Hey guys. I am a new owner of an 04 convertible. I believe it is a touring model based on the stickie above. It is a 6 speed with 19" ADR wheels and Nitto tires.

I have noticed that the slip light comes on quite a bit when I am going around turns slowly. It does cut engine power and the car limps along. It is very annoying and I have had many cars with traction control, stability control, dynamic this control, etc. I have never had a car behave like this and my last 2 convertibles were C5 vettes!

I have noticed that the rear tires are 275/30-19 and a plus 2 upgrade over the 17" wheels would call for 275/35-19. I believe this means the total height of the rear tires is too low? I believe I saw a similar thread here on the forum about this. I have taken the car in to the dealer and they tell me it is normal. I find this impossible to accept. I can't even go around turns in this thing and have any fun with the VDC/Slip light coming on all the time.

I love the car and just want to get this solved. I think the dealer is full of it and need to take the car there and show them what is happening. I expect they will tell me to pound salt and wonder if I should just buy new rear tires to solve the problem. Any help would really be appreciated! Thanks!

 

IMO, i think you may need to check how old the tires are and watch your driving habits a bit more. the older a tire gets, the less traction they have and if you are not use to driving a rear wheel car, you can easily lose traction when driving in curves or turns. so yeah, it may be time to get new tires

 

Thanks for your input but I am used to driving a rear wheel drive sports car. My last 2 were vettes and I also had a Cadillac CTS-V with 400 horse through the rear wheels.

The problem is that the slip light comes on at low speeds around sweeping turns in the dry. If it were wet, I might agree but it is not. I thought perhaps the computer was getting fooled by the difference in height of the tires. If that is the case, new tires will solve it. I just wanted some opinions before buying tires. Thanks!

 

in that case, it has to be the tire grip or something on the road you can't see. i know my tires are getting a bit low because mine kicks on with just a minimal press on the gas when leavign from a stop light sometimes

 

You didn't say what size the fronts are. The height/diameter of the tires are not as important as the difference (stagger) between the fronts and rears.

VDC & TCS work off of the rotational speed of each of the four wheels. You you turn, the system expects to see a certain amount of difference in the spees, if your tire sizes are outsize the normal ranges then the SLIP light will kick in.

 

Its all about the tire height. You should be running a 35 series in the rear. These cars have a staggered tire setup from the factory, which means the rear tire should be a bit taller than the fronts. You need to calculate the difference in height from the factory and stay within +/-3% of that number.

 

I have 245/35/19 in front and 275/30/19 in the back and its fine. The VDC gets unhappy when you have a certain percentage difference in overall diameter between the front and back. What size are your fronts?

 

The dif between 245/35 and 275/30 is -.97%. That is not the problem.

 

Thanks guys. The front tires are 245/35-19 and the rears are 275/30-19. This presents a difference in the stagger from what I have read on the forum. If this is the problem, then new rear tires in 275/35-19 should fix it.

I just want to be able to have some fun in the car and this is driving me nuts. The previous owner only clocked 5K/year and I don't think he even drove it much in the last year before trading it in at the dealer.

The ADR M-Sport rims are very nice but he never met a curb he didn't like. Does anyone know if I can send the rims back to ADR to have them redone?

These are my first posts on this forum and this place is very active. This is great!

 

Nothing wrong with your tire stagger my friend. Don't get new tires if you don't need them as that will not fix your problem.

 

Thanks Jokestrap! I will go to the dealer next week and take the tech out for a test drive to show them what is happening. Hopefully they will agree that it a problem and then fix it.

 

Good luck. With a short test drive, they should fix it.

 

quote jokestrap "Nothing wrong with your tire stagger my friend" and "-.97%...isnt the problem"

no offense, but this is partially bad information.

to the OP, you do have the wrong tire sizes. 275/35/19 would be the correct tire size for the rear with the fronts you are running. TCS expects a taller rear tire, not the same diameter as jokestrap suggests.

the reason I say "partially" bad information, is over the years on this forum there have been a few people that have reported no problems with 275/30 (matched with 245/35 front).

However, the majority have had problems with that size. It is a common complaint on this forum. Vice versa, I have never heard anyone have a problem with 275/35/19 as this matches the stock rear diameter.

 

I stand corrected.

It 'might' be your problem, but I do not have a problem with the same setup.

 

Thanks guys! I will probably get new tires anyway. I really want 18" rims and not 19s. I like the way the rims look and they ride fine but when I changed rims on my vette, I went from 18 to 19 and then back down to 18 again. I thought the ride/handling was best with the 18s and I lowered the car to take care of the gap. I think I will do the same thing here.

This forum seams pretty active with people selling wheels so maybe I will post here before eBay.

 

Yeap, the problem is definitely in your tire sizes.

245/35/19 are 25.8" diameter
275/30/19 are 25.5" diameter

The rears are shorter than the fronts - a VDC no-no.

Diameters vary slightly by tire brand so Jokestrap's setup might work for him but definitely not guaranteed to work for every setup that matches.

 

Agree. VDC is happy when the rear tires are 10mm taller than the front.

 

Thanks guys! I am now looking for new wheels and tires for my Z. I will sell the ADRs with the tires and hopefully someone will enjoy them.

 

Man... I have the same problem with my 20s. 245/35/20 & 275/30/20....

is that my problem too then? Cuz 35s in the rears would be pretty high, no?

 

The rears aren't the problem, it's the front 35's that are too high. They are taller than the rears: 26.8 F / 26.5 R. The stock heights were around 26.0/26.7 so your rear is close but the front is 0.8" higher than stock. You needed a 30 series in the front for a height of 25.8", pretty close to stock.