Hypermiling and tire pressure...

So I've been hearing a lot lately about "hypermiling" and keeping your tires properly inflated. I've heard that for the best fuel economy, you're supposed to keep your tires inflated to the max psi that they're rated to...

Now I'm not sure if that's bogus or what, but it certainly doesn't sound right. That would mean I'd need to be running 50psi in my 32x11.5in BFG MTs... Can someone clear this up for me?

I do know that I used to run 40psi in my tires when i had my truck, but I think it had only 29in tires or something. Will my mileage improve if I inflate my tires to 40psi? (BTW, they're currently at 31psi).

you're mileage might improve alittle at the cost of ride quality and accelerated tire wear.An over-inflated tire will go bald in the center of the tread pretty quickly.
The manufacturers max psi rating is for hauling heavy loads or when the tires are used under a heavy vehicle.

So I would say "myth busted"

Inflate them to 50psi and drive it around...I bet you drop the psi pretty quickly.I had discount tires mount my tires and they inflated them to 40psi(34x10.50x15 super swampers)and until I got home I thought my suspension was sitting on the bump stops!!!I quickly dropped the psi to around 28psi and the ride quality went back to usual.

To find the perfect psi do the credit card,chalk line,or wet tire tread test.

You may save some in gas but you'll trash the middle of yoru tire tread that way.

I inflate to where my tread contact pattern is even, that's 25psi with my 35's, 32 with my 31's.

Don't waste a bunch of time and effort trying to get great mileage out of a Cherokee, that's a pretty worthless battle.

thanks for the advice. yeah, trust me I'm not kidding myself and trying to get prius-like mileage out of an XJ or anything, but with the cost of fuel I definitely wouldn't say no to a few extra miles per gallon. I don't mind a rough ride, either... so maybe I'll inflate them a little bit and see what happens...

With a street tire, it works great. I wouldn't think there'd be a great reduction in rolling resistance with a luggy MT though. I can't imagine there being enough of an improvement to offset the cost of the tires, and I would think they would wear very quickly at max pressure, but well under max load.

Hypermiling and modified offroad vehicles... c'mon, be realistic here.

I've played around with it just to see, and you can get a few extra mpg's just by the way you drive, trying to anticipate traffic & lights, accelerating slowly, planning ahead so you don't have to use your brakes & waste momentum, etc. It's not much fun driving that way but it does help a little.

Max inflation will equal accelerated tyre wear, loss of cornering traction, increased braking distance, reduced traction from stop and poor ride.
Why would you pay less now in mileage only to pay more quickly to replace your tyres?

What would be a good pressure for a BGF MT 32x11.5, 25, 28 psi? I think the tire shop set them to 32 as per the sticker on the door.

Mudderoy said:

What would be a good pressure for a BGF MT 32x11.5, 25, 28 psi? I think the tire shop set them to 32 as per the sticker on the door.

Click to expand...

Your question has already been answered a few posts up:

outlander said:

To find the perfect psi do the credit card,chalk line,or wet tire tread test.

Click to expand...

Every vehicle is different, the best way to determine your proper PSI is to do the chalk trick. With a full tank of gas and your spare in/on the jeep, start at like 30psi and draw a line across the surface of your tire (edge to edge) and drive it a bit to see how it wears the line, you want to adjust the PSI till the line wears evenly across.

xj92 said:

I've played around with it just to see, and you can get a few extra mpg's just by the way you drive, trying to anticipate traffic & lights, accelerating slowly, planning ahead so you don't have to use your brakes & waste momentum, etc. It's not much fun driving that way but it does help a little.

Click to expand...

Depends on the person, if I need to get somewhere it gets set aside, but if I got time or just kinda out running errands/screwing around I'll do it. IN the latter cases, it does seem to be enteraining to me, I just may be easy to entertain though:laugh: