In the RWD world a old trick is to spin your slicks on a clean patch of cement or pavment and look and see how even the darkness is, once you have the darkness even then in theory your using the entire contact patch evenly. but this dont seem to hold true for FWD does it? i mean every one seems to run lower then 10 psi in there slicks, but when i did this test today starting at 8 and working up from there it wasnt until above 10 that the contact patch started to get darker in the center, at 8 and 9 ect it was very dark on the edges and very light in the center. so if we arent using the entire contact patch at lower PSI why does every one say its the best PSI to get a 60 ft?

 

i also want to add that after a few uses of new slicks at low psi like 7 or 8 ect every thing but the very edges gets all jaggy and rippled up, like the edges are th eonly thing firmly pressed to the track and thus staying very smooth the center area just gets ripped up.

 

hmm, interesting. In for others experience.

 

Lower the pressure and watch your 60ft's and see how much tire spin you get. Every set up is a little different.

If you don't believe it works for all the FWD Civic's and Interga's out there. Run your's a 10psi

rota92 was down to 4-4.5psi.

 

Is your alignment correct? Did you have the car aligned with the slicks on the car?

Remember air pressure increases as they heat up and the tires also grow under high speed.

People say to use these low pressures because that seems to be what everyone gets their best times from

 

its not so much the contact patch as it is the wrinkle.

fwd is completely different than rwd.

 

Since we've been selling wheels and slicks, we get the question of whats the best Tire pressure to start out with almost on a daily basis.
My opinion is that there ISNT an exact tire pressure to really recommend. What I usually tell people who have never ran slicks before or at least never ran a slick in new setup is to start high. You can never go wrong by starting at a higher PSI and work your way down. There are alot of factors involved suck as track conditions, slick compound, HP, tire size and so many more.

Depending on your setup, I suggest to start out at least 10psi if its your first time. YES it may spin in some big power applications, but you just have to go through the trial and error of finding that sweet spot for your car.

If you know you're making 600hp, Its obvious that 10psi may be a little too much. So how about trying 9 psi, then work your way down to 8. If its better significantly, try 1/2 psi increments to see if that makes a difference.

In theory, looking to see the contact patch trial on regular cement, may seem like it would work. But once you get to the track, conditions change on how hard you want the car to hook. So there's no real exact way to calculate on a tire pressure to always use. Its an ongoing educated guess based on how the car reacts, track conditions, weather, etc.

In general though, starting out at a higher tire pressure than super low is best. You can always work your way down as you need to. Keep in mind too low of a tire pressure can also hurt the performance and posibility of breaking parts if the tire hooks more than you need to.

 

i generally run 7.5 psi...seems to work well, I have gone as low as 6.5

 

no its not that, I might have gave you the wrong impression, im not exactly new to FWD this is my 3rd season running in the points chase in the FWD class at my track,but i have over 15 years of RWD racing under my belt. i know that low pressure gets me the best 60s what im wondering is how does it do it when we clearly are only really getting grip on the out side edges of the slicks due to the centers not being pushed out. at a good track i get 1.6 and i dont think thats to bad for a full weight street car complete with sound system and a baby seat. i just was hoping for some science as to the reason why we break the rule of running a PSI that gives a even colored contact patch when u burn out, i seem to also get my best 60s around 7-7.5 psi but when i do a burn out on a clean spot i can see its only edges of my slicks making a mark.

 

Also keep in mind, the lower your pressure is, the thinner your contact patch will be at higher speeds as the tire grows. This could make your car unstable up top or spin the tires up top. I would never think to go as low as Ryan did, we're at 7.5 psi. We found that to be a happy medium. The car has plenty of bite on the launch (1.28 60') and is very stable up top. We never change tire pressure at the track per conditions either. We let the clutch setup and 2 step do their job.

 

thats something i been playing with, well not the clutch but rather the antilag and launch RPM , seems i get my best 60s when im pretty much frying first gear all the way to the 60 ft mark if i hook first at all it slows me down.

 

ya with a turbo car, you have to ride that first gear a bit.

Also Tony(Garcia), your running higher tire pressure, most likely because you have beadlocks. The other guys have to run a lower pressure to get it to hook with out the beadlock.

 

so is the center of the slick getting all choppy a normal thing for every one who runs low PSI? some say to rotate the tires to re smooth them back out some. the edges of my slicks look smooth and fine but the rest is all tore up and i think these tears are hurting my traction.

 

rotating them doesnt do anything. like i said its all about more wrinkle. my slicks have always wore evenly.

 

do yours get choppy and all grained up after a few races? or do they stay smooth like velvet liek a RWD slick does?

 

Sometimes if they chatter its from the tire climbing over itself. Try leaving with a bit more power, it seems to clear it up, if its chattering off the line. BTW slicks should be smooth.

Will, we run the same pressure in the crx with rim screws only. Beadlock just helps the tire from distorting unevenly or slippimg off the bead.

 

i never get any shake or chatter , but my slicks are never smooth longer then a event or 2 they always get chopped up, well the very edges are smooth as velvet , the RWD theory would say its due to the center not pressing firmly to teh track so its tearing , but like we just discussed if i raise teh pressure enough to keep the slicks smooth then i slow down. so any theory as to why my slicks get chopped and grained badly after a few races? i typically run 7-8 psi they are 23x8x13 MH on bogart flystars

 

I bet if you didnt have beadlocks or the screws, you'd have to run lower tire pressure. That was my point.

 

Have you tried different launch rpms with a bit more pressure?

 

slicks get worn and wont look smooth after awhile. I'm assuming the graining you are talking about is just normal wear and tear on the slick.

 

Maybe, but from what I've seen its the opposite. My understanding is that beadlocks or screw make it possible to run lower pressure.

 

Post up some pics of the tires.

 

I didnt read the whole thread but remember that with rwd mostly is on a straight axle where the tires dont have camber changing in and out like a fwd honda would.

 

ok BRB i will go take a pic now and upload it.

 

Will is right about old slicks wearing funny. How new are they?