I finally got a chance to bring my roadster to the track last WE. I had lot of fun but my front tires did not…The car had quiet a lot of understeer in the tight corner and after the last session I noticed a lot of damage on the front left tire. The ambient temperature was around 105F and the pressure in my tires was 36PSI cold. During the event the pressure in the front tires went up to 46 PSI (hot). I eventually lowered the pressure down to 42-44 PSI (hot). Were my tires under inflated, over inflated, or is the damage only the result of too much understeer…(I run the stock tires on the 17’ wheels)

Loic

 

Another pic

 

Last one

 

The top picture is normal it's from the heating and cooling, and heating and cooling... then eventually chunking away.

The sides actually look fine as well, doesn't looking like you were rolling over that much.

When I ran an event on street tires, I typically ran them 48 - 50 hot. Then gave GREAT feel, and VERY little rollever.

If you are going to continue these events, I would strongly recommend the Hotchkis swaybars... that should for the most part eliminate any push you might have been experiencing.

... Or should I say, slow in... fast out?

 

The hotchkis sway have already been order...

 

Yep..looks normal and the sways will help a ton. I have the adjustments set at soft front and medium rear. The car becomes very neutral and you can throttle steer the rear much easier but not to the point of experiencing snap oversteer (anyone who's driven an S2000 on the track knows what I'm talking about)

 

man... that is nothing, and completely normal... I used the OEM 18" tires for two track events and after the first weekend the fronts were in pretty bad shape. After the second weekend, the fronts were so badly chunked that I was certain I wouldn't even make it home.

The RE040 is not a good track tire. It cannot handle the heat of prolonged run sessions. I noticed that after four hot laps the tires get greasy and lose grip. I'd take one slow lap to cool the tires and then I could get three or four more hot laps.

I tries TOYO T1-S, but I didn't like the soft sidewall...

Now I use a dedicated set of track wheels and tires...

hope that helps...

PeteH

 

That's a good idea...
Where can I find a set of cheap 18' rims that I will use only few times a year on the track? Looks doesn't matter, as long as they fit on the Z and as long as they are 8' width ore more....
Could even put a set of R tires....

 

there's a guy that I see at the track with a G35c.... he has an extra set of G35c 18" wheels that he put 245/40-18 Hoosiers onto... he has tons of grip! I've seen sets of the G35c wheels for sale for about $800 in the classifieds section. The Hoosiers are a different story.

Where you get expensive is the 18" track tires... not too many choices and they are all expensive... my original plan was to buy 18x9 OZ Superleggerra and put 265/35-18 Michelin Sport Cups all around... the tires were almost as expensive as the wheels...

I bought the wheels (17x9 Enkei RPO2J) I have now from another Z owner, they already had Kumhos on them... I used up the Kumhos and bought the AO32Rs. I'm happy with them and there's a decent selection of 17" track tires.

PeteH