v8 Full Time 4WD & Spare Tire Size

[Rebar]

So I am looking at doing a lift and upgrading to a larger tire size...

I came across an old post where the below comment was posted:

"Don't forget the spare tire too- need to run the same size with the full time 4x4"

I have to admit I made the prior assumption that I could just use one of my stock wheels/tires as the spare, but this comment threw me off.

Will it cause damage to the truck if one of the tires is smaller?

Thoughts?

 

[jdkilroy]

I think you can use a smaller spare to get you home without any problem but you wouldn't want to run that way for long. The traction systems are based upon differentials in wheel speeds but depending on the difference between your spare circumference and that of your other three tires, I doubt it would be enough to cause a problem. Handling would not be optimal with a different sized tire on one wheel, so again, you would want to square things away as soon as you could.

 

[Acidmeld]

As a temporary spare the stock size will be fine. The diffs are open front and rear so the tires will spin freely. Recently I had to use my stock 265/65/17 spare with the 265/70/17 duratracs. It was just fine, even the Trac didn't act up.

 

[Rebar]

I really appreciate the responses and it makes more sense to me. (Sinking feeling in stomach is gone now.)

I would only ever run the spare long enough to get home or to the shop. (Would expect handling to be at least mildly annoying and the truck to pull to one side.)

Thanks again!

 

[stanleybb50]

See if the tire shop has a used 265-70-17 to use as your spare. Worth trying.

 

[Rebar]

See if the tire shop has a used 265-70-17 to use as your spare. Worth trying.

Thank you for the suggestion. I was thinking about doing something like this, but need to figure out what the largest tire is that I can jam on an 18" (limited) rim and still fit under the truck. I am of the impression that if I get too large a tire, it won't fit in the space provided for the spare.

 

[jediwebdude]

When I upsized to 275/70 17, I purchased a 5th tire in that size. Discount Tire gave me nice trade-in value on the stock spare tire.

Only problem was cramming it into the spare storage area. Had to deflate, cram it in, and then inflate since it has TPMS.

 

[message]

I run 265/70/17 throughout and do a five tire rotation as recommended per the manual.

 

[rebelbowtie]

Toyota uses the same Torsen T3 center differential that Audi uses in all its Quattro cars and per my owners manual for my Audi it is safe to run a 3% difference in rolling diameter on tires from front to back.

 

[kai920]

Toyota uses the same Torsen T3 center differential that Audi uses in all its Quattro cars and per my owners manual for my Audi it is safe to run a 3% difference in rolling diameter on tires from front to back.

Even 265/70-17 to 265/65-17 has greater than 3% difference in rolling diameter(barely)

Question is if you only do one wheel, does it effect front to back, or only side to side. Do you have to do swap both tires on front or back before it will effect the center diff or is one tire enough to effect the center diff?

 

[jimithing]

When I upsized to 275/70 17, I purchased a 5th tire in that size. Discount Tire gave me nice trade-in value on the stock spare tire.

Only problem was cramming it into the spare storage area. Had to deflate, cram it in, and then inflate since it has TPMS.

Uh, so do you carry a compressor in your car in case you ever need to use that spare? I'm assuming you'll have to deflate it to get it back out.

 

[rebelbowtie]

Even 265/70-17 to 265/65-17 has greater than 3% difference in rolling diameter(barely)

Question is if you only do one wheel, does it effect front to back, or only side to side. Do you have to do swap both tires on front or back before it will effect the center diff or is one tire enough to effect the center diff?

The front and rear axles have open differentials do it wouldn't effect side to side