What tire pressures are folks running in 615s for autocross. I've been using 33 front 35 rear hot and am wondering if this is too low. These are 205/50-15s on 5.5 inch Fuchs rims.

try 39 front and 41 rear.

reset before every run...



KT

QUOTE (billd @ Mar 18 2006, 05:11 PM)

What tire pressures are folks running in 615s for autocross. I've been using 33 front 35 rear hot and am wondering if this is too low. These are 205/50-15s on 5.5 inch Fuchs rims.

Last year on my 215's on 5.5" rims I (and the codrivers of my car) found the most traction at lower pressures (low 30's) I think i finished running 32 or 33 lbs on both ends.

This year I'm running 615's on 6.5" rims but I haven't had a chance to do any tuning. Post back when you find what works best for you!

There seems to be a difference between the older 215s and the newer 615s. The 615s can (?) get by with lower pressures than the 215s.

I don't remember exactly but the 615s can run high 20s, low 30s. sean_v8_914 and Brad R were twiddling Sean's 615s at last Sunday's AX. PM either of them for exact details.

I ran 33 all around today and was pretty pleased with the results. I may try 32 next time.

QUOTE

try 39 front and 41 rear.

Did you at least try the high settings?


KT

QUOTE (trekkor @ Mar 18 2006, 03:18 PM)

try 39 front and 41 rear. reset before every run... KT

that is what I ran when I had my falkens.

I tried to tell him.


KT

I know everyone is different, but that is what I ran in 2004 with my Falkens which was my first year AXing and most of 2005 before I switched to Kuhmos. For Indiana weather on blacktop that is what worked best for me. Won my class both years

Since I'm a expert now everyone should follow my advice

QUOTE

Since I'm a expert now everyone should follow my advice

Yes!!


KT

I will not recomend here but rather report my results. the 215s of olde had a more pliable side wall (per falken rep) and the higher pressures helped the tires from rolling. I painted the edge of the tread and side wall to read side wall deflection under cornering. the wear marks on teh paint confirmed this.
when I bought my 615s, one of the guys at Evans sports Arena store had just come back from the product launch presantation for the new 615 Falken Azinis. he was going off proudly about the improved sidewall stiffness and handed me a Co brochure that confirmed this.

Sunday I started the day 7am cold at 26.5 F/R
after 4th lap at around 10ish I was 31f 32.5r The rear is a wee loose
1pm after 2 laps, brad measured the center R temp to 150 with the inner/outter aroud 105 and dropped 1 or 1.5 psi front and rear
I dropped 1.5 seconds. Brad came bach and measured the read temps again showign the rear center hotter than the inner/outter temp and dropped another 1 psi . I found all kinds of traction worth another 1 .41 seconds.
I wish we had used the pyrometer sooner

I think it was about 60 deg ambient temp with frosty cold tarmac for teh first 4 practice laps.
in teh afternoon timed session the pavement was warm to the touch and teh air was about 65 and windy cool.
I weigh 168lbs
german OG Fuchs

Sort of a high jack. sorry
I got bit by the tire pressure gremlin.
my old set of Hammered Hoosiers. 67 runs Yea I know but I'm just down to the wear bar. Probably coulda done better on streets.
started at 28 PSI tires tried to grip and would suddenly snap let go.
pumped up to 32 PSI and tires slipped but was more linear and at least I could control the slip.

Note to self: re-align car and stay with slicks.

QUOTE (trekkor @ Mar 19 2006, 07:07 PM)

QUOTE try 39 front and 41 rear. Did you at least try the high settings? KT

I tried 36/36 and it was definitely slower. Also at the higher settings chalk on the tires showed that the wear ended a good quarter inch short of where it should, so 36 is definitely too high. I did one run at 32/32 and didn't notice much of a difference, but I ran out of runs before I could really tell.