Is smaller spare ok on AWD?

all of witch was why i wasnt saying for a full time use. but i wasnt fully understanding the concern for the transfercase in using a smaller spare in temporary situation.

Reply to
Christopher Thompson
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I'm not sure if you have your math quite right but I did notice it with my PT 4WD with exactly the same tire combination.

Reply to
TBone

I was just out with the wife's Envoy and decided to pay attention to things. The knob is labeled 2HI, A4WD, 4HI, 4LO. So I guess I could do it in 2HI and be okay. I'd think that you would be able to in AWD if it didn't sense a slip, Also as Nosey pointed out the difference in size isn't that much. Were it me, I'd do it.

Roy

Reply to
Roy

It may have been tire pressure or even a tread pattern difference you felt. Even if you can notice the difference while driving it's not enough of a diameter change to cause any damage. If it's only going to be used as a spare it shouldn't matter much.

I didn't do any math. I cheated. I used this:

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I checked the website math against my own and it came out pretty close.

245/70/17 tire: 245/25.4*2*70/100+17=30.5039" diameter 30.5039*3.1415927=95.83" circumfrence. 63360/95.83=661.170 revs per mile

265/65/17:

265/25.4*2*65/100+17=30.5629" diameter 30.5629*3.1415927=96.016" circumfrence 63360/96.016=659.890 revs per mile

The difference is 1.28 tire revolutions per mile. IMHO, not enough to cause any damage.

Reply to
Nosey

Fair enough. I didn't feel it during normal driving but had one hell of a time getting it into and out of 4WD and could feel it pulling while in it. I thought that my transfer case was acting up until I remembered that my spare was still the old size and when I removed it the problem went away. I don't know where they are getting these numbers from but my 265's were at least an inch taller than my 245's, not .06 taller like the chart says but if the tires that Miles is switching to are also just about the same diameter as the old ones, then he should be fine.

Reply to
TBone

The 245 and 265 in the tire size is the section (tread) width in millimeters. It doesn't tell you the diameter.

Reply to
Nosey

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