[the #6]

I've noticed 2x spoke patterns on some MTB wheelsets and wonder about their durability. If I'm not mistaken, Stan's newest ZTR Race wheelset uses a 2-1 cross in the rear? Is that 2x on the brake side and 1x on the drive, or vice versa? And how well would something like this hold up to average cross country riding? I've always used 3x spoked wheels and see the disclaimers that disk brake manufacturers have saying to only use their brakes on 3x wheels. What gives?

 

[mtnbiker72]

Less cross equals shorter spokes, which for weight weenies means a little less weight. The Stans ZTR Race is a weight weenie wheelset that puts lightweight performance over durability.

 

[the #6]

Well, that does answer my question.

Maybe I should have worded that: Is 3x really necessary or would a 2x wheel be addequate for most people? Sorry for the mix-up.

 

[mtnbiker72]

Well, that does answer my question.

Maybe I should have worded that: Is 3x really necessary or would a 2x wheel be adequate for most people? Sorry for the mix-up.

It depends on the rim as much as anything. Using less crosses will have a higher spoke tension. If a rim is designed to work with a higher spoke tension, then a 2x can certainly be quite durable. I've a ran 24 hole 2x Mavic disc wheelset in the past and the spokes and rims held up fine (the hubs were another story, but not from being 2x). With the NoTube rims, you are limited to 90 or 95 kgf spoke tension, depending on the rim, so it doesn't seem like a good idea. But would a 2x be adequate for some people, yes it would

 

[meltingfeather]

It depends on the rim as much as anything. Using less crosses will have a higher spoke tension. If a rim is designed to work with a higher spoke tension, then a 2x can certainly be quite durable. I've a ran 24 hole 2x Mavic disc wheelset in the past and the spokes and rims held up fine (the hubs were another story, but not from being 2x). With the NoTube rims, you are limited to 90 or 95 kgf spoke tension, depending on the rim, so it doesn't seem like a good idea. But would a 2x be adequate for some people, yes it would

There's no reason that I can see why a 2x wheel would necessarily have higher tension than 3x. A 24h wheel, definitely, but would you mind explaining your reasoning?
OP-
weight weenieness is one reason people do it. 2x wheels are also slightly stiffer than 3x wheels, all else equal, but IMO you couldn't tell the difference on the trail.

 

[mtnbiker72]

There's no reason that I can see why a 2x wheel would necessarily have higher tension than 3x. A 24h wheel, definitely, but would you mind explaining your reasoning?

I was thinking with a 24 or 28 hole rim, which it is more common to see 2x on. I can see no reason to use 2x on a 32 or 36 hole rim.

 

[shiggy]

I've noticed 2x spoke patterns on some MTB wheelsets and wonder about their durability. If I'm not mistaken, Stan's newest ZTR Race wheelset uses a 2-1 cross in the rear? Is that 2x on the brake side and 1x on the drive, or vice versa? And how well would something like this hold up to average cross country riding? I've always used 3x spoked wheels and see the disclaimers that disk brake manufacturers have saying to only use their brakes on 3x wheels. What gives?

Most wheels with fewer crosses also have fewer spokes. This is entirely normal and necessary as with fewer spokes you can not have as many crosses without having issues with spoke overlap at the hub flange.

Basically, a 4X 36 spoke, 3X 32 spoke and 2X 24 spoke wheel all have about the tangental spoke angle. It is also common for a 28 spoke wheel to be 2X.

It is the tangental angle that lets the wheel transfer torsional (rotational, drive/disc braking) loads. The closer the angle is to 90 degrees the better. The wheel will generally be more stable.

The number of crosses has little to do with the lateral "stiffness", though in some cases fewer crosses can increase it.

It appears Notubes is doing it on 32 spoke wheels for weight reasons. Not a pattern I would want.

 

[meltingfeather]

I was thinking with a 24 or 28 hole rim, which it is more common to see 2x on. I can see no reason to use 2x on a 32 or 36 hole rim.

gotcha... and i agree. i was just hoping you had some juicy bit of wheel info i hadn't happened across yet. :thumbsup:

 

[the #6]

Thanks for the info guys! That's exactly what I was wanting to know!

 

[meltingfeather]

also, all else equal (including # of spokes), a 2x wheel will have larger stresses from lateral deflection and lower stresses from radial deflection.
i don't see any good reason to do it other than matching the number of spokes with the lacing pattern to get a good spoke angle, as shiggy described.