That bolt pattern is 5/10 on 7.25. Common GMC up through '90's. 5 bolts used on front
(with large plate on some)the nuts tighten against, 10 bolts used in the rear, no spacer plate, thus the 5/10 notation. Earlier GMC trucks also used this pattern with smaller hub-easy to make hub spacer to use modern wheels on older axle.

Farm trucks in the late '50's used 22.5 tubeless wheels and tires with the advent of tubeless tires(only.). These wheels are somewhat rare in the 'States. Modern use is only 19.5's that look undernourished on large truck.

Ed

Last edited by Phak1; 09/21/2023 1:14 AM.
'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.