Rotate in the spare after 20k?

[LaxCummins]

I've got a tire (BFG Rugged Trail) in my set of 4 currently on the truck that is showing sidewall cracking - semicircular cracks in the outermost layer of the sidewall, between the lettering and the sidewall tread.



I've got 20k on the 4 tires. I tried to get the dealer to rotate in the spare - I haul a 4 horse trailer on my QC SB (gooseneck) and don't want to run the risk of blowing that tire out. The dealer wouldn't do it - said that the diameter difference would be too significant for the 4WD.



So, knowing what we do about the 4WD system (and the fact that I'm only using it in low traction situations) - would you rotate the brand new spare tire in (and remount onto the chrome wheel)? I'm certainly not flipping for a new set, which is what the dumb@ss dealer recommended.



Thanks for your opinions,



PC

 

[keimmmo]

I rotated in the spare on the 01. 5 every 2-3 rotations. I replaced the original Michelin tires at just over 100,000 miles and they still had tread. I was getting worried about the overall condition... especially cracking. I do not see it as a major problem to put your new spare on with the worn tires.



Steve

 

[lschultz]

All the trucks I have owned I have never rotated the spare in on them but its your truck so do what you want.

 

[rbattelle]

I doubt the diameter difference would matter very much, but there is a way to have peace of mind. Just develop a rotation pattern that will keep the spare tire on the front axle through 2 rotation periods. Rotating every 6000 miles, then, would run 12k miles into the spare tire before it goes on the back (which has the LSD). The fronts wear faster than the rears (unless you're always doing burnouts).



I think working the spare into the rotation is an outstanding idea.



-Ryan

 

[Eric_77]

I had to put the spare on my jeep (I know different animal but I think it applies), and had to use 4wd. Well it started "skidding" the spare as it was turning slower than it needed and then it was a major PITA to get the 4wd to unlock as getting the drivetrain to have slack in it was almost non-existant for the unlock event to happen.



In 2wd it was fine.

 

[LaxCummins]

Did it

Well, I rotated it into the rear. My mechanic (NOT the dealer) thought that it might cause slight pull if it went in the front. So far so good - no noticeable behavior. I figure that since it takes an act of god to get the limited slip to engage that I should remain trouble free. Since the center diff (tcase) is open, I should be fine.



Thanks,

LAXCummins

 

[DJennings]

Do you have a limited slip/trac-loc? If you do, say goodbye... two wheels turning at different rates (because of diameter difference from a new tire/used tire) will probably burn it up.

 

[LaxCummins]

Trac-loc? No. Factory LSD? Yes.



Need some facts to back that second part up.



What are acceptable tolerances? Since we know that all tires vary slightly from the factory and they'll vary when you rotate from front to rear due to differences in wear from front to rear. Why do trucks come with spares then? If you get flat on the road according to the dealer's thinking, you have to flat trailer the thing and replace the whole set even though you've only got 20k on them? Just trying to get the facts here.

 

[rbattelle]

I wouldn't worry about it. I doubt it will kill the limited slip. BTW, there are 2 limited slip systems in use: 10. 5 axles use a "trac-rite" and 11. 5 axles use a "trac-loc" (or is it vice-versa?).



-Ryan

 

[LaxCummins]

Must be vice-versa because the AAM web site only discusses the Trac-Rite - for the range of their diffs.



http://www.aam.com/technology/tech_prod_dl_diff.html



That's why I put a no for the trac-loc... Or Trak-Lok as the Dana registered trademark is known... No Dana axles under my truck!



Back to the original issue!

 

[rbattelle]

I'm sorry, I mis-quoted earlier. Service manual says both the 10. 5" and the 11. 5" axle use a "trac-rite" limited slip unit. Sorry!



-Ryan

 

[DJennings]

Burn might have been a little harsh. Prematurely wear out would have been better. I think you need to look at the difference in tire circumference and decide based on that.



Your Trac Rite will be working 100% of the time to overcome a difference in tire size (however minimal). The greater the difference, the more its working, the earlier it will wear out, and the more heat it will create.



You're right about wear difference from front to rear, but I think you rotate them often to minimize this. Most tires will run around 50k miles, so you are putting a new tire in there after the other four have potentially 40% wear (Again, I think you should do some measurements to decide if it is tolerable).



Sorry I upset you, but I don't think you should rotate a new tire into 4 tires that are "potentially" almost half worn. The front/rear issue is only an issue on dry pavement in 4 wheel drive. Off road or in low traction situations, you'd never notice it.



It's your truck, so ultimately its up to you.

 

[JVolpe]

If you dont rotate in the spare, lets say 24000 miles down the road, when you have a flat/problem and have to put the spare on you wind up with the problem. By then the tires may have a real difference in circumference. So what is the answer. It looks like rotating in the spare from the beginning is the right thing to do, but unless you have 5 identical rims it is a real pain. I am not even sure I remember the correct sequence for rotating 5 radial belted tires.

 

[rbattelle]

I rotate like this:



Spare -> RF

RF -> LR

LR -> LF

LF -> RR

RR -> Spare



I began rotating my spare tire in at 12000 miles (second rotation, as I rotate every 6k). I love rotating the spare in. Makes things very convenient.



-Ryan

 

[klenger]

I like the idea of doing this, but would want a matching wheel to do it. How hard would it be to find a "take off" chrome steel wheel?



By putting the spare on the front 1st (assuming some miles on the truck), you don't have to worry about different size tires and the LSD on the rear. By the next rotatoin, the spare would have a few miles on it and may not matter as much.

 

[rbattelle]

I like the idea of doing this, but would want a matching wheel to do it. How hard would it be to find a "take off" chrome steel wheel?

Not hard. Try Ebay and try posting a new thread in the 3rd gen forums asking if anyone has any take-offs for sale. That's how I got mine!



-Ryan

 

[klenger]

If someone had a set, would they want to sell just 1 and break up the set? I'll have to consider this.

 

[Tim]

I think you guys are overstating the circumference thing. Two tires can be the same brand and size, and come out of the same mold, and still not be the exact same size.



Your truck is moving and turning all the time. The rear axleshafts probably nearly never spin the same speed. To worry about 1/4" of circumference is unnecessary in my opinion.