Possum,

Seems like you were asking about 20" tires, can't find the post now, anyway, 22.5's with 10 bolts are pretty common, it might be worthwhile to switch while you are at it, might even find tires and wheels together for a decent price. It is getting harder to find any tire shops to work on multi-piece rims, especially on the road.

Ed

'37 GMC T-18 w/ DD 4-53T, RTO-610, 6231 aux., '95 GMC running gear, full disc brakes, power steering, 22.5 wheels and tires.
'47 GMC 1 ton w/ 302, NP-540, 4wd, full width Blazer front axle.
'54 GMC 630 w/ 503 gasser, 5 speed, ex fire truck, shortened WB 4', install 8' bed.
'55 GMC 370 w/270, 420 4 speed, grain, dump bed truck from ND. Works OK.