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Author Topic:   How about some advise?
Eljojo
Dirt Freak

Total posts: 273
posted March 23, 2003 09:41 PM
I just searched and read dirtforum info on tire presssures-using passenger radials. It looks like most everyone is running less than 20 lbs of pressure. Here's the q-why? does lower air pressure help in forward bite of side bite? Does it help the car hook up or turn? Would you want to increase pressure on a tacky track and lower it on a slick one? Please help me out here! This dirt racin' ain't as easy as it looks! Ya get 5 hot laps and think the car is ok...then a couple hours later ya get to your feature and the wet clay has turned to dust and you're on an ice skating rink! This could take me till I'm sixty to learn if I don't get some help!

Flatlander
Dirt Freak

Total posts: 310
posted March 23, 2003 10:32 PM
this si my opinion just my opinion the low air helps in two ways the sidewall flex ans a bigger footprint to grasp what track you haveI will however if ran on the back too low make you're car loose and onthe front it could make it tightI myself may increase the RF alittlo on a tacky rack but run the others pretty low and will air the RF RR LR up a little on adryslick so I can try and feel the track a little betterdon't make big changes write down what the changes cause and adjust from there I like a loose racecar but you may like a tight cars and will have to adjust accordingly use stagger and offset to help you also

justin
Dirt Maniac

Total posts: 167
posted March 24, 2003 01:10 AM
Flatlander is right on. Your tires also act like a spring. Raising your tire pressures increases its spring rate and decreasing lowers it. It can also be used to adjust your weight percentages. Addidng air to a tire will cause that corner to gain weight and vice versa. Air pressure adjustments are used to fine tune the car, not to make big adjustments.

Justin

[This message has been edited by justin (edited March 24, 2003).]

rico 08
Dirt Freak

Total posts: 372
posted March 24, 2003 02:23 PM
Some people run the RR way too low on a tacky track and risk breaking a tire down or breaking a valve stem,don't worry about going fast in the hot laps thay don't pay very well!It's the feature and a dry slick track that will pay big if you can win.

Eljojo
Dirt Freak

Total posts: 273
posted March 25, 2003 08:48 PM
Thanks guys! My only experience with street tires has been on a pavement street stock, and we ran the tires up to 45lbs! I ran last weekend at 28 (lf) and 32 everywhere else. Seemd a bit short on forward bite and wanted to push just a bit on the way out. Dropping the lf those 4 lbs changed us from 50.4% to 51% crossweight! I plan to run this weekend at Tazwell and will give the low air pressures a test.

Flatlander
Dirt Freak

Total posts: 310
posted March 26, 2003 10:58 PM
IF YOU GET A CHANCE TO PRACTICE TRY 20#rf 18# lf 16#ACROSS THE REAR AND IF YOU NEED TO LOOSEN IT A LITTLE DROP A # in the RR if you are afraid of the low air play with the press write them down and remember you are going to gain so it may act a little diff at the end if it changes to much adjust the press accordingly until you get it right jusdt remember write it down every change and what you think it does

odb93
Dirt Freak

Total posts: 214
posted March 27, 2003 09:54 AM
Here is another question.....What effect is had on the tire when it is run lower than the manufacture suggests?

Flatlander
Dirt Freak

Total posts: 310
posted March 27, 2003 12:13 PM
Well I'm not a tire expert but the ratings are highway ratings and when you use them to race you abuse them But you also don't expect 40000 miles out of them either you just havt to experiment and do what works and make a decision on if you want them to work marginally and last all year or put them on the edge on use them up IMO

dirtrace54
Dirt Forum Racer

Total posts: 91
posted March 29, 2003 03:21 AM
I have had great luck running 24 RF 19 LF 21 RR and 17 LR. You might just try these

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