The Great Tire Pressure Debate
- Thread starter fleming442
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But that's the point: what do you do when you change the tire size from what's on the door jamb sticker? Especially, when the technology on tires has advanced 35-40 years.....
2 additional psi on the RR takes 1% of wedge out of the car, the lower the pressure the more heat it will build. 6 psi on the LR, keep the sidewall smashed, sipe the tread blocks around the circumference to keep the tire cool on a slick track, across the block when youre trying to get the tire to fire in the heat race deeper the better. Shallow for the feature, grind with a 20 grit and go width wise with the traction grabber.
Oh wait.
Oh wait.
The real trick is to suck it down to nothing with a deflator that way there is as little atmospheric air as possible.and the nitrogen you are using works alot better than humid air...
As a once-certified lowest possible level ASE front end alignment tech who has never worked in automotive environment since initial and now-long-lapsed certification from the late 80's (worked at a truck shop before joining the Navy for experience, went to tech school for front end alignment while in the Navy and took the certification- then when I got out of the Navy I worked in everything BUT automotive because it paid way more), I will pose this...
Let's say your car weighs...oh, say, 3,800 lbs without the tires. You go to a larger tire...so now your car weighs...3,800 lbs.
Air pressure is sorta like your springs, the car will sit a certain height with the same weight on it. If you never get in it, or put anything in the trunk, the car height never changes. Change the weight too much, you may need to change the tires. The tires you picked can hold more weight (load rating) so that's good. But it's the air pressure that holds the car up off the ground. Your new tires probably hold more VOLUME of air, but the PRESSURE should be the same to hold up that 3,800 lbs.
Start with the recommended placard pressures on the door jamb or owners manual. Then monitor your tires and adjust according to what you see. If it's wearing faster on the outer edges, add a bit more air. If it's wearing in the center more than the outer treads, lessen the air pressure. If it's wearing unevenly on only one edge, get the alignment checked.
A "now you know" tip: Every tire is the same sidewall height at the bottom when it's flat.
Let's say your car weighs...oh, say, 3,800 lbs without the tires. You go to a larger tire...so now your car weighs...3,800 lbs.
Air pressure is sorta like your springs, the car will sit a certain height with the same weight on it. If you never get in it, or put anything in the trunk, the car height never changes. Change the weight too much, you may need to change the tires. The tires you picked can hold more weight (load rating) so that's good. But it's the air pressure that holds the car up off the ground. Your new tires probably hold more VOLUME of air, but the PRESSURE should be the same to hold up that 3,800 lbs.
Start with the recommended placard pressures on the door jamb or owners manual. Then monitor your tires and adjust according to what you see. If it's wearing faster on the outer edges, add a bit more air. If it's wearing in the center more than the outer treads, lessen the air pressure. If it's wearing unevenly on only one edge, get the alignment checked.
A "now you know" tip: Every tire is the same sidewall height at the bottom when it's flat.
I use 35psi at all times in all my 15" tire vehicles. 40-45 psi in a 16" or 17". Tire wear is perfect. Now, if you want to start a real pissing contest, ask what to use in TRAILER tires.
Easy. Around here in the South, you don't. You take them off once the blocks are in place.
Every tire wants what it wants for pressure. If equipped as the car left the factory and used as intended, the pressures on the door are what you should start with. If you start modding, racing, hauling, etc that's when it's up to you to find out what the tire wants.
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