New rims wanted as I’d like a bit more width (Fnarrrr Fnarrrr..). The ones I have spotted have the same ETRO size, ie 559, but a tad wider, ideal.

Will it mean new spokes for the build? Will the length of the old ones be an issue?

I may even try and do the build myself, and borrow a mates truing stand. If I fail, I’ll take the sorry bits to the LBS…

You need to know the effective rim diameter (ERD) of both rims – if the same, then you can reuse spokes.

ETRO is to do with what tyres do you mean ERD’s match ?

if the later then yes if the former its irrelevant for spoke calculation

ERD is what you need. As long as you’re on the ballpark it should be ok, though knowing whether your current spokes are bob on, a little short, or a little long will help (look at the top of the nipple in the rim bed, does any spoke poke through the top of the nipple?)

The ETRO size of 559 is the Euro equivalent of 26″ (like 650b is interpreted as 27.5″ even though it isn’t) rather than the ERD size, which is used to calculate the spoke lengths.

The other issue is that old spokes (and old rims) can make building a PITA as they’re much harder to get even tension with.

If it’s a first attempt, there’s a really good (and free) guide on the sheldon brown site. And buy/borrow the Park tension meter, it makes getting the tension even a lot easier than doing it by feel. My first attempt was done by feel, and they lasted a while. My second set was done with the tension meter and they’ve been better than any other wheel I’ve ever used, hand or machine built. It’s possible to do it right by feel, but you’ve no objective way of knowing how much tension is right, or what the acceptable range is, especialy important on modern eyelet-less rims, you want the tightest spoke to be just under the max tension, and everything else as lcose as possible.

And measure the ERD yourself, you might find the rims bigger or smaller than expected. Do it with a set of spokes of a known length threaded into the nipples you intend to use, then measure the gap between them in the middle and add t the length to get the correct ERD, also worth checking how round the rim is as the ERD can vary if the rim isn’t pefect!

Go and buy Roger Musson’s book. It’s only £9 and you’ll never have to pay someone to build/true your wheels again. There’s instructions in it on how to build a truing stand too. Works great. I got an offcut of 18mm MDF for B&Q for £1. A few bolts and brackets and some paint that was lying in the cupboard and bingo!

Whole thing cost less than a fiver.

No issue using old spokes, they won’t make it harder to get even tensions. Just check for obvious damage. Old rims will make it a bit more tricky, as the’ll be less round than brand new ones. I built my first set of wheels using old rims and it takes a bit longer, but still totally do-able for a first time builder.

The ERD is the only measurement that matters when it comes to spoke length. Ignore ETRO. Also ignore the ERD measurements you find on the internet for your rims (that includes measurements from the manufacturer). There’s too much deviation in the manufacturing process. Measure them yourself using 2 old spokes. If you dont know their exact length, chop them down accurately to 200mm each. Measure from the threaded end and chop off the elbow end. Fit them through opposite holes on the rim and screw the nipple down till the top of the spoke is flush with the bottom of the slot on top of the nipple. Measure the distance between the 2 spokes (it helps to join the 2 ends by taping an elastic band between them) and add 400mm. That’s your ERD. Measure on your old rims too. If they’re the same (or a couple of mm out) you should probably be ok with the same spokes. If not, you’ll have to calculate spoke lengths yourself. Don’t try and measure the old spokes and they’re not properly straight and it’s very hard to get an accurate measurement.

You’ll have to buy and measure the rims, then order spokes. You can’t buy them all at once.

Thanks all for some top advice. The wheels, as they are now, are in good shape and I’ve only had to true them a fraction since running them. So I’m pretty confident that a swap won’t be an issue.

If the spoke lengths/ERD aren’t compatible is there a way to calculate what length I should be getting to replace them? Presumably, this is something I could find out online?

Google wheelpro – it has a spoke length calculator on it, assuming you know the rim ERD and hub measurements.

Wheelpro is Roger Musson’s site. That calculator will be fine. You can use the hub measurements from the manufacturer, as hubs are manufactured to much tighter tolerances. Measure the rim, as described before and plug in the numbers. Definitely invest in the ebook, if you’re gonna do it yourself. There seems to be a lot of info to get your head around, but it’s all fairly straightforward if you take your time and make sure you understand what you should be doing.

A rim swap is totally fine, assuming the spokes are the correct length. You won’t know that till you’ve dismantled your old wheels and measured the rims, then compared them to your new ones.

@ citizeninsane – how difficult was it building up that 823 rim?

I have one I need building up but due to the additional complexity (?) of the nipple holders it seems to put people off 🙁

Actually an 821, but close enough. 🙂 It’s no harder than a standard rim. Just takes longer and is a bit more of a faff.

You’ll need some Loctite 243 and the Mavic (or Park) wrench for the nipple cups. Lace spoke through the hub, put the nipple cup over the spoke and screw on the nipple a couple of turns. Then position the nipple in the correct hole on the rim and lightly screw the nipple cup into the rim, leave threads showing though. Then put a drop of Loctite on the nipple cup threads and tighten with the special wrench. 5.5Nm, if I remember correctly. Once you’ve done them all, put a drop of oil on the exposed spoke threads and nipple and screw the nipple down so it just covers the spoke threads. This means all the spoke threads will be evenly engaged.

After that, you just continue as normal. It’s the first bit that makes it a faff and the main reason it takes longer.