Spoke length
 

Hey, I'm new to working on bikes and am about to try to build my first back wheel with this set up;

Shimano FH-M565 Rear Hub
Mavic XM317 MTB Rim
DT Swiss Competition DB Silver Spokes

My main issue is that I don't know which length of spoke to order. Any help with this would be brilliant. Also, any opinions on the set up are welcome but I am restricted by cost a bit and I only go off road occasionally.

Thanks

Oh, and the wheel is 26".

DT Swiss has an awesome online spoke calculator:

http://spokes-calculator.dtswiss.com...px?language=en

You don't need a login to use it but if you want to store your data for future reference, it's painless to create an account. I haven't tried your combo but that hub and rim are most likely in their database, making it much easier than if you had to find PCDs, centers, ERD, etc.

Hint: if the calculator spits out two different lengths, as long as they are within a couple millimeters of each other, you can order all the same length for drive and non-drive sides (cheaper). Good luck!

EDIT - - The DT Swiss calc doesn't seem to have your hub in the database. SPOCALC does, though, and it's a good tool too. If you want to doublecheck Spocalc, take your hub specs from it and plug them into the DT Swiss calculator to be sure.

There are numerous spoke calculators out there but I prefer this one.
http://www.wheelpro.co.uk/spokecalc/

You can use the ERD listed on the rim makers website but it's always a better idea to measure yourself after you have the rim.

Ok, when I plugged the rim into DT Swiss calc it auto input the diameter as 545mm, when I thought 26" was 660mm. Do you know why? The two calculators gave the same answers when the same diameter was put in but two more questions were raised that I hadn't anticipated.

1. How do you decide the number of crossovers and does it make any difference?
2. The Spokecalc database records the FH-565 as being only 8 speed compatible but a review I read of the hub said it was 9 speed as well. Do you know if it is 9 speed compatible? As this information seems to be hard to find online. If it isn't what would you recommend for a 9 speed hub? My budget would be £30.

Cheers.

The number you are being given is the ERD, or Effective Rim Diameter. This is determined from where the nipple beds into the rim, so varies slightly from rim model to rim model due to its cross-section. The 26" wheel size (or 660.4mm) is the nominal outside diameter of a 26" tire, not the rim size.

Yes, it makes a huge difference. You will want to do cross-3. Cross 4 is overkill and you don't want to do cross-2 on an MTB wheel.

Cassette bodies for 8- and 9-speed are the same width; they just narrowed the spaces between the cogs when they developed 9-speed.

Excellent resource here. Well worth the small cost.

Thanks guys that's a massive help.