I have just noticed that my 2 front tyres (both PIRELLI ROSSO) look different in size diameter wise. One is a 245/40 ZR 18 93Y AO and the other is a 245/40 Z 93Y MO. The MO one looks larger in diameter than the AO one though the tyre size is identical,the gap from wheel arch to top of tyre is also about 5mm more on the AO side than the MO side. Can someone shed some light on this or am i going mad. Both front springs were replaced a year ago so im definately sure the ride height should be the same on both sides?
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First you'll need to check a few things like tyre pressures are correct and the same, and also tread depth. Then measure distance from centre of hub to outside of tyre at the 12 o'clock position. If there is a difference not due to wear, then it must be down to spec of tyre.
You do get size differences even though they are the same size of tyre specs. This happens between brands and sometimes between individual tyre ranges within a single brand.
Cheers
Steve
You do get size differences even though they are the same size of tyre specs. This happens between brands and sometimes between individual tyre ranges within a single brand.
Cheers
Steve
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Incidentally.... AO are tyres made for Audi, and MO are tyres made for Mercedes.
It has been the belief of (most of) this forum's members for some time now that there is no difference between manufacturer-specific tyres and 'normal' tyres, so it would be very interesting if it did turn-out that the differences between the two tyres actually relate to their AO and MO ratings....
It has been the belief of (most of) this forum's members for some time now that there is no difference between manufacturer-specific tyres and 'normal' tyres, so it would be very interesting if it did turn-out that the differences between the two tyres actually relate to their AO and MO ratings....
RESULT: I swapped the tyres over this evening and I can confirm that the 245/40//18 AO are 5mm smaller in diameter than the 245/40/18 MO,they are both Pirelli Rosso so this may just apply to this make only. The 5mm gap is now on the other side where the AO tyre is now fitted. I have psi on both at 35 and tread is 6mm ish on both. Lesson learnt for me only use MO only for my W211
