Welcome to the North American Subaru Impreza Owners Club Tuesday September 16, 2014
Home Forums WikiNASIOC Products Store Modifications Upgrade Garage
Click here to visit TireRack
Tire & Wheel Forum sponsored by The Tire Rack

Losing traction? Need new tires?
Click here to visit the NASIOC Upgrade Garage...
Here you can view your subscribed threads, work with private messages and edit your profile and preferences Home Registration is free! Visit the NASIOC Store NASIOC Rules Search Find other members Frequently Asked Questions Calendar Archive NASIOC Upgrade Garage Logout
Go Back   NASIOC > NASIOC Technical > Tire & Wheel

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.
* Registered users of the site do not see these ads.
Reply
 
Thread Tools Display Modes
Old 07-16-2009, 02:07 PM   #26
sniper1rfa
Scooby Specialist
 
Member#: 141040
Join Date: Feb 2007
Chapter/Region: NESIC
Location: Designing things
Vehicle:
07 2.5i wagon
UGM

Default

Quote:
Originally Posted by Grath View Post
Tire width can vary from manufacturer to manufacturer, even model to model. One 225 may not be the same as another 225, can this be true for circumference as well?
Yes. At worst, the OP should measure the tires in question before using them in that manner.


Quote:
Originally Posted by BeatLA View Post
I argued an article from tire rack, not a legal disclaimer.
You don't think that's part legal disclaimer? They don't want to be responsible for anybody's non-standard setups.


Quote:
The different tires are going to have different wear ratios and will sooner or later result in problems.
True.


Quote:
I just feel it's excess wear on the diffs as the tires are going to have different grip levels.
The wear in the diffs is only due to the LSD, and the LSD will only wear if it's dealing with uneven wheels speeds as a constant thing. The DCCD is smart enough to deal with minor deviations in speed (turning, improper tire pressures) which would more than overshadow the minute difference in tire circumference IF the OP measures them to be the same.

So, differential wear is not the problem with running different tires, as long as you measure them.


The vast differences in grip and rain performance may be a big problem, however, since the vehicle dynamics will change by a huge amount (especially in a slide). If you're aware and drive way under the practical limit, that shouldn't be a huge problem. Just don't drive like you've got a full set of good tires. Drive like one will explode or something.
* Registered users of the site do not see these ads.
sniper1rfa is offline   Reply With Quote
Old 07-16-2009, 04:37 PM   #27
Jons_uurx
Scooby Specialist
 
Member#: 189180
Join Date: Sep 2008
Chapter/Region: SCIC
Location: Bakersfield,Ca
Vehicle:
04 wrx jbp stg dos
03 Infiniti G35s

Default

i have two different sets of kumhos on my car ive never had an issue. I do have a friend with an sti that had different tires and his wheels would lock up sometimes it was becomming an issue so he took it in, they replaced something i wanna say center diff or something like that and it was still doing it so they said maybe the new part is deffective so they replaced it again and still nothing. Finally they concluded its was caused by the different tires he had installed, so the dealer made him buy four brand new tires on the spot that cost him almost $1000 (from the dealer) but has never had the problem again.

Last edited by Jons_uurx; 08-25-2009 at 01:31 PM.
Jons_uurx is offline   Reply With Quote
Old 08-22-2009, 02:01 AM   #28
lotarg
Scooby Specialist
 
Member#: 90940
Join Date: Jul 2005
Chapter/Region: Tri-State
Location: NY & CT
Vehicle:
2005 Infiniti G35
Grey

Default

Good info in this thread. I was wondering same the same thing about tires on AWD
lotarg is offline   Reply With Quote
Old 08-22-2009, 02:28 AM   #29
mangboy
Scooby Newbie
 
Member#: 218309
Join Date: Jul 2009
Chapter/Region: SCIC
Location: los angeles / antipolo PI
Vehicle:
2002 wrb wrx wagon
blue

Default

Quote:
Originally Posted by Crawdads View Post
The same manual also states that the brake pads and linings should be replaced with only Genuine Subaru parts.

Following directions and recommendations while allowing for common sense is the best approach.
strong point right there..
mangboy is offline   Reply With Quote
Old 08-30-2009, 05:29 PM   #30
maxpowr
Scooby Guru
 
Member#: 159243
Join Date: Sep 2007
Chapter/Region: Tri-State
Location: medford nj 08055
Vehicle:
sg3 Turbo Tek Tuned
Hakt Ecu e85 30r 6spd

Default

first off i have an 02wrx so no dccd. i bought 2 continental contitrac 225 50 17 all seasons off a bmw from craigslist for cheap. i was gonna buy 2 more new continental contitracs new from tire rack for like 150$ each...free shipping. i heard these were a good quiet all season radial. i was linked here by a buddy who suggested uneven tire wear could be bad for my diffs. but then i read tire racks disclaimer about uneven tire wear.

i don't have a tool to measure the tread depth but they look 80% compared to what new would be.

so general concensous is that using two older and two new is not recommended by subaru but may not be as distructive as the rumor spreaders may say?

i have had a really beat front drivers side tire for a couple months now and a passenger rear that consistently losses air down to 22psi. so i have been unknowingly wearing my diff away?

my experience with nasioc has been alot of "oh you should never do that!" when alot of people do it with no real documented consequences.

i don't want to hurt my car...but i'm looking at spending 300$ or 600$ on tires...and the craigslist tires look really good to me...but i don't have the ability to properly calculate each wheels complete rotation per mile...

thanks
guys
maxpowr is offline   Reply With Quote
Old 08-30-2009, 05:41 PM   #31
Crawdads
Scooby Specialist
 
Member#: 30907
Join Date: Dec 2002
Chapter/Region: SWIC
Location: Cat Keyboard Cat
Vehicle:
SWP GDB-G

Default

Quote:
Originally Posted by maxpowr View Post
first off i have an 02wrx so no dccd. i bought 2 continental contitrac 225 50 17 all seasons off a bmw from craigslist for cheap. i was gonna buy 2 more new continental contitracs new from tire rack for like 150$ each...free shipping. i heard these were a good quiet all season radial. i was linked here by a buddy who suggested uneven tire wear could be bad for my diffs. but then i read tire racks disclaimer about uneven tire wear.

i don't have a tool to measure the tread depth but they look 80% compared to what new would be.

so general concensous is that using two older and two new is not recommended by subaru but may not be as distructive as the rumor spreaders may say?

i have had a really beat front drivers side tire for a couple months now and a passenger rear that consistently losses air down to 22psi. so i have been unknowingly wearing my diff away?

my experience with nasioc has been alot of "oh you should never do that!" when alot of people do it with no real documented consequences.

i don't want to hurt my car...but i'm looking at spending 300$ or 600$ on tires...and the craigslist tires look really good to me...but i don't have the ability to properly calculate each wheels complete rotation per mile...

thanks
guys
The Spec is 3/32s of tread depth...that is the MAX difference that is within tolerance for the differential...anything more is bad for the viscous coupling.

Measure the difference. (no tool is needed, beyond a ruler or a coin).

This thread isn't really about the same thing as your situation...its true and accepted that running different tread depths is bad for the diff.

Again, you need to measure your tires...if you want, you might also get the new tires shaved down a little so they are within spec.
Crawdads is offline   Reply With Quote
Old 08-30-2009, 05:54 PM   #32
BoneJj
Scooby Newbie
 
Member#: 222089
Join Date: Aug 2009
Chapter/Region: South East
Location: South West Florida
Vehicle:
2010
Satin Pearl White

Default

Quote:
Originally Posted by BeatLA View Post
Still not buying it. I know diffs can't read, but if you have 2 different sets of treads running, it's going to be working to figure out why there's better traction in the front or back 100% of the time. I think it's just not good business to run different tires on any AWD car.
he has a WRX not an STI, so he's only running a direct drive system... it's not like he's got the automatic that puts varying amounts of force to the different wheels

at least that's my impression...

If he had an STI with that option then it could pose a problem.
BoneJj is offline   Reply With Quote
Old 08-30-2009, 09:08 PM   #33
Crawdads
Scooby Specialist
 
Member#: 30907
Join Date: Dec 2002
Chapter/Region: SWIC
Location: Cat Keyboard Cat
Vehicle:
SWP GDB-G

Default

Quote:
Originally Posted by BoneJj View Post
he has a WRX not an STI, so he's only running a direct drive system... it's not like he's got the automatic that puts varying amounts of force to the different wheels

at least that's my impression...

If he had an STI with that option then it could pose a problem.
Old thread buddy...it just got dragged up with a new question.
Crawdads is offline   Reply With Quote
Old 08-30-2009, 11:07 PM   #34
aboothman
Scooby Specialist
 
Member#: 127745
Join Date: Oct 2006
Chapter/Region: NWIC
Location: Humboldt County
Vehicle:
06 WRX 30r 6 speed
99L EJ255 6 Speed

Default

Wow, if you guys are worried about different types of tread messing up your diffs (assuming same tire sizes) then you should all park your cars and go get something a little more "safe"....like a focus.

Considering the job that our differentials perform every time we turn, the difference between different treads is nothing.

A couple of these guys have it right, but many of you are freaking out over nothing. As long as the tires have a diameter within 3/32" then you will be fine. I would worry more about differences in grip than anything, but that is more a matter of how you drive than anything.

As for the WRX vs STI center diff question, as long as the DCCD is in Auto mode it will be
open 99% of the time.
aboothman is offline   Reply With Quote
Old 08-30-2009, 11:16 PM   #35
BoneJj
Scooby Newbie
 
Member#: 222089
Join Date: Aug 2009
Chapter/Region: South East
Location: South West Florida
Vehicle:
2010
Satin Pearl White

Default

Quote:
Originally Posted by Crawdads View Post
Old thread buddy...it just got dragged up with a new question.
oh my bad....

but yeah... this is where tire rotation comes into play... every 3-6k depending on your driving habits. I personally just do it with each oil change... That and it helps out with prolonging time between tires and such.

This is one thing I didn't really consider though when I bought my car. I did some digging shortly after I put my down payment on the car and figured out it's not all that big of a deal.
BoneJj is offline   Reply With Quote
Old 08-30-2009, 11:20 PM   #36
BoneJj
Scooby Newbie
 
Member#: 222089
Join Date: Aug 2009
Chapter/Region: South East
Location: South West Florida
Vehicle:
2010
Satin Pearl White

Default

Quote:
Originally Posted by Crawdads View Post
The Spec is 3/32s of tread depth...that is the MAX difference that is within tolerance for the differential...anything more is bad for the viscous coupling.

Measure the difference. (no tool is needed, beyond a ruler or a coin).

This thread isn't really about the same thing as your situation...its true and accepted that running different tread depths is bad for the diff.

Again, you need to measure your tires...if you want, you might also get the new tires shaved down a little so they are within spec.
I've heard of having a tire shaved before but never ran into a place that actually does it... How rare is it that a place can actually do this?
BoneJj is offline   Reply With Quote
Old 08-31-2009, 09:02 AM   #37
Crawdads
Scooby Specialist
 
Member#: 30907
Join Date: Dec 2002
Chapter/Region: SWIC
Location: Cat Keyboard Cat
Vehicle:
SWP GDB-G

Default

Quote:
Originally Posted by BoneJj View Post
I've heard of having a tire shaved before but never ran into a place that actually does it... How rare is it that a place can actually do this?
Usually its only offered on new tires, TireRack does it...and you were planning on buying the tires from them anyway.
Crawdads is offline   Reply With Quote
Old 08-31-2009, 05:08 PM   #38
BoneJj
Scooby Newbie
 
Member#: 222089
Join Date: Aug 2009
Chapter/Region: South East
Location: South West Florida
Vehicle:
2010
Satin Pearl White

Default

Quote:
Originally Posted by Crawdads View Post
Usually its only offered on new tires, TireRack does it...and you were planning on buying the tires from them anyway.
not me but yeah that's interesting. I order a lot from discount tire direct, they always have the tires that I need and all for the right price. Tirerack wants way too much for shipping..... Screw that.....

I don't have any of those places near me so yeah, shipped all the time. The places near me want way too much for the same tires....
BoneJj is offline   Reply With Quote
Old 09-01-2009, 12:09 PM   #39
sourcandy
Scooby Newbie
 
Member#: 212410
Join Date: May 2009
Location: Houston, TX
Default

This thread kills me. How did you come to determine that 3/32 difference of tread depth is the magical number that makes the diff explode from excessive heat/usage?

From my understanding on how a diff works, even if the VLSD was being used, the diff would have to sustain SOO MUCH heat to even warrant the possibility of damage. The fluids will disperse heat which will go to the case that has air moving over it at what 65 70mph?

I may be new to subbies but I'm not new to mechanics or the automotive world. The VLSD I've seen fail is because the Viscous liquid is comprimised.
normal open diff failures are usually do to one wheel spinning excessivly faster than the other, IE burn out. The spider gears in side the diff are usually the weak link and once one goes it usually grenades the whole thing.

I understand the point that if you car is electronically monitoring wheel speeds to sense traction loss then yes, I would be slightly more concerned, but still I doubt the electronics will think that one worn tire compared to a less worn tire translates into slippage and has to enable VLSD.
sourcandy is offline   Reply With Quote
Old 09-02-2009, 11:37 AM   #40
andypaintguns
Scooby Newbie
 
Member#: 222450
Join Date: Sep 2009
Default

id say make sure all tires are the same
andypaintguns is offline   Reply With Quote
Old 09-02-2009, 12:07 PM   #41
nhat
Scooby Guru
 
Member#: 140163
Join Date: Feb 2007
Chapter/Region: MAIC
Location: 3MI Racing
Vehicle:
03 STi
hellaflunctional

Default

1. the op never reappeared in the thread
2. why is he buying cheap ass h-rated tires
3. don't buy cheap ass h-rated tires
nhat is offline   Reply With Quote
Old 09-02-2009, 12:52 PM   #42
DavidB
Scooby Newbie
 
Member#: 207743
Join Date: Apr 2009
Chapter/Region: International
Vehicle:
2006 Impreza-98 swap
Silver

Default

So, If i have 225/40R18 on the front and 235/40R18 on the back, this will cause damage?

what about different traction? say on the back grips less? on 50-50 deff
DavidB is offline   Reply With Quote
Old 09-02-2009, 12:56 PM   #43
BeatLA
Scooby Specialist
 
Member#: 182396
Join Date: Jun 2008
Chapter/Region: NESIC
Location: Potholeachusetts
Vehicle:
2005 WRX Wagon
2004 FXT for Mrs. BeatLA

Default

Quote:
Originally Posted by DavidB View Post
So, If i have 225/40R18 on the front and 235/40R18 on the back, this will cause damage?

what about different traction? say on the back grips less? on 50-50 deff
Considering your shorter tire (225's) spin 10 times more in a mile...I'd say it's probably not the best idea.
BeatLA is offline   Reply With Quote
Old 09-02-2009, 06:45 PM   #44
strictlyJDM
Scooby Newbie
 
Member#: 197798
Join Date: Dec 2008
Location: San Francisco Bay Area
Vehicle:
2006 WRX Wagon
White

Default

i did that exact set up on my wrx and had no problems. if you have wrx, your front diff is open anyways. For the track, no. For everyday, just getting to work/school/home/where ever, you'll be fine. make sure you run the same tire size though and i believe it would only be a problem if you had race tires front, some crap winter tires back. Also, it would only be a problem if you run different tires left and right side of the car not front and back.

i can get into more detail but i honestly don't have the time, you'll be fine.
strictlyJDM is offline   Reply With Quote
Old 12-10-2009, 02:32 PM   #45
drifte
Scooby Newbie
 
Member#: 209749
Join Date: Apr 2009
Chapter/Region: MWSOC
Location: Iowa
Vehicle:
04 XT
Silver

Default

Im looking at buying a forester and I am still contemplating the purchase. One thing I noticed was someone replaced just 1 tire with a different brand. The other 3 have good tread and are the same size. Now I didnt stop to think and measure actual circumference, but we did check tread depth and the difference was less that 3/32. Everything else checked out (turbo oil drain seep, doesnt seem like a big deal). What do you guys think...?
drifte is offline   Reply With Quote
Old 04-20-2011, 06:14 PM   #46
Mr.Chow
Scooby Specialist
 
Member#: 256390
Join Date: Aug 2010
Chapter/Region: MWSOC
Location: Manitowoc, WI
Vehicle:
2004 Baja Turbo
Dark Blue

Default

Quote:
Originally Posted by Crawdads View Post
Tires can be searched by size, but wheels must be searched by make/model.
I think this is probably because they're concerned with offset more than anything.
Mr.Chow is offline   Reply With Quote
Old 04-20-2011, 07:30 PM   #47
sniper1rfa
Scooby Specialist
 
Member#: 141040
Join Date: Feb 2007
Chapter/Region: NESIC
Location: Designing things
Vehicle:
07 2.5i wagon
UGM

Default

12-10-2009, 02:32 Pm
sniper1rfa is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
How bad is running two different Tire Brands (front & back) BeBop86 Newbies & FAQs 22 07-28-2008 04:34 PM
Running different tread tire, any problems? Eluder Transmission (AT/MT) & Driveline 7 05-25-2007 06:39 PM
anyone know if I can run two DIFFERENT vid cards at once (non SLI) waktasz Off-Topic 11 01-23-2007 01:00 PM
Is it possible for me to run two different auto-x classes in the same auto-x? Swine Motorsports 9 05-04-2005 01:13 PM
What is the performance difference between these two turbo's? Homemade WRX Normally Aspirated with bolt-on Forced Induction Powertrain 4 04-18-2003 12:29 PM


All times are GMT -4. The time now is 06:02 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2014 Axivo Inc.
Copyright ©1999 - 2014, North American Subaru Impreza Owners Club, Inc.