Spoke length calculation + rounding up or down?


I’m currently waiting to build a rim, I have a 24" halo combat rim, 16mm alloy spoke nipples and a Koxx ISIS hub.

I intend to get it built up with 3 cross spoke pattern with 14 guage spokes (2.0mm)

Could someone tell me what length spoke I need? I have a figure which I have got but I’d like to hear if someone else comes to the same conclusion.

Did you use this spoke length calculator on the UK UDC site?

Yeah, as it has both my rim and hub preset. But It gave me 230.98 and the spokes I want to buy are only available in even numbers. Should I round up or down? (I’m using dt spokes with 16mm nipps)

Going from 231 to 232 isn’t that much of a difference, and the last thing you want is to have a spoke that doesn’t extend to the flat on the inside of the slot on the nip. Spokes that are a little on the short side are the main reason people break nipples.

From reading about it abit more, I’m guessing the UDC spoke calculator defaults to 14mm nipple length, so am I right in thinking that due to me using 16mm nipples, that I should subtract a further mm away. and use 230mm spokes anyway?

And jtrops, from what I have read the worst thing is that if your run out of thread by having the spokes too long opposed to having it too short (as from what i’ve seen when using 16mm nipples spokes rarely reach the flat end of the nipple anyway.

Could do with some 100% clarification, as I’d hate to spend all this money on spokes and wheel building for it to be wrong.


Rims do vary even within what are meant to be identical ones, the difference can easily be 1mm in my experience.

As a general rule you should go short rather than long.

16mm nipples are more than likely too long for DT spokes. You will be off the end of the thread with them.


Hi Roger, How about with the UDC spokes? would a 230 length be enough? (they are not dt nipples they are 16mm unbranded)


The spokes we have have 10 or 12mm thread so should be ok with the longer spokes. I have built Combat rims with standard width hubs no problem with the 230 and 16mm nipples.