can i replace the factory rear tire 275-40-18 with a 275-35-18??? would there be any issues that i should be concerned about???

 

Someone correct me if I am wrong, but does that mean the 35 tire is 1/2 inch shorter in total height than the 40 tire?

I think your replacement rear tire would be 1/2 inch shorter in total height than the non-replaced tire. Since it is in the rear...if it is the passenger side...when you are alone driving in the car... Normal!

hahhaha

Really.. I am guessing...no real clue.. just wanted a shot!


Gary

 

it depends on what size tire you're running up front. you should try to retain aprox the same DIFFERENCE in diameter between front and rear tires as the originals.

 

 

This is not a good idea. You will cause TC problems.

 

so if i am running the original size tire up front 245-45-17 i can't put a 275-35-18 size tire on rear is this correct????????? would a 275-35-18 tire even fit factory rim to replace 275-40-18????

 

Why do you want to run a smaller tire?
No, you should not put that size tire on the rear.
Here is a calculator you can play around with if you want.

http://www.miata.net/garage/tirecalc.html

 

As mentioned above - it depends on what you're running in the front. You say you are running the stock sized 245-45x17. I guess the real issue is that you apparently do not understand what these numbers mean.

Take a look at this page from Discount Tire's page that explains what each number means - http://www.discounttire.com/dtcs/infoSidewall.dos

Now that you understand this point - the 35 or the 40 is the aspect ratio, which is the relation of the sidewall height to the width of the tread. A lower number means that the sidewall is less tall than a larger number. The 35 aspect ratio has nothing at all to do with rim width, and it will fit with no issue on the stock 9.5" wide wheel.

But the issue on a Corvette is that the traction control system expects to see the rear wheel spinning slower than the front wheel. There are wheel speed sensors in each hub that "talk" to the EBCM (Electronic Brake Control Module) that controls traction control as well as the ABS and the Active Handling if so equipped. If the rear wheels are spinning faster than the front wheels - this condition is interpreted as wheel spin and traction control will be invoked - meaning that timing is retarded and brake is applied to the rear wheels to attempt to halt the condition.

Now - it is important to know that a taller tire revolves slower than a shorter tire. According to this chart http://www.discounttire.com/dtcs/infoTireMath.dos also from Discount Tire's web site - we can estimate that a 245-45x17 is 25.68" in overall height and spins at 785.33 revolutions per mile.

The stock 275-40x18 is 26.66" overall diameter and spins at 756.45 revolutions per mile, meaning that the rear tire is almost one inch taller than the front, it spins slower and there will be no complications with the T/C system.

The tire you are proposing - 275-35x18, is approximately 1/10th of an inch shorter than the front tire and spins at 788.47 revolutions per mile, which is faster than the front tire by about 33 rpm. There is a good chance that you will have issues with T/C.

So unless you are going to change the front to a shorter tire, or the rear to a taller tire - you likely have an issue.

 

.
Long story short...Don't do it
.

 

Maybe a little long, but an excellent explanation of why not to do it.
Randy has always supplied great info.

 

Great write up and much appreciated. Thanks for the education...



Gary