replacing tires on a quattro equipped car.

[tdn]

A week ago I was run off the road and my car hit a curb, both tires on my passenger side were blown and the rims had some damage.

Insurance is replacing both tires and rims. I mentioned that all tires have to be within a certain range on my car, but the shop insists that putting the new tires on the back and the two good used ones (I'm estimating 65% tread left) on front will be fine.

The shops closed right now and I can't get my manual which is in my glove box. I can still call my insurer today and have them make sure all four tires are replaced, but before I do that I want to be 100% sure. If someone can check their manual for me I'd appreciate it.

[biketsai]

As long as they are the same size, there is no problem. I haev 4 different tires on.

[tdn]

I probably wasn't clear.

All the tires are the same. Two new and two old. Old ones have about 65% left, so the tires aren't all the same diameter.. Audi says quattro equipped cars can only have so much differance (3/32" I believe) in diameter otherwise you run the risk of some expensive damage. I explained this to the shop, but they insist that by putting the two older tires in front and two newer in back, that all will be well.. even though I'm no longer within Audi's specified range.

I just want to verify 100% that either I'm right or wrong before I call up my insurer.

[tdn]

As long as they are the same size, there is no problem. I haev 4 different tires on.

And for the record, you might be in the wrong. Just because you're running 4 16" tires for example, doesn't mean they're the same diameter.

[djwimbo]

Just because you're running 4 16" tires for example, doesn't mean they're the same diameter.

exactly. I'm not saying damage will occur, but as far as recommendations go. Buy 4 tires of the exact same size and style/brand/etc. for the best results.

A tire for a 16" wheel, say a 205/55R16(stock size for swing wheels), can vary about .25" depending on the manufacturer.

Same goes for profile sizes. My 245/50R16's on my old Camaro were .375" wider than the 255's on my buddies Acura.

If your insurance company has any brains they'll replace the other two as well. If not, change insurance companies, or explain to them the damage that could possibly result.

[audimuse]

curious why they are planning on putting the new ones in the back where less weight is put on during braking. if they only replace the two put the new ones of the front because of wear, etc... but like some are saying, i would def. talk your insurance company and talk them into replacing all four for safety percautions. good luck.

[audiness]

running two new tires and two old tires on a quattro car will not hurt anything. You just "shouldn't" run different brands/sizes

[onemoremile]

The general rule of thumb is a 3% difference. 25 / 24.5 = 1.02 so 1/4" of tread wear is doable without overheating diffs.

I'd put the new tires on the front. Or wear them in on the rear and rotate to the front after a hundred miles or so. The fronts wear more quickly since they provide steering, braking, and acceleration while the rears do only a portion of that.

Another option is to take the insurance money and check with Doc at Tire Rack or ebay's discount tire online auctions. The set of Sumitomos I'm on cost less than a single Pilot Sport and my fancy snow tires were less than half the store price.

[ChescoS6]

my fancy snow tires were less than half the store price.

Which brand and size snow tires are they and where did you purchase them? I will be buying a set soon. All Seasons aren't cutting it

[onemoremile]

http://stores.ebay.com/discounttiredirect

When searching for a set add a 4 at the end like so: 245/40-17 4.

I run Yokohama Guardex in a 245/40-17. They were 186 each plus shipping from tires.com and less than 400 shipped from their ebay store. When balancing them their local manager says the ebay store is better than his discount.

[SpoolinPelican]

A tire for a 16" wheel, say a 205/55R16(stock size for swing wheels), can vary about .25" depending on the manufacturer.

Same goes for profile sizes. My 245/50R16's on my old Camaro were .375" wider than the 255's on my buddies Acura.

Different types(all season/truck/performance) of tires are also measured differently, as well as the variences between manufacturers.

[Siena]

From experience, and from current tests, the directives are fit newer tyres on the rear, regardless of drive configuration.

When a car loses lateral grip, it's the rear that breaks traction, and causes the "pendulum" effect - hard to correct.

If the front breaks traction laterally, at least the wheel can compensate.

Current directives in Europe are to fit newer treads on the rear.

[01Audi1.8T]

Which brand and size snow tires are they and where did you purchase them? I will be buying a set soon. All Seasons aren't cutting it

Pick up some 15's and get snow tires for those. Much cheaper. I bought Passat 15's and Bridgestone Blizzaks. $375 for wheels and tires and they stick like glue in the snow.

[Spykce]

Our owners manual states that "All four wheels must have the same rolling radius. Different tires on the front and rear wheels may impair the vehicle control and damage the all wheel drive system because of constantly different wheel speeds. Proper function of the system is not affected by unevenly worn tires"

Therefore as long as the tires are the same brand you should be good. However if you can get 4 new ones I would, who doesn't love new tires?

[onemoremile]

No. Rolling radius is the key term there. Circumference is more appropriate though. If stock diameter is 25" and you have 1/4" of tread wear then the diameter is now 24.5" which is a difference of 2%. The Torsen center diff will try to match speeds front to rear and they can't possible match. This causes the gears to load which creates heat which is what causes the failure. This is why a small percentage of mismatch is ok but larger percentages cause real problems. This is also why you should never put a smaller spare on the front of a front wheel drive car. Not only is it harder to steer and brake but the differential and traction control system can go through hell.

[tdn]

My insurer (Liberty Mutual) is saying they're basically only responsible for the damage caused, I'm trying to get them to understand that their way of fixing the damaged caused can cause me even more damage and money down the road.

The Auto Body shop (Webster Auto Body in Somerville MA - Stay away) which is supposed to be the ones handling this through my insurer is basically saying I'm full of shit and that whomever is telling me this is "pulling my leg" - I mentioned the owners manual and he's sticking to his guns... I'm not sure why, I don't think he loses out on this by any means. So I'm dealing with the appraiser directly to hopefully get this resolved.

They're just tires, I'll shell out the cash for them if it comes down to it.. but I was hoping my insurance company would do things the right way. They're one of the most expensive insurers in my state and I'd like it if the extra cost would count for something. Minor issue, but I've been contemplating leaving them so this might be the straw that does it.

[onemoremile]

I doubt the insurance company will budge. Hopefully the tires on the car were relatively expensive. For example, if a couple $230 Pilot Sports were damaged you could get a full set of replacements for the same money.

[tdn]

I agree. They won't budge, but it's because the Auto Body won't budge. They told me that there are two ways I can get this done, one is if the Auto Body says it's needed and two, is if the appraiser's supervisor gives him the go. Since for some strange reason the Auto Body is being a complete ass about the whole thing, I have to hope my appraisers supervisor gives him the ok, which I doubt I'll get.

I'm lost as to why the Webster Auto Body is not willing to listen to me, my owners manual or even any Audi Mechanic in my entire state. The guy seemed very cool until I mentioned this to him, he told me it would be fine, I told him I'll have to disagree based on the advice of Audi of America and now it seems he's out to prove me wrong.

It might seem silly as they're just tires, but I'm not letting this go yet. I know of one way the insurance might have to pay up.. which is through another shop. It might end up costing me some out of my own pocket, which sucks considering this shouldn't even be an issue.

[tj19855]

I recommend you get all 4 new.