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Desert Fox
Veteran
Date registered: May 2013
Location: Tucson, Arizona
Vehicle(s): G500 2002
Posts: 191
| Replacing Tires in Sets?
I have one tire that needs to be replaced. I read in the manual that "front and rear tires should be replaced in sets." Does this mean it is okay to put 2 new tires (i.e. 2 new rear tires) on the vehicle instead of all 4? I've read various opinions on the web about the importance of the tread measurement and circumferences of all 4 tires needing to be very close or the vehicle can be damaged. Thank you for your thoughts. |
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Desert Fox
Veteran
Date registered: May 2013
Location: Tucson, Arizona
Vehicle(s): G500 2002
Posts: 191
| Re: Replacing Tires in Sets?
Just called the dealer service department and the rep said a set of 2 would be okay. I'd still appreciate any thoughts or experiences with this. Thank you. |
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Boy G
Expert
Date registered: Feb 2007
Location: Bushveld, South Africa
Vehicle(s): Diesel G's: 617A and 602
Posts: 1683
| Re: Replacing Tires in Sets?
I believe as folows. A diff will always send power to the path of least effort. You can have one big wheel on an axle and one small one and it will work. Do not lock the diff.
You can put one big wheel on the front axle and one small wheel on the rear axle. On a 460. Do not engage 4x4 or on a 463 do not lock centre diff and it will work. Putting a slightly different sized tyre on will work but if you need 4x4 you can cause damage esp on a hard surface.
An example which I did not personally witness but was told first hand.
A friend of mine based in the Congo would from time to time drive to Uganda in an old 300 GD 460, and there was one place which had deep thick mud and was the only place where he really needed 4x4. He understood his predicament well and used it very carefully because he had two different diff ratios between front and rear. For some two years he had a 240 GD front diff. In mud it was like propellors in water. It worked. It would not on sand or asphalt.
I am sure your question is how much difference is ok. I am sorry i dont know! But I would imagine very little.
Edited by Boy G 9/6/2014 1:29 PM
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| Re: Replacing Tires in Sets?
Desert Fox - 9/6/2014 1:10 PM
Just called the dealer service department and the rep said a set of 2 would be okay. I'd still appreciate any thoughts or experiences with this. Thank you.
I would say that it's probably also dependent on how worn the pair on the other axle are. If they are almost done, I would change all four. |
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Desert Fox
Veteran
Date registered: May 2013
Location: Tucson, Arizona
Vehicle(s): G500 2002
Posts: 191
| RE: Replacing Tires in Sets?
Thank you. I have 7/32nd on the tires that would be up front and the new(ish) ones in the back would be 10/32. Does that help the conversation? |
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kerry460
Elite Veteran
Date registered: Apr 2006
Location: tasmania australia
Vehicle(s): 1984 300GD LWB WAGEN
Posts: 611
| RE: Replacing Tires in Sets?
G,,day . different brand tyres will vary in diameter , and a small difference in diameter will make a considerable difference in circumference .
there can also be a difference if the load capacity is different or the tyres were made in different factories , even if the same brand and size.
and it is circumference , the distance a tyre travels in one rotation will determine how much extra work the diff needs to do to compensate .
how much difference is acceptable ????? a small difference is acceptable ,
on a 460 , I think the small difference you mention will be acceptable.
but if you want to . when fitted to the vehicle do a rolling circumference test to see how much difference there actually is .
put a chalk mark dead centre at bottom of tyre and on the ground , roll the vehicle 1 rotation of tyre and measure the distance on the ground .
this will give you an accurate idea of the true difference travelled between the new and old tyres .
kerry |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: Replacing Tires in Sets?
here is the thing:
differentials are designed to sometimes work (allow different rotation on both sides)
they do not like to constantly work (like me)
tires left to right, as well as front to rear, should have about the same size
about the same size is good enough
if sizes left to right and front to rear are clearly off the diffs have to work
meaning the spiders will constantly rotate
the resulting heat buildup will severely damage the diffs
those diffs will cost you more than new tires
I remember a story from the G test department where a 460 was intentionally driven for hours in a big circle
so the diffs were forced to constantly work (spiders, remember?)
due to the heat buildup both diffs were completely destroyed
but don't panic
if you are on an expedition and can't find the right replacement tire in Peru, you can still drive (carefully though) for days or weeks with 2 odd tires.
check your diff temp on occasion and take it easy
however, 2 odd tires on one axle at 70mph for 6 hours from Sacramento to LA and your diff is history |
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Brent
Expert
Date registered: Apr 2006
Location: SW Colorado USA
Vehicle(s): '13 Wolfsburg GTI
Posts: 1754
| RE: Replacing Tires in Sets?
I would lean towards replacing all four and not taking a chance, especially if the truck is mostly a pavement rig. The 3/32 difference in tread depth is probably inconsequential if the tires are otherwise identical. Still, with a front to rear difference, it is the differential in the t-case that could be damaged. You are probably fine but, tires are cheap by comparison. I would get 4 and craiglist the remaining tires from the old set for whatever cash they would bring. |
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Gilamonster
Veteran
Date registered: Sep 2013
Location: New Mexico
Vehicle(s): G #1 (mix of a 460, 461 & 463), #2 is a 2000 G500
Posts: 151
| RE: Replacing Tires in Sets?
I've been wondering the same thing myself regarding the use of a spare tire while out on an extended trip. I see this as a good argument to regularly rotate tires to balance the wear and tear; including the spare(s). |
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| RE: Replacing Tires in Sets?
Gilamonster - 9/8/2014 12:12 AM
I've been wondering the same thing myself regarding the use of a spare tire while out on an extended trip. I see this as a good argument to regularly rotate tires to balance the wear and tear; including the spare(s).
Most definitely! My spare is always included in a 5 tire cross rotation (SP->RF->RR->LF->LR->SP) every 5k miles. |
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Gilamonster
Veteran
Date registered: Sep 2013
Location: New Mexico
Vehicle(s): G #1 (mix of a 460, 461 & 463), #2 is a 2000 G500
Posts: 151
| RE: Replacing Tires in Sets?
Thanks Dutch for the rotation order and frequency info.
I'll use that with the G500 which has one spare. My camper has two spares so that makes it easier. |
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thebigblue
Date registered: Jan 2012
Location:
Vehicle(s):
| RE: Replacing Tires in Sets?
4x4abc - 9/7/2014 7:52 AM
here is the thing:
differentials are designed to sometimes work (allow different rotation on both sides)
they do not like to constantly work (like me)
tires left to right, as well as front to rear, should have about the same size
about the same size is good enough
if sizes left to right and front to rear are clearly off the diffs have to work
meaning the spiders will constantly rotate
the resulting heat buildup will severely damage the diffs
those diffs will cost you more than new tires
I remember a story from the G test department where a 460 was intentionally driven for hours in a big circle
so the diffs were forced to constantly work (spiders, remember?)
due to the heat buildup both diffs were completely destroyed
but don't panic
if you are on an expedition and can't find the right replacement tire in Peru, you can still drive (carefully though) for days or weeks with 2 odd tires.
check your diff temp on occasion and take it easy
however, 2 odd tires on one axle at 70mph for 6 hours from Sacramento to LA and your diff is history
So after a long days drive in the french apls my diffs would be smoked - really ? |
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4x4abc
Date registered: Apr 2006
Location: La Paz, Baja California, Mexico
Vehicle(s): 02 G500
| RE: Replacing Tires in Sets?
you'll be fine in the alps - it'll be a constant switch of direction combined with long straights
but your diffs will get warm
the harder you are on the throttle, the hotter they get |
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DUTCH
Administrator Doppelgänger
Date registered: Apr 2006
Location: US, GA, Atlanta
Vehicle(s): 2015 Audi Q7 3.0 TDI,2018 Sprinter
Posts: 9963
| RE: Replacing Tires in Sets?
Gilamonster - 9/9/2014 1:03 AM
Thanks Dutch for the rotation order and frequency info.
Just keep in mind that you can't do a cross rotation pattern, if the tires are unidirectional. |
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