hellomellobello

I just got new tires on my G37, I have H&R Springs with 19x8.5 (245/40/19) and 19x10.5 (265/35/19) Those are the new tire sizes I put on today just couple hours ago.

However while I'm driving, especially in the beginning after i turn on the engine, the SLIP light will come on when I try to accelerate. When the skid light is blinking, i cant accelerate more and have to let go of the gas.

Does anyone know why this is happening? This JUST started to happen after I put the tires on.

Please let me know if you have any idea.

thanks in advance.

JSolo

iTrader: (14)

Your back tires are spinning faster than the front tires for the same distance traveled. Car thinks you're out of control, thus traction control kicks in.

Didn't you do your research on tires sizes, diameters, circumferences, revolutions per mile before buying???

hellomellobello

I see, I suppose I didn't do a thorough enough research. Are there any solutions to this besides getting new tires or will it be alright to just drive around like this?

JSolo

iTrader: (14)

Disable traction control?

Maybe one of the folks with uprev tuning can chime in on whether or not different rpm (revolutions per mile) can be programmed into the ecu or not. My guess is not.

For anyone considering staggered tire sizes, THEY MUST BE WITHIN 3% DIAMETER OF THE ORIGINAL TIRE SIZE AND OF EACH OTHER

hellomellobello

ah ok, last question, it doesnt damage the car in any way right? Sorry for the novice questions but I am not too fond of the topic.

JSolo

iTrader: (14)

If the computer is trying to get all wheels to spin at the same or similar speeds, then you'll end up with premature brake wear.

Your ABS will be inoperable as it depends on precise wheel speed measurements. Your car will run strangely. Sort of defeats the purpose of these safety features.

You dont say what tires you got, but bridgestone and michelin both have a 30 day return on most of their tires. If the brand you got has this option, i'd exercise it asap.

hellomellobello

But if I turn off ASC, it'll be alright then?

Varjo

Not if you like having ABS work properly..... it's honestly just not a smart idea.

G37andalf

Totally agree with the other posters. There is a lot of info here on the forum to review.

I'm in the research process also and using google with the search string

Tires site:myg37.com

Tires can be customized with whatever you want.

ai3j50

One thing you might also want to consider is new tires come with a coating on them that lasts for about 300 miles and it does make the tires feel "slippery"

Kirkules

The 245/40 spins 755.3 times per mile. The 265/35 spins 767.1 times. The difference of 11.8 times is 1.5% of the smaller number. Well within the 3% mentioned above. That said, the fronts should be the smaller tire in a staggered set up, in this case they are taller.
It would seem the best solution would be to replace 2 of the tires. Do the math and fitment on your rims, but if you are changing the aspect ratio by 5 from front to rear, you will need at least a 30 mm difference in width to keep the sizes close. If you either go to 235/40 in the front or 275/35 in the rear the difference will drop to around .4% but the fronts will still be slightly taller. Not sure if this will cure the issue, but it will be a heck of a lot closer.

JSolo

iTrader: (14)

^^Interesting. I thought the 3% was based on diameter, not on revs/mile.

Although not mentioned, I assume stock size was 225/45/19, which has an overall diameter of 26.97", compared to 265/35/19 which is 26.30", difference is .66", or 2.48% of stock.

From the owner's manual, vdc is used to reduce engine output to reduce wheel spin.

As for ABS, I think i need to retract my statement above about it being fully inoperable. ABS is triggered when wheel lockup occurs, which means that wheel is not rotating and has 0 speed. On the other hand, you can have a loss of traction with a wheel that's not locked, but whose speed is significantly different from other wheels. These nanny features are designed to work properly together.

http://www.1010tires.com/Tools/Tire-...0R19/265-35R19

Ai3j50 is also right, new tires typically require several heat cycles for any mold release agent to be fully released and tire considered fully cured. If the OP is accelerating quickly, I can see this being a possible issue, but if it's normal acceleration, then other factors are at play.

Keep in mind, it's not just the difference of front to rear, but also of front to rear to stock. Car's ecu is calibrated to expect a certain quantity of pulses from the speed sensor at the wheel for a given speed. This is based on stock wheel size and gearing. Start messing with any of these variables and the system becomes confused.

Kirkules

You could be right on diameter. I didn't think about that - just assumed it was circumference / revs/mile. Either way we agree the front & rear should be closer in outside dimensions.
No idea about vs stock. I have seen what you are saying on other cars. Does the wheel sensor drive the speedo on G's? If it does then I agree there too.

hellomellobello

I see..... so if i do continue driving with this current set up, there is a chance of brake failure?

NJ Torque

iTrader: (5)

Check the brake fluid? Thats the first thing if it might be low...