Tyre Sizes

[LatinR33]

Hey all I have the following tyre sizes

Fronts - 235/45/R17 and Rear 255/40 R17

Just wondering if i need to follow these tyre sizes exactly when purchasing tyres or will other sizes fit?? For example the rear would a 205/40 R17 fit?? Im not too sure how tyre sizes work so if anyone wants to explain please go right ahead.

[Baz]

It really depends on the rim size that you are running on the rear to whether a 205 width tyre would fit. But I dont think you have the slightest chance in hell of fitting one on. The rim width would have to be less than 7" wide in order to be able to have a chance of fitting it on and considering you have 255's on the rim I would think it would be 8" wide or more than likely wider than that.

When working out profile sizes of tyres, the second number is the profile worked out as a percentage of the tyre width.

So in your example -

- A 255 width tyre, 40% of 255 is 102

- A 235 width tyre, 45% of 235 is 105.75

These are both of a similar profile so it is a suitable match for the car for front and rear.

A 205 width tyre, 40% of 205 is 82 which has a substantially less profile height. So even if you could fit that tyre on that rim it has a much smaller profile so it wouldnt be suitable to your setup. Good drifting/burnout tyre though.

Cheers,