Wanted bits to get 21" and 18" rims and knobblies on a 1150 GSA
 

Hubs, spokes, rims all wanted

Any recommendations on tyres for the rather lardy 1150 GSA

Thanks, Mike

Decent knobblies on 1150 GSA
 

Got a scruffy and cheap set of spoked GS wheels, seems a shame to break them down but I need those hubs!

Will regular 250 / 450 Moto-X rims be OK, are they strong enough. Do they work with BMWs somewhat unusual X-Spokes?

Certainly cheap on fleabay.

Any advice appreciated - c'mon there must be some words of wisdom available.

I'm pretty sure your wheels have 40 spokes (please count to make sure). Most (all?) MX/Enduro-bikes has 36 spokes so they doesn't fit.
Both Behr and Excel makes rims for 40 spokes but they are hard to find. You don't want the flat type.
Another option is to use 18 and 21 tubeless rims from airheads, this will give you the option to run tubelss tyres.

Woody's Wheelworks (US) can do this modification for you, but I'm sure there are other options. A friend of mine had Woody's wheels on a 1200GS (18+21) and it was a nice setup.

I have a set of centerlaced Behr rims on R80GS hubs (same problem as you with 40 holes and x-spoked wheels) and they are very strong.

Speak to Central Wheels, they are the daddies at rebuilds and know their rims. MX rims are built to take a proper hammering so should survive OK