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Correct tire pressure for 20"s?

Juanmiguel

Juanmiguel

New member
The T/A is running on 20"s, 255/35 R20. The streets here are CRAP so I have to be careful for holes, speedbumps, idiots, etc. I'm not setting them at 30lbs as I don't want to get the tires or the rim damaged in one of these things.

I really never had a car with such low profile tires before so a friend of mine recomended me to set them to 40lbs, and I did. So far so good, they've been holding up decently. The problem is obviously that the ride is quite jumpy, the tires are harder as it is.

I just wanted to know what kind of pressure you guys use or know is best.
 


the tire should have the proper air pressure marked on the sidewall. if you run to much or to little, the tires can start wear un evenly.
 
Max press is 50lbs. but it doesn't say what's the propper. I just used that google search thing that everybody is talking about and it looks like most recomend 40lbs for that tire size.
 
Oh well, maybe I can try to run the rear tires at 35lbs sometime. The rear end bounces like crazy when I go WOT from a dig and the pavement is not all good I have to let go off the pedal.
 
35-40 psi will be fine, the more pressure you run, the more center wear you get, the less pressure, the more edge wear. I run 36 psi in mine all the way around, if i was racing i'd drop pressure for better grip. i wouldn't reccomend anything over 40 psi though
 
when i had my last 2 trucks i ran bfg all terrains 33's x12.5 wide. and if i ran at full psi, the tires wore better, if i ran at 35 ish or even 40 the out sides of the tread would wear first and the center would still look new.

so after talking to people who ran the same tire told me to run them at 50 psi and they would wear better, and they did, so maxing out the psi is up to you, and how it feels to you and how the tires wear on you. every car rides different so its play time.
 


of course it will its bigger and a truck tire, but maxing out psi or running low psi will wear the tire differently, car or truck, thats all i was trying to say. you need to find where the car and tire and driver are happy when running aftermarket wheels and tires.

too much air the center thread sticks out and wear off, to little the sides wear off first, you want flat contact with the road. even wear so your tires last.

back in the day tire shops used to have a sticker they stuck on the tire, then drive it a few miles, and the sticker would show if your tires were wearing evenly. no idea if thats still around tho.
 
Yeah I explained the same thing in my post above. I think running 40 psi in a passenger tire is probably a little on the high side. 35-38 is generally a good rule of thumb for better wear, of course you need to drop it for better handling.
 
I'm going to try lower pressures on the rear. That's my main problem, lot's of bouncing and spinning on uneven surfaces. TCS has to work hard on each corner lol.
 


ladder bars work for coil sprung rears, look like these.

620-20462.jpg


leaf springs get traction bars. like these.

lw21607.jpg


you can also make ladder bars work on a leaf spring, ive seen it done, how well it works is another story.
 
The transmission mount got shot a week ago. I couldn't find it anywhere by the way, not local autoparts, not autozone not even at the dealership I had to order from rock auto.

After taking off the broken mount we found out it was a different one than it should, an older style mount:

Old model:

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Newer model:
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These came with the previous gen trans ams. I haven't noticed any wheel hop in the past couple of days. Maybe it was because the mount was almost done and/or it was a different one.
 
0 PSI Cuz they run flats.

But seriously though, 40psi is what I'd start with. If its too solid, take 2-3psi out. If its too soft and bouncy, add 2-3 psi until it feels right to you.
 


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