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Tire PSI?

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Old Jul 8, 2005 | 02:24 PM
  #1  
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Tire PSI?

What psi should i put in my tires i just got new rims and i gave it a lil gas and the tires started screeching and i realized i had like 10 psi of air in them and now i put in like 32 to each is that about how much should be in?
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Old Jul 8, 2005 | 02:31 PM
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yeah I think its 32
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Old Jul 8, 2005 | 02:33 PM
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any where from 30-40. Doesn't really matter if you keep them equal all around. I pump mine to 40 when I autox.
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Old Jul 8, 2005 | 02:33 PM
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I'd love to say somthing smart *** about getting the entire wheel rather than just the rim, but I won't. Try 35 front, 30 rear. You want ~5 psi less in the rear to help discurage understeer. Actuslly, now that I think about it I believe I'm running 40 and 35, but you get the general idea.
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Old Jul 8, 2005 | 02:38 PM
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raising the pressure in back will decrease understeer/ increase oversteer.
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Old Jul 8, 2005 | 02:58 PM
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Funny, I had the opposite effect. Original info came from the "RX-7 Performance Handbook". It said to decrease rear pressure to decrease understeer, and when I tried it on my car it proved absolutly true.
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Old Jul 8, 2005 | 03:06 PM
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put bleach in your tires
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Old Jul 8, 2005 | 03:13 PM
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wait, yeah, I think I said that wrong. oops.
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Old Jul 8, 2005 | 05:38 PM
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For stock sized tires, use the Mazda factory recommendation plaquard (found in the owners manual and in the car tire sticker) + 2 psi.

There is no reason to go with any pressure above 34 psi on a street driven vehicle, and even at that will probably result in abnormal and increased tire wear.
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Old Jul 8, 2005 | 05:45 PM
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I keep 35psi in all my tires all the time.
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Old Jul 8, 2005 | 06:08 PM
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Check the sticker on the inside of the door jam. 32 front and rear.
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Old Jul 8, 2005 | 08:03 PM
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First, look on the sidewall of tire for p.s.i. let all air out, and start over. New tires require constant fresh air, so change it daily, along with diaper, cause that question is related to common sense. Really, give me a break.
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Old Jul 8, 2005 | 09:07 PM
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I agree with Monbo, look at the sidewall of the tire and inflate to the pressure stated for the tire you now have on the car. Using Mazda stated pressures for tires made 17 or more years ago simply does not make a lot of sense.
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Old Jul 10, 2005 | 09:02 PM
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Originally Posted by Jodoolin
I agree with Monbo, look at the sidewall of the tire and inflate to the pressure stated for the tire you now have on the car. Using Mazda stated pressures for tires made 17 or more years ago simply does not make a lot of sense.
This is just about the dumbest advice I have head this month. Of course Mombodogs reply is pretty close as well, but I am assuming he is just being sarcastic with his reply and not the least bit serious.

The pressure listed on the sidewall is the maximum tire pressure. It is not the recommended tire pressure, it is not the suggested tire pressure. It is the maximum tire pressure that the tire can contain before it starts having damage. Damage not limted to sidewall and tread delamination. And this damage ofetn occurs with even minor impacts of curbs, ruts, or potholes (all things seldom found on a race track- in case you wanted to argue that some racing bodies crank the tire pressure up).
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Old Jul 11, 2005 | 12:17 AM
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Understanding tire pressure is, I guess, something new to motor vehicles. Iceman, your knowledge is much greater than most of all the people combined on this site. However, Mark Martin, mr. Viagra, just told his pit crew to let 1/2 pound out of left rear to tighten up the car, over the pot hole he just encountered in turn #4. I'm guessing that racing a car at 200 mph for 500 miles is just pure luck. If you start at 10 psi, and it squeals, check in the wheelbarrow and guage accordingly. Do what works for you, as for me , I'll stick with works for me, tire rating minus 5. Never lost one yet due to ignorance, and yes, I do check pressure and oil everday, before my key hits the ignition. I run heavy equipment, and I know my priorities.
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Old Jul 11, 2005 | 12:58 AM
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No one here can tell you what your tire pressure should be.... we all run different tires.

If you're just going to go ahead and set your tires to any pressure that anyone tells you, set it to the stock values listed by mazda. If you want to do it right, check the contact patch and make pressure adjustments accordingly to maximize traction.
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Old Jul 11, 2005 | 08:44 AM
  #17  
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Originally Posted by Mombodogs
Understanding tire pressure is, I guess, something new to motor vehicles. Iceman, your knowledge is much greater than most of all the people combined on this site. However, Mark Martin, mr. Viagra, just told his pit crew to let 1/2 pound out of left rear to tighten up the car, over the pot hole he just encountered in turn #4. I'm guessing that racing a car at 200 mph for 500 miles is just pure luck. If you start at 10 psi, and it squeals, check in the wheelbarrow and guage accordingly. Do what works for you, as for me , I'll stick with works for me, tire rating minus 5. Never lost one yet due to ignorance, and yes, I do check pressure and oil everday, before my key hits the ignition. I run heavy equipment, and I know my priorities.
Heavy equippement tires are a whole 'nother beast, and should not be confused with road tires on a passenger vehicle.

If you really wanted to know what tire pressure would be optimal, you would chalk the tires in at least 4 places (so that even if your alingment is fucked; you can still test), and measure the tread temp.

Then go drive your normal drive to work or school, or whatever.

At work (or school, or whatever) then you would check tire temp and wear patterns on the sidewall chalk.

Then you would try adjusting up and down tire pressure by 1 to 2 psi and make the same drive again. The idea is the lowest tread temp, and the least amount of sidewall wear as shown by the worn off chalk marks.

Higher tread temps are bad as you will wear through the center of the tire faster (Uneven tire wear). More sidewall wear, would indicate too low tire pressure and again uneavn tire wear. Remember with uneven tire wear, there is uneven tire traction!

Maybe this will be a little bit of an education for you Mombodogs as just blindly using the tire rating is a very very poor choice for setting tire pressure for daily use; well, unless you like uneven tire wear and incosistent traction across the thread.

Now luckly for the stock Mazda used sizes, Mazda has already done that testing for us, and posted it as the recommended tire pressure. The recommended tire pressure would be for any tire in the stock size and would provide the best compromise between handling, wear, and performance (with performance including tire life as well as traction).

Now for racing conditions, then yes you would increase the tire pressure, but using the same method outlined above.

This same method of finding out the tires sweet spot also works for non stock sized wheels and tire combinations.

*edit<Now if you really want to be consistent, you would use nitrogen in the tires as it does not leak out as fast as conventional N/O2/CO2 air does, and tends to heat more evenly. As a third benifit, nitrogen will not rot the tires out from the inside as any moisture mixed with O2 (as found in conventional air) will do. I personally use only nitrogen in all my cars (as tire re-inflation is almost zero with it) but not all tire shops make it available.>

Last edited by Icemark; Jul 11, 2005 at 09:34 AM.
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Old Jul 11, 2005 | 10:49 AM
  #18  
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Thank you Ice for that detailed expanation on proper inflation. I guess that I should put a hehe or haha when I intend to show humor in my responses. I am new to RX7 and have certainly learned more here in 1 month, than I could have anywhere else. I hope that we can all now figure out proper p.s.i.
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