Wheelbuilding Q: Ryde Andra 40/Shengyi Hub, have I got this spoke calc right?

[Bush mechanic]

Hey all, hoping to run this past anyone who has relevant experience - I've built a few wheels in the past but I have not come across the term 'zig zag' for rim drilling. I've got a Ryde Andra 40 (36H 700c) on the way, and want to lace this to a Shengyi SX2 rear hub.

Ryde give the ERD as 600 for this rim, but do I need to worry about the 'zig zag 2mm' and the angle they provide? See Andra 40 - Ryde


I'm assuming the zig-zag is a 2mm offset from centre of the rim, which if put into Grin's spoke calculator gives me the following (600mm ERD, 31.4mm outer rim width):


Does this sound right? Greatly appreciate the advice as always.

 

[Bush mechanic]

Further to last, I do have an Alex DM21 in the same size - it's a narrower lighter rim but has eyelets, where the Andra does not. The narrower width isn't too big an issue for this bike (commuter) but I think the significantly more solid construction of the Andra will still outperform and outlast the Alex. @Chalo I think if anyone could make a fair comparison here it's probably you , is there any reason to use the lighter rim with eyelets?

 

[docw009]

Measure the ERD yourself. It's the main unknown. The rest of the measurements are simple and have a minor effect, but if you get the delta to the top of the nipple off, your spokes will be off by that amount.

I used the seller's ERD on the last wheel I built last Fall. It was off, at least for the way Grin defines their tool. I had to reorder shorter spokes.

 

[Bush mechanic]

Measure the ERD yourself. It's the main unknown. The rest of the measurements are simple and have a minor effect, but if you get the delta to the top of the nipple off, your spokes will be off by that amount.

I used the seller's ERD on the last wheel I built last Fall. It was off, at least for the way Grin defines their tool. I had to reorder shorter spokes.

Fair point, I've played around a bit and the offset (again I'm assuming this has got to be what they mean by 'zig zag') hardly makes a difference. I've found that in the past my spokes have protruded a bit after using Grin's calculator, maybe 1 mm out of the end of the nipples, but nothing dramatic.

 

[Chalo]

You can use a spoke calculator that takes into account the stagger between the holes on one side and those on the other. But for 2mm I wouldn't bother. Both those rims are deep enough that if the spokes run a tiny bit long, no problem.