Hey what do you guys recommend for tire pressure for 1/4 mile racing? Should there be more in the rear tires or no? Also what should the tire pressure be for daily driving (it's time to check mine)??? Thanks.

 

I use anywhere from 27-22 psi in the front depending on the traction that day. It would be best to pump the rears up to 40 psi or so but I never mess with it.

 

you can lower it some, with stock tires it wont make much of a difference. probly better to keep close to regular pressure (32 psi or so) in the front, maybe pump the rears up to 40ish.

 

Would you explain why it won't make a difference on stock tires? And then what kind of tires will it make a difference on and why?

 

kinda overgeneralized. i'm goin on what my buddy told me, that on regular street tires, deflating them wont make much of a difference. lower pressure will create more contact area, but then it'll make more resistance up high, so things will get cancelled out. i've tried lowering the pressure down below 20 psi and also keeping it at 35 psi, on the same night of course. actually got better traction at stock pressure than at lowered pressure. Also, my trap speed was about .1 lower with the lowered pressure, which to me shows there is more resistance at higher speeds. My 60' times throughout the night were almost the same, and times didnt vary much.

 

your right, lower tire pressure will hurt trap speeds a bit, but the extra traction will give better ET's. I am more worried about ET than trap. Lowering your 60's will give greater advantages then the disadvantage of more rolling resistance. Getting out of the hole is what good times are all about.

Lowering the tires pressure is only useful if a person is spinning their tires too much. If spinning is not a problem then I would not lower the psi.

 

Ya, ET would be affected more by the 60' times. I'm also speaking from the view of an auto tranny, so with a 5 speed i can see that traction would be more important still. I ahvent had much of a problem spinnin my tires on takeoff, so maybe thtas why pressure hasnt made a difference

 

So pump it up a bit to 35-40 psi in the rear, and deflate it to around 25 psi in the front for racing, and 32 psi for regular driving? Just wanna make sure I don't pop/shred my tires.

 

I leave my pressure alone. Normally around 38psi in 245-40-18

 

Lowering pressure on street steel belted radials actually decreases driving traction...the belts take up the slack and bulge the center of the tire towards the center (inner part) of the wheel...

This is why if you drive around with low tire pressure all the time the outside edges of the tire wear the most...the footprint is totally uneven (with majority of the pressure on the outside). Do a test. Lower your tire pressure to 20 PSi, go out to the nearest street, and do a little burnout. You'll notice the tread patteren is missing either all of or the majority of the center section...with two dark strips where the outer tread is.

 

Really, I did not know that. I will do a little burn out with my track wheels and tires before I leave for the track in the morning. I do know that I am able to pull better 60' with lower tire pressure.

 

Well, laid a little rubber this morning. I could not see any significant sign of the tread pattern missing the center section. Maybe a tad. Then I went to the track and pulled a 2.14 60' at 25psi.

 

Ditto here Mike. I have seen my best 60' with 25 psi, as well - 2.195. I run more consistent low 2.2x's with reduced tire pressure...At GLD, getting out of the hole without wheelspin is virtually impossible w/o slicks. Any advantage is nice with street tires.

Fernando

 

What do you mean by "track tires and wheels" ? Are they DOT approved for street use slicks?

 

Firestone Firehawk FTC's I think. Just some 205/65 15" all season radials.