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Discussion Starter #1
Ok so i need some new rear tyres never really looked at the width and profile till now....

The rears are 255/40 ZR 17 Potenzas
The fronts are 235/45 ZR 17 Potenzas


Is that alright/safe to drive or should i be worried?

If so what tyres should i buy and what size?
 

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Discussion Starter #3
Will have to look at the wheels when i get home to find out, as im not sure what make they are.
 

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same size potenza's on mine, good tyre i like them, but in the wet can be a bit whiley... in the dry all good, might goto toyo next seem a good price and good reviews...

Cheers
Dazzler
 

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The reason for the difference is that whoever fitted them tried to keep as close to the correct original overall wheel size on standard higher profile tyres on standard wheels as possible, as that keeps the speedo correct.

To do that as you go to wider tyres (as is frequently done with rears) you need to reduce the profile, which results in lower profiles on the rear. This is because the profile (40 / 45 etc) is a percentage of the tread width in simple terms, i.e. the rear profile is 40% of the "255", which is about the same measurement as the 45% of the "235"..

I hope that was clear, if not go here for the full story:

www.carbibles.com

Aitch
 

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Discussion Starter #9
The reason for the difference is that whoever fitted them tried to keep as close to the correct original overall wheel size on standard higher profile tyres on standard wheels as possible, as that keeps the speedo correct.

To do that as you go to wider tyres (as is frequently done with rears) you need to reduce the profile, which results in lower profiles on the rear. This is because the profile (40 / 45 etc) is a percentage of the tread width in simple terms, i.e. the rear profile is 40% of the "255", which is about the same measurement as the 45% of the "235"..

I hope that was clear, if not go here for the full story:

www.carbibles.com

Aitch
Thanks alot for that mate exactly what i wanted to know.:bigthumb:
 
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