Spoke count for a commuter wheel build

[John the Monkey]

I think we are on the same page basically. There are times when people get confuse with different types of rim and spokes. A touring wheel with 24 spokes must have pretty strong rim otherwise I don't see how such wheel could handle the weight.

I think so - we're gradually meeting in the middle

 

[Spoked Wheels]

...although Schraner's 24 spoke touring wheel used spokes from the commercially available DT Swiss range (but, as you allude to, the stronger rim put the weight on par (or "comparing favourably"!) with a 32 spoked wheel). I think, if I remember Schraner's book correctly, he favours a deep section rim to provide the extra strength, rather than an overbuilt box section.

The part about "sharing the load" is essentially what Brandt says (I think) - but the stiffer the rim, the wider the area that's loaded - so for differing rim stiffnesses, you could load, say, four spokes at a particular point in the rotation (but with the spokes further apart). Returning to Brandt (p39) he says "for a common 36 spoke wheel, the load affected zone spans about four spokes. If the spokes are tensioned to 100Kg, the wheel could support a 400kg load". If we trust that calculation, Schraner talks of deep profile rims being able to take higher spoke tensions ("up to 337lbs" (152kg) p32) - even assuming fewer spokes means, say, only two spokes form the load affected zone, that's still a load of slightly more than 300Kg. If the rim is stiff enough that the load affected zone spans more than two spokes, that goes up, of course (I can't say how likely that is).

There were a couple of things in your quote from Jobs Brandt's book that stayed in my mind and I really needed to find out more

Jobs Brandt's book was the first book I ever bought on wheel building but I found it a bit hard to read at the time, when all you want to do is learn to build a wheel. The second part is dedicated for such a task but IMHO his way of putting things in a book is a little harder to follow than Roger Musson's book. Having said that the book certainly has it merits. From reading just a few pages I can understand a little better why some reputable wheel builders don't like to build with certain components or components combinations. I knew enough not to go there but I can now understand it better, at least some of it, others I'm not sure, Harry Rowland for instance will not build with H+Son rims, I don't get that one I'm now going to read Jobs Brandt's book cover to cover . The principles are the same as to what Roger Musson's.

The chapter on strength and durability has some very interesting points I think. I don't think it differs from my initial statement "Spoke count isnt a strength thing? Mmmm the way I look at it, it comes down to strength. More spokes for heavier rider, more spokes for durability, more spokes for bad roads.... I'm talking about well built wheels where spokes are properly tensioned."

JB says "
Strength is a measure of the greatest load the wheel can carry before it collapses.
Durability is a measure of how far the wheel will travel before it loses alignment.
The two are related, but are not the same."

"A wheel can collapse when the spokes in its load-affected zone become loose.
The load that will cause collapse is roughly equal to the sum of the tension in
four or five spokes. Therefore, the tighter its spokes are (up to a point), the
greater a wheel's load capacity." Needles to say how badly some factory wheels feature in this department

"Because wheel strength is closely related to the number of spokes in the load-
affected zone, the number of spokes per length of rim is kept about the same for
different wheel sizes. A large wheel must have more spokes than a small wheel
to achieve the same strength." This statement can reinforce the experience of Schraner and his 24 spoke touring wheel. I just don't see how standard 700cc road wheel could stand the punishment but a 26" wheel is another matter.

"If its spokes are tensioned to 1000 N, a 36-spoke wheel will support approxi-
mately 400 kg. This is considerably greater than the average rider's weight.
However, loads of 400 kg or more sometimes occur when a wheel strikes a bump
in the road at high speed. If such overloads occur often, the nipples of slack
spokes can unscrew, reducing tension to affect both wheel alignment and
strength." This is why a higher number of spokes is a good idea for riding on bad roads.

 

[Crankarm]

Some years ago Monty at Condor used to do wheel building Master classes. I always wanted to go on one but never found the time, preferring to leave the building of my wheels to him. I had various wheels built by him heavy rims, light trims, low spoke counts, high spoke counts, they were all and still are strong and true even after 15 - 20 years. I have just found a good wheel builder locally after having several wheel build disasters done by people in LBSs who claimed to be able to build wheels properly, but in all honesty shouldn't be trusted with a knife and fork let alone to build a bicycle wheel. For me I see good wheel building as an art, a gift, a bit like a concert pianist, so would only ever get a set of wheels build by some one who knows what they are doing and who is good. Being far from home with an unrideable wheel is some thing I care not to repeat. I know you can make repairs and true etc, as I have done it, but the point is, not to be in that situation in the first place.

 

[Spoked Wheels]

Some years ago Monty at Condor used to do wheel building Master classes. I always wanted to go on one but never found the time, preferring to leave the building of my wheels to him. I had various wheels built by him heavy rims, light trims, low spoke counts, high spoke counts, they were all and still are strong and true even after 15 - 20 years. I have just found a good wheel builder locally after having several wheel build disasters done by people in LBSs who claimed to be able to build wheels properly, but in all honesty shouldn't be trusted with a knife and fork let alone to build a bicycle wheel. For me I see good wheel building as an art, a gift, a bit like a concert pianist, so would only ever get a set of wheels build by some one who knows what they are doing and who is good. Being far from home with an unrideable wheel is some thing I care not to repeat. I know you can make repairs and true etc, as I have done it, but the point is, not to be in that situation in the first place.

Like with most crafts I guess you need some talent. I don't what it is about LBS and wheel building but there aren't many that give wheel building a good name.

I haven't done any touring as yet but I can imagine how worrying must be to find yourself with a wheel needing attention in the middle of nowhere, annoying when knowing that a well built wheel would have avoided the problem in the first place.

Glad to hear you've found a wheel builder you can trust.