you should learn truing your wheels rather than carrying spares and replacing broken spokes. Machine spoked wheels usually need re-truing when they are got out of storage because the spokes are loosened. They usually need taken up about half turn to a turn. The other thing to keep in mind, you need to ensure that your wheel must line up with the middle line of the frame, otherwise, spokes will keep breaking.

 

Both of those are possibilities. I did prestress and true both wheels when I first had them and at about 100 miles, but it's something I'm in the process of learning so I'm not brilliant at it. Misalignment in the frame (bent frame?) is certainly also possible, but wouldn't that cause spoke failure on one side only?

The first time I found a broken one I put it down to just a bad spoke, but started carrying a couple of spares just in case. Then I got 3 at once. Haven't had any since, so maybe it was bad spokes, though I did retrue the wheel once I got home, so that might have something to do with it.

 

I do use so pretty terrible roads and sometimes carry loads on the back rack (dead Muntjac, 30kg of trout, that sort of thing) but the previous wheel never had spoke trouble.

Misalignment in the frame (bent frame?) is certainly also possible, but wouldn't that cause spoke failure on one side only?

 

no, I meant correct dishing so when you look from the rear wheel to the front wheel, the bike is symetrical along the middle line.

no, I meant correct dishing so when you look from the rear wheel to the front wheel, the bike is symetrical along the middle line.

OK, thanks. It's not that one then. The rim is centred in the chainstays. It's a hub geared, coaster brake wheel so symmetrically dished, or close to. Replaced a hub gear drum brake wheel, so that should be the correct dish for the frame.

 

I do use so pretty terrible roads and sometimes carry loads on the back rack .

 

would you consider a full suspension bike? a rear suspension would help eliminating broken spokes.

would you consider a full suspension bike? a rear suspension would help eliminating broken spokes.

I suspect that would change a device for breaking spokes into a device for breaking racks, or maybe seat posts. Are there racks for suspension bikes which will take 30kg?

 

I have owned a full suspension bike, which I bought because of the quality of the local roads. Found it very hard work (it was a cheap one) and eventually got rid.

 

A trailer might be the best answer when I'm expecting to carry a load, but it's not always expected ( a choice roadkill, for example).

yes, the Thule will take 60kg easily or a trailer as you said. Marwoodhill has a trailer that carries his other half.

When you get 4 broken spokes, you should rebuild the whole wheel.

Marwoodhill has a trailer that carries his other half.

Isn't the correct device for that a tandem ;-)

When you get 4 broken spokes, you should rebuild the whole wheel.

 

That's probably what I will end up doing, if it continues to misbehave. Maybe upgrade to a 7 speed hub and use the stainless steel rim from the original rear wheel. When I bought my current rear wheel I didn't realise wheel building was something you can do at home (and it cost the same as a loose hub, which probably says something about the quality of rim and spokes...).

When you get 4 broken spokes, you should rebuild the whole wheel.

 

That's true....it indicates that there's fatigue at the elbows and all spokes should be tightened to their proper level, stressed and de-stressed before ensuring that the spoke tensions are all within parameters. The problem is that machine-made wheels are usually radially correct but the machine cannot carry out the above procedures which are essential if the spokes are not subject to fatigue. I tend to buy factory-made wheels as they are cheaper than buying the same components and building my own wheels...but I always go through the above procedures before I use them.

I suspect that it is the bend that gives the trouble.

I do wonder if the older spokes had a slightly different shape at the bend, or received stress relieving treatment after being bent.

It really doesn't matter about some of the explanations given here.

I contend that modern spokes are prone to snapping, older spokes were not.

If this is the case, why aren't manufacturers doing something about it?

 

Not true I'm afraid. "Rustless" or "galvanised" spokes of yesteryear were never as strong as today's spokes and broke with monotonous regularity. Good quality modern stainless spokes are made with superior materials and superior manufacturing processes and the double-butted ones are designed to flex and elongate which reduces fatigue at the elbow. That said, the most important element in ensuring a strong and durable wheel is not the components used but the builder.

Not true I'm afraid. "Rustless" or "galvanised" spokes of yesteryear were never as strong as today's spokes and broke with monotonous regularity. Good quality modern stainless spokes are made with superior materials and superior manufacturing processes and the double-butted ones are designed to flex and elongate which reduces fatigue at the elbow. That said, the most important element in ensuring a strong and durable wheel is not the components used but the builder.

if you read my original post you will see that I am speaking from 65 years of experience with spokes, bikes, motorised bikes, motor cycles and my old MG Midget.

if you read my original post you will see that I am speaking from 65 years of experience with spokes, bikes, motorised bikes, motor cycles and my old MG Midget.

 

Err....well done but I have over 65 year's experience with rustless spokes on bikes......mind you it could have been one year's experience repeated over 65 years.

I've repaired bikes and wheels for paying customers and KTM in this thread has also built wheels for a living and I'd be interested in his opinion on the subject.

 

And again Sheldon who usually knows about these things said:

"The material of choice for spokes is stainless steel. Stainless is strong and will not rust. Cheap wheels are built with chrome-plated ("UCP") or zinc-plated ("galvanized") carbon-steel spokes which are not as strong, and are prone to rust."

Edited October 12, 20169 yr by Georgew

Galvanised mild steel has a much higher fatigue resistance than stainless. I would have thought they would last the longest. Is mild steel strong enough? I would have thought so.

Galvanised mild steel has a much higher fatigue resistance than stainless. I would have thought they would last the longest. Is mild steel strong enough? I would have thought so.

 

Best to have a look at some of these threads where the subject of spokes, fatigue and build have been done to death. Lots of good stuff here by people who have built wheels for a living and are very knowledgeable.

 

http://forum.cyclinguk.org/viewtopic.php?f=5&t=104884&p=998883&hilit=spoke+fatigue#p998883

 

http://forum.cyclinguk.org/viewtopic.php?f=5&t=103903&p=986447&hilit=spoke+fatigue#p986447

http://forum.cyclinguk.org/viewtopic.php?f=5&t=102872&p=971871&hilit=spoke+fatigue#p971871

http://forum.cyclinguk.org/viewtopic.php?f=5&t=102007&p=959966&hilit=spoke+fatigue#p959966

Stainless steel is notorious in the sailing world for suddenly giving way.

It suffers from crevice corrosion, which might be what is occurring at the J bend.

Georgew.

Thanks for those links, very interesting.

Thinking back, I never had trouble with British built vehicle spokes.

I've never had to give spokes much thought as in over forty years of cycle-camping I've never broken one....discounting the time I fell into rail tracks in Troyes and broke my rear hub. For that time though I loaded up with tent, all my camping gear and tools and spares and every year cycled from Belgium or Calais down to the south of France before criss-crossing the country and heading north to Belgium again. Over two months loaded cycling and pedalling every day and without any spoke breakage. I always carried a few though but used them on other people's bikes.

Blackgates Engineering (blackgates.co.uk) supply 2, 4, 5, 6, 7, 8 & 10BA washers made from brass or steel in packs of 100 for £4. Some small stainless available M3 to M6.

If the J-end isn't sat properly in the hub hole this could place pressure on the bend and cause a break.

Graham at Tiller Cycles recommended to me to use brass spoke washers a couple years ago and seems to have helped me.

http://www.tillercycles.co.uk/page2.html

Also Sheldon Brown mentions them

http://sheldonbrown.com/wheelbuild.html#washers

The next point is lacing.

I read Sheldon Brown's comments, but was surprised to see that my Bafang 8-fun motor has the spoke heads all on the same side, not alternating in and out. They are one cross.

But I saw that Cwah's Brompton has the same arrangement, but zero cross which Sheldon considers inadvisable because the wheel can 'wind up'

Any thoughts?

Heads all on one side is better when you need you off-set (dish) the rim. Cwah has a radial spoke pattern because it's a big motor in a small wheel, which doesn't leave room for crossing the spokes.

alternating heads is better, the spokes run straight without squashing on one another.

I've been wondering about that too. My front motor wheel has a very simple lacing pattern, alternating heads but only crossing one spoke on the same flange (cross 2? since the spoke on the opposite flange is also crossed), done with what look to me like massively thick spokes. Any reasons for that? The motor is a smallish one in a 700c wheel, so there would be room for a more conventional cross 3 pattern. I assume it's someone's idea of a high strength wheel, though general opinion is that thinner spokes (with more crossings?) are better. I have to say that my limited experience doesn't support that. Both of the original wheels on my dutch bike had thicker than normal spokes and no spoke trouble, my current replacement rear wheel has standard spokes and breaks them (but I think there are other reasons for that). All these wheels have hub brakes.

 

I've also come across a Claude Butler Torridon, again hub braked, with a good collection of broken rear spokes. I rebuilt that wheel myself (first one I've done) using cheap spokes bought on line. It came out OK, I learned a lot, but its only done about 200 miles, so I can't say if it will prove reliable.

 

Apologies for all the questions, but I'm just getting into wheel building and trying to find out, particularly about motor wheels. It's already occurring to me that I bought a wheel when I would have done better to build one...

woosh use 2-cross pattern with alternating heads on 26" and larger with good statistical results. All wheels are manually trued.

 

edit: d8veh pointed the error.

Edited October 14, 20169 yr by trex