Did your 97 come with 265's stock? If it came with 245's, it is 7.75% difference with 285's, and with 315's it is 13.57%

 

Unknown. I bought it with 117K and it had 285's. I confirmed error with GPS and mile post times for both tire sizes.

Randy

 

My Speedometer was corrected by Dealer for 285.
The 315's need additional 5.4% correction... based on this site... http://www.sjdsm.com/tech/tire_size.htm

RJ

 

FYI - Got an answer to my own question. While calling on my biggest AG customer today, I meet a Michelin Factory Dist. Mgr.
He said all tire Mfg's build in a 10% saftey factory in their tire ratings...weights, pressures, speeds, etc.

RJ

 

RJ-- There's a lot more at stake here than just sizes and tire pressures.

Some people lose a lot of mpg with 315s, others actually gain some, and this without exceeding posted sidewall limits.

Tire design and construction have more to do with mpg than most people think. For example, a 19.5" setup with hwy tread will give good mpg even with the larger diameter. This is because they are 1) stiffer, 2) taller, and 3) rated for higher pressure.

But around town, those same 19.5s will cost you mpg because they are MUCH heavier, and it's inefficient to accelerate and stop all that extra weight.


The Toyo ATs have a rep (based on tire reviews I've read) for having a little more rolling resistance than some other AT tires. As much as I love so many Toyo tires, I confess that their AT leaves me with the impression that it's not as good a tire as Toyo's other offerings. Anyway, the rolling resistance probably hurts mpg a little bit. All in all, a little over 1mpg isn't too bad a penalty.

You have to keep in mind that your 285s were Michelins-- known for low rolling resistance and good hwy MPG. I'd suspect that a 315 sized Michelin would outperform a 315 Toyo AT, just because the Michelins are designed more for hwy performance and mpg (and don't do much else very well, at least my A/Ss on my truck)

The perfect tire for me would be an E-rated M55 in a 315 size. That would be a dream come true, imo.

In the meantime, I'm still hoping someone will make an E-rated 315 with moderate tread. We don't all need big mudders.

 

Check out Maxxis web site they offer some. We only have about 5K on the mudders but they are holding so far and have performed remarkably well. I'm considering their commercial tire for my '99 depending on the mudders life. I have been very disappointed in my BFG commercials.

BTW Hohn, I finally blocked my waste gate with the VA. WOW. I'm curious, what boost where you getting? I beleive my W/G is opening under drive pressure. I stabilze at 32. But it will push 34 then bounce a little first.

Randy

 

That's about what I was getting in the thin air here.