my rear tyres are fecked MOT time is 2 weeks away!

 

getting some goodyear F1s i have 17inch alloys and the tyres on there at the moment are 255/40/17 zr should i stick with this size or change to something else

 

i know its a boring thread but needs sorting :)

 

 

thanks guys and gals greg

What size do you have on the fronts?

 

IMO with 17s this (255/40/17) is probably the best size to chose. It's also a pretty common tyre size so prices are reasonable too. 265/40/17 and wider are rare, more difficult to source and are therefore unecessarily expensive.

 

Also the wider the tyre the less grip it can have in the wet.

 

HTH

 

Richard :smw:

What size do you have on the fronts?

 

IMO with 17s this (255/40/17) is probably the best size to chose. It's also a pretty common tyre size so prices are reasonable too. 265/40/17 and wider are rare, more difficult to source and are therefore unecessarily expensive.

 

Also the wider the tyre the less grip it can have in the wet.

 

HTH

 

Richard :smw:

 

 

what about 245/40/17 will they grip better than 255s

What you have to remember greg, is the rolling radius of the tyre.

For example, the rolling radius of a 185/70 is the same as a 205/60, it used to be a drop in profile height, ment going up 2 sizes in width.

To keep your rolling radius correct, and therfore your speedo as accurate as possible!!, the correct rear size should be 245/45x17's, but if you stay with the 255/40, or go for 265/40, you wont be too far out.

For reference, on a tyre marked as 245/45x17,

245 is the width in mm,

45 is the profile height as a percentage of the width,

17 is obviously the size of the wheel in inches.

Sorry to bore you all!!!

And Richard is correct, the wider the tyre, the less grip you can have in the wet, as the tread wears, if your suicidal enough to drive a Z in the wet!!!!!!!!

thanks for the reply shunter..yes i did take it in mate ..no it dident bore4 me :D

 

cheers also richard,

 

greg

what about 245/40/17 will they grip better than 255s

 

Doubt it will make much difference TBH. Also it is down to the make of the tyres.

 

I had Avon ZZ1s in stock sizes (245/45/16 rear) and when I replaced the alloys, I got 255/40/17 Goodyears F1s on the rear. The grip is now way better in both the dry and wet, but that is probably mostly down to better tyres.

 

I do think the car handles better in general with the extra 10mm of rubber, though :cool:

 

Richard :smw: