Suburban Tire Pressure Question

[Lee R.]

I just changed my stock wheels & tires on my 89 Suburban 2500 to a set of 33" x 12.50" x 16.50" on 8.25" x 16.5" rims. What would you recommend for a on road driving tire pressure?

Thanks
Lee

[Bob Gervais]

Well, they're not the same size but here's what I run: 1500 Sub with 32x11.5x15 tires at 40 PSI. They're load range C, and max pressure is 50 psi. I tried them at that, but it was a little high. I only use 50 PSI when I'm towing.

[aggiedave98]

Bob,

I have the same tires as you. The factory door sticker settings says like 32 in front and 41 in back or something like that. I understnad these are different size tires, but how did you decide to go with the same pressure in the front and the back?


Also, how do you determine what tire pressure you should have for oversized tires?

Dave

[Bob Gervais]

Well, PSI is PSI regardless of tire size. I tried the factory settings, and the front seemed to mushy, even with the stock 235-15's. I do a lot of highway driving, so I started to play around with pressures until I found one that I liked. No tried and true method on my part, I just kept adding air until I liked the handling, and it gave a comfortable ride.

One thing that I did take into account when guessing on pressures is that the 32's have a taller sidewall, lending them to flex easier. I figure that's what made them feel mushy.

[aggiedave98]

Bob,

Thanks. That was my point w/ the bigger tires... PSI isn't equivalent b/c you have more tire to compress and absorb bumps and more tire to flex sideways.

Thanks for the response.

[Bob Gervais]

Not a problem. With mine it took a little trial and error to get what I felt was the best ride, and good handling (well, as good as possible in a tank like ours )