I have 3.5 suspension and 1" body. Was just wanting to know if the upgrade from 33's to 37's would I need to upgrade anything in the drivetrain? Im running 4:10 gears locked front and back. Spartan lockers... thanks for any advise
I run Military OZ 37's on mine. 4" BDS YJ springs with a 1 inch body lift. Lock right up front, Detroit in the back with 1 piece shafts and a truss. With a healthy sbc i have to be very easy on the skinny pedal. Been running this for almost 3 years mostly at URE. In that time i have broken a front U joint, one rear axle shaft the output shaft on the Dana 300 and a rear driveshaft. It never breaks when i think it will, generally lets go on something easy. Is it ideal? Hell no, but the tires are cheap and if you are careful it works. Worst part for me is braking capability. YJ booster and MC, larger early 78 discs up front with Hawk pads and i dont feel all that safe.
With all that being said.... I have a pair of CUCV tons that im working on
37's are roughly 12% bigger than 33's. A move to 4.56 gears will keep your power at about the same level it is now. I feel that lower gears are easier on axle shafts and u-joints, but the lower the gear the weaker the R&P get. I had 4.88's with 38" tires and a granny 4-speed. I loved that gear combo.
My CJ has 4.10 gears, Locked d30 and AMC20, superior shafts all around.
I popped a few front u-joints (spicer I think) in my front axles with 35 BFG and/or 36 TSL SX.
Also bent the rear AMC20 housing with the SXs on.
I noticed a huge difference in on road acceleration when going from the lightweight 35BFGs on aluminum wheels to heavy 36 SX on steel bead locks. 4.56 or even 4.88s would be better. I think the 35" BFGS with 4.10 is the sweet spot for pavement pounding in a non-OD manual transmission with a 258.
