My Hope Hoop (enduro tech thingy) on my long suffering hardtail is getting past its best. Two or three fairly large dings in the rim and I can’t get it anywhere near straight without silly spoke tensions.

In any case, I have some spare rims knocking about and thought I would lace a WTB i25 rim onto the pro 4 (not boost) rear hub.

Does anyone (in order of preference):

Know of a site where I can enter the particulars to get the right spoke lengths.

Or

Just know them for this combination.

Or

Know of a calculation method?

It is not a super urgent one as the other rim isn’t cracked and it still seals tubeless, but any help would be gratefully accepted…

https://www.prowheelbuilder.com/spokelengthcalculator

(Disclaimer: obviously you are accepting the risk that the data on the site may be incorrect)

I normally use freespoke http://www.kstoerz.com/freespoke/bench.php?action=add&hubid=1

Or edd https://leonard.io/edd/

I cannot recommend highly enough that you (don’t be lazy and…) check the ERD yourself and also confirm that the hub measurements given are a good match to the one you have before ordering spokes.

I’ll second the edd link… Been using it for years for my wheel builds

Thanks for the help folks!

I have used three or four of the guides and got the result of 72 & 73mm spokes to fit the ST i25 650b rim to a Hope Pro 4 non-boost rear hub to within 0.5mm each time.

I took a bit of a punt and unlaced the rim from the front hub of the spare wheelset because that has the same hub flange diameters (57mm both sides) as the Pro 4 rear hub. Turns out those spokes are 72/73 so no need to order new! It is from a front wheel that was not used a lot, so the spokes are in good nick.

Now just need to figure a way of swapping rim and spokes at the same time to minimize my chances of cocking the lacing up…

Actually just one random query if I may (an odd one perhaps and just a random thought I had).

The rim is not eyeleted, is it a totally stupid idea to put a washer in where the nipple contacts the inside of the rim to spread the load a bit more? Assuming I can find 32 suitable washers and it is not a totally stupid idea, obviously.

I can’t comment re washers but if you Google thebiketube lacing a 32 spoke wheel the video is fantastically good. Chap uses 3 cross whichnus basically the bomb proof method but it was also useful for a 24h 2 cross wheelset I built.

The guide at this link is really good if you are not used to building wheels. Wheelpro

IMO no need for washers as the rim is designed to take the nipple directly. A dab of oil from a cotton bud on the inner face of the rim spoke hole will help with the build.

Sapim HM washers are a few quid on ebay, I’d always get new nipples though if reusing spokes, sapim polyax are my go to nips. Measure the erd yourself with the park two spoke method. I’ve built that set up with washers using 273/4 I think. Definitely 274 on one side but the washers add 0.7mm.
I’ve seen cracks on stans and raceface arcs so I opted to use HM washers just to be on the safe side. I don’t usually buy non eyelet rims.

I’ve somehow ended up with a bag of sapim nipples, pm me if you want them. Re the lacing just tape new rim to old wheel (with valve aligned) and swap direct if you haven’t already dismantled the wheel 🤔