Should I go the extra mile or stay where I am???

[Compaq888]

When my tires were 32psi all around I got 24mpg mixed driving. When they were 40psi I got 28mpg. Now I'm at 44psi, I'm getting about 29mpg, but since I do a lot of city driving I'm at 27.6mpg

The max rating on the tires is 44psi. I want to go to 50psi but I'm scared for safety of turning and braking. The weird thing is I have better traction at 44psi than at 37psi. At 37psi my car had a lot of understeer but with 44psi the understeer almost disappeared. I even took very hard corners and it hooked up, there was almost none understeer.

I want to go to 50psi for even better mpg. I hope to see 30mpg mixed driving which is 50/50 cty/hwy.

What do you think I should do, stay at 44 or take it up to 50?? If I take it up to 50 I won't go beyond that.

[SVOboy]

My friend put 50+ (gauge went to 50) in his tires on his civic and I beat the hell out of it and the steering was fine. Normal understeer of course but we did some crazy drifting in that bucket. You should be plenty fine at 50. I think dan's tire limit is 35 and he's at 50.

[Compaq888]

But can the tire blow from this high pressure, remember when you drive the pressure in the tire increases.

[SVOboy]

I have yet to see a tire blow from 50 psi.

[Compaq888]

ok if I put 50psi in the front what should my back tires be???

Right now my setup is 44psi for the front and 41psi for the back. Car handles great.

[Matt Timion]

I am personally only comfortable with the max PSI rating of the tire. My fear however is probably fueled by the fact that I've bought more tires than any other car part since I've been driving. Me and tires do NOT have a good history.

[krousdb]

Originally Posted by SVOboy

My friend put 50+ (gauge went to 50) in his tires on his civic and I beat the hell out of it and the steering was fine. Normal understeer of course but we did some crazy drifting in that bucket. You should be plenty fine at 50. I think dan's tire limit is 35 and he's at 50.

The Prius has 44 MAX rated tires but I have had them at 50PSI for about 60k miles with no problems. I had them at 60psi for another 3k but the ride was a little bumpy. This subject has been discussed at some length and like SVOboy said, no one has ever been able to provide me with evidence that any tire has blown after being inflated to 50PSI. According to someone whom I would consider an expert, auto tires are designed with a minimum 120psi explosion rating. Truck tires are designed for 300-400 PSI.

I am not going to recommend that anyone do anything. Just providing data. Remember that there are hundreds of Insight drivers with 50+ in thier 44max rated tires. Again, I have never heard of a failure. What is quite clear is that there is more blowout danger associated with underinflated tires than with overinflated tires.

All that being said, I doubt that you will notice much of a gain, maybe 1/2 MPG.

[JanGeo]

start by jacking up the rear tires and see how freely they spin - my Geo would rotate really easy like a bike tire - many revolutions very little drag. If they don't turn easy repack the bearings with teflon grease i.e. Slick50. Next check the front for brake drag and work the caliper to make sure they are moving freely and retracting enough.

[Compaq888]

Originally Posted by Matt Timion

I am personally only comfortable with the max PSI rating of the tire. My fear however is probably fueled by the fact that I've bought more tires than any other car part since I've been driving. Me and tires do NOT have a good history.

Care to explain why you and tires don't have a good history?

[Sludgy]

My brother once blew out a rear tire as we were heading to Maine for vacation. His Datsun was heavily loaded, and we had just driven about 30 miles in hot summer weather.

The point is that you might be able to overinflate tires safely IF you don't load them to max weight AND if you watch out for hot weather and the frictional heat that comes with extended highway driving.

I would guess that a 44 PSI-rated tire could be safely inflated to 50 PSIG when HOT. Inlating to 50 PSIG cold means that you'll have maybe 60 PSIG after a long ride on a hot summer day.

On a hot Fourth of July, you don't want four firecrackers under your car.