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Discussion Starter #1
Hi, I'm changing my tires to Michelin PS4S and have seen on here many others have done the same but are people just using the regular PS4S or the AO homologated tire?

Is there much difference between them?

Thanks,

Nate.
 

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I have non AO PS4S's and find them superb.
 

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Without inside information or thorough side by side testing it's impossible to determine the difference between a standard tyre and a homologated tyre. Very little info is published for the general public. In this case there is little or no price difference between them, so I'd probably go for the AO tyre - they come standard now on the 2019 facelift. Your car is fairly new so if for any reason you sell it back to an Audi main dealer, then an Audi homologated tyre will have some value, even if you don't feel it on the road. If they sell it as a Used Approved, then I'm fairly sure it will need AO / RO1 tyres fitted.

Something rather odd though is that the AO tyre has a poorer wet grip rating (B) and poorer economy (E) rating than the non-AO tyre (A / C). I asked Michelin why this would be the case but never received a solid answer - only that the AO tyre was their recommendation based on the thorough manufacturer approval process.

It looks like the RO1 / RO2 homologations are being phased out and replaced with AO across the Audi range.

Gen2.1 5.jpg
 

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AO stands for Audi Option. (MO Mercedes, N Porsche, K Ferrari...see list in link below) It means that the tyre has gone through a testing process by the car manufacturer in a number of categories. In some cases the tyres may be exactly the same as the non-homologated versions, in some cases they are not e.g. the older RO1 tyres for the Gen1 had a narrower shoulder. There are normally only two or three tyres approved for each size, e.g. on the gen2 20" tyres the following are approved :- PZero (the newer PZ4), Michelin PS4S and Michelin PSC2.

Personally I think the homologation process is of more value to the tyre manufacturer than the customer, but I'm open to others opinions. I have a C class which had MO approved PZeros fitted as standard - they were the worst tyre I have ever owned - extremely hard riding, poor life and I had a catastrophic failure of a front tyre at less than 9,000 miles. Similarly the PZeros on my gen1 were very brittle after just over 3 years and there was such a difference in every performance category when I changed them out to non-Audi approved Goodyear Eagle F1s.

https://www.tyres-pneus-online.co.uk/reading-tyre-markings-advice.html
 

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AO stands for Audi Option. (MO Mercedes, N Porsche, K Ferrari...see list in link below) It means that the tyre has gone through a testing process by the car manufacturer in a number of categories. In some cases the tyres may be exactly the same as the non-homologated versions, in some cases they are not e.g. the older RO1 tyres for the Gen1 had a narrower shoulder. There are normally only two or three tyres approved for each size, e.g. on the gen2 20" tyres the following are approved :- PZero (the newer PZ4), Michelin PS4S and Michelin PSC2.

Personally I think the homologation process is of more value to the tyre manufacturer than the customer, but I'm open to others opinions. I have a C class which had MO approved PZeros fitted as standard - they were the worst tyre I have ever owned - extremely hard riding, poor life and I had a catastrophic failure of a front tyre at less than 9,000 miles. Similarly the PZeros on my gen1 were very brittle after just over 3 years and there was such a difference in every performance category when I changed them out to non-Audi approved Goodyear Eagle F1s.

https://www.tyres-pneus-online.co.uk/reading-tyre-markings-advice.html
Thank you very informative, thanks for taking the time to write this.
 

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Sometimes it can be other details to the tire...back in the day the 03 RS6 required a very particular Michelin PS2 that was an Audi and RS6 specific tire...it did not have the wheel/rim protector on the inside edge like the normal PS2...if it had it the tire would rub against the front suspension on any turn in. When I switch out what came with my RWS it will be the PS4S audi version.
 

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Discussion Starter #9
Thanks for the info guys. Maybe the AO have a slightly different compound that gives the variations in wet grip and economy.
I have 2 sets of wheels one 19 inch that came with the car and have homologated tires on them so would put those back on if I ever sell it back to Audi and also have some 20's which is what I'm buying the Michelin's for.
Considering how much it rains in the UK I'm leaning towards the non AO with better wet grip :D
 

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I think AO means that Audi get ££ for every tyre sold and the tyre manufacturers sell more tyres. Only my theory!
 

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I think AO means that Audi get ££ for every tyre sold and the tyre manufacturers sell more tyres. Only my theory!
Does anybody really believe that Audi does extensive tires testing on all the different tires for each model car. its all $$$ This is company that does its own emissions software !!!!
 
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