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  #1  
Old 08-18-2003, 01:23 PM
TranceLvr TranceLvr is offline
 
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Question AVS sport tire pressure

I have had my AVS sports running at factory recommended tire pressure since I got them. They seem to be OK, but I am a complete novice when it comes to figuring out what pressure to use. Any tips or hints would be greatly appreciated.
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  #2  
Old 08-18-2003, 01:28 PM
in_d_haus in_d_haus is offline
 
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If you are running on the street use the factory recommended pressures.
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Old 08-18-2003, 01:31 PM
TranceLvr TranceLvr is offline
 
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Quote:
Originally Posted by in_d_haus
If you are running on the street use the factory recommended pressures.
Sorry, should have clarified. I meant to say when I am at an Auto X.
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  #4  
Old 08-18-2003, 01:32 PM
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Nick325xiT 5spd Nick325xiT 5spd is offline
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You probably want to up the fronts.
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  #5  
Old 08-18-2003, 03:35 PM
sshuit sshuit is offline
 
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I'm relatively new to the autocross scene but I'm running my car with 42F /42 R at the moment.

I also have full stiff UUC sways mounted front and rear and I'm still getting a bit of understeer at times.....

going to run 42F / 37R at the next event and see if I can't get the rear end a little bit looser

I suggest running higher in the front for sure and then tune the front based on tire roll-over and the rears based on what the car is doing.....


Quote:
Originally Posted by TranceLvr
I have had my AVS sports running at factory recommended tire pressure since I got them. They seem to be OK, but I am a complete novice when it comes to figuring out what pressure to use. Any tips or hints would be greatly appreciated.
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  #6  
Old 08-18-2003, 04:27 PM
Akakubi Akakubi is offline
 
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Quote:
Originally Posted by sshuit
I'm relatively new to the autocross scene but I'm running my car with 42F /42 R at the moment.

I also have full stiff UUC sways mounted front and rear and I'm still getting a bit of understeer at times.....

going to run 42F / 37R at the next event and see if I can't get the rear end a little bit looser

I suggest running higher in the front for sure and then tune the front based on tire roll-over and the rears based on what the car is doing.....



Start with those pressures, but then drop down as you go run after run. You need only as much pressure that you do not roll the sidewall. If you run 42 cold throughout the whole session, the air will expand and infact will be like 47-50 hot, effectively reducing your contact patch and causing tons of understeer.

Just play with the pressures. Mark the sidewalls with chalk to better see if you roll, and drop doen from there. The same applies to the rears. Sometimes you can have the difference of 7-8psi front to rear if you don't roll and want the car to rotate better.
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  #7  
Old 08-19-2003, 09:00 AM
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Depending on the tires and the camber you may need more tire pressure than just preventing the sidewall from rolling. You are looking to keep as much tread on the ground as possible under load. Under load with lower tire pressures the center of th etread goes concave, which is not good for traction.

For autoX ask the fast people in your area what they are running.

For street I recommend +4 psi front, +2 psi rear for better and more neutral handling.

For autoX, I run higher than that.

But until you are running consistantly enough to run similar times on each run, you will not be able to really tune pressures. But try higher and higher pressures, keeping the same front/rear balance and see what you think. Once you get to a pressure setting that seems fastest, then start playing with front/rear balance. As you go up in pressure, you will get to the point where the tires seem to slide more than they did, then back down a little.

There are guys running as high as 50 psi for Autocross in WRXs,
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Old 08-19-2003, 09:15 AM
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Quote:
Originally Posted by Pinecone
There are guys running as high as 50 psi for Autocross in WRXs,
xiT drivers have done that with the OEM all seasons too.
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  #9  
Old 08-19-2003, 09:17 AM
TranceLvr TranceLvr is offline
 
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So I am seeing that I should increase my front pressure for sure. I should probably invest in a 12V pump for the track then. Thanks for the ideas all
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  #10  
Old 08-19-2003, 09:23 AM
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Quote:
Originally Posted by TranceLvr
So I am seeing that I should increase my front pressure for sure. I should probably invest in a 12V pump for the track then. Thanks for the ideas all
Keeping a 12v compressor in your car is just a plain good idea. I see a lot of people use them at autocrosses, but I find it easier to use a free pump at a gas station on the way to an event. The 12v compressors can be very slow when you have to put 5-10 pounds in each tire after you get to the event.
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  #11  
Old 08-21-2003, 06:02 AM
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Quote:
Originally Posted by ·clyde·
xiT drivers have done that with the OEM all seasons too.
That's nothing, I once ran an event in my Fiat 850 with a pair of snow tires on the rear. Nothing like a rear engined car with even LESS traction in the rear. After finally getting up to about 55 - 57 psi, I managed to come in second.
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  #12  
Old 08-21-2003, 06:04 AM
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Quote:
Originally Posted by ·clyde·
Keeping a 12v compressor in your car is just a plain good idea. I see a lot of people use them at autocrosses, but I find it easier to use a free pump at a gas station on the way to an event. The 12v compressors can be very slow when you have to put 5-10 pounds in each tire after you get to the event.
Maybe in your area.

I can't remember the last time I saw a FREE air pump at a station. Normally 50 cents for not enough air to do all 4 tires to normal pressures.

The best is a compressor at home and an air tank. Pump the tires up at home, fill the air tank and away you go.

Of course if you really get crazy about this, you will run autoX pressures on the street.
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  #13  
Old 08-21-2003, 07:19 AM
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There are plenty of gas stations in suburban MD that have free air, you just have to look a little.

Having a compressor at home would be nice. So would having a garage

What's crazy about running autox pressures on the street?
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  #14  
Old 08-21-2003, 07:25 AM
SpaceMonkey SpaceMonkey is offline
 
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Quote:
Originally Posted by ·clyde·
What's crazy about running autox pressures on the street?

Last edited by SpaceMonkey; 08-21-2003 at 07:29 AM.
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  #15  
Old 11-20-2004, 02:49 PM
guzplace guzplace is offline
 
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what about the maximum tire pressure printed on each tire ?
if you have 50 PSI then you're gonna exceed that when hot and would the tire blow up ?
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