chucky

Wheel will be undished rear w/ 24 spokes, 90mm flange diameter, 56mm flange width, rim ERD 604mm.

I was going to use a 2x as appropriate for a 24 spoke wheel, but the height of the flange is making me think maybe I should take it down even further to 1x. According to the spoke calculator bracing angle for 2x will be about 6 degrees.

What do you guys think?

Yo!

On a rear, go 2x for strength.

chucky

But isn't a higher cross number weaker laterally? All else being equal lower cross numbers are typically advised for lower spoke counts and are ALSO advised for large flanges. Since I have both shouldn't I use a doubly low cross number or risk lateral weakness.

mihlbach

You should build it 2x for 24-28 spokes and 3x for 32-36. Your wheel will have plenty of lateral stiffness. 1x will work too, but will put more stress on the hub flange.

chucky

Why is everyone ignoring the size of the hub flange? Typical advice is that the strongest cross pattern for a given spoke count depends on the size of the hub flange with particularly larger hub flanges (like the ones in question) warranting fewer crosses.

Is that wrong or are you guys just parroting conventional wisdom for small flanges? It's not just a matter of lateral stiffness, but also spoke fatigue due to excessive bending at the nipple.

Retro Grouch 

A 90 mm hub flange is huge! A typical low flange hub generally has about a 30 mm flange diameter.

The issue is the angle that the spokes enter the rim. If that angle is too tangential, the spokes will break at the base of the nipple. Since 2 cross is typical for 24 spokes on low flange hubs, I'm thinking 1 cross would be more appropriate for this build. Even at that the spokes will be leaving the hub at such a tangential angle I doubt you'll have flange break out issues.

Actually, I'm wondering if 1 cross might still be too much. I'm wondering if there's a way to lace such a wheel with no crosses but the spokes still leaving the hub on a tangent angle.

Yo!

If you wanted you could run a half radial lacing (radial drive and 1x non drive). Sheldon says don't radial drive wheels, but this guy on spokeanweel thinks differently:

"The half radial rear wheel mixed lacing pattern has become fairly popular over the last few years with pre-built bicycle wheel manufacturers. If done properly this lacing can offer increased drive side lateral strength, when compared to a standard, fully crossed, rear wheel pattern. Ironically most of the manufactured rear wheels with this mixed lacing are done backwards, the non drive side is radially laced. The biggest problem with multi-speed rear wheels is the imbalance of the lateral strength's, this causes the majority, if not all, of the problems that plague these wheels. It is beyond my comprehension why someone would do a special lacing that does not work to correct this problem.

A properly built half radial rear wheel will be radially laced on the drive side. It would also be best to lace the drive side so the spoke heads are on the inside of the flange. "

What is your application for the wheel? Are you using this for track?

mihlbach

what hub are you using?

Samwiches

Isn't the whole idea of half-radial to strengthen dished wheels? He said there is no dish.

wearyourtruth

yeah seriously. it's not a chub hub. is it a sturmey archer or some other internal x-speed?

chucky

Thanks, I think I will cross post this in the Mechanics forum.

Yeah it's actually going to be an Shimano Alfine rear and SA drum brake front w/ dynamo.

Both have approximately 90mm flange diameters and the spoke calculator conveniently gives the same spoke sizes all around (at least to the nearest even mm). The Alfine isn't technically supposed to be dishless, but it's close enough and I'll prolly use an offset spoke bed rim to make it even closer.

mihlbach

Does that hub really exist with 24h? Is is a straight pull hub or does it use normal J-bend spokes. I've seen a photo on the internet somewhere of a shimano alfine 24h hub with straight pull spokes. It was laced 2x.

wearyourtruth

yeah i've only seen 32h and 36h?

chucky

The Sturmey Archer front hub only comes in 36H and the rim I'm lacing doesn't come in 36H, so since I'm a featherweight I'm lacing it with 24 spokes as per https://www.sheldonbrown.com/rinard/36-24.htm

The Alfine comes in either 32h or 36h and although I suppose I could get a 32h rim for it, for consistency, elegance, and looks I'm going to do the rear the same as the front...especially since the spoke lengths all work out to be the same.

After some discussion in the mechanics forum I've decided to do a 0.83 cross pattern, which is basically 1 cross except the narrower spacing of the 36h hub makes the spokes more radial/less tangent. Hopefully this will subdue the tangent angle enough to prevent problems at the nipple while still allowing the wider spacing of the holes on the larger diameter flange to give enough clearance for interlacing (or else I'll just do all heads-in which has been scientifically tested to give over 10% more lateral stiffness...perhaps at the expense of overall resistance to being ****ed up?).

I could actually also do a 0.17 cross which is basically zero cross with a little tangent angle (as suggested by Retrogrouch), but that seems excessive to me.

mihlbach

Here..I found the 24 hole striaght pull Alfine hub I mentioned earlier.
https://www.flickr.com/photos/pocketbeagle/3257691941/