Although the term “street tire” is stretched quite thin when it comes to the current crop of R-compound DOT track and autocross tires, there’s still a big difference between those nearly bald gumballs and true racing slicks.
Racing slicks tend to be lighter, stickier and more responsive than their street-bred counterparts. After all, slicks don’t have to meet DOT requirements …
Q: if my tires are running under/over temp as a whole (not an individual tire nor front/rear ends or left/right sides), what do I adjust? Spring rates? Other?
fearlesfil said:Q: if my tires are running under/over temp as a whole (not an individual tire nor front/rear ends or left/right sides), what do I adjust? Spring rates? Other?
A: Depends.
You don't just take A tire temperature, you take at least 3 at the inside, middle and outside edges of the tread. For example, if the inside edge is hotter then you could be running too much camber or too much toe out. Middle too hot? Maybe drop some air pressure. You see where this is going, there are thousands of conditions and fixes.
In reply to fearlesfil :
If the tires temps are even across the tire but over or under temp there are a couple of things specifically when it comes to slicks you can go do. You can go with a harder or softer compound. You can also change width. It is not uncommon for slicks to come in different widths for a given circumference. You can fit a wider or narrower tire without altering the gearing.
This was kind of addressed but the biggest thing I noticed was I lost the ability to steer with the throttle as easily. The window of throttle steer was very narrow which I really didn't care for.
In reply to JG Pasterjak :
The one thing nobody has spoke about yet is what slicks do to the car. Higher cornering speeds increase oil control difficulties. With street tires you might get by with baffles one way traps and an accusump.
Not with racing tires.
Not so much with cars but I've seen people fit slicks to motorcycles and it destroyed the balance. Mainly due to a lack of chassis rigidity.
In reply to frenchyd :
I didn't need baffles or an accusump with my 350Z on slicks. Just a deeper sump. Oil pressure never dropped at CMP or Roebling. However, I do plan to add both when I get the chance.
In reply to 350z247 :
If you have a camera, run a few hard laps with the oil hot and the camera pointed at the oil pressure guage.
Deep dumps and other band aides don't change the physics. Jaguar XKE carries 22 quarts in an 8inch deep sump with baffles. Turn 5 at Road America provides me with seconds of Zero oil pressure from 100 PSI as I stop from 155 to the 30? Mph cornering speed and accelerate up the hill to turn 4 Every lap the oil pressure would drop. Until I finished the race at 20 PSI luckily I had plenty of experience . changing bearings and it didn't take all that long Every race produced the same results. Road Atlanta I was forced to change the bearings between sessions after adding an accusump.
Following that I bit the bullet and put on a dry sump like every racing Jaguar has had since 1954.
Not only do slicks impact oiling control but they also put additional strain/shock loading on drivetrain parts like bearings, axles, differentials, etc.
If you all had proper two stroke cars like those of us running Formula 500s you wouldn't have oil starvation issues.
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