Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - "Inflation pressure does not affect grip": Autospeed article.

autoteach · 05-02-2010, 04:37 PM

Well, I have to weigh in, although it seems that my opinion, like others, will be dismissed because "we don't know". Belts in automotive tires, unless specified, are at ~15 degrees. Try to even wrap a piece of tape around your tire repeatedly at this angle. How many revolutions did you get around the circumference? Some tires are 0 degree belted, but are mostly found in motorcycle tires where deformation at lean angle becomes important. Because of this...
Tires do bulge at the center, pressure does affect traction, and stopping distance, and not in the way that you are describing. I have, and I suppose that it will be argued, more experience than most(albeit the few who have worked in racing/automotive repair) with tire inflation. I have seen car, truck, and heavy duty truck tires that have experienced life at various tire inflations. All of the over inflated tires have worn faster in the middle, all the under inflated had worn on the outsides. This starts to happen in less than 5000 miles to a measurable(meaning able to be determined with measurement) degree. Both over inflated and under inflated tires drastically affect handling of the vehicles, in accel, brake, and lateral, and for the vehicles that travel down the road, there isn't a good blanket policy that you can apply to them.

I won't come back to argue, as I know my data. My toyota pickup (1989) called for 35psi, this would make the rear of the vehicle harsh, and unpredictable. Minor amounts of throttle could break them loose, wet or dry. 4wd would not engage in any favorable way. The center began to wear considerably within one oil change. Braking with these pressures would cause the rear tires to lock almost instantly. After this, I adjusted the tire pressure to accommodate sidewall height, which is relative to rolling diameter (not actual diameter). It improved all these aspects, which in my mind is far better than mpg. This has held true for almost every truck and car that I have seen in the last 15 years, and I doubt that it will change until tire construction changes.

05-02-2010, 04:37 PM	#109 (permalink)
autoteach Master EcoModder Join Date: Apr 2010 Location: belgium, wi Posts: 262 Bus - '94 Ford School Bus huge Stupid - '01 Chevy Blazer LS 90 day: 21.38 mpg (US) hawk - '00 Honda Superhawk Thanks: 2 Thanked 24 Times in 19 Posts	Well, I have to weigh in, although it seems that my opinion, like others, will be dismissed because "we don't know". Belts in automotive tires, unless specified, are at ~15 degrees. Try to even wrap a piece of tape around your tire repeatedly at this angle. How many revolutions did you get around the circumference? Some tires are 0 degree belted, but are mostly found in motorcycle tires where deformation at lean angle becomes important. Because of this... Tires do bulge at the center, pressure does affect traction, and stopping distance, and not in the way that you are describing. I have, and I suppose that it will be argued, more experience than most(albeit the few who have worked in racing/automotive repair) with tire inflation. I have seen car, truck, and heavy duty truck tires that have experienced life at various tire inflations. All of the over inflated tires have worn faster in the middle, all the under inflated had worn on the outsides. This starts to happen in less than 5000 miles to a measurable(meaning able to be determined with measurement) degree. Both over inflated and under inflated tires drastically affect handling of the vehicles, in accel, brake, and lateral, and for the vehicles that travel down the road, there isn't a good blanket policy that you can apply to them. I won't come back to argue, as I know my data. My toyota pickup (1989) called for 35psi, this would make the rear of the vehicle harsh, and unpredictable. Minor amounts of throttle could break them loose, wet or dry. 4wd would not engage in any favorable way. The center began to wear considerably within one oil change. Braking with these pressures would cause the rear tires to lock almost instantly. After this, I adjusted the tire pressure to accommodate sidewall height, which is relative to rolling diameter (not actual diameter). It improved all these aspects, which in my mind is far better than mpg. This has held true for almost every truck and car that I have seen in the last 15 years, and I doubt that it will change until tire construction changes.