The X-Challenge is a bit of an odd-ball set-up on the front as the nipple holes are only 0.250"(really small) and there is no Excel 21x1.60" rim with that small a nipple hole. Some of the stock Honda, Yamaha, Suzuki, Kawasaki wheels have 0.280" nipple holes(there are only a couple aftermarket, the better quality double signature Excels that have as small as 0.300" nipples holes, most come with 0.320" nipple holes), so you may be able to find a nipple with 0.280" body diameter and 3.5mm gauge to fit the stock 3.5mm gauge spokes. There are no aftermarket spoke kits that I know for the G650 X-Challenge.
You may be able to order some in Europe from Alpina(Italy) or Bulldog/Central Wheel(UK)(these companies may also be able to custom drill the rim for your stock spokes and nipples and lace pattern), but likely would be special order, as this is an uncommon project since G650 was only around for a few years.
Hope that helps.
Originally Posted by Perun
Hello from distant part of Europe!
I want to instal Excel rim on OEM front hub of my BMW X-challenge, and I would really appriciate if you could help me to clear some things, since I am to far to use your services.
I want to use Excel IC_408 rim, used on KTM's, is that a good match?
Can I use OEM spokes and nipples, or should I look for something else (and what else)?
Thank you and keep up the great work!