tire pressures for 295 rivals at autox

[Arustik]

On the mobile here sorry for the brevity.

Any advice for tire pressures on Rivals? First time out on them for me. Car feels fairly good but interested in seeing what you guys recommend that has worked successfully.

Thanks!

 

[csamsh]

I've been running 28-29 pounds, and the same front and rear. Other street tires I've run like more in the front but these seem to push unless the front and rear are about the same

 

[Arustik]

Whoa seems really low. I 100% agree they push if different pressures. I have them at 35 now car is balanced but would like moarrr grip. I'll go down to 30 and chalk the sidewalls and give it a go

 

[Further]

That is pretty low. I'll start at 28-29 as a cold temp, but they get up to 35 hot.

 

[Arustik]

I've been running 28-29 pounds, and the same front and rear. Other street tires I've run like more in the front but these seem to push unless the front and rear are about the same

Cold or hot

 

[ocpony]

Cold pressure

28-29 cold. Only 1-2# more in front but a lot depends on mods and suspension setup.
Also, depends on if u can really get them up to decent temps on the course.

 

[Apex50]

Between 32-34 (hot) work best for me

 

[ocpony]

^^^

^^^

 

[Arustik]

34 hot seems to work well for me at -3.5 degrees of camber

Thanks for all your responses guys I guess I wasn't too far off when starting at 35 hot.

 

[csamsh]

Should have specified cold

 

[Vorshlag-Fair]

We just did a track test (last Friday) on 295 Rivals and played with tire pressures. Went out with 27F/25R cold pressures. After a number of laps the centers of the tires were notably colder.

Put 35psi hot up front, and 32 rear hot, and it worked a lot better. Dropped time, tire temps were more even. Damn, this car was hooked UP!

We tend to run a tad lower than that on the 315-335 Rivals, but not much. I want to test the 335 square set-up with more pressure, to see how it works...

 

[Arustik]

Interesting results. You having the lower rear PSI and not understeering is likely due to your camber which I'm assuming is -4 or -4.5? I found when I ran staggered pressures (which I'm highly used to running in BMWs) my Mustang was understeering badly.

 

[csamsh]

Interesting results. You having the lower rear PSI and not understeering is likely due to your camber which I'm assuming is -4 or -4.5? I found when I ran staggered pressures (which I'm highly used to running in BMWs) my Mustang was understeering badly.

Could also be due to "C4 Corvette"

 

[Arustik]

Could also be due to "C4 Corvette"

Valid point my man.

 

[Vorshlag-Fair]

Interesting results. You having the lower rear PSI and not understeering is likely due to your camber which I'm assuming is -4 or -4.5? I found when I ran staggered pressures (which I'm highly used to running in BMWs) my Mustang was understeering badly.

I almost always run less rear pressures than the front, on a front engined (aka: front heavy) car. Sometimes the fastest tire pressures tested will be the same on both axles, but almost always a 2-4 psi stagger, with more front than rear. This C4 has limited camber (more negative up front than out back, as shown below, and nowhere near -4 degrees), soft stock springs, and still has lots of body roll.

And it doesn't understeer... at least not when I drive it.

But every car is different. The S197 is more front heavy than this car, that's for sure, and I tend to run more pressure stagger on front heavy cars. I adjust pressures by measuring tire temps, by driving feel, and by lap times.

 

[Arustik]

Terry with the -4 degrees of camber I was referring to your Mustang on Rivals.

 

[Vorshlag-Fair]

Terry with the -4 degrees of camber I was referring to your Mustang on Rivals.

Ohh.... yea, we ran the Mustang on 315mm Rivals with -3.5° up front, but that is where I usually end up on the front camber on all McStrut cars with street tires. We go to -4 on R-compounds often as well.

Personally I abhor understeer on my own cars, and will go to great lengths to prevent it. Sometimes to my determent...

 

[Arustik]

^^ at least your car looks good oversteering, understeering, balanced ... the list goes on and on