Snapping driveside spokes – anything I should do differently next build?

I had a pretty big weekend on the gravel bike this weekend, most of it ridden with a broken spoke on my rear wheel and no rear brake!

It’s the second driveside spoke that’s snapped on this wheel, although to be fair the spokes themselves have now done approx 6500km of ‘enthusiastic’ gravel riding under my clumsy 90kg, and both wheels have had rims replaced with the same spokes. Funnily enough the Sapim alloy nipples seem to be outlasting the Sapim double butted spokes!

Anyway, I’m hoping it’s just general fatigue that’s causing the snapped spokes, but before I treat myself to new rims and a set of CX-Ray spokes, am wondering if there is anything else different I should do, perhaps go 3 cross instead of 2 cross? 3 cross would increase the spoke angle at the rim which I’m not too keen on as I’m going for deeper rims anyway which will already increase the angle at the rim a wee bit.

Otherwise, is 6500km offroad and a rebuild decent mileage for a set of spokes?

Ta

What part of the spoke snapped, at the bend or shaft?

Personally I’ve not had spokes snap unless I’ve hit them with something, stone, stick or big pothole.  (probably should be trying harder). I’m a lightweight at 72kg though.

I guess you did all the stress relief and little flags for spoke wind up?

The book I use says 2 or 3 cross makes no difference to strength of build,but I think your logic around spoke angle is sound. (Roger Musson)

wheres it snapping – J bend , Butting transition or thread ?

also – where did you get them.

When i was looking there were a whole slew of ebay sellers/ali express doing sapim and DT “branded”spokes direct from china much cheaper than local – which makes me suspect fakes flooding the market. so much so i went to bricks and mortar to buy my Sapim double butted  – (singletrackbikes in fife)

ive got them on 28hole carbon rims – Was fastidious on my use of the tensionmeter though  -bad hangovers from the early days of carbon rims at the shop.

I always do 3x, never broke a spoke, and that’s on a commuter with heavy panniers (both a road bike and a 26er MTB. I have re-used spokes. Although it say’s not to re-use spokes, I have, without issue !

Both snapped at the thread.

I used a tensionmeter but a cheap one, so just used it as a guide to even tension, didn’t trust the actual figures but I got as close to the maximum tension of the rim as I was comfortable doing (obviously driveside, non-drive was slacker).

Spokes came from RyanBuildsWheels (now BristolSpokeCo), they certainly weren’t any cheaper than RRP so hopefully not knock-offs!

I’ll admit I’ve maybe not taken de-stressing as seriously as I could in the past, just squeezing paired spokes as hard as possible with my hands wrapped in a dish towel or something, but would lack of de-stressing not have manifest itself a lot earlier?

That’s good to know about 2x or 3x though, ta.

I wonder if the rebuild is your issue.

I had a Hunt 4seasons rear road wheel that I fairly catestrophically mashed the rear rim hitting a huge pot hole. Dented and out of true. Had it rebuilt onto a crash replacement rim using the same spokes and I got several snapped spokes over a period of time until I got annoyed with it.

Rebuilt the same rim onto the same hub with new ACI double butted spokes (wheel originally had Pillar triple butted spokes I believe) and haven’t had a single one snap yet. And since then I’ve moved to having to take more kit on the commute to work in a pair of pretty weighty pannier bags.

Spoke count is only 24 on that back wheel too – even one spoke snapping can put the wheel quite out of true.

but would lack of de-stressing not have manifest itself a lot earlier?

Not necessarily.Y

Not saying this is your issue but in that scenario

Youl have a larger dynamic stress than design. But it will reduce the number of cycles yes but you’d have to be catastrophically loose to induce that level of load for close to immediate failure.

If your spokes have destressed through use and are now sitting somewhere between visible loose and correctly tensioned and are being abused.

It will lead to a lowered life  through cyclic loading/unloading rather than immediate catestrophic failure

Equally it’s drive side as that’s where you often have the weight in the right place to achieve max loading through traction. Brakes can apply a much higher forced immediately but your weight going forward rarely gives you the traction for a reaction force comparible to that of under pedal load.

Id expect snappage at the j bend if the rebuild was the issue.

In the same breath I’ve rebuilt many personal wheels reusing the same spokes because I’m tight ….and toured fully laden across Canada on some of the same.

If they are snapping where the thread starts, could it be that your drive side spokes are slightly too short, How many threads are showing outside the nipple. Maybe go a size up rather than down, even if down is slightly closer? Although you’d think they’d just strip the alloy nipple thread rather than snap. Failing that I guess it’s just buy some leather riggers gloves and get de-stressing!

I’m sure Ryan’s spokes are kosher. The ones from him that I’ve bought in the past are all going strong still.

Another option for good,cheap spokes is Cycle basket in Newtown, although the postage ain’t cheap. They sell ACI spokes, which aren’t as well known as DT or Sapim, but are light and have been reliable for me.

Musson’s e book is simple and excellent BTW.

I’ve rebuilt loads of wheels over the years and not had spoke breakages. However I’ve have had it on a few machine built wheels.

The fact it’s the drive side that has less hub to rim angle (I don’t know the actual terms!) so has higher spoke tension the issue? Is it a 135mm hub with a 700c/29 rim?

Are the nipples corroded from road salt?

Are the nipples corroded from road salt?

Not that I can tell, in order to get the wheel spinning through the frame whilst out on the trail I had to tighten and loosen a whole bunch of spokes, all nipples turned smoothly enough. I applied copper grease to the threads during the last build for this reason, wonder if there’s some sort of reaction between the stainless steel spoke and the copper grease? You’d think the nipples would fail first!

Is it a 135mm hub with a 700c/29 rim?

A 130mm DT350 with a 135mm end cap, so arguably marginally less dish than standard as the wheel centre is slightly more towards the non-drive side.

I wonder if that means the drive side spokes ARE too short as per lesshaste’s suggestion, as I probably calculated length based on a standard 350 hub without the reduced dish…

Use Sheldon Brown’s PowerSpoke(tm) pattern.

I find that once one spoke goes, it’s only a matter of time until another one goes, I’m not sure if it’s because they’re all equally fatigued/corroded or the action of the first spoke snapping put extra stress on other spokes around it.

I have however never snapped a plain gauge spoke, despite putting thousands of single speed km’s on them, this has been the case both pair of wheels I’ve ran (one pair I built without a jig or tension gauge). Where I’ve had a fair amount of butted spokes snap. Maybe superlight butted spokes aren’t ideal for daily abuse, all year round in Scotland, or it could be the power you put out ;)