Tire Size and AWD [Merged 5-7] diameter radius rolling different sizes size

[King Salami]

Gurus - I've got an 92 TSi AWD that I recently had to replace a tire on. All other tires are about 20% worn. Will the difference in tire diameters (due to wear; tire brand & size for the new tire is the same) cause any harm to my transfer case/AWD system?
I know wheel/tire size differences are very important on an AWD, but would 20% wear on 3 tires vs. 1 new make a difference? Since I rotated my tires, I'm experiencing an odd low-pitched "hum" or "grumble", especially when downshifting or raising off the throttle.
I've asked the guys at Discount Tire and my local Audi dealer, but they didn't seem too concerned.

 

[jt1583]

what about getting the tire patched?

 

[AWDlaserRS]

You will be okay with 2 different tires in the front or rear, I have had 2 different pairs for about a year now.

 

[n0va91TSI]

are patches or tire repairs strong?

 

[Defiant]

are patches or tire repairs strong?

It depends on the damage. Used to be you weren't supposed to patch a radial more than about 1½" from the centerline, depending on the tire and model. The amount and type of damage to the tire is also crucial- a simple nail or screw hole will patch up with a plug in most cases, and plugs work fine and can be done in the driveway without a jack. See what the shop tells you.
One new one is kinda dumb, but it won't affect the drivetrain enough to kill it.

 

[n0va91TSI]

thanks ill try a patch and if that doesnt work ill get new fronts and get the backs when i can afford it

 

[anduril]

if her name is Erica i was in the car for one of the crashes :laugh:

Yup, that'd be her My g/f is driving the 3rd Talon she owned.

 

[greathuskie]

this girl i know bent one of her rims and i was going to give her one of my old ones (same style) but the tires are different, would it be ok for her to use a different tire but with similar tread on the one tire then the rest? shes an autoAWD

 

[wishihadatalon]

as long as there is no size diff. hold one wheel up to the others. if its smaller or bigger you will eat one of your diffs.

 

[DSM90AWD]

I've an AWD and one of my tires is near bald due to a poor balance after being plugged. Bad new is that Dunlop no longer sells the W-10 so need to get a different Model.

Question is.. can I just replace two (both rears) if the size/profile is the same as the fronts? I have 2/3 tread on the three good tires so would hate to junk them.

I know that performance-wise the tires may be slightly different.. more concerned with messing up drivetrain parts.

 

[DE91TSI]

I've seen it done with no ill effects but i work for NTB in DE and we are told by the company not to do that on anything awd. Im guessing they have paid for a few transfer cases and decided its not worth the liability plus 2/32nd would fail a PA inspection there almost at the end of there life anyway. oops i thought you said 2/32nds not 2/3rds oh well as long as you keep a very similar tread you shouldnt have a problem

 

[UCSLugRacerX]

Try to get tires with the same size aspect ratio (overall height) as your front tires. As long as that's ok, then your center diff will be happy.
In terms of mixing and matching tires, as long as you try to match the tires' "stickiness" with the ones you'll have on the front, then you'll be almost ok.
Read the sidewall of your front tires, and try to match:

Tread wear
Speed rating
(and maybe price)

If you put cheap/non sticky tires in the rear, and you've got sticky tires in the front, then you'll have oversteer.
If you put MORE expensive and very sticky tires (maybe wider) in the rear, then you will have (cornering limit) understeer. Although the understeer tendancy will be the same as before you had the old tires on. This set-up will make the car more stable.

With varying tire compounds, you will vary the tires' slip angles degrees (or the point of which the tire slips extremely, and the car slides drastically). By matching them as closely as possible, the car will be more neutral while turning, and you should be fine.

 

[DSM90AWD]

I've seen it done with no ill effects but i work for NTB in DE and we are told by the company not to do that on anything awd.

Actually.. was your shop that did the plug (Kirkwood Hwy?).. get me a deal on some 215/45/17s and all's forgiven

BTW.. I found a couple online shops / eBay that can do 4 name brand shoes for < $400.. so may go that route. Just pisses me off that I've got to waste the remaining 3.

 

[DSM90AWD]

With varying tire compounds, you will vary the tires' slip angles degrees (or the point of which the tire slips extremely, and the car slides drastically). By matching them as closely as possible, the car will be more neutral while turning, and you should be fine.

Was looking to replace with the Dunlop SP9000 which are the same tire (all-season WR-speed rated) but diff tread design.

Thanks for the information

 

[DE91TSI]

Im actually at the one up on concord pike by the concord mall. I can get you a deal on the tires the company will beat any advertised price so find the best internet price you can and print it out ill hook you up.

 

[jtmcinder]

Im guessing they have paid for a few transfer cases...

And you'd be guessing incorrectly, which is why you're not supposed to guess. The VC for the center diff (which is what suffers when the front and rear diameters or grip levels are unequal) is in the transmission, not the transfer case.

- Jtoby

 

[DSM90AWD]

And you'd be guessing incorrectly, which is why you're not supposed to guess. The VC for the center diff (which is what suffers when the front and rear diameters or grip levels are unequal) is in the transmission, not the transfer case.
- Jtoby

But would the same height tire with slightly different grip characteristics make that much of a deal to your VC unless your car is mainly for Auto-X

BTW.. the replacement for the Dunlop W-10 (which I have) seems to be the FM901. Both have UQTG ratings of 200AA.. and similar tread design.. so would think they'd have similar rolling resistance.

 

[I_love_my_TSI]

I Planning To Put On 2 Same Kuhmos 225 40 18 In The Front ....and 2 Same Nittos 225 40 18 In The Rear..

Have Any One Experience This?? Will This Damage The Awd System??

 

[blackGSX2g]

I Planning To Put On 2 Same Kuhmos 225 40 18 In The Front ....and 2 Same Nittos 225 40 18 In The Rear..

Have Any One Experience This?? Will This Damage The Awd System??

The factory manual recommends to have all the same kind, but in reality...as long as they are the same size, you will be fine.

 

[c5chris]

It's generally a concesus that in an AWD system, you gotta have te same tires. This makes sure you got the same rolling diameter, same "bite pattern" and balaced weight on all corners. Some people will tell you that you don't. This applies now but down the line, say 15K miles, you'll have tires that had worn more and bald due to the different tire compounds. a 400 treadwear tire will outlast a 180 treadwear tire. One tire will be bigger AND heavier than the other.

Get a cheap set of Kumhos 711, they are 99/tire at Tirerack. It's better to spend more now in tires (400 bucks) than to spend more on a burnt center differential. Parts and labor for this will cost over a grand or two.

The cost of owning an AWD. But hey, they are fun and really a different breed of cars.

 

[I_love_my_TSI]

Thanks Fellas for your replies. I'm very low on $$$ for now ,,so I will just put on the mix match tires for a few week till next pay day..

 

[Alex_95TSI]

Ok im gonna buy new set of USED tires this or next week.
Most used tires places usually have a hard time of stocking 4 of the same brand sized tires and i know how important it is to have matching tire sizes on all four corners!

Different tire manufac's make same sizes the once mounted some brands are actually bigger or wider than others and thats where my concern is. Miniscule or major ?
Im planning on 225/50 all matching brands, but in event they dont have same brands what should i do?

Pass until they have same brands or just get same size and overlook the brands?

 

[herostar]

Get all the same brand, and off of the same vehicle.

 

[Alex_95TSI]

That is what my heart is tellin me but the wallet is skeptical...

Anybody notice something 'weird' running 2 different brands of tires?

 

[seminoles2005]

sometimes different tire brands have different widths, my copper 205's were just as wide as my kuhmo 215's

 

[boostaddictgsx]

On an All Wheel Drive car, this is critical. It is well worth it to get a good set of matching tires, and a good alignment. That's one thing people don't often think about. Do it right the first time to save yourself some trouble down the road.

Also, I ran Yokohama AVID V4's 225/50/R16 all the way around. Before that I had three Yokohamas, and one no-name brand tire of the same size. I pulled to the right(no-name tire on front right wheel) constantly. So to answer your question, I have noticed something 'weird' running two different brands. I very strongly suggest that you bite the bullet and get all four of the same brand, whatever the cost may be.

Best of luck,
Brendon