Load rating?

[Sprode]

I searched for a while, I swear:

I am looking to replace the fulltime summer tires on my A4 with high performance A/S tires, as last winter in the mid-atlantic was almost impossible to get through. I am running the stock TI wheels, 235/40/18 and was looking thru tirerack for my options and the Continental DWS seemed to be the choice if the tests on site are accurate.

TEST: http://www.tirerack.com/tires/tests/testDisplay.jsp?ttid=124&

Tire: http://www.tirerack.com/tires/tires.jsp?tireMake=Continental&tireModel=ExtremeContact+DWS&partnum=34YR8ECDWS&vehicleSearch=false&fromCompare1=yes

The question I've got is that the load rating on them is a 91, where IIRC, I am supposed to have a 93 rating.

Is this a big deal? Do I need to be at 93? Will I have to look into another tire? Are there any other tires that people recommend in terms of high performance A/S?

[Sprode]

According to:

http://blog.tirerack.com/blog/audi-tires/0/0/load-rating-and-load-capacity the tire is supposed to be able to take half the weight of the heaviest axle. Assuming a 60/40 ratio for the 07 A4 (i think its a little more favorable than that) and an overestimated (with passengers) 4000 pounds, that should give a required load rating of 4000*.6/2 which is 1200 pounds. This is much lower than the stock rating, and seems like the 91 should be fine as a 91 rating is 1356 vs the OEM 93 at 1433 lbs.

Thanks in advance for any help you can give.

[Doc@tirerack]

What you have to look at is Audi's Gross Axle Weight Ratings (on the white sticker in your doorjamb). The front axle carries 2,491lbs and the rear 2,469 (if my info is correct), so each tire needs to carry at least half of the larger number (or 1,235 lbs). The Conti carries 1,356 at 36 PSI or higher so you're fine AS LONG AS YOU MAINTAIN THAT PRESSURE. If you are not able to keep an eye on the pressure and it falls too far, the tire will be overloaded and will fail. The OE tires with extra load capacity give you a little more breathing room if the pressure drops over time (you will lose around 2 PSI every month due to the air migrating thru the sidewall, and around 2 PSI for every 10 degree drop in ambient pressure).


We hesitate to sell the "standard load" tires for the simple fact that most people (even with TPMS monitors) don't check pressures often enough to keep the lower load tires in a safe range. If you were to order the standard load tire and reference the vehicle online, we'd call you to let you know our concerns.

[VMRWheels]

What you have to look at is Audi's Gross Axle Weight Ratings (on the white sticker in your doorjamb). The front axle carries 2,491lbs and the rear 2,469 (if my info is correct), so each tire needs to carry at least half of the larger number (or 1,235 lbs). The Conti carries 1,356 at 36 PSI or higher so you're fine AS LONG AS YOU MAINTAIN THAT PRESSURE. If you are not able to keep an eye on the pressure and it falls too far, the tire will be overloaded and will fail. The OE tires with extra load capacity give you a little more breathing room if the pressure drops over time (you will lose around 2 PSI every month due to the air migrating thru the sidewall, and around 2 PSI for every 10 degree drop in ambient pressure).


We hesitate to sell the "standard load" tires for the simple fact that most people (even with TPMS monitors) don't check pressures often enough to keep the lower load tires in a safe range. If you were to order the standard load tire and reference the vehicle online, we'd call you to let you know our concerns.

Very good information!

Indeed, keeping tire pressures at the specified amount is of great importance! Also keep in mind, a warm tire, say after driving on the highway, will offer a higher PSI than a cold (possibly near freezing) tire; When checking to verify minimum PSI, always check cold tires rather than warm. There have been cases of TPMS alerting the driver of low PSI when the car is started, then a few miles down the road shutting off, for this exact reason.

[Sprode]

Thanks for your reply.

A couple questions then:

First, I did not find the weight info on my doorjamb, just tire info.

Also, that is almost 5000 pounds. Is this with passengers? I am pretty sure my car is not that heavy and I am also fairly certain it is significantly heavier in front. Assuming it is a typo and should be 1,469 this is pretty close to the off-the-cuff calculation I did above. Does the load rating not take into account the weight of passengers? Is there a calculation I could do other than simple linear interpolation to find a minimum PSI? For example if the LR is 1356 at 36 psi, can I assume 0 LR at 0 PSI, draw a line, pick out 1235 and find my minimum PSI that way?

If this will not work, and especially as the temp is swinging like crazy as we enter fall around here, can you recommend another comparable tire for me?


What you have to look at is Audi's Gross Axle Weight Ratings (on the white sticker in your doorjamb). The front axle carries 2,491lbs and the rear 2,469 (if my info is correct), so each tire needs to carry at least half of the larger number (or 1,235 lbs). The Conti carries 1,356 at 36 PSI or higher so you're fine AS LONG AS YOU MAINTAIN THAT PRESSURE. If you are not able to keep an eye on the pressure and it falls too far, the tire will be overloaded and will fail. The OE tires with extra load capacity give you a little more breathing room if the pressure drops over time (you will lose around 2 PSI every month due to the air migrating thru the sidewall, and around 2 PSI for every 10 degree drop in ambient pressure).


We hesitate to sell the "standard load" tires for the simple fact that most people (even with TPMS monitors) don't check pressures often enough to keep the lower load tires in a safe range. If you were to order the standard load tire and reference the vehicle online, we'd call you to let you know our concerns.

[Doc@tirerack]

Look for GAWR (gross axle weight rating) should be one each for front and rear axle along with a total vehicle weight. The GAWR is the max that axle can carry, for example the front axle has the engine above it and the rear carries the gas tank and its fair share of the passenger/cargo weight. While it may only be you in the car with no luggage and 2 gallons of gas, we have to put a tire on the car that can handle every possible pound and then some. (I have been told there has been litigation against drivers who were involoved in an accident and found to have tires that did not meet load).

In your size, look at the Goodyear Eagle GT or new Yokohama AVID ENVigor as alternatives to the Conti with an XL rating........


http://i.ebayimg.com/05/!!gVjCLQ!2E~$(KGrHqUOKnIEw9VyLDzbBMW+(TrSPQ~~_4.JP G

(taken from ebay, 2007 A4 2.0 Quattro)

[Sprode]

Doc,

Your advice has been great. I appreciate it and just picked up 5 new yokos as I hadn't seen that tire before. I also put your name in for the rep.

Thanks.

[Doc@tirerack]

Just saw it.... thanks for your support !

[dubswede]

great info. thanks guys.

i too am looking for a winter tire substitute for full-on dedicated snow tires as i'd like to run my 'winter' setup in the summer if i feel like it since i love the wheels so much. the continental extreme dws was the leading choice up until now.

i look forward to going home and looking at all my different sets of wheels/tires for my cars with the load rating as a point of interest.