Pulled spoke, rideable or not

General cycling advice ( NOT technical ! )
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The utility cyclist
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Pulled spoke, rideable or not

Postby The utility cyclist » 21 Jan 2021, 6:01pm

Never had a pulled spoke before so.
This wheel suffered a walloping into a deep depression at a mini rbt, was focusing more on the 40 ton HGV bearing down on me from the left and just didn't see the grey disguised gouge in the grey road so I hit the edge of it with my full weight on the saddle :x Managed to ride the 15 miles back without problem just a bit of adjustment on the brake to stop the pad hitting the rim but actually not that much out but there's a bit of a hop obviously.

Could I continue to ride this as is and simply straighten it out a bit and put up with the hop, is it worth trying to compress the lifted bit of rim up as well or is it simply a case of salvaging the Deore hub and spokes? It'd be for utility/commuting duties for the most part including 30+mph descents, tyre would be 32mm folding if that might have any bearing.
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Brucey
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Re: Pulled spoke, rideable or not

Postby Brucey » 21 Jan 2021, 6:54pm

when you hit a rim hard enough to create a radial dent inwards, the main effect is that a few spokes see lower tensions than normal. Slightly increased tensions are seen in all the other spokes of the wheel, and significantly increased tensions are seen either side of the radial dent. It isn't impossible that such an impact might cause such damage, but it is (IME) unlikely.

It is much more likely that the rim was cracked already (esp if this is a DS spoke) and the impact conferred something of a 'coup de grace' to the wheel. If this is the case then where the spoke has broken the rim will have a radial bulge outwards (along with a sideways deformation of course).

It is somewhat academic of course but if you examine the crack faces using a magnifying glass (or via close-up photography) you may be able see that the crack faces are either shiny and new or slightly discoloured, if they are old. It might at least be some comfort that the hole you rode through might not have caused the whole problem. There may be cracks around other spoke holes too.

You can of course reinforce the cracked part of the rim using glass-fibre etc and make the wheel work again but there is as much effort in this as there is in rebuilding the wheel with a new rim, and it is of course a waste of time if there are cracks elsewhere. Also it doesn't take much to throw the wheel out of balance which is something you probably need to bear in mind too.

You can ride quite a long way on a wheel which is missing a spoke but that wheel is compromised; the loads are increased in other spokes nearby and further problems are inevitable.

Nothing (especially nothing lightweight) lasts for ever....

cheers
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mumbojumbo
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Re: Pulled spoke, rideable or not

Postby mumbojumbo » 21 Jan 2021, 7:18pm

Do not ride but save hub and spokes-you can tape another rim to existing wheeland rebuild.

hamster
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Re: Pulled spoke, rideable or not

Postby hamster » 21 Jan 2021, 7:45pm

It's ridable but there is the substantial risk that it's going to fail and buckle. I've ridden 3000 miles on a rim which is split around one spoke: I know it will go at some stage in the future, but every extra mile is free. It's still staying true, but the moment it starts to move I'll ditch it.

alexnharvey
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Re: Pulled spoke, rideable or not

Postby alexnharvey » 22 Jan 2021, 10:28am

Would a large oval rim washer add any strength? Can't quite tell if it would be wide enough to span on to good material. Also is it strong enough to take the tension it would see if not supported by the spoke bed?

https://www.spokesfromryan.com/product/ ... le-washer/

Jamesh
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Re: Pulled spoke, rideable or not

Postby Jamesh » 22 Jan 2021, 12:10pm

alexnharvey wrote:Would a large oval rim washer add any strength? Can't quite tell if it would be wide enough to span on to good material. Also is it strong enough to take the tension it would see if not supported by the spoke bed?

https://www.spokesfromryan.com/product/ ... le-washer/


A washer might be a very useful item to carry in tour if the spoke bed is accessable.

Cheers James

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The utility cyclist
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Re: Pulled spoke, rideable or not

Postby The utility cyclist » 23 Jan 2021, 12:51pm

thanks for all replies.
Spoke bed wasn't damaged before, the wheels are cleaned fairly meticulously and regularly so no cracks before and nothing around any of the others.
I'm sorely tempted to keep running it until it properly goes but may as well just salvage what I can and be safe, the run down to the supermarket/next town is a fast descent and quite bumpy at the bottom so it's only going to exacerbate things, it'd be going onto the commuter as a replacement so is likely to get heavier loads than the bike it has come from.

I don't do wheel building, don't think I have the patience or the talent to do it though it would be very helpful in terms of sorting wheels out for my exact needs without the need to go to a wheel builder.
so either I find someone who can build onto a rim or I just sell the bits, it's probably less expensive just buying another wheel - hence the wanted ad.

Jamesh
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Re: Pulled spoke, rideable or not

Postby Jamesh » 23 Jan 2021, 1:27pm

Hi

Wheel building isn't terribly difficult.

I have built two pairs with some success despite being of limited patient and even less intelligence - I've set the bar nice and low for my kids!!!

Replacing a rim is even easier.

Measure the inner diameter of the rim and order a new one.

Take the new to the old and systematically transfer the spokes across.

True up and tension.

I've found the wheel is pretty much in true straight away once it's laced up just needs the tension increasing gradually.

More on drive side less on nds.

Cheers James

cyclop
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Re: Pulled spoke, rideable or not

Postby cyclop » 23 Jan 2021, 2:07pm

I had a spoke pull thru,though different circumstances i.e.rear mech touched the spokes whilst descending a stony track in the forest,ripped a spoke out.I fashioned a support plate,drilled a spoke hole,placed in the rim well,sealed with clear silicone and its been fine since(8yrs or so)I,m not hard on my mtb,fire trails mainly and with discs,both of which might be relevant.Rim,mavic 317 disc.

Brucey
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Re: Pulled spoke, rideable or not

Postby Brucey » 23 Jan 2021, 8:28pm

The utility cyclist wrote:...Spoke bed wasn't damaged before, the wheels are cleaned fairly meticulously and regularly so no cracks before and nothing around any of the others...


I need hardly point out that if a wipe with a rag and the Mk1 eyeball was a reliable crack detection system, there wouldn't be a whole industry devoted to finding cracks using other, better, methods. IME 'visual crack detection' is least reliable on surfaces which are dark-coloured and are also not perfectly smooth to start with. Like yours.

Also if the cracks start inside the rim, there is nothing to see until they break the outer surface.

Cracks in dark-coloured rims are notoriously difficult to spot, until they open up; I confess I have even got as far as building a wheel using a cracked rim before spotting the cracks....d'oh!

cheers
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