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Old 07-28-2017, 08:41 PM   #8 (permalink)
EcoCivic
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Quote:
Originally Posted by gumby79 View Post
Take the weight on a single tire divide it by the psi = the size of the contact patch . Eg my dodge 2500lbs rear axle ÷2 =1250÷side wall max+20%96psi =13.02^" Vs proper air for flat even wear@60psi =20.8^" which one will work better under anything other than straight line?
The performance gained in cornering from raised psi is the over inflated tire being convex compensating for the lack of camber and less slip angle (the difference between how much the wheel turns Vs how much the tred turns)
Eg. the tred is pushed sideways in a hard corner,
Over inflated stock camber, when it will run on the center and sholder.
Data plate/stock camber , sholder and side wall and some center.
Low air will fold under running on the sholder and sidewall when low enough the rim makes contact normally resulting in a flip.
Proper air with proper camber, will run flat.shoulder to shoulder

If you want the ultimate advice get a $20 Infered temp gun. The air is proper when the tire reads the same +-2°f across the tread. As in the formula above this psi # is in a constant state of flux.as you change what or how many things in the car and burn gas so will the weight distribution and volume . Go for 1/2 tank and normal load to get your psi/temperature

One more thing to consider is excessive shock loading/jarring causing abnormal suspension part wear= higher maintenance cost and slower cornering speed (slopy steering add RR )
Great point about wear on the suspension parts from the bumps/vibration, I wondered about that myself. I have been running 38 PSI in the tires since I got the car with 15K miles on it. It now has 227,700 miles on it, and the front end is starting to show its age. I just changed the front control arm bushings and all 4 sway bar links, as they were starting to wear out. The lower ball joints are also starting to develop play, I am going to change those this weekend, and the CV axles are starting to click. Besides that though, all the suspension is original. I don't know that those parts failing even has anything to do with the high tire pressure though. The car lived almost its whole life in Chicago, and their roads are horrible and full of large pot holes, so that probably has a lot to do with it. But maybe if I ran the recommended 30 PSI in the tires the suspension would still be original and in good shape. Who knows, either way I can't complain about the longevity of the suspension for just starting to give me issues with this many miles on it though.
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