Hi
I am looking to build a pair of XM481 x DT 350s classic w/ J Bends (Boost)
Does anyone know what spoke length I need to order for front and back? Also how can I determine this without actually having the rims and hubs yet as I want to order everything as 1 batch.
Thanks
Carlos
dt swiss spoke calculator is the way
Hi there, DT Swiss have a spoke calculator which can help you: Spoke calculator - DT Swiss
Sensible advice, wait until you have everything in your hands and measure, then put the results into a calculator. Second riskier option, believe the specs online and hope…
in-hand measurement always a good choice but since he is using dt hub and rim, i’ve found the calculator to be plenty accurate
True, I’m rarely using matching brands or the calculator from the actual company! Last rim I used, the manufacturer listed one ERD on their site, the supplier had the same image just with the value deleted and a wheelbuilder/parts shop online had it listed with the correct value (6mm different IIRC)!
If OP has any issues with the calculator, feel free to post and ask for help. Pretty straightforward but the different hub generations can be a bit confusing sometimes. I wish they would just let you plug in the hub serial # to automatically populate that field.
This is brilliant!! Thanks all! I was going to consider going with Sapim Race spokes and Sapim Nipples but with this calculator, I’m inclined to stick with DT. Should make a robust AM/XC wheelset for my natural trails and races. Still haven’t decided if I should got for 240s or 350s. 240s are on sale just around 80 euro more expensive but I notice the new DT 350 has the same 36t ratchet as the 240s… I do a lot of technical climbing so engagement is important.
Also - if anyone has any recommendation for DT branded spokes and nipples - I assume DT Competition spokes would be the go-to.
I only use Sapim spokes now, they shouldn’t be any different from the same thickness DT versions.
There’s got to be a similar stock build for this combo. The service section shows the spokes and nipples they use.
I’ve had the same issue, and I just bought a spoke threader.
Here’s a 3x 21mm deep wheelset - FR 1500 CLASSIC | DT Swiss
293mm rear
297 / 299mm front
15mm nipples
The exact spoke, tension, and nipple hole matters, so error on the side of 2mm shorter or so.
Sapim have been my go-to since they are easiest/cheaper for me to order from europe for delivery to the US. (Currently lots of international sale restrictions on DT components from europe to the US).
Yes it is technically best to find a close spoke profile match on the DT calculator for the sapim spoke being used, but overall there is like 1mm difference in calculated results between the thickest straight gauge spoke and the thinnest butted spoke or aero bladed spoke.
In other words, spoke choice hasn’t been an issue for me across ~10 wheelset builds in regards to the calculations.
I’ve built a couple sets of mtb wheels, but used the XM421 rims and DT350s, one set 27.5, the other 29 (but SuperBoost for my Pivot). The 27.5 set worked out great, using the DT Swiss calculator. I’m pretty confident the DT Swiss calculator gave me an incorrect (too long) spoke length on one side of the rear wheel, with the spokes extending past the top of the nipples, and a few of them I ran out of threads, and so the dish is a little off (because I had to add my tension on the other side), and I sacrificed a tiny amount of tension to be closer to centered. I have the oem DT 1900 set, so I checked against that when I realized there was an issue, but I have almost 500 miles on them with no issues…they’re “compliant” 
. So, I recommend you double check the spoke measurements manually, when you get the rims/hubs and before you lace them.
do you have the spoke lengths and stuff handy for that build that went awry?
genuinely curious if it is an issue with the calc, or perhaps wrong hub entered (all the sub models etc in the drop down can be very confusing).
Did you use the DT washers?
So I’ve ordered all the parts;
XM481 Rim (28 spoke) - 62 euro
DT 240 EXP 6 bolt Boost - 230 euro
Sapim Race Spokes (Silver) 296mm for left and right. (30 cent each)
Sapim Brass 12mm Nipples (Silver) 296mm (15 cent each)
Estimater says 296.5 left and 295.5 right - Sapim only does intervals of 2mm.
Went with sapim cause of cost and availability - DT spokes don’t seem easily accessible unless you get boxes of 100s.
I have a truing stand and tension meter - so will give it a shot to build myself, then send it to a friend who owns a bike shop to do the final adjustments.
Think I marginally saved money with all the sale prices compared to buying a finished wheel.
Was going to go for a Hope Pro 5 until I saw 240’s were on sale. Hope I made the right decision!
Will let you guys know how it goes 
Also - I only ordered the back wheel as my back wheel is completely toast. I’ll probably order the front wheel next month
I’d have gone 298 both sides, but hopefully there’s wiggle room in the calculation. The calculator I use says to never go shorter, and the Sapim double square nipples tolerate excess length well.
Keep us updated on the build!
Sounds about right
Calculator says 295.5 rear left and 296.5 rear right with a 12mm nipple.
I ordered a 12mm nipple with 296mm spokes
The FR 1500 has a 15mm nipple and 293mm spokes
I wonder if its the same exact rim but XM481 is AM and FR1500 is DH
How do i check the spoke lengh? Just lace them as I plan and ensure there is enough thread vs the amount of tension required?
I think he means what I said in my initial reply:
Yes, used their washers, and DT Comp 2.0/1.8 spokes, and their standard brass 2.0/12mm nipples. I swore I made good notes, but I only notes that I could have used 294 mm for the front wheel both sides (instead of the calcs 293 & 295).
It appears I may have misremembered because I do have a solid note that, for my 27.5 wheelset front (calc’d 272mm & 274mm), the 274 is too long and so dish is offcenter.
So, sorry for causing worry. EIther way, it all works fine. I have about 6k miles on the 27.5 set and over 4000 on the 29er set, of rooty, punchy trails. I don’t know that I’ve ever had to true the 27.5, and pretty sure I touched up the true of the 29s once in the first year.
As far as measuring, there’s a couple methods, once you get the rim (and hub, but you have the center to center dimensions from DT Swiss’ calculator, and I verified those dimensions on mine), then you can use a couple spokes and nipples (and washers if required), and a rubber band to measure the true ERD measurement to plug into a calculator. It’s what you would do if you were mixing and matching components. I didn’t trust myself, which is how I ended up going with DT Swiss rims…because I figured I could trust their calculator.
I downloaded Roger Musson’s The Professional Guide to Wheel Building. Good reference if you’re going to be doing this regularly. I’m sure there’s plenty of free references online, too, these days.
Bascially. Park makes a spoke measuring tool… but since the spoke and rim stretch, the spokes and nipples seat differently, and other factors it’s not an exact science. I do all this math like everyone else and still end up trimming spokes most of the time. Always order a few mm shorter than you calculate.