I took my hubs and rims to get laced last weekend. I brought an extra set of assembled wheels for reference and the guy doing the lacing said BMW’s didn’t have an offset (meaning they were “0” or centered). So i took the extra set home thinking he was the expert. However, it is a shop that mostly specializes in Japanese bikes.
I remembered reading something about there being an offset many years ago and I looked into it. It turns out that the /5 motorcycles do have an offset (because of the drum brakes and hub).
Some say that wheels with disk brakes do not have an offset but not according to the spec sheet.
I called the the person doing the lacing and he was very nice to talk to.
His name is AL and the shop is Johnson and Wood in North Hollywood.
Here is a piece of advice written by the BMW motorcycle guru Duane Ausherman:
Before you cut the old spokes, install the wheel, with or without a tire. Measure to each side of the swing arm. This will tell you just how centered it is. If you need to move it over a bit, calculate it.
Then lay the wheel down on a flat surface. If it is a drum brake, it is very easy. Have the drum side down. Now find 3 nuts that will just fit under the rim. The thickness of the nuts gives you the current off-set. Now calculate in any correction needed for the wider tire.
Now find 3 nuts of the off-set you desire. Hold the rim off the flat surface to give you the off-set. Lace the spokes in by hand and a bit at a time bring the nipples up to snug. The rim is now laced to the correct off-set that you desire. Put it in your tuning jig and finish up. As long as you do equal tightening to each nipple, the off-set won’t change.
I have done many dozens this way and it is much faster than using the BMW off-set tool.
Attached is the BMW spec sheet from 40 years ago. Hopefully this will serve as a guide for others out there who are lacing rims.