HELP!!! Christmas tree dash

[Danieljmoreno131]

I bought some nitto tires 285/30/20 (front) and 315/35/20 (rear) and now my tire pressure light, traction control light, stability track light, ABS light, brake light, service power steering comes on as well as goes out and the wheel gets stiff and then the service stability track goes off too. I drive for about a minute and then that's when all the lights come on. As soon as I start driving and when I start to brake I can feel something happening with the brakes. Like if it's trying to read something hence the sensors I'm assuming. Is it because the front tires or is it the back tires or both? What do you guys think is the problem?

[Nick S]

If your overall tire diameters are different enough front to rear then the car is seeing different wheel speeds between the front and the rear and this is likely causing your Christmas tree dash.

[Danieljmoreno131]

What can I do to fix the problem?

[DjBeToV]

Depends what size you want to keep then adjust accordingly. Those sizes are well over 3/4" difference from one another.


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[chuckie669]

Correct size is
285/40-20 = 28.9" tall, 9.0-10.0 wheel
315/35-20 = 28.7" tall, 10.5-11.0 wheel

Your rear is right, but you are running at 26.73" tall on your front. That will really screw with the sensors in today's cars. I'd suggest picking up the correct tire, but maybe someone has a way to rig the system.

[Danieljmoreno131]

I heard I could get the computer recalibrated. If I still run those tires would it affect the car performance wise or not too much to notice you think? I appreciate everyone helping out though!

[Gstick]

I personaly wouldn't drive the car till you get this sorted out.

[L99CAMA2011]

Originally Posted by chuckie669

Correct size is
285/40-20 = 28.9" tall, 9.0-10.0 wheel
315/35-20 = 28.7" tall, 10.5-11.0 wheel

Your rear is right, but you are running at 26.73" tall on your front. That will really screw with the sensors in today's cars. I'd suggest picking up the correct tire, but maybe someone has a way to rig the system.

285/35-20

[chuckie669]

Originally Posted by L99CAMA2011

285/35-20

I think that's right for a zl1 but not the ss (just noticed he had 1le so maybe) . I just follow the great tire guide on c5.
http://www.camaro5.com/forums/showthread.php?t=62838

Edit: Sorry if i mislisted the size for the 1le as it does have what you showed.

[GPFAZ]

285/30/20 (front) = 26.73 inches
315/35/20 (rear) = 28.68 inches

That's 1.95" difference between the front tires and the rear tires !!!

The abs/stabiltrack/traction control all work together using the wheel speed sensors. How are these systems and modules supposed to do their job when the front and rear wheels are moving at such different rates than each other ? There is only a small tolerance on this system and it's probably to accommodate the tread wear differences.

[Danieljmoreno131]

I definitely need that 285/40-20 to make up the difference then huh

[PROZ11]

Originally Posted by Danieljmoreno131

I definitely need that 285/40-20 to make up the difference then huh

Yup..

.

[Danieljmoreno131]

The 285/40-20 won't rub in the front will it?

[Jugdishian]

Originally Posted by Danieljmoreno131

I heard I could get the computer recalibrated. If I still run those tires would it affect the car performance wise or not too much to notice you think? I appreciate everyone helping out though!

Well yes your car's performance will be affected greatly. There is a reason the engineers decided on a square 285/35/R20 tire setup...which was to make it as neutral as you could get with a factory car. By putting on a 315 rear you basically introduced a large amount of under steer that will greatly degrade the handling of the car. Have not heard of someone going with a 285/30/R20 front with this but I would suspect it is much worse than sticking with the stock size fronts. My advice is to sell those nittos and go back to your square stock size factory set-up....if you want wider than go with 305/30/R19 front and back like the z28.