deepakvrao

Hi Guys,

I'm 75kgs, and live in India. Roads I ride on are largely good, but there are the occasional potholes, and a number of 'speed breakers', which I dont slow down much for. Even my carbon 56mm wheels have 24/24.

Just saw that all our wheels have 24/24. Just ordering a new LB carbon wheelset, and the default for the build I want is 20/24. Depth 46mm. I think with deeper rims, the stress on the spokes is less?

I get that the rear carries more of the weight, but doesn't the front take the majority of the assault when you hit a pot hole or the like?

What would you guys suggest?

shelbyfv

Fewer spokes=less import duty

WhyFi

If the rear is carrying more weight, why would the front take more abuse?

deepakvrao

Don't know, but I think it hits the potholes first and harder?

deepakvrao

You think maybe that you are being funny? Nope. Just being an ass.

datlas 

If 24/24 works I don’t see a problem with 20/24. More weight over the rear wheel, plus more torque. That’s why sometimes higher spoke count in back.

Bah Humbug

Yep. The November boys even say they often like 20/28, and when I finally get disc brakes I’ll likely get 24/28 just for a bit of extra security.

Then again, most of my wheels now are 18/24, and they’ve been fine.

caloso

I'm about the same weight and my Williams 58s are 20/24. Rock solid and true as the day I bought them.

deepakvrao

Thanks
Than guys. 20/24 it is then.

canklecat

My weight varies from 66-70 kg and last year I rode 16-spoke wheels all year on some pretty bad roads, no problem. Aluminum rims, not carbon fiber. It's a 10-15 year old set of Bontrager Race Lite Aero wheels that had a so-so reputation but I've had good luck with 'em. Just now needing to replace the rear bearings but the rims and spokes are fine. Haven't even needed to true them.

I was kinda surprised. I really thought wheels needed at least 32 spokes to hold up on our roads. But well designed and built wheels seem pretty tough.

colnago62

One reason some ride higher spoke count wheels is if there is a spoke breakage during the ride, the wheel has less deflection. This seems more important for bicycle tourists and riders who get out into rural areas then the average cyclist.

guadzilla

With no scientific evidence to back it up, I'd say the same. Even riding on 37s @ 50psi today, hitting a couple of road imperfections jarred the front wheel quite hard. Was worried I might have broken a spoke, actually (no damage, though).

DrIsotope

I've been on 20/24 on my rim brake bike since day one, and I've got a good +20kg on you. I do 24/24 for discs.

thecycleclinic

Lower spoke count works on the front as there is less weight over the front wheel.

For disc brake same drilling front and rear is common because disc brske load the spokes more than rim bakes. Simple maths demonstrates this.

i bet someone now posts i don't think that true- they obviously don't get the physics of wheels.

guadzilla

Can you share this simple math?

znomit

And the physics of wheels.

guadzilla

"Round is better than square"?

deepakvrao

I absolutely have no clue about the math, but I do think that it's accepted that disc brakes stress the spokes more? Or not?

guadzilla

I dont know the answer to that. If I had to guess, I would say no - seems to me that braking force is transferred more to the bike fork/stays (where the calipers are mounted) rather than to the spokes (I would expect that the hub body absorbs a lot of the braking stress, as far as the wheel is concerned) - whereas, with a rim brake, the increased friction force on the rim definitely puts more stress on the spokes.

But i could be wrong.

November Dave

Good thought, but it's kind of opposite to that actually. Think of how your rear hub works when you're pedaling - it transfers "go" from the hub to the rim through the spokes. This is torque. When you stop a disc brake bike, it transfers "stop" from the hub to the rim through the spokes. Also torque. That's why you don't see all radial laced disc wheels, but it works just fine in rim brake front wheels - radial is terrible at transferring torque. In a front rim brake wheel, you don't transfer the "stop" from rim to hub, you just stop the rim and that's that.

This is old but still applicable.

deepakvrao

Yup. Makes sense. Thanks. Nice read.

guadzilla

Great stuff, thank you.

sfrider 

Rim brakes exert radial forces, so add to normal riding load, and radial lacing works well. DBs are effectively hub brakes, so exert torsional forces, but the force is the same since the brakes need to scrub the same amount of energy in both cases. Although DBs can do it quicker, so can exert higher forces, and I suspect this is why a few spokes are added. From my sample of 3 front DB wheels, all three use 2-cross lacing, which makes intuitive sense.

fietsbob

Not 'road' bikes .

Touring 1, 36_40. & I built my own, 40_48..

Brompton Mk2 20_28 My Bike Friday uses a 24 spoke rim , and a 36 hole hub .. build skips every 3rd hole in hub..