Wheel lacing question

lotus49

I was looking at the back wheel on my Giant Defy 3 yesterday and noticed that the drive side spokes cross but the non-drive side spokes are simply radial.

I understand why they need to cross but I am curious about two things. Is it typical that this is the case only on one side of a rear wheel and is it always the drive side?

Lycra-Byka

If hesitate a guess that its to do with strengthening the drive side to counter rotational torque. I've seen a lot of wheels use this pattern.

ugo.santalucia

The drive side experiences torsional load, the non drive side gets less of it... These days most rear wheels are laced with that pattern. My take is that it saves time. I never use it as I don't really see any benefit in it

Lycra-Byka

ugo.santalucia wrote:

The drive side experiences torsional load, the non drive side gets less of it... These days most rear wheels are laced with that pattern. My take is that it saves time. I never use it as I don't really see any benefit in it

I'll shut up then. :oops:

lotus49

ugo.santalucia wrote:

The drive side experiences torsional load, the non drive side gets less of it... These days most rear wheels are laced with that pattern. My take is that it saves time. I never use it as I don't really see any benefit in it

That was my initial guess but when I thought about it, I couldn't see how this was the case. The torsion is effectively applied to the whole hub since it's solid and doesn't flex materially (or so I presume). The hub is supported by the bearings, skewer and frame so I would have thought the torque on the non drive side would be exactly the same as the drive side - am I missing something?

When you lace a rear wheel (and I know you have a lot of experience doing this) do you use a crossed pattern on both sides and do you usually have more spokes on the drive side or are your wheels fully symmetrical?

rpd_steve

If you laced a wheel to be radial on the drive side and with x on the other then all the torque would need to be transmitted via the hub. There is not 'much' flex in a hub, but there is some, and it makes sense to remove all unnecessary forces and stresses where possible- it can only help.

ugo.santalucia

lotus49 wrote:

ugo.santalucia wrote:

The drive side experiences torsional load, the non drive side gets less of it... These days most rear wheels are laced with that pattern. My take is that it saves time. I never use it as I don't really see any benefit in it

That was my initial guess but when I thought about it, I couldn't see how this was the case. The torsion is effectively applied to the whole hub since it's solid and doesn't flex materially (or so I presume). The hub is supported by the bearings, skewer and frame so I would have thought the torque on the non drive side would be exactly the same as the drive side - am I missing something?

When you lace a rear wheel (and I know you have a lot of experience doing this) do you use a crossed pattern on both sides and do you usually have more spokes on the drive side or are your wheels fully symmetrical?

The 2:1 lacing pattern is only used by factory wheels makers to keep the tension equal on both sides of the wheel. The result is a weaker wheel of course... plus it requires hubs drilled appropriately. You can do it using a 24 H rim and a 32 H hub, lacing 16 spokes on the DS and 8 on the NDS but the result is less than impressive as the holes on the NDS don't fall bang on in the middle of those on the DS... the all construction looks a bit odd to be honest.

thescouselander

RPD Steve wrote:

If you laced a wheel to be radial on the drive side and with x on the other then all the torque would need to be transmitted via the hub. There is not 'much' flex in a hub, but there is some, and it makes sense to remove all unnecessary forces and stresses where possible- it can only help.

I have a back wheel laced exactly like that - seems to work quite well.

Monty Dog

I built my CX wheels radial DS and 2x NDS - mainly because I had enough CX Ray spokes of the right length for radial. Plenty of discussion of spoke patterns on weight weenies - as the hub is torsionally pretty rigid, then it doesn't really matter which side is laced radially.