Pre-Chase Tip: Check those tires

[James Hammett]

This is a fairly contentious subject so I'd advise anyone to do their own research and their own testing before buying into any one-size-fits-all recommendation. I got the sidewall minus 10% thing from here:

http://www.milesgallon.com/tire_pressure_calculator.php

Chris Longhurst of http://www.carbibles.com/ reports up to 25% greater gas mileage in his Subaru by over-inflating his tires. The 'net is full of anecdotal evidence from hyper-milers showing over-inflation increases fuel economy without uneven tire wear. But it's hard to find anything authoritative beyond what seems to be cut & pasted advice even on reputable websites. Dunlop's site mentions over-inflation being a problem with "van, pickup, or RV tires":

http://www.dunloptires.com/care/proper_inflation.html

So can it be inferred they have no problem with over-inflating passenger car tires? Maybe?

Kurt Berger, consumer products manager at Bridgestone/Firestone: “If one wants to experiment with slightly higher than recommended pressures, we would advise doing it incrementally and within a limited range, carefully noting any negative performance characteristics that may occur as a result. In any case, never exceed the maximum inflation pressure listed on the sidewall of the tire.â€￾

Bridgestone/Firestone's http://www.tiresafety.com site that they set up after all their tread separation issues doesn't mention uneven wear in its definition of over-inflation: "rough ride, bruise damage, and suspension system strain".

I figure there's a very strong incentive NOT to condone anything but the OEM recommendation due to a real or perceived liability risk.

 

[Chris Gullikson]

I have 215/65/16 tires on my Chrysler mini van and put new tires on several years ago with the recommendation from the tire dealer to run 44psi per the max cold pressure rating. Tire wear after 20 or so thousand miles showed excessive wear in the center of the tire due to over-inflation. I now run 35psi per vehicle recommendation and have not noticed decreased fuel consumption and the ride is better.

 

[James Hammett]

I've had a set of soft compound tires that showed a band of excess wear in the middle due to ballooning from centrifugal force. So I wonder if some reports of this type of wear would have happened over-inflated or not. I don't doubt that some tires just can't handle being over-inflated though.

 

[Greg Campbell]

This is a fairly contentious subject so I'd advise anyone to do their own research and their own testing before buying into any one-size-fits-all recommendation.

Chris Longhurst of http://www.carbibles.com/ reports up to 25% greater gas mileage in his Subaru by over-inflating his tires. The 'net is full of anecdotal evidence from hyper-milers showing over-inflation increases fuel economy without uneven tire wear.

IMO, 25% sounds far too high, even if the factory suggestion was on the low side. FWIW, I once ran a A-B-A test that suggest a ~6% increase at modest freeway speeds - about 2 MPG in my old Accord. That's going from my usual 40 to the sticker's 32 and back. OTOH, my test was short, only 1 tank for each round, and was conducted over somewhat variable conditions as I drove around the western US for several weeks. My numbers do jive with the average results reported by the hypermiler crowd. (Those that don't go off the OCD deep end and fill their tires to 70PSI. ) Think of it as reducing the cost of gas by 15 cents a gallon.

Like James suggests, anyone with an interest in the issue should try running an extra 4~5 PSI for a tank or two. It really can't hurt anything.

 

[Steve Polley]

This is a fairly contentious subject so I'd advise anyone to do their own research and their own testing before buying into any one-size-fits-all recommendation. I got the sidewall minus 10% thing from here:

http://www.milesgallon.com/tire_pressure_calculator.php

Chris Longhurst of http://www.carbibles.com/ reports up to 25% greater gas mileage in his Subaru by over-inflating his tires. The 'net is full of anecdotal evidence from hyper-milers showing over-inflation increases fuel economy without uneven tire wear. But it's hard to find anything authoritative beyond what seems to be cut & pasted advice even on reputable websites. Dunlop's site mentions over-inflation being a problem with "van, pickup, or RV tires"

Looks like this guy at carbibles.com is more worried about his mpg than safety and wear and tear on the vehicle. We would never go over the OEM recommendation for liability and tire wear reasons. Courts would have a field day with us if we knowingly overinflated our customers tires. What each owner of the vehicle does to their tires is their business I guess.

 

[James Hammett]

The different shops I've been to always over-inflate my tires. I've read it's a liability thing...better to over-inflate than to risk under-inflating.

 

[Larry J. Kosch]

Track Bar??

I like to drop a 1/4 of a pound out of the right front as peak heating is reached, helps free up the van going into the corner.

Uhmm, think you better check your track bar setting or adjust the tire stagger on the right rear to make the van turn better!