Winter tire technical question, need help

[mapleinwind]

Hi guys,

my first post here, woho:)

so my question is that... i have a 4wd car and one winter tire on my winter rims blowed at the end of last winter. since those winter tires are relatively old, i cannot find that brand/model any more.

In order not to waste those three good winter tires, i am thinking about getting only two brand new tires (other brand) and put them in front and choose two good ones from those three old winter tires to put in rear.

I went to two tire shop this morning, and all those mechanic are trying to sell me four tires... They told me that the drive axle will be broken if i use different tire brand in front and rear (of cause they are all the same size). I am thinking if they are making it too serious and just want to get more money out of my pocket.

Please provide some technical hint, thanks. just feel bad to waste those three good tires.

btw, my car is a Audi, if the different all wheel drive system (e.g. audi vs subaru) matters! :lol:

[Pete_Coach]

They are wrong. There is a potential for damage to the drive axles if the tire tread is different left to right but not front to back. You have a transfer case that will overcome differences in traction.
Having said that, you need to be aware that if your car electronically senses where the power should be and constantly shifts between front and rear, you can put undue stress on that system of you have too great a difference in traction.
I would suggest you get 4 tires but if you cannot, two will be OK if the others still have good traction. I do have concern though since you mentioned the tires are so old you cannot find the brand anymore. Models change frequently, just like cars but the brand (Toyo, Firestone, Michelin etc) should be out there somewhere. Get tread patterns that match as closely as possible.

[sonyminidiscman]

its not gonna make a difference. think about it, if you are on dry road, ur wheels has equal traction, spins at the same rate...

if you are on heavy ice/snow....... none of your wheels will get the same traction, so you think in this case, your audi will break? i don't think so

[hightech]

My suggestion is to sell the existing 3 tires on craigslist/kijiji and get a new set of 4 tires. The money you would get from the existing rubber would offset the cost of the new tires, and you will have piece of mind knowing that there would be no issues of any sorts.

[coffeeguy]

They are wrong. There is a potential for damage to the drive axles if the tire tread is different left to right but not front to back. You have a transfer case that will overcome differences in traction.
.

wrong again.

You absolutely must replace all four tires at the same time. If you are making a major change in tread pattern (and potentially tire diameter), you must switch all four tires or your all-wheel drive system may be damaged.

http://www.wheels.ca/article/2748

I own a four-wheel drive vehicle. Can I replace only two tires instead of the four?

Generally, this is not a recommended practice. The small difference in rolling diameter between the worn and the new tires can be enough to damage the center differential of such a vehicle or to adversely affect the intended bias between front and rear torque distribution.

The four tires on an all-wheel drive vehicle should be of the original size; they should all be of the same brand and model and they must have even wear. Replace them in sets of four to avoid expensive damage.







http://www.apa.ca/template.asp?DocID=93

[KawaiiTentacleBeast]

If you still have the owner's manual it should tell you how much difference in tread the differential can tolerate.

[macnut]

i am thinking about getting only two brand new tires

For any given tire size, when looking at different brands & models,
the variability in tread depth, width, overall diam. and revs. per mile. is much greater than most people imagine.

If you can find 2 new tires with a tread pattern that is similar to your current (3) tires, take the next step.

Use tirerack.com to compare the two different tires in that size.

The revs. per mile might differ by typically 1%.
May not sound much, and the Audi awd system may be more forgiving than Subaru's, but is it worth a gamble?

[GadgetShopper]

I have a FWD mini van.

I had to replace one of the rear tires last year, and couldn't find the same make and model in the shop that I went to. They just gave me one that matched the size. I am pretty sure the thread patterns are very different. Shall I replace both of my rear tires? BTW, they are winter tires.

[Pete_Coach]

wrong again.

You absolutely must replace all four tires at the same time. If you are making a major change in tread pattern (and potentially tire diameter), you must switch all four tires or your all-wheel drive system may be damaged.

http://www.wheels.ca/article/2748

I own a four-wheel drive vehicle. Can I replace only two tires instead of the four?

Generally, this is not a recommended practice. The small difference in rolling diameter between the worn and the new tires can be enough to damage the center differential of such a vehicle or to adversely affect the intended bias between front and rear torque distribution.

The four tires on an all-wheel drive vehicle should be of the original size; they should all be of the same brand and model and they must have even wear. Replace them in sets of four to avoid expensive damage.
http://www.apa.ca/template.asp?DocID=93
Well, we can start a my research is better than yours war but it serves no one any good. In fact, there is an ongoing debate on this subject with neither side winning. A true AWD user, one that does the heavy off road type of driving may have trouble but in fact, the type of driving that is normally done by most AWD drivers, there should be no harm at all. I have difficulty with quotes from retailer,t hey are a bit more self serving than others, so I am just wary of the purpose.
Anyway, I still maintain that if the new and old tires are mixed n the same axle, there can be problems but front to rear, should be no significant problem. Here is my cut and paste to back up my argument :) ;
http://www.4x4abc.com/4WD101/diffautoAWD_AWD.html
"There are some AWD vehicles where it does not matter what you do. Replace one tire, replace 2 - it does not matter. Those AWD vehicles are true AWD, in the sense that they are full time 4WD or permanent 4WD powering all 4 wheels with about equal force. Most Subaru (except Impreza), BMW X5, Audi, some Toyota, Mercedes, etc. are in that group of true AWD. These AWD vehicles have a differential between the two permanently powered drive shafts. They are the ones that will survive a replacement tire that is slightly larger or slightly smaller (like when you have to buy a used (larger) tire in Mexico because nothing else is available)."

[AGR-1]

since those winter tires are relatively old, i cannot find that brand/model any more.

If you would be a tire shop what would you tell a customer in light of the above?

If you would be the owner of the car what should you do to have proper tires for the upcoming winter?

If you would be a tire shop and someone insisted on buying only 1 tire what would you do?

[Pete_Coach]

since those winter tires are relatively old, i cannot find that brand/model any more.

If you would be a tire shop what would you tell a customer in light of the above?

If you would be the owner of the car what should you do to have proper tires for the upcoming winter?

If you would be a tire shop and someone insisted on buying only 1 tire what would you do?
I presume you are commenting on what I said last? If so, I would say exactly what I said to him in my first post on this subject.

Having said that, you need to be aware that if your car electronically senses where the power should be and constantly shifts between front and rear, you can put undue stress on that system of you have too great a difference in traction.
I would suggest you get 4 tires but if you cannot, two will be OK if the others still have good traction. I do have concern though since you mentioned the tires are so old you cannot find the brand anymore. Models change frequently, just like cars but the brand (Toyo, Firestone, Michelin etc) should be out there somewhere. Get tread patterns that match as closely as possible.
Is this OK with you? :)

[CaptSmethwick]

As others have said, 4 new ones are better than two but, given that the Audi uses an open differential, you are not going to damage your AWD system by operating on tires have slightly different diameters front and back. The type of AWD system you have is the key to the answer to this question and you should be fine.

The downsides, though, are:


you'll have to treat your tires as if they are directional and only rotate them front and back (or, pointlessly, side-to-side)
you may get some premature wearing of your breaks if your Audi's stability control kicks in a lot because of differences in tire rotation


You could overcome the 2nd by bringing your new tires to a specialty tire shop to get them shaved to match the diameter of the old ones - not really worth it given that your treads aren't matching any way. Frankly, these downsides would be enough for me to follow hightech's advice to sell them on kijiji and buy 4 new ones.

[DavidY]

Look at the date code on the three existing tires. If they are more than 6 years old, you may want to replace them with a set of four new winter tires anyways. You might want to keep one or two of the newest and best conditioned tires for spares (ideally, the same treads on two).

Dave

[AGR-1]

@Pete_Coach

I was not commenting on your post, which was good and informative.

I was commenting that a tire shop that sees 3 older winter tires will suggest 4 new tires, and will not be interested in selling only 1 mismatched tire or 2 mismatched tires and have the possibility of some sort of come back / liability.

The OP for his own safety, the safety of his passengers (family) should use 4 matching winter tires with over 50% tread depth remaining, how technical is 4 good winter tires?

[mapleinwind]

Very busy recently, almost forgot about this post... Thanks for the hot replies from all you RFDs. I really appreciate it as my first post in this forum:lol:

I have gotten two brand new winter tires installed in the front and picked two good ones from those three OLD winter tires. Actually those three tires are Pirelli snowsport 210, which are pretty good winter tires and just two years old (but very hard to find in current market and expensive too!). And also the third one was put in the trunk as spare tire:cheesygri

So no big waste at all for this winter!