Correct AR for 285R18's
10-07-2003, 10:20 PM
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Correct AR for 285R18's
I have 10.5 inch rear rims for a 996. 265 and 275 sidewalls look stretched. I would like to get 285's but I'm not sure if I should get a 30 or 35 aspect ratio so as not to mess up the perceived "smart brain" in the car's program. For what it is worth, the car has no PSM, so it's not that smart. Looking at R compound tires to be used exclusively for DE. Any help appreciated.
10-07-2003, 10:27 PM
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Unless Porsche stopped including it in their owners manual, it should tell you in there what percentage difference in size the ABS system can handle.
10-07-2003, 10:48 PM
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Thanks Bill, I just looked at the manual. My car is a 99 model, and the manual doesn't detail that info. All it says is to use N1 or N0, and 265's for the rear tire. Wonder if Viken would know this?
10-08-2003, 01:57 PM
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On a 10.5 inch rim you should use 285's or 295's. The easy way to figure what aspect ratio to use is to head to the tire rack website. There you can find full specs including the rolling diameter of the wheel/tire. You want to keep wthe diameters within 3 percent (max) of the same rolling diameter if I remember correctly. Chose the width and aspect ratio which gets you very close to the diameter of the fronts. On a 25.4 inch diameter, you should aim to be within 0.5 inches and 0.7 inches max difference. Note that same size tires from different manufacturers often have different diameters so check several brands.
10-08-2003, 02:29 PM
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Re: Correct AR for 285R18's
Originally posted by Arthur
I have 10.5 inch rear rims for a 996. 265 and 275 sidewalls look stretched. I would like to get 285's but I'm not sure if I should get a 30 or 35 aspect ratio so as not to mess up the perceived "smart brain" in the car's program. For what it is worth, the car has no PSM, so it's not that smart. Looking at R compound tires to be used exclusively for DE. Any help appreciated.
I have 10.5 inch rear rims for a 996. 265 and 275 sidewalls look stretched. I would like to get 285's but I'm not sure if I should get a 30 or 35 aspect ratio so as not to mess up the perceived "smart brain" in the car's program. For what it is worth, the car has no PSM, so it's not that smart. Looking at R compound tires to be used exclusively for DE. Any help appreciated.
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10-15-2003, 09:28 PM
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Conversion rate
Can anyone tell me the conversion to metric on the ff tire sizes, please?
24/64-18
27/65-18
If it helps any, these are Michelin slicks.
Thanks a bunch, again!!!!
24/64-18
27/65-18
If it helps any, these are Michelin slicks.
Thanks a bunch, again!!!!
10-16-2003, 04:12 PM
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Eugene,
Thank you. That last onbe was it. I've just been so used to TireRack's method. Never got slicks before, and it all looks strange to me.
Thank you. That last onbe was it. I've just been so used to TireRack's method. Never got slicks before, and it all looks strange to me.
