8 speed suntour freewheels that had a mix of 2.8mm and 3.0 spacing.

Original chain spec would match , so sometimes installing a narrower chain on a system spaced for wider, can lead to the chain skating over or between the front chain rings.





RShea: You might ask your buddies or LBS if they could stick an 8 speed cassette wheel in your frame just to make sure things will work out. Try the shifting (still don't know: friction or index and how many speeds), and make sure your happy with it before you buy. If your bike has friction shifting, you might be ok.

[CantDog]

Or...you could just buy a NOS hub on ebay. A quick search for freewheel hubs yielded a whole bunch of campys, shimano, etc for under 50 dollars a set.

[RShea]

Sorry for the delay in posting. The SunTour Accushift is switchable between index (what I usually have it set for) and it has a friction option if I remember correctly by changing the dial on the shifter levers.

As for the issues of 8 or 9 speed, the SunTour is only a 6 speed now so the expense of 8 or 9 speed could be pretty high (chain, freewheel, maybe a derailer, etc if I understand the issues.- all assuming the 8 spped fits in the frame drop out.)

Going to start by seeing what the shop recommends (maybe a full rebuild of the existing with the spokes washers as suggested) for the wheel and then decide if I'll pursue it or go back to the tubular rims I have for the ride.

Thanks for the insight and comments.