EROCK said:
The rim measures 11 inches wide so I'm assuming they're 10.5s. What's the lowest pressure you recommend with a 10.5 wide rim and 33x 12.50 15 BFGs Load C's?
A 10.5" wide wheel would be very unusual. Typical wheel widths for jeeps running 12.5" wide tires on 15" or 16" diameter wheels are 8 and 10". Less typical are 12" wide wheels and those are usually limited to rigs that run sand, snow or other conditions that require very wide tires for flotation, i.e. 13.50 and 14.50.
If I were guessing I would guess that
@EROCK has 10" wide wheels. However, for majority of jeepers there really isn't much difference in lowest suggested air pressure for 33x12.50 tires on 10" or on 8" wide non-beadlock wheels - 10 psi or so.
One exception might be deep snow. On a recent snow run I participated in, everyone without beadlocks was airing down to about 8 psi with no adverse results. The beadlocked guys were airing down to 3-4 psi.
As for whether one should be running 8" wheels rather than 10" wheels with 12.5" wide tires, the common wisdom is 8" but that is largely based on the belief that 8" wheels are less prone to losing a bead at very low pressures than 10" wheels, and that narrower wheels are better protected against damage from rocks by tire sidewalls that bulge more on 8" wheels than on 10" wheels. In reality, the risk of losing a bead on either width wheel is very small down to 10 psi and one can damage any wheel on the rocks no matter how wide or narrow. In the end it comes down to personal preference, one's sense of aesthetics, and whether one needs to be concerned about keeping the tires under the fender flares to avoid unwanted attention from law enforcement.
I have run 8" wheels and 10" wheels through the years with equal success. My most recent wheel purchase was a set of 8 inchers. However, I will probably avoid the "8 vs. 10" debate entirely with my next set of tires. 17" rims appear to be becoming the new 15's with a much larger selection of wheels and tires. My next tires are likely to be 35x12.50R17 on 17x9 rims.
Back to
@EROCK 's query about tire pressures for his 33x12.50 tires: My suggestion would be to start with 14-15 psi trail pressure and experiment, then move down to 12 psi and experiment some more to see if that is enough, and only if it is not experiment with anything lower. I recommend starting with a bit higher pressure with graduated stepdowns and experimentation because it is more valuable to gain personal experience based on one's own observations than to blindly follow advice found on the Internet. One won't have access to the Internet out on the trail when one has to make a real time decision about what to do in a difficult situation.
