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I have a 14 A6. We flip between winter wheels 18's and summer wheels 20s. In Oct 2015 we had a blow out and had to replace all 4 winter wheels. We purchased and ordered through Audi Denver. Everything is fine. Recently we got a nail in the left rear tire. I take the vehicle to Discount this morning for a free repair. Discount tells me the wheels we have on the vehicle do not have the recommended load index of 100. The Michelin X-ice tires specs we have are pasted below. They have a load index of 99 instead of 100. Because of this, Discount would not repair the tire. I know Audi dealer will repair but I have questions. Should I have concern that we brought and installed tires that are "not compatible" with the vehicle through Audi and unbeknownst to us. What are the technical or safety implications of having a tire out of load index spec? Should I pitch a fit with the dealer for installing these or let it go and just have them repair it? Talking with the Audi service guy he says the recommended load index for our vehicle is 97h, 97v or 100. We have 99. Your thoughts?
Shell, if you check the Owner's Manual you will find a section where tire inflation pressures are listed that cover the minimum load rating for a given wheel size and whether it's supposed to carry the XL rating in addition to the values you mention.
According to Tirerack, if you go down to 215 and 17 inch, this tire seems to be fine for the A6, but yes normally Audis in that weight class need XL (Extra Load) and not SL (Standard Load) tires and indeed at least for summer tires the A6 calls for a load rating of 100 XL.
Also, Audi dealerships in general don't repair tires. A repaired tire no longer guarantees the speed rating on the sidewall. With the low speed limits in North America, though, that's less of an issue, but I've yet to hear of an Audi dealer that repairs tires. All the ones I know refuse. I have my indy shop repair my tires and so far haven't had a blowout, but I don't take my car to the track. If I were to track it, a patched tire would be a big no-no.
I am surprised the 17" fit on the car. For my car i wanted as small as possible from audi and i did not believe them that 17 wont fit, so i had them show me as they said 19 was the smallest that would clear brakes but we found specific rim cleared 18".
Now onto your question on the load ratings, my winters are 225/50/18 with load index of 99 with speed rating of H. My summers are 255/35/20 with load index of 97 and speed rating of Y.
I think the tire shop maybe being too fussy i would try another place. No tire shop has complaint about my setup as i confirmed with my regular tire guy about my tires before i went ahead with the purchase. If the side wall is small then you need XL tires.
I have never blown a tire but have had a flat with my summers because i drove through a construction site.
100xl rating is recommended, but not required. Technically all you need is a load rating that is above half the gross axle weight rating, and a 99 rating is only 25kg less than a 100 rating (800kg), yet both are far above the minimum rating required of max total load weight of about 2400kg. You could probably even get away with a load rating of 90-91, but 97 (Audi's recommended minimum) and above gives a very good safety margin. XL means it is reinforced and the tire can be comfortably inflated to a higher psi to accommodate a larger load. I believe your manual will state a 225/55 R17 97H as a compatible tire, around page 245.
I am actually surprised they let you have a non-winter designated tire in the T speed rating, as almost all shops will not install tires not rated for the maximum speed of the car unless they are a true winter tire.
I apologize I pasted the wrong tire spec as it relates to what Audi ordered and put on the wheels for Winter. We have Michelin X-ICE 225/50R-18 99H installed on it and those tires (According to Discount Tires) are out of spec for my vehicle. But from the comments below it seems like these tires are perfectly acceptable.
Shell, that could certainly be an acceptable alternate 18" size that's considered safe for the car. You should verify the XL or Extra Load designation is on the tire.
99 is 1709lb
100 is 1764lb
that's per tire...the A6 is nowhere near 6836 total for 99 and 7056 for 100. The A6 3.0T is about 4000lbs. so you still have about 1800lbs to spare.
01-30-2018, 08:00 AM
Tire load rating - should i be concerned or not
