Drew;
So I guess 75 mph @ 4250 would be a little over the top,eh?
I'm actually trying to get some passable used 11.00R-22.5's for it now-it's my understanding that those would bring my rolling diameter from 38" to around 44",good for 75 mph @3665 rpm.
I hope that'
s true! That's about the only viable option to gear it up. The rear is what it is-no optional gears for it that I'm aware of. (Maybe find a different 2 speed axle,but that'd likely mean different wheel lug pattern.) Maybe a change to a 5th gear over transmission,but then there's getting a PTO set up for it and possibly driveline mods. 3 speed Brownie,same problems,and a longer speedo cable.
I think my stock six hole wheels with 11.00's will be about the tallest rubber I can install.
And regarding fuel economy,I wasn't considering that an option,so-no harm,no foul.
Speed
