Wheelbuilding / Wheel Building / Wheel build help

Looking at having a wheel built up with the SP PL-8 Disc hub.

Rims offered are: Exal XR-2, Exal LX17 and Rigida Sputnik. ALl these will be fine I guess? Rigida sputnik rings a bell so I must've read about it here..

Will be for putting on my loaded commuter bike so doesn't need to be fancy.

Dont get the XR-2, very narrow. Sputnik if you don't care about weight, LX17 if you do. Sputnik will last FOREVER and has a nice 19mm internal for wider tyres

I have two bikes with xr22t and one with xr26t but none with xr31.

I guess it's the same but a bit more aeros?

I have three XR31. One crashed, one on the Mason and one being built to an old Powertap.

Basically, yep. Bit more aero, bit stiffer, bit heavier. More aero than a Zipp 303 at low yaw angles, allegedly. I like them.

P. S. I've got 4 bikes with XR31Ts (some with poncier summer hoops too) and one with XR22Ts. I feel I should get some 26s just to complete the set.

have a recurring issue on work bikes where our rims are cracking- happens underneath rim tape - cracks follow the rim round connecting spoke / nipple holes. If that makes sense

Rims are Ryde Andra 40, 36h.

Anyone got any ideas on how to try and prevent this from happening, or suggestions for a rim that could replace them? Need to be heavy duty!!

cracks follow the rim round connecting spoke / nipple holes

Lateral tensile stress in that region comes from tyre pressure. What tyre section and pressure are you using?

Need to be heavy duty!

There's not much that's heavier than Andra 40

tyre section varies between 2.15” / 2.25”

Tyre pressure should be around 55psi

And the bikes are rated to carry up to 150kg of cargo (not including bike and rider)

the bikes are rated to carry up to 150kg of cargo (not including bike and rider)

The bikes might be, the rims maybe not so much. Manufacturer's spec says 180kg maximum total system weight. Tyre width and pressure don't seem to be outside normal bounds, you're bang in the middle of the size range and 4 bar in a 54-56mm tyre is at the top of the range obviously, but not what anybody would call over-pressure on a heavy metal rim. On the other hand, "should be around" might be hiding a multitude of sins. By my back of a fag packet calculation, your width/pressure is going to be pretty squishy if all-up weight creeps up past 250kg - it's basically the same squish as me running 2 bar on my MTB, which is fine for me off road where I like the tyre to move about a bit, but your riders might be sneaking another couple of bars in while you're not looking to get lower rolling resistance and tighter handling on tarmac.

Thanks, much appreciated. Think we’ll lower the recommended psi to 50, and emphasise that it shouldn’t go over. See if that improves the lifespan of these Ryde rims...

Wheel nerds, if I'm replacing a rim with currently a 562 ERD with one that's 550 ERD, am I likely to need to need new spokes and nipples, or is that difference small enough to reuse everything?

am I likely to need to need new spokes and nipples

Yes.

Ta.

In your wheel builds, could you consider adding nipple washers as Andra 40 has no eyelets, perhaps washers would help reduce the stress risers at the drillings?

Or could you obtain Big Bulls which have eyelets, might stop the rims cracking?

Don't think they were cracking around the nipples, it was along the inner well bed.

Oh, along the outer wall, I see what was meant by ‘under the rim tape’. Ignore me!

i calculated spoke length based on flip-flop track hub (spoke length equal as wheel will be dished to the middle of the hub) - this was a mistake as hub was not flip-flop - just the drive side threaded for single cog. as such drive side spokes are too long and rim is dished naturally (all spoke tensions being equal) too far to the non drive side - can i correct this just by re dishing the wheel or am i likely to encounter problems?

I don't understand why if you calculated spoke length based on flip-flop, your DS spokes are too long. If anything, I'd expect your NDS spokes to be too short.
No harm in trying to re-dish the wheel, but you may run out of adjustment space on the spoke threads.

ah, you may be right - either way rim is naturally dished to the NDS - could well be because NDS are too short rather than DS too long
is is purely a question of adjustment space on the spoke threads? what about relative tension between DS and NDS?

you may run out of adjustment space on the spoke threads

Trigonometry says you get a lot of dish for a little change in effective spoke length, so this is unlikely unless you're already very close to the limit

what about relative tension between DS and NDS?

Trigonometry says the tension ratio is fixed by the dish and there's fuck all you can do about it, so it's not worth worrying about. If you were making a huge change to the dish and the wheel was already close to being badly designed, you could push it over the edge, but if we're just talking about changing from a double-sided track hub to a single-sided one, we're not in that territory.

That's because spoke tension should be higher in the DS. Center it and it will be right

it's the relationship between spoke length / dish / tension that i couldn't imagine....the trigawotsit...
thanks for comments - will hold off ordering new spokes

Black, Straight Pull, 2.6mm Steel Bladed spokes.

Who will sell me some?