Spokes Aint Spokes - or are they?

Martyn Goodwin

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Recently a fellow Vincentier had a rear wheel rebuilt after multiple spoke failure. Here is what he tells of the experience.

"I have had Brian Morgan of All Spoke Services in Perth (Western Australia) rebuild the Rapide back wheel with all new spokes and he has supplied half a dozen spares. It turns out that that the same spokes were used for both inners and outers whereas they each should have had a slightly different head bend. He advised me not to use stainless as they work harden and would probably snap in the sidecar situation.”

So – are there different spokes used on the inner and outer parts of the Vincent wheels? Does this just apply to rear wheels or does it apply equally to both front and rear?

And if the wheel builder “down under” is correct, what are the specifications, especially around the head bend, for each spoke position?

Further – the suggestion– nay – recommendation is that SS spokes not be used as they work harden and are more prone to break than non-SS spokes.

I am now wondering about the experience of others in this regard.

Martyn
 

david bowen

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all spokes are the same both sides of the wheel But I have found that some of the spokes that you buy now have the wrong bend on the head, this is the same as the front wheel Iget my spokes from central wheels UK they do the wheels for the national motor cycle museum Birmingham UK
 

vibrac

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I have used ss spokes for my smaller lighter machines I would hazard a guess that many will recount the experience of Russell and his wheel breakup on a trip on the continent after a previous arduious trip to Turkey.
I have gone as smaller than standard for a racing machine and there are also butted spokes to consider but SS spokes for a stressed vincent..? but then how many are stressed nowadays?
 

john998

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Not to keen on stainless spokes, had a pair of wheels built with stainless spokes and Radellei? stainless rims. In the rear I was constantly replacing spokes, so had it rebuilt with standard ones. Shortly after while cleaning the bike found that the rim had cracks from the spoke holes.
Now re built with Central wheels stainless rim and standard spokes. As an aside to that I found it to be impossible to get a tyre on the new rim. it appeared over size. Sent it back to central wheel and they fitted the tyre. Not looking forward to a road side puncture. John.
 

chankly bore

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Further to my previous posts on the subject. The head size and bend radius are both critical. Spokes should be all the same. If they need to be different then something is WRONG!!! Sometimes fractures are caused by an adjacent outer spoke touching a nearby oversize head creating a stress point. Not work hardening- at least in my experience.I would like to know where the spokes broke, i.e. at what point on their length and I would like to see the heads and bends.I have had no trouble with Central Wheel Components stuff,apart from needing to ease the heads a bit as above, but there are some crap spokes around that will even cause brake drum fracture. Re spoke tension- it helps if you ain't got cloth ears.Was the wheel laced "across 4?"
 

highbury731

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Current bicycle practice is to lace the final outer spokes behind the inners at the final cross. Are motorbike wheels laced in this way?

Once Vincent wheels start to collapse, the remaining intact spokes exit the elongated spoke slots. Would it be feasible to put say a pop rivet here after assembly to prevent this?
 

Monkeypants

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After reading Davd Dunfey's posts on using a spoke torque wrench for wheel building , I purchased one. David suggested that many wheels done without a torque wrench are not sufficiently tight and have big differences in spoke tension throughout the wheel. On checking some existing wheels for spoke tension, I found the same thing .
Tension varied from 15 lbs t.o 60 inch pounds on the same wheel, a professionally built wheel at that and running true to within .015.
Most of the wheels checked had an average spoke tension of around 30 inch pounds.
Excel wheel company recommends spoke tension be set at 60 inch pounds, while Buchanans go even higher at 80 inch pounds. Butchanans now use a spoke torque wrench on all their builds
I used the torque wrench last week to lace a Devon alloy rim to the Vincent rear hub. Devon provides inner and outer spokes for the back hub, but only one bend of spoke for the front hub. This is because of the greater width of the rear hub.
The process was pretty simple using the torque wrench. I used an ordinary spoke wrench to bring the spokes up to very light, but quite uneven tension and get the rim roughly concentric and centred over the hub. Starting at 15 inch pounds and adding ten inch pounds per rotation , I finshed with the torque wench at 60 inch pounds. Without even trying to true the wheel this automatically brought it almost on spec, just 20 thou total runout one way and 15 the other. A bit of weaking with a regular spoke wrench brought the rim to within 5 thou of concentric both ways. Spoke tension is within 5 inch pounds of even all the way around the rim.
I wonder how many broken spokes are due to under or over tension and uneven tension resulting in just a few spokes carrying most of the load?
 
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dagriise@online.no

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My two cents on this one... (having laced wheels since i was 13 years old... ) Generally there are quite some variables to look at when you asses a wheel/spoke/ rim set up. Regarding spokes one should always buy good quality spokes, with rolled/not cut threads.(usually this can be seen by the threads being finer, and rised a little.) As I live in a, mildly speaking, wet part off the world (Bergen Norway) the stainless items, both for rims and spokes has been a great thing, though it may be worth thinking twice if you have a really -and i mean really, heavy duty set up. As an example when building my Egli rear wheel, i had to have the spokes specially made by CWC, to get a thigh fit through the flanges of the rear hub. As someone mentioned the head angle is important, BUT one should also look at the length and thickness of the actual curved bit, from the bend to the head. I have seen lots of spokes with to long and thin sections through the flange, causing failure, and loosening spokes due this section being to long, witch leads to the full run of the spoke bending and flexing. An other absolute NO NO, is the spoke/nipple coming out of the rim dimple, at the wrong angle... This will most likely lead to a clean break just where it enters the nipple. Talking about cracks, this is mostly down to either the sheet steel being to thin or brittle. I suppose a torque wrench is a good thing if you want to be sure, but i wouldnt bee to absolute to whats the correct torque, as both the alloy, and profile of the rim means a lot to how much tension you put on the spokes. The basic rule of getting the wheel right is to tighten it evenly. First tighten the spokes down to the point where you have, lets say, a few threads left showing out of the nipple, and then go on giving them a turn or two, all the way around. Always use a good spoke wrench, and a very light lubricant on the threads. WD 40 or somthing that will go away. (Stainless nipples on stainless spokes has there own anti mar, lube to keep the nipple rotating) This wil most likely give you a well set up wheel, and be aware if the squares on the nipple start "going" you are to tight! When buying spokes, i always recommend people to send a sample of the old ones, AND insist that nearly correct isn't correct!

Again just my two cents..

Regards Dag

Norway.
 

Monkeypants

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Hi Dag

I laced my first rim at about that age as well. The rim came in a box along with some new spokes and most of a 1963 AJS 500CS Scramber, the near square bore/stroke factory 12 to one CR model, that I later sold for $300:mad:.
The difference is that wheras you have been busy lacing delicate bicycle wheels andmotorcycle wheels during all the years since, it was about 45 years to my next wheel build:D
So the torque wrench really helped me get a feel for inch pounds rather than foot pounds.
Now I have been reminded of it,I want that AJS back.All alloy engine, just over 40bhp from factory and revved to the moon. Bright yellow too.
Glen
 
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davidd

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Martyn,

I have always used Buchanan SS spokes (one size or style) on the racer and street bikes. Buchanan ships directions with their SS spokes that tell the builder to torque the spoke to 80-100 inch pounds or the spokes will break. I have never had a broken spoke. If you are not going to use a torque wrench, I would use steel spokes. They will survive all sorts of abuse with fewer failures. I would probably recommend steel spokes for sidecar work, but I have had such good luck with the SS on my bikes that I would definitely give SS a try on my own sidecar machine. You should not try these high tensions with re-plated rims as the spoke nipple area is polished too thin and the nipple will pull through.

Just for reference, this is the wrench I use. Mine is preset, but they do make an adjustable:

http://www.fasstco.com/shop/spoke-torque-wrench

David
 
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