Low profiles and traction issues?

[craZed]

88sinZ wrote: keep in mind wear rates of the tires as they heavily influence grip characteristics

try this, check your psi in the morning before you go driving, now after youve gone driving and warmed the tires a bit check them again, thermodynamics in action! keep this in mind when adjusting :wink:

18x10s are some nice hunks of meat! are they on all 4 corners?

I always check pressure after driving for that reason.
Fronts are 18x9 265/35. I love onramps and the like!

[craZed]

NIVO wrote: you want a nice tire roll out, or mor sidewall and diameter to hook good.

30 and 35 series tires are not for drag racing. I went with 40 series instead of 35 on the rears for a few reasons explained to me by Adriano, one was for a little more meat on the rear to save the lip from pot holes and a few others were based on performance driving and sidewall.

I chose this profile because overall diameter is very close to stock.
However, this last time at the track my speedo showed ~116 through
the traps but the trap speed was 111.
I've seen your pics of the new wheel/tire combo and I must say they look awesome. I will look for 40s next time. That should help with several factors, the dig, speedo accuracy, stretch the gears a little and fill in some
wheel gap.

[craZed]

Here is a pic for those who may be interested.
She has a bumper cover now.
http://www.ibconceptions.com/z/upload/t ... C_0237.JPG
another http://www.ibconceptions.com/z/upload/t ... C_0329.JPG
Incase you are wondering the cars are in order;
my car(blackhawk), fishes car, autoworks car(black bitch), stinkys car
and bemis car.

[NIVO]

craZed wrote: Here is a pic for those who may be interested.
She has a bumper cover now.
http://www.ibconceptions.com/z/upload/t ... C_0237.JPG
another http://www.ibconceptions.com/z/upload/t ... C_0329.JPG

LOL thats right, you have the 18x9 front and 18x10 rears!

[Jason84NA2T]

[quote]craZed wrote:

Check your pressure, and try adding along with lowering pressure to see how it affects traction.
They are at 20 psi, and I dont feel comfortable going any lower.

On a side note, Stinky drove it today and agreed there is an issue.
He thinks my tires might be too wide, spreading the weight across too much area. I am reluctant to agree with that.

No... generally you cannot underload tires, only overload them if they have too small of an internal volume for the weight you're applying.

Width alone will almost always benefit traction, different tire compounds have better or worse lateral grip than our "accelerative" grip(torsional?).

My thinking... lower profile tires will always have a smaller contact patch during acceleration given the same width in mm. This is during the dig, and during higher speed acceleration (1-2-3). This means your toe and camber settings WHEN THE CAR IS ACCELERATING (the suspension is compressed and camber gain is at maximum when the car pitches rearwards) are more sensative because the tire makes up for less of the difference. If you put on wider, lower profile tires then it is even more essential to run the correct camber and toe settings... even decrease camber towards 0 due to slightly less need, again because of the lower sidewall.

IMO you might simply need more spring or damping force (if only to reduce excessive camber gain), toe or camber adjustment, or some mix.

Hope this makes sense, but making a car go fast in a straight line and making it go fast around corners are vastly different.

[Taris Blue]

hey crazed...what offset are you running those 18x9's with 265/35's in the front? I have been trying to figure out if I could run a 265 up front on a +15 offset wheel...based on what I could calculate from people on wheelshow, I figured it would be cutting it real close but I didn't really have any deffinitive proof that it would fit so I was going to go with a 255 instead...let me know please, maybe I will change some of my plans.

[craZed]

Taris Blue wrote: hey crazed...what offset are you running those 18x9's with 265/35's in the front? .

18x9 +24 (tires come extremely close to the strut tube)
18x10 +22

[craZed]

Jason84NA2T wrote:

No... generally you cannot underload tires, only overload them if they have too small of an internal volume for the weight you're applying.

Width alone will almost always benefit traction, different tire compounds have better or worse lateral grip than our "accelerative" grip(torsional?).

My thinking... lower profile tires will always have a smaller contact patch during acceleration given the same width in mm. This is during the dig, and during higher speed acceleration (1-2-3). This means your toe and camber settings WHEN THE CAR IS ACCELERATING (the suspension is compressed and camber gain is at maximum when the car pitches rearwards) are more sensative because the tire makes up for less of the difference. If you put on wider, lower profile tires then it is even more essential to run the correct camber and toe settings... even decrease camber towards 0 due to slightly less need, again because of the lower sidewall.

IMO you might simply need more spring or damping force (if only to reduce excessive camber gain), toe or camber adjustment, or some mix.

Hope this makes sense, but making a car go fast in a straight line and making it go fast around corners are vastly different.

Yes, I have most of those bases covered. I will do some research on
tread compounds.
I have done the camber mod http://www.ibconceptions.com/z/upload/t ... C_0266.JPG
Have eibach springs and gary's seats. Have iluminas, but they are leaking due to sand blast material finding its way into them.
I have noticed the toe does move around a little, because I goofed up
on the camber slots making them a little wider than the through bolts.

[Taris Blue]

how close are those 265's to the outside fender?

[craZed]

Very close. They look to be the absolute widest that will fit in there
without any modifications to the fender.