GOOD MORNING DON! I just checked my tire books, a 23-8.50 X 12 should take five gallons plus/minus a half gallon for valve stem fill, or 75%.
And before someone asks, a 23-10.50 takes 6 gal +/- a half gallon. And a 6-12 about THREE gallon, maybe 3-1/2. My book is WAY too old to have the 26-12.00X12's.
FRANK - Don & Wayne told you the correct scoop on removing the PTO rockshaft on the frt of a 129, no need to remove the grill & hood, pull the bushing on the left side and the rockshaft slides right out. IH spent a L-O-T of time designing everything on the frt of the 1X8/9's so that it works that way...
Maybe I'm lazy, but in over forty yrs of wrenching on CC's I've NEVER removed a grill casting. But I might have to remove the 982's grill to repair the governor in that POS Onan this summer. And take the old casting off the 70 for replacement.
STEVE B. - Nice work on the forks!