Spokes

[Dave Y Fenni]

I own a Volt metro LS. I went for a ride yesterday (recovering from knee operation). A 17 mile trip, got home and there was this tinkling sound. On investigation 8 spokes snapped, rear wheel. Contacted supplying dealers, they contacted Volt. Basically I am too heavy for the bike, but there is fix at my expense. Thicker gauge spokes and a modified rim.
Any one out there had anything similar?

 

[Andy-Mat]

I own a Volt metro LS. I went for a ride yesterday (recovering from knee operation). A 17 mile trip, got home and there was this tinkling sound. On investigation 8 spokes snapped, rear wheel. Contacted supplying dealers, they contacted Volt. Basically I am too heavy for the bike, but there is fix at my expense. Thicker gauge spokes and a modified rim.
Any one out there had anything similar?

It sounds as though they might/should have mentioned that before they took your money when selling you the bike!!
I have to admit that I have never given my weight a thought before buying......of course I would expect to be informed from the seller....
Regards
Andy

 

[vfr400]

I own a Volt metro LS. I went for a ride yesterday (recovering from knee operation). A 17 mile trip, got home and there was this tinkling sound. On investigation 8 spokes snapped, rear wheel. Contacted supplying dealers, they contacted Volt. Basically I am too heavy for the bike, but there is fix at my expense. Thicker gauge spokes and a modified rim.
Any one out there had anything similar?

You need thinner spokes on the same rim, not thicker ones. They broke due to metal fatigue, not because they weren't strong enough. you'll see that they all broke at the elbows, not in the middle. You should change to 14 gauge (2mm) spokes which are more elastic, so you don't get the massive change in stress at the elbows that heavy guys make when they ride a bike with inelastic spokes.

 

[sjpt]

Bad luck: Volt's web site Rider Weight: 11 Stone (Please note 11 Stone is the weight of the test rider and our e-bikes are capable of carrying riders well over this specified weight) is not very helpful.

If lots of spokes went at once it sounds as if it might have been an impact issue rather than fatigue. I just replaced 10 spokes on a cheap 48 spoke tandem wheel, and having noticed slight faults on the rim intend to replace the wheel. From what I have read just recently researching this, it is best to have double butted spokes to prevent fatigue breakage (for the elasticity you mention, but retaining greater thickness especially at the J bend end where most spokes break), but to have heavier spokes to avoid impact issues.

I just asked Spa if one of their wheels (https://www.spacycles.co.uk/m2b0s176p349/SPA-CYCLES-Handbuilt-Wheel-Rear-Sputnik-Deore) built with 2/1.8mm double butted spokes on the non-drive side and Sapim strong (single butted, 2mm but 2.3mm at bend) would be suitable for a replacement tandem wheel; they suggested that Sapim strong both sides would be best. I'm also considering a similar handbuilt wheel from SJS, https://www.sjscycles.co.uk/wheelswheels-rear/700c-622-rear-wheel-36h-ryde-sputnik-rim-with-deore-hub-8910-speed-in-black/ This has plain gauge spokes; I think 14g/2mm but I'm checking.

Sapim Strong might be best for your rebuild, main part 14g as vfr400 suggests, but stronger at the bend.

Generally most people say that the quality of the wheel build is the most important feature, not the exact spoke choice.

Lots of comments at 'Wheels for big guys' at https://forum.cyclinguk.org/viewtopic.php?f=1&t=131002

 

[Nealh]

For all my wheel builds I use 2mm/14g Sapim strongs and have had no issues.

 

[tonyw]

For all my wheel builds I use 2mm/14g Sapim strongs and have had no issues.

Modern stainless spokes like sapim/dt etc are very strong indeed. They will pull through the rim, or you'll round off the nipple before breaking one. As said above, if spokes are breaking, then almost certainly the wheel was built badly (poorly tensioned, not stress-relieved). Blaming breakages on rider weight or pot-holes is generally BS.

 

[Dave Y Fenni]

A bit of news!
Volt contacted me today by email. They want the wheel back. New rim with different spokes. As the bike is at my local bike shop, hoping for a spoke repair. Volt will pick up wheel from them and they said will return it by this Friday?
Will post the outcome!

 

[Dave Y Fenni]

Modern stainless spokes like sapim/dt etc are very strong indeed. They will pull through the rim, or you'll round off the nipple before breaking one. As said above, if spokes are breaking, then almost certainly the wheel was built badly (poorly tensioned, not stress-relieved). Blaming breakages on rider weight or pot-holes is generally BS.

I don't understand spoke geometry. What I do understand, is if something is larger in diameter, surely it will be stronger. Looking at Sapim 12g or 13g ebike spokes have diameters of 2.3mm or 2.6mm.
I am no Geraint Thomas, but from the same part of the country. Not looking for lightness, my ride is a Volt Metro LS, with 20" wheels, coming in at 22kg with the uprated battery, so another 0.5kg is neither here nor there?

 

[sjpt]

Something larger is stronger and more rigid. However, that rigidity can cause more stress at key points (mainly at the J bend where the spoke meets the hub), and that over time can lead to fatigue breakages. The extra strenght can be more than offset by this extra stress. Double butted spokes can stretch a fraction in the centre and thus relieve stress at the ends. Sapim Strong are single butted: 14g (2mm), but 13g (2.3mm) at the J bend.

 

[vfr400]

I don't understand spoke geometry. What I do understand, is if something is larger in diameter, surely it will be stronger. Looking at Sapim 12g or 13g ebike spokes have diameters of 2.3mm or 2.6mm.
I am no Geraint Thomas, but from the same part of the country. Not looking for lightness, my ride is a Volt Metro LS, with 20" wheels, coming in at 22kg with the uprated battery, so another 0.5kg is neither here nor there?

It's not the lack of strength that makes them break. It's metal fatigue. When you have inelastic (strong) spokes, you get more difference in tension between those at the top of the wheel and those at the bottom when you have weight on the wheel.

Basically, when you sit on the bike, your weight is hanging on the top spokes. The effect is that as the wheel rotates, the spokes at the top are pulled tight and the ones at the bottom are pushed loose, so the tension goes up and down once per rotation of the wheel. The more stretchy thinner spokes can keep a higher tension when they're at the bottom, and the load is spread more evenly around the wheel, so the cycling of the load, which causes metal fatigue is less.

We've told you which spokes to use, i.e. 14g. It's your bike, and you can use whichever ones you want.

 

[Nealh]

Use 14g tried, tested and works.
14g has a bit more elasticity and give.

Try lacing a new spoke in to a wheel when replacing a broken one, 14g is so much easier to manipulate then a 12 or 13g.

 

[Dave Y Fenni]

Ok, lets see what Volt comes back with. I take on board what you have all said.
Thank for the input. 14g it is

 

[vfr400]

Most bike shops and even the manufacturers haven't got a clue, neither have the Chinese. When i met the Volt guys a few years ago, they didn't even know how to derestrict their bikes.

 

[Woosh]

Most bike shops and even the manufacturers haven't got a clue, neither have the Chinese

that's a bit harsh.
if the flanges of the motor and the rims are made to fit 13 gauge spokes then it makes sense to use 13 gauge spokes.
You can use 14 gauge spokes but I can't see the benefit other than 14 gauge spokes are lighter.
Most wheels are trued on machines, with QC done by humans. I usually nip up all the (machine trued) spokes about a sixteenth of a turn or less just to check their tension while prepping the bikes.

 

[vfr400]

Most bike shops and even the manufacturers haven't got a clue, neither have the Chinese.

that's a bit harsh.

Hmmmm!

14 gauge spokes but I can't see the benefit

I rest my case.

 

[Woosh]

Hmmmm!


I rest my case.

from the manufacturing point of view.
I keep stainless spokes for all my bikes, they don't sell well. I know it's a relief for you!
For those who want to be technical, just take a close look at how the spokes hug the flange of the motor at the J bend where breakages occur.
if you are curious, buy both sizes and take some close up pictures how the 14 gauge sits in the well.

 

[Dave Y Fenni]

For a numpty
To check the tension on a wheel (something, I have never done) at the nipple is it clock wise to tension, or anticlockwise? As I said above, wheel geometry is new to me. Woosh stated that he nips up wheels with a sixteenth of a turn?

 

[Nealh]

Yes, CW to tension.

 

[Woosh]

For a numpty
To check the tension on a wheel (something, I have never done) at the nipple is it clock wise to tension, or anticlockwise? As I said above, wheel geometry is new to me. Woosh stated that he nips up wheels with a sixteenth of a turn?

if you tighten your spokes or true your wheel for the first time, you would want to know how tight you want your spokes to be.
I have a spoke tensiometer, so it's not difficult to check, but if you don't, first make sure that all the 36 spokes are tightened at least until there is no slack and you start to feel the pressure turning the spoke key.
Then starting from the spoke nearest to the valve, tighten half a turn all 36 spokes.
Now you need to make sure that the rim runs true. If the wheel needs truing, watch a few youtube videos how to true your wheel. Assuming your rim runs true (both horizontally and vertically, within +/- 0.5mm-1mm), now it's the time to tension up all your spokes. If you have a tensiometer, you want to see 125kgs-135kgs. If you don't, watch the spokes when you tighten the nipples, stop as soon as you see the spoke shank starts to twist with the spoke key when you turn the key. That's the sweet point, it corresponds approximately to about 130kgs tension.
This is the 13G spoke key I use, it's colour coded, it's red.
https://www.wiggle.co.uk/x-tools-pro-spoke-wrench-1/
You find plenty similar on ebay.
never tighten a spoke that already feels tight (no slack and pings with a clear sound) more than 1/4 (90 degrees) of a turn at a time, check and nip up all other spokes before tightening more the same spoke.
If you use the wear groove on the rim as guide, note that one turn of the nipple shortens the spoke by 1mm, a quater turn = 0.25mm.

 

[Dave Y Fenni]

Picked the bike up today from Local bike shop. New rim, new spokes. all silver, not black
Cost to local shop £30, have not had anything from Volt!
Riding and time will be the decider!