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Discussion Starter #1
I was wondering, when it comes time to put winter tires on, is it ok to put them on either the front or rear wheels? Or is it necessary to put them on all four? Just curious.
 

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Throw things off is a massive understatement. It could destroy your diff.
 

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yeah with AWD need to replace or change 4 at a time
 

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i know your supposed to flat bed the car, but i thought i read something in the manual that said you could tow it by the front wheels but you had to disconnect a fuse or something.
 

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Discussion Starter #8
Thanks for the responses.

Looks like the most cost effective route would be to get a winter set of rims and tires, and put them on myself in November, then switch back to the summers at the end of March or so.

I guess the only challenge will be the whole Tire pressure sensor thing.........still not familiar with how those get changed-out.
 

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Those will likely need to be activated so you can either buy four, put them in the winter wheels, and pay $ each time switching back and fourth or just forget about them and check your pressures.
 

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Throw things off is a massive understatement. It could destroy your diff.
How much wheelspin do you get? Might destroy your center diff if you have the throttle modulation of a bag of rocks.

i know your supposed to flat bed the car, but i thought i read something in the manual that said you could tow it by the front wheels but you had to disconnect a fuse or something.
Pretty sure it said disconnect the half shafts.
 

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i know your supposed to flat bed the car, but i thought i read something in the manual that said you could tow it by the front wheels but you had to disconnect a fuse or something.
It depends on the year, model, and type of trans.

How much wheelspin do you get? Might destroy your center diff if you have the throttle modulation of a bag of rocks.



Pretty sure it said disconnect the half shafts.
Worst first post ever. Please don't provide bad information that will cause expensive damage. Please don't state your personal opinion as fact (especially when you are wrong).
 

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Simply running tires with different tread depths front/rear will destroy the center diff.. no wheel spin required.
Worst first post ever. Please don't provide bad information that will cause expensive damage. Please don't state your personal opinion as fact (especially when you are wrong).
If you guys want to enlighten me as to how asymmetric tire selection will grenade your center diff be my guest.
 

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If you guys want to enlighten me as to how asymmetric tire selection will grenade your center diff be my guest.
Uh...wut? Not sure if serious or just retarded...
 

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nousablenames133 said:
If you guys want to enlighten me as to how asymmetric tire selection will grenade your center diff be my guest.
Directly from the user manual (Page 11-53, in mine):
WARNING: All four tires must be the same in terms of manufacturer, brand (tread pattern), construction, degree of wear, speed symbol, load index and size. Mixing tires of different types, sizes or degrees of wear can result in damage to vehicle’s power train.
From here:
Four-wheel drive and all-wheel drive vehicles are equipped with additional differentials and/or viscous couplings that are designed to allow momentary differences in wheel speeds when the vehicle turns a corner or temporarily spins a tire. However, if the differentials or viscous couplings are forced to operate 100% of the time because of mismatched tires, they will experience excessive heat and unwarranted wear until they fail.



I'll take Crown on the rocks, please. Oh, and I'm not going to take off my shoes.
 

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This thread is shaping right up. :rotfl:
 

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Good information, I did not know this. My car came with 2 different sets of tires on them, but they're both worn about the same. Guess I'll get around to swapping all 4 out.
 

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If you guys want to enlighten me as to how asymmetric tire selection will grenade your center diff be my guest.


No one said it will grenade the center diff, but it will wear it out rather quickly and cause it to start binding up. It's not a difficult concept to explain at all. If your tires are different diameters that will cause them to rotate at different speeds, therefore just driving on the highway is similar to constant wheel spin as far as the diff is concerned. Causing the diff to be constantly working over heats it and wears it out.. simple as that.


This is why Subaru tells you to rotate your tires at every oil change and to always replace all four tires at the same time.
 

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Thanks for the input. Let's break down everything you said down. As far as I know, again correct me if I'm wrong, 2002-2007 WRX's used open diffs front, and VLSD's center and rear. 2008+ WRX's use open front and rear, a center VLSD and VDC.
Not sure on STI's but I think they use helical (torsen) front, DCCD Center (torsen + electromagnetic variable locker), and a Salisbury LSD in the rear. The OP was asking about front/rear asymmetric setups, not hillbilly (left/right asymmetry) so I'm going to ignore the front and rear differentials since they only control left/right power distribution. I'm also going to ignore overall limit vehicle response because unless you hit something or you go hooning, it will not affect the center differential.

Now let's say the OP wants Blizzak WS60's in 225/55/R16 on the front and Dunlop SP Sport 600's in 245/40/R18 on the rear.

Four-wheel drive and all-wheel drive vehicles are equipped with additional differentials and/or viscous couplings that are designed to allow momentary differences in wheel speeds when the vehicle turns a corner or temporarily spins a tire. However, if the differentials or viscous couplings are forced to operate 100% of the time because of mismatched tires, they will experience excessive heat and unwarranted wear until they fail.
Using the TireRack.com tire size calculator Tire Size Calculator - Discount Tire Direct

There is a 0.02" (0.078%) difference in outer diameter. Looking at manufacturer specs, their tolerance is to the tenth of an inch, there is a 0.1" difference or 0.389% difference in OD. Assuming the snow tires will wear faster than the summer tires, the difference will momentarily go to zero. And assuming you put on a set of bald Blizzak's with new Dunlops, the difference in OD will peak at 1.47" or 5.72%.

Consider that the OP will probably run this staggered setup during the Winter when it is cold, consider that conductive and convective heat transfer vary linearly with temperature difference (I'm guessing radiative heat transfer is negligible although it varies with Delta T^4). If you're saying a staggered Winter tire selection will grenade your center diff, what are your thoughts on track use during the summer?

manufacturer, brand (tread pattern), construction, degree of wear, speed symbol, load index and size. Mixing tires of different types, sizes or degrees of wear
Manufacturer, brand, tread pattern, construction, and size will greatly affect overall vehicle response, but will not affect center diff behavior if the vehicle is operated under the traction limit.
Load index and speed rating will have no affect as long as they are not exceeded.
Degree of wear will have the greatest affect on center diff life. As long as you use reason, don't mismatch bald/new tires. Your diff will not catastrophically fail.

I want to end this by saying, I am not arguing that a staggered front/rear setup is good/smart/advisable whatever, but it is not as bad as previously stated.
 
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