Had to replace my two worn out front tires on the Blazer. Was told by the tire shop that I should replace three. Because one in the back was worn down more than the other. But I just had them replace the two on the front. How important is it to have the same circumference of the tires on a 4WD?
Tire Circumference With 4 Wheel Drive..
- Thread starter Warstud
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Very if you use 4wd. I would replace all 4 if you use 4wd.
Originally Posted By: Warstud
Don't understand why all 4 have to be within 2/32. Same axle yes.
Try running tires not really close in circumference on a Subaru and you'll understand.
It wouldn't matter on a part-time systen.
It does matter with full-time AWD.
Don't understand why all 4 have to be within 2/32. Same axle yes.
Try running tires not really close in circumference on a Subaru and you'll understand.
It wouldn't matter on a part-time systen.
It does matter with full-time AWD.
Actually it depends on what type of awd system you have. Is there a differential in the xfer case? Is it clutched or electronically monitored or controlled?
If you only use 4wd in slick conditions then don't worry too much about small differences. We have one almost new tire on the back of the Tracker, others down 1/4" and I think it actually binds less than ever on the highway.
Most manufactures of full-time 4WD like Subaru, Audi and ?states that all 4 tires must not exceed 1/4 inch in CIRCUMFERENCE. For my 225/60/17 tires the 1/4 inch CIR= ~ 2/32 in tread depth difference.
Since you have a differential in your transfer case that allows the system to operate in an auto setting, the tire shop was right. The tolerance in those systems is low for differing tire diameter, even caused by wear. The system can effectively wear itself out because it senses one wheel always going a slightly different speed than the others.
On a purely part time system like on my F 150, it doesn't matter since all the slipping is supposed to occur at the tire/driving surface interface, which is why you are only supposed to use it in appropriate conditions.
On a purely part time system like on my F 150, it doesn't matter since all the slipping is supposed to occur at the tire/driving surface interface, which is why you are only supposed to use it in appropriate conditions.
Originally Posted By: Eddie
Most manufactures of full-time 4WD like Subaru, Audi and ?states that all 4 tires must not exceed 1/4 inch in CIRCUMFERENCE. For my 225/60/17 tires the 1/4 inch CIR= ~ 2/32 in tread depth difference.
Same here with my 2013 Subaru Outback.
Most manufactures of full-time 4WD like Subaru, Audi and ?states that all 4 tires must not exceed 1/4 inch in CIRCUMFERENCE. For my 225/60/17 tires the 1/4 inch CIR= ~ 2/32 in tread depth difference.
Same here with my 2013 Subaru Outback.
My father-in-law couldn't be "bothered" with the hassle of rotating his tires n his '04 CRV. Front tires went to wear bars, rears at least 5-6/32". Ended up he needed all four tires and just over $1000 to fix the center differential. He totally burnt the fluid and whatever clutches are in it as the "real time 4WD" was trying "real hard" to get all four spinning teh same on dry pavement.
Do all four tires on a 4WD/AWD need to be identical? Yes and no.
On a 1972 Chevy, Ford, Dodge with an NP203 full time 4WD transfer case, no. It has a center diff, front diff, and rear diff, with no clutches or monitoring electronics. All four tires can rotate independently of each other.
On a 1972 Chevy, Ford , Dodge with a n NP205 art time transfer case with a 2WD setting, NO.
A vehicle of this construction should never be placed into 4WD in a high traction situation, so then the diameters only matter when in the slick stuff, and then it really doesn't matter anyway.
On a modern AWD, or 4WD with "auto" setting yes, as these are active when driving even on pavement, and a larger diameter tire will be seen as a slipping tire.
On a 1972 Chevy, Ford, Dodge with an NP203 full time 4WD transfer case, no. It has a center diff, front diff, and rear diff, with no clutches or monitoring electronics. All four tires can rotate independently of each other.
On a 1972 Chevy, Ford , Dodge with a n NP205 art time transfer case with a 2WD setting, NO.
A vehicle of this construction should never be placed into 4WD in a high traction situation, so then the diameters only matter when in the slick stuff, and then it really doesn't matter anyway.
On a modern AWD, or 4WD with "auto" setting yes, as these are active when driving even on pavement, and a larger diameter tire will be seen as a slipping tire.
What surprises me is the amount of AWD vehicles that come with donut spares ...
Why does it have a donut spare if you are not supposed to use a different size spare tire?
Why does it have a donut spare if you are not supposed to use a different size spare tire?
Originally Posted By: Miller88
What surprises me is the amount of AWD vehicles that come with donut spares ...
Why does it have a donut spare if you are not supposed to use a different size spare tire?
A donut spare is designed to just get you home, or to the nearest repair shop, so you're not stranded on the side of the road. You're not supposed to drive on it any more than that, even if it's a 2wd vehicle. Driving at a low speed for just a few miles two different sized tires won't hurt anything.
What surprises me is the amount of AWD vehicles that come with donut spares ...
Why does it have a donut spare if you are not supposed to use a different size spare tire?
A donut spare is designed to just get you home, or to the nearest repair shop, so you're not stranded on the side of the road. You're not supposed to drive on it any more than that, even if it's a 2wd vehicle. Driving at a low speed for just a few miles two different sized tires won't hurt anything.
My thoughts exactly - I'm going to speculate that the owners manual on those with donut spares are full of maximum speed warnings and maximum distance warnings or admonishments to get to a service center as soon as possible.
Quote:
Why does it have a donut spare if you are not supposed to use a different size spare tire?
Cheaper for the auto maker to supply. Weighs less to carry around so less impact on C.A.F.E.
Why does it have a donut spare if you are not supposed to use a different size spare tire?
Cheaper for the auto maker to supply. Weighs less to carry around so less impact on C.A.F.E.
Originally Posted By: asand1
, and a larger diameter tire will be seen as a slipping tire.
The larger tire rotates SLOWER. Isn't one of (all of?) the other tires that will considered to be slipping?
, and a larger diameter tire will be seen as a slipping tire.
The larger tire rotates SLOWER. Isn't one of (all of?) the other tires that will considered to be slipping?
You are correct.
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