245/40ZR17 on 17" sets off TCS

[Yawwn]

Hello All,
I just picked up my 245/40ZR17 Michelin Pilot Sports for my new 17*8 rear wheels. It turns out that my TCS indicator keeps blinking, and I cannot accelerate quickly because it keeps kicking in.
I went down from a 18*9 to this "minus 1" wheel because I bent three of my four wheels. The wheel does not come in a 17*8.5 or 17*9, and 245 is the largest width recommended for a 8" width wheel.
However, I think the sidewall is not perfectly vertical, and may even flex outwards a very slight amount. I measured the diameter of my 255/35ZR18 on my 18*9, and it is approximately 25". Measuring this new 245/40ZR17 tire gives me ~24.2". I think this difference in height is setting off the TCS. Do you think a 245/45ZR17 tire may resolve this? I know that it is supposed to be ~25.7" in diameter, but I'm assuming that since there is some angling on the sidewall, this may bring down the overall diameter to something closer to 25".
The other alternative is the 235/45ZR17 tire, but since the sidewall will be perfectly vertical on this tire, I may end up being even larger in diameter than the 245/45ZR17.
I made sure that the tires were inflated to 33psi front and 40psi rear.
BTW, my front tires have not changed. They are 215/40ZR17. However, they used to be on 17*8, and are now on 17*7. Again the sidewall on the 8" used to be at a slight angle inwards and are now exactly vertical on the 7".

Do you all think it is the width of the wheel that is causing this? Do you think the 245/45ZR17 will resolve this?
Any suggestions will be greatly appreciated!

[This message has been edited by Yawwn (edited 08 May 2002).]

 

[Enzo]

Yawwn,

I think the problem comes from the Michelin (worst tires I ever tried) because I have exactly the same problem with my Michelin Pilot Sport mounted in the same size on my second set of wheels !

I never had a problem with my previous set of Pirelli PZero in the same sizes on the same wheels !

I really hate the Michelin Pilot Sport !!!!!

Now, I use a 17"/17" Bridgestone S03 combo (215/40/17 & 255/40/17) and ... no more problem with the TCS !

David

 

[nsxtasy]

TCS will work if you keep the ratio between the outer diameter of the front tires to that of the rear close to stock. They say it needs to be within 5 percent but I would suggest keeping it even closer, within 3 percent, given the 2 percent variance in outer diameter as a tire wears from new to worn. Thus, if you use a tire whose outer diameter is 3 percent larger than stock in front, then you would need to use a tire in the rear whose outer diameter is between 0 percent and 6 percent larger than stock.

You can use a tire calculator such as the one at http://www.powerdog.com/tiresize.cgi to calculate the percent change in the outer diameter of the tire.

Assuming your car is a '91-93, here is how the sizes you're using work out:

Front
205/50-15 stock
215/40-17 +3.04 percent

Rear
225/50-16 stock
245/40-17 -0.57 percent

You'll need to either select a rear tire whose outer diameter is closer to 3 percent larger than stock, or select a front tire whose outer diameter is closer to -0.6 percent smaller than stock.

(Re-work the numbers if you have a '94 or later NSX, to reflect the different stock size for your year).

Do you think the 245/45ZR17 will resolve this?

Yes, it will. The 245/45ZR17 is 3.31 percent larger than stock.

[This message has been edited by nsxtasy (edited 08 May 2002).]

 

[Yawwn]

Thanks David and Ken! I really appreciate your help. I will order the 245/45ZR17.

Are the settings in the TCS computer different between the 91-93, and 94+ cars?

Take care,
J.

 

[nsxtasy]

Originally posted by Yawwn:
Are the settings in the TCS computer different between the 91-93, and 94+ cars?

I would think they would have to be, to take into account the differences in the tire sizes. But I'm only speculating.

Here are the stock sizes, with percentage change from '91-93:

Front
'91-93 205/50-15
'94-01 215/45-16 +2.37 percent
'02 215/40-17 +3.04 percent

Rear
'91-93 225/50-16
'94-01 245/40-17 -0.57 percent
'02 255/40-17 +0.70 percent

 

[OMEGA]

I am having the same problem with my NSX I just bought. My question is that can I drive with the TCS off until the rears need replacing or am I risking doing damage to any of the TCS systems. I can buy new tires now if I have too but with just buying the car with brand new tires, doing the 60k and 90k and paying shipping and sales tax I would love to have a couple of months before buying new tires.

 

[Nimbus]

You can always just unplug the TCS computer behind your seat to save the hassle of manually turning off your TCS everytime you start your car, not to mention saving the TCS light bulb on your dash.

 

[OMEGA]

Thanks, I will try that. Now to see if I can get the Acura parts dept to take back the Fuel Relay I just bought.

 

[nsxtasy]

My question is that can I drive with the TCS off until the rears need replacing or am I risking doing damage to any of the TCS systems.

You can drive with the TCS off without damaging the TCS system. You can either switch it off each time you drive the car, or disable it as noted in the above post.

 

[apapada]

Yawwn,

I think the problem comes from the Michelin (worst tires I ever tried) because I have exactly the same problem with my Michelin Pilot Sport mounted in the same size on my second set of wheels !

I never had a problem with my previous set of Pirelli PZero in the same sizes on the same wheels !

I really hate the Michelin Pilot Sport !!!!!
David

Now, that's some very technical & mature reply !