Is it ok to change rear tires thats 235 50 17 to 255 45 17?

Question

I have a 2004 nissan 350z with front and rear tires that are different sizes. I will keep the front to the factory specs but i was wondering if i can change my back tires. i will go from 235 50 17 to 255 45 17. will this jeapordize my safety or performance?

my car is a rear wheel drive...

Answer 1

The real question is why do you want to go to a different size? What it is you are looking to get?

In terms of fitting... there have been options on the car for as wide as 265 in the rear, so the 45 series at 255 width should work without an issue.

The size difference is less than 1%, meaning that you will need to be over 100mph before you actually see an indicated difference on the speedometer more than 1mph... your oddometer will be slightly off though over time.

For performance, you will be adding more grip to the back. Though when the factory used the wider tires in the back, they used 245 in the front... this may not be an issue though. You cannot simply keep going wider and wider in the back without taking into account that you will eventually force the car to understeer by lack or grip in the front, relative to the back... conversely though, getting too wide in the front will also lead to understear as wider tires do not work at as wide of slip angles as the more narrow tires.

So what are you looking for? If you want more grip in the rear, this will get that... but if you ever drive at or near the car's limits (and you would need to if you are looking for more grip), then you need to be aware you are going to make at least a small change to the car's balance.

Also, in terms of performance, the larger tire will weigh more... not much, but considering this is rotating unsprung mass, even small changes will have some effect (more weight to move and to stop). Some decrease in ride quality will come with the lower profile tire as well.

Lastly, the increased contact patch on the drive wheels will also increase rolling resistance and will cause at least a slight decrease in gas milage.

Answer 2

is it front or rear wheel drive?you should at least keep the tyres on the drive axle to original size or you will change the gearing and lower fuel economy.

Answer 3

i have seen a Z with 22's on rear so must be heaps of room. if anything will increase overall traction.

Answer 4

Why?

The people who designed and built your car clearly feel the OE size works better. How many automotive engineering degrees do you have to 2nd guess that?

Answer 5

in case you're changing the tire, then that is going to on the least extra healthy on the wheel/rim. the different factor to contemplate is the clearance you presently have around the tire and rim you presently have put in on the automobile. you could desire to furnish us with extra assistance, you could desire to ask your community automobile fix save (Midas, Meineke, Sears vehicle, NTB, Pep Boys, and so on), or you could desire to easily have them positioned on and verify the clearance your self. good success.