Author Topic: Wasted tires  (Read 635 times)

November 22, 2017, 11:08:04 PM
Reply #15

berndp

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And the moment you turn your steering wheel there is a difference between the left and right wheels as well.
I don't think JBH meant change in tire size, but rather rotational speed, which is what the diff reacts to. The diff couldn't be bothered about the tire size "per say", but only the rotational speed.

As we all (should) know, when turning, the outer wheel has to turn much faster (more), to keep up with the inner wheel, hence the need for someting to allow for this mis-match, aka the diff.
Subaru Forester 2005 2.5 Xsel
Always looking for a tar free "road"
Brackenfell, W'Cape

November 23, 2017, 05:27:45 AM
Reply #16

sav

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Yep that is true, there is a very old video on YouTube explaining it nicely.
We are talking center diff though.

EDIT:
Here is the video:
Quote
https://www.youtube.com/watch?v=yYAw79386WI
« Last Edit: November 23, 2017, 07:52:57 AM by sav »
2007 XT Premium Sportshift (Decat, VF48 @ 1.2 bar, STi TMIC, Chett tjooned, BBK, coilovers, etc etc eish!)

May the Forester be with you...

November 23, 2017, 07:50:32 AM
Reply #17

sav

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And some further reading:
https://www.lesschwab.com/learn/article/replace-all-4-tires-on-your-awd-vehicle


But hey, if you feel that you're too clever and know better it's fine, just remember that 4 tyres are cheaper than a transmission rebuild.
2007 XT Premium Sportshift (Decat, VF48 @ 1.2 bar, STi TMIC, Chett tjooned, BBK, coilovers, etc etc eish!)

May the Forester be with you...

November 23, 2017, 11:18:47 AM
Reply #18

jbh

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The moment you turn your steering wheel say left your car turns left. Your left wheels then follow a shorter "path" than the right side wheels and thus turn slower than the right side wheels. This thus do have an influence on your diffs. If it was a bakkie derived vehicle with a locked diff you will eventually damage your diffs on a tarred road. On gravel or sand the wheels scrub the difference off.
On our vehicles the diffs are not locked and can handle the turns on tar indefinitely. Subaru's should theoretically thus be able to handle a small difference between wheel circumference.
When my son bought his 2007 Forester it had different size tyres on the back against the front wheels. While he waited for the correct two tyres to be ordered he once felt the diffs after a few hundred kilometers on tar. It still was cool.
jbh
Southernmost point of Africa
Ex:2003 Forester XSel Dual Range
Now: 2009 XS Dual Range. LSS sump guard.
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November 23, 2017, 11:45:43 AM
Reply #19

jbh

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jbh
Southernmost point of Africa
Ex:2003 Forester XSel Dual Range
Now: 2009 XS Dual Range. LSS sump guard.
Pedders Suspension. Aluminium heavy duty Radiator.

November 23, 2017, 12:00:44 PM
Reply #20

sav

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LOL. Just watch the 193x video, it explains it in a way that even those who think they know will understand.
2007 XT Premium Sportshift (Decat, VF48 @ 1.2 bar, STi TMIC, Chett tjooned, BBK, coilovers, etc etc eish!)

May the Forester be with you...

November 25, 2017, 11:45:40 AM
Reply #21

jbh

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Unfortunately some people do have a problem understanding and need pictures to explain something basic.  ;)
jbh
Southernmost point of Africa
Ex:2003 Forester XSel Dual Range
Now: 2009 XS Dual Range. LSS sump guard.
Pedders Suspension. Aluminium heavy duty Radiator.

November 25, 2017, 01:53:58 PM
Reply #22

sav

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Ok. Glad to see you have recovered from your fanny wobble the other day.
« Last Edit: November 25, 2017, 01:55:52 PM by sav »
2007 XT Premium Sportshift (Decat, VF48 @ 1.2 bar, STi TMIC, Chett tjooned, BBK, coilovers, etc etc eish!)

May the Forester be with you...