Welcome to the North American Subaru Impreza Owners Club Thursday April 17, 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 12-03-2010, 01:00 AM   #1
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default Staggered wheel - same tire size question

Please do not come in here to comment "zomg dont you know that staggered is bad for AWD" because I dont care what you have to say.

So the wheels are the same weight, and within a couple of mm from the outside due to the wider pair having a higher offset than the narrower lower offset pair..

my question is - to achieve similar looking sidewalls, would it be acceptable to run two different tire brands. I would match the treadwear rating likely, i just want to run a tire that runs "narrow" on the narrower wheel, and a tire that runs "wide" for the size on the wider wheels. to, in theory run a set up that is closer in appearance to non staggered..

what i want to avoid is the one pair looking stretched or bulged in comparison to the other two.

cliff notes: two different tire brands for front and rear = ok? or = problematic? and if so please explain why
* Registered users of the site do not see these ads.
pnutbutta is offline   Reply With Quote
Old 12-03-2010, 01:31 AM   #2
DrDanimalSize
Scooby Specialist
 
Member#: 254097
Join Date: Aug 2010
Location: Montreal, QC, Canada
Vehicle:
2010 WRX Hatch

Default

Two different brands may run 'tall' or 'short' as well. Why not just find two different sized tires with the same brand and same diameter? 225/45/17 and 255/40/17 for instance, and several others too if you check the specs on tirerack.com
DrDanimalSize is offline   Reply With Quote
Old 12-03-2010, 01:35 AM   #3
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

the issue is diameter

compare the revs per mile and diameter

Last edited by Uncle Scotty; 12-03-2010 at 01:44 AM.
Uncle Scotty is offline   Reply With Quote
Old 12-03-2010, 10:13 AM   #4
nySulli
Scooby Specialist
 
Member#: 32617
Join Date: Feb 2003
Chapter/Region: Tri-State
Location: NY
Vehicle:
2008 STi
DGM

Default

I wouldn't run different tire brands or even different models of tires within the same brand even if they had the same wear rating

its an inexact measurement of tire wear, its more an estimate then a standard, and you could very likely end up with a significant difference in diameter as the tires wear

Sticking with the same model of tire will help minimize the possible wear differences between the 2, but I think you'll still run into issues since you won't be able to rotate your tires

its your car, so go for it if you want, just don't come back and cry if your center diff goes out on you and subaru tells you to pound sand if you try to get it covered under warranty
nySulli is offline   Reply With Quote
Old 12-03-2010, 11:19 AM   #5
feint05
Scooby Specialist
 
Member#: 152984
Join Date: Jul 2007
Chapter/Region: SCIC
Location: san diego
Vehicle:
2004 jewbaru
jewbuilt, polish tuned

Default

what scotty said plus
same size and diameter wheels ex: 17x8 brand a and 17x8 brand b diffent offsets=fine
mixed tires same size= possible different circumfrences, different wear rates, differing grip= unstable, unreliable, unpredictable, and possibly unsafe.

i totalled my first subaru and i feel mixed tires was a contributing factor
feint05 is offline   Reply With Quote
Old 12-03-2010, 07:01 PM   #6
sc00by4life
Scooby Guru
 
Member#: 97135
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Bothell
Default

As stated before, you the issue is the rolling circumference of the tires. Spread tires across different widths, and the circumference changes. Staggering offsets is A-OK, but widths + tires is a no-no.
sc00by4life is offline   Reply With Quote
Old 12-03-2010, 08:43 PM   #7
PlasticFoamMan
Scooby Specialist
 
Member#: 197764
Join Date: Dec 2008
Chapter/Region: NESIC
Location: Broston
Vehicle:
02 WRX Stage DD
PRND 01G

Default

I ran two different tire brands for quite a while as the result of the lazy dealership replacing a bubbled sidewall with a different brand on the rear when I purchased my WRX (both rear of course). Diameters were the same, ware ratings the same, never ran into any problems.

Even if I did encounter resulting mechanical trouble, it would have given me a great excuse to kick the 4eat

(Also, Keep in mind that staggering wheel width will change the aspect ratio of the tire and cause different diameters, i.e. b/c of stretching etc. Only stagger offset)
PlasticFoamMan is offline   Reply With Quote
Old 12-04-2010, 05:58 PM   #8
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default

thanks for the input fellas. plastic foam man - stretching the tire does not change diameter of the tire, as least thats based on current literature.

the wheels are 18x8 +38, and 18x9 +42, and was planning on running 225/40/18 all around.
pnutbutta is offline   Reply With Quote
Old 12-04-2010, 07:03 PM   #9
sc00by4life
Scooby Guru
 
Member#: 97135
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Bothell
Default

Quote:
Originally Posted by pnutbutta View Post
thanks for the input fellas. plastic foam man - stretching the tire does not change diameter of the tire, as least thats based on current literature.

This is incorrect. Stretching a tire reduces its overall rolling diameter.

Quote:
the wheels are 18x8 +38, and 18x9 +42, and was planning on running 225/40/18 all around.
you WILL burn out your center diff with this combo, not to mention you increasing the amount of understeer our cars are already notorious for.

18x9 or 18x8 all around. there is absolutely 0 reasons to run staggered widths on a subaru.
sc00by4life is offline   Reply With Quote
Old 12-04-2010, 10:15 PM   #10
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default

Quote:
Originally Posted by sc00by4life View Post
This is incorrect. Stretching a tire reduces its overall rolling diameter.
do you have proof of this? tirerack has listed on their website information stating it does not.


Quote:
you WILL burn out your center diff with this combo, not to mention you increasing the amount of understeer our cars are already notorious for.

18x9 or 18x8 all around. there is absolutely 0 reasons to run staggered widths on a subaru.

the reason is because i cant find these wheels non staggered - was not offered. i've never driven my car hard enough to get understeer. it's a 2.5i daily driver, never seen the track, and likely never will.

could i not just pull the awd fuse and run fwd only? will i still burn out the center diff that way?
pnutbutta is offline   Reply With Quote
Old 12-04-2010, 10:34 PM   #11
sc00by4life
Scooby Guru
 
Member#: 97135
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Bothell
Default

i dont need to prove anything, its called logic. if you stretch out a 225 over a 9" wheel, it will have a different circumference than if you put it on a 7" wheel. if the sidewall has to flex to fit the width of the wheel, that lowers the effective height of the sidewall.

it doesnt matter if you see track time, that is something that ANYONE will encounter. Subaru doesn't just have an "awd fuse" like the skylines do. if these wheels aren't sold in non-staggered sets from where you are seeing them, its a good hint that you shouldn't buy them. why can't you just get 2 pairs of fronts then?

Last edited by sc00by4life; 12-05-2010 at 01:05 AM.
sc00by4life is offline   Reply With Quote
Old 12-04-2010, 10:35 PM   #12
LTBlackBird
Scooby Specialist
 
Member#: 222367
Join Date: Sep 2009
Location: Charlotte, NC
Vehicle:
2004 Impreza WRX STi
Platinum Siver Metallic

Default

Wow....
LTBlackBird is offline   Reply With Quote
Old 12-04-2010, 10:48 PM   #13
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default

Quote:
Originally Posted by sc00by4life View Post
i dont need to prove anything, its called logic.
Quote:
Section Width

A tire's section width (also called "cross section width") is the measurement of the tire's width from its inner sidewall to its outer sidewall (excluding any protective ribs, decorations or raised letters) at the widest point. This measurement is made without any load placed upon the tire and after the tire has been properly mounted on its industry assigned measuring rim and has been inflated and reset to its test pressure after 24 hours.

Because a tire's section width is influenced by the width of the rim upon which the tire is mounted, the correct industry assigned measuring rim width for the tire size being measured must be used.

The width of a tire mounted on a narrow rim would be "narrower" than if the same tire was mounted on a wide rim. NOTE: because the overall diameter of a steel belted radial is determined by the steel belts, there is little, if any, change to the overall diameter of the tire due to differences in rim width.

The industry rule of thumb is that for every 1/2" change in rim width, the tire's section width will correspondingly change by approximately 2/10".
http://www.stanceworks.com/forums/showthread.php?t=3216

- cited from tirerack.
pnutbutta is offline   Reply With Quote
Old 12-04-2010, 11:03 PM   #14
jdmboy
Scooby Specialist
 
Member#: 240161
Join Date: Mar 2010
Chapter/Region: MAIC
Location: MD
Vehicle:
2002 wrx wagon R.I.P
87 bmw e30

Default

ok im going to be "that guy" and ask why your trying to do this in the first place? im not trying to flame you but regardless of what anyone on here says your risking damaging your car over this and i guess i want to know why you would take that risk.
jdmboy is offline   Reply With Quote
Old 12-04-2010, 11:13 PM   #15
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default

found a set of wheels ive been dreaming of for this car ever since i bought it. already have the wheels, and will be running them regardless. a few years ago everyone was terrified to run anything lower than 45et, now guys are out there on 10 and 11s with +18et and what not..

same weight, similar poke, same diameter, i dont see what the problem will be.. owners manual also states that 1/2" in diameter difference is acceptable.
pnutbutta is offline   Reply With Quote
Old 12-04-2010, 11:22 PM   #16
jdmboy
Scooby Specialist
 
Member#: 240161
Join Date: Mar 2010
Chapter/Region: MAIC
Location: MD
Vehicle:
2002 wrx wagon R.I.P
87 bmw e30

Default

well if thats what your into then go ahead and do it, i personally would never do that to my car ever, but its your car so do what ever you want to it but like i said regardless of what anyone says your taking a risk because theres not a lot of people that do that type of thing to their subaru because honestly it makes absolutely no sense.
jdmboy is offline   Reply With Quote
Old 12-05-2010, 12:04 AM   #17
sc00by4life
Scooby Guru
 
Member#: 97135
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Bothell
Default

Quote:
Originally Posted by pnutbutta View Post
The wheels you are looking at, are more than 1/2" apart.... you arent looking at an 8 and an 8.5", you are looking at 8 and 9". That means (going by the information you posted), that rolling circumference will change by 4/10'ths of an inch.

Low offsets =! a proven mechanical issue. extra hub stress is a bit different than burning out a center diff in 10,000 miles. If you want to do it, go for it, but unlike low offsets, this WILL cause proven issues.

Last edited by sc00by4life; 12-05-2010 at 01:04 AM.
sc00by4life is offline   Reply With Quote
Old 12-05-2010, 12:54 AM   #18
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default

Can you show me where these proven issues are though? I've searched and can't find any first hand accounts of staggered wheels actually causes problems on a Subaru.

And about the 1/2" difference, that is regarding diameter, not width. So, 4/10th aka 2/5 of an inch difference in rolling diameter, being less than 1/2", is within tolerances...

I am not here to challenge YOU, I am merely discussing what I believe could be a myth when taking into account the numbers:

- 1/2" tolerance in difference of rolling diameter = 50%
- according to your calculations 2/5th of an inch in difference of rolling diameter = 40% (10% under max tolerance, tricky math I know lol).
----- I'm not so sure how a difference in diameter of wheel equates to different rolling diameter, unless you were taking into account tire size in that calculation.
- Confirmation from tirerack that only section width changes by stretching, not overall diameter due to the steel belted tire. Bare in mind it will only be a mild stretch.
- Weights of the wheels are identical - literally to the decimal, so rolling mass would not be different.
- difference in offset, is the 9" wheel pokes only 0.356" or 9mm over the 8. (not really a significant difference in my opinion.

Discuss.
pnutbutta is offline   Reply With Quote
Old 12-05-2010, 01:03 AM   #19
sc00by4life
Scooby Guru
 
Member#: 97135
Join Date: Sep 2005
Chapter/Region: NWIC
Location: Bothell
Default

The information that I got from Subaru, said that the tolerance is only 1/4". Google subaru "torque bind".

Last edited by sc00by4life; 12-05-2010 at 01:09 AM.
sc00by4life is offline   Reply With Quote
Old 12-05-2010, 01:25 AM   #20
pnutbutta
Scooby Specialist
 
Member#: 192572
Join Date: Oct 2008
Chapter/Region: E. Canada
Location: Toronto
Vehicle:
2007 Impreza
CGM

Default

Ok, well difference between 1/4" and 2/5" is only 3mm. PSI of tire can make more a difference than that.

I would assume that Subaru uses a conservative figure for that.

I will keep searching and see if I can find any first hand accounts of staggered widths being a real world issue, lots of hypotheticals out there.. Don't forget people run spacers all day to clear brakes which would disperse weight differently front to back. I would assume rolling mass stuck outwards and stress due to that would be more of an issue than a few mm of difference in diameter. Which according to tire rack, there shouldnt be anyhow.
pnutbutta is offline   Reply With Quote
Old 12-05-2010, 12:27 PM   #21
Byzantium
*** Banned ***
 
Member#: 207826
Join Date: Apr 2009
Chapter/Region: MAIC
Location: Katabatic
Vehicle:
85k 2002 WRX
Correct Fitment Crew #034

Default

Quote:
Originally Posted by pnutbutta View Post
thanks for the input fellas. plastic foam man - stretching the tire does not change diameter of the tire, as least thats based on current literature.

the wheels are 18x8 +38, and 18x9 +42, and was planning on running 225/40/18 all around.
That's a preposterous tire size for those wheels. You need to run larger.

Quote:
Originally Posted by pnutbutta View Post
Can you show me where these proven issues are though? I've searched and can't find any first hand accounts of staggered wheels actually causes problems on a Subaru.

And about the 1/2" difference, that is regarding diameter, not width. So, 4/10th aka 2/5 of an inch difference in rolling diameter, being less than 1/2", is within tolerances...
Uh wrong. Subaru's allotted tolerance is not 1/2" diameter, it's 1/4" in circumference. That's a huge difference. 1/2" diameter difference is a 1.5" difference in circumference. 2/5" is not in spec, it's 5 times what the stated manufacturer specs are.

Quote:
Originally Posted by sc00by4life View Post
not to mention you increasing the amount of understeer our cars are already notorious for.
The contrary is the case. He's dialing out understeer at the expense of steering response.

Last edited by Byzantium; 12-05-2010 at 12:38 PM.
Byzantium is offline   Reply With Quote
Old 12-05-2010, 02:57 PM   #22
DrDanimalSize
Scooby Specialist
 
Member#: 254097
Join Date: Aug 2010
Location: Montreal, QC, Canada
Vehicle:
2010 WRX Hatch

Default

Quote:
Originally Posted by Byzantium View Post
That's a preposterous tire size for those wheels. You need to run larger.

Uh wrong. Subaru's allotted tolerance is not 1/2" diameter, it's 1/4" in circumference. That's a huge difference. 1/2" diameter difference is a 1.5" difference in circumference. 2/5" is not in spec, it's 5 times what the stated manufacturer specs are.
225/40/18 is a fine size for the 8" rim, but too small for the 9" one. If you don't mind running a little taller rubber all around, you could go with a 225/45/18 and a 255/40/18 on the rear, which are both listed as 26" tall http://www.tirerack.com/tires/tires....el=Exclaim+UHP

1/4" in rolling CIRCUMFERENCE???? that's only 1/32" in terms of tread!!! I think that's highly optimistic on the part of Subaru, because 1-2psi would make a greater difference than that. So would a pair of heavy rear-seat passengers and some luggage (which is fairly common on long trips). Does that mean if I take a couple of heavy dudes on a vacation that my diff will blow up? I think not!
DrDanimalSize is offline   Reply With Quote
Old 12-05-2010, 03:04 PM   #23
jdmboy
Scooby Specialist
 
Member#: 240161
Join Date: Mar 2010
Chapter/Region: MAIC
Location: MD
Vehicle:
2002 wrx wagon R.I.P
87 bmw e30

Default

Quote:
Originally Posted by DrDanimalSize View Post
225/40/18 is a fine size for the 8" rim, but too small for the 9" one. If you don't mind running a little taller rubber all around, you could go with a 225/45/18 and a 255/40/18 on the rear, which are both listed as 26" tall http://www.tirerack.com/tires/tires....el=Exclaim+UHP
those tires are too tall IMO
jdmboy is offline   Reply With Quote
Old 12-05-2010, 04:07 PM   #24
Uncle Scotty
Scooby Guru
 
Member#: 16200
Join Date: Mar 2002
Vehicle:
OK Houston
we have an Uncle

Default

Quote:
Originally Posted by jdmboy View Post
those tires are too tall IMO
no doubt
Uncle Scotty is offline   Reply With Quote
Old 12-05-2010, 04:53 PM   #25
DrDanimalSize
Scooby Specialist
 
Member#: 254097
Join Date: Aug 2010
Location: Montreal, QC, Canada
Vehicle:
2010 WRX Hatch

Default

1" taller than stock. They'll fit. 4% error on the speedo isn't so bad
DrDanimalSize 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
Need help with 17in wheels-max tire size solort Tire & Wheel 5 12-02-2010 03:53 PM
Same boring tire size question sb04wrx Tire & Wheel 7 01-11-2010 02:32 PM
16" Wheel/Tire Size Question capt.sensible Tire & Wheel 13 01-17-2005 09:27 AM
Specific wheel/tire sizing question JoShYo Forester Forum 2 11-13-2003 10:56 AM
Wheel/tire size question Rock_Strongo Tire & Wheel 0 09-28-2003 05:16 PM


All times are GMT -4. The time now is 10:33 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.