AlexCyclistRoch

Tire pressure really only makes a difference on tubular wheels.

rpenmanparker 

Huh?

Bike Gremlin

I'd argue that. The fewer the spoke count, the more tension each spoke takes. Spokes get fatigued sooner, so the job needs to be done again sooner.

If you're paying someone else to do it, it's the same to you - only price difference is extra spokes.

rpenmanparker 

That is not true. It is an often repeated falsehood that lower spoke wheels have higher individual spoken tension. They do not. Spoke tension is determined by rim strength. It is almost always set around 120kgF for the rear drive side. As necessary to dish the wheel for the rear non-drive side. And around 100 for the front. Maybe a little higher. No matter how many or few spokes, one doesn't vary from that significantly.

Bike Gremlin

For rim of the same strength and rigidity, if a wheel has less spokes, then fewer spokes take the load (and tension) - so more to each. The load is divided over fewer spokes, so they are more stressed.

That is often compensated by stiffer (heavier) rim and spokes, but then the weight loss is a lot smaller, only slight aero advantage left.

rpenmanparker 

Please rethink what you said. When you build a wheel, you measure the tension in each spoke. There is no wheel tension that is divided over the spokes. There is each spoke tension which is individually set. If I set a spoke to 120 kgF on a 36 spoke wheel or on a 20 spoke wheel, it is still 120 kgF. What you are saying is just wrong.

Bike Gremlin

When the wheel is loaded, the load is carried by spokes - so the smaller spoke count, the more load-stress on each spoke.

rpenmanparker 

No. There is no a priori load on the wheel. The total load on the wheel is the sum of the load on each spoke. If you have 20 spokes at 120 kgF, then the total load on the rim is 2,400 kgF. If you have 36 spokes at the same tension (which is the real life case), then the total load is 3,600 kgF. You are letting the tail wag the dog.

rpenmanparker 

I assume you are not talking about externally applied loads during riding, but rather the loads applied when building the wheel. That is, after all, what we are discussing: building the wheel, not riding it.

Bike Gremlin

I'm discussing durability. Riding loads and stresses.

noodle soup

I love how he moves the goalposts on you.

Bike Gremlin

Not at all. Talking all the time about more spokes giving greater durability, with a very slight weight penalty and a slightly greater aero penalty.

Not even trying to challenge and discuss wheel building techniques. Considering that both 24 and 36 spoke wheels are built properly.

rpenmanparker 

I'm glad we got that cleared up. As you can see, I was talking about wheel building and assumed the highlighted quotation referred to that wheel aspect as well. It never occurred to me that you had changed the subject...until it did.

So yes, a lower spoke wheel will see larger individual spoke tension increases (and decreases) in response to applied loads from the environment than a higher spoke wheel.

Bike Gremlin

My point wasn't about harder building wheel, but the second part of the sentence, about the job needing to be done more often, so not being that easier in the long run.

rpenmanparker 

The difference is de minimis. I discard my old wheels and build myself new ones with different features so often, there is no such thing as a redo.

Bike Gremlin

The fewer the spoke count, the more chance of a spoke breaking, others being fatigued as well, before the rim, or the hub need replacing as well.

My main argument is still that 36 compared to 24 spokes, all other things being equal, makes a more durable, stronger wheel, and in case of a spoke breaking, leaves the rider a good chance of riding home without problems, or doing decent roadside repairs if having a spare spoke and wanting to do it on site.

rpenmanparker 

No argument there. It is just a non-issue for me. You should keep in mind, however, that many folks are more concerned with the 99% (the time that they are riding the wheels) than the 1% (the time when there is a problem). Why sacrifice the joy of really light, low spoke wheels, because you are worried about a problem some years down the line?

Bike Gremlin

Because, unless racing (other riders, or a stopwatch), you hardly notice the extra spokes.
But the few spoke wheels, especially rear, can ruin joy, more often than (well built) 36 spoke wheels.

rpenmanparker 

Low spoke wheels are a joy unto themselves.

Bike Gremlin

Can't argue that.

Mr IGH

How bad must one's wheelbuilder be that 36 spokes are required? So many examples of 240lb riders on Shimano and Mavic low spoke count wheels yet every wheel thread is replete with failed wheelbuilders demanding their clients/victims ride 36 spoked wheels. I'd feel sad for the victims yet they seem so proud of their low quality builds.

rpenmanparker 

Cheer up. It is not necessarily true that the high spoke count IS required because of low quality construction. It is just that it is thought to be necessary despite high quality construction. Oh, wait a minute. That might be even sadder.

Bike Gremlin

Good quality built is understood. I've explained the pros and cons of lower and greater spoke count. Each will choose for themselves.

I prefer to have some over engineering, especially on critical parts - like wheels, frame and brakes.

BlazingPedals

Bah! I've got 24-spoke wheels that I've ridden 10,000+ miles without being out of true, and I'm 220. I suspect the spokes aren't being relieved properly after truing. Try having someone else true it up.

Mr IGH

With 15 posts in a 49 post thread you've crossed the line to overreaching dead-horse-beating. It wouldn't be so bad if you weren't so wrong. Oh well, it's the Road Cycling Forum, I expect nothing less