Hey all,
i am going to get the pirelli atr tires soon. 275/55/20.

would there be any bad mojo from using the 275/60/20 spare when needed, or should i just get a 5th pirelli for a spare?

the smaller tires rotate about 21 times more per mile then the stock tires. i would think this would cause issues, but am not sure.

Thanks!

 

i dont think there would be any issues from using a smaller tire but just remember it isnt meant to be driven on forever. if you look at most cars, the spares they come with are way smaller than the regular size tires.

 

Assume your rear tire goes flat and you need to use your spare (which is smaller than the other four). The process you would have to use would be to remove a front tire and place it on the rear as the rear wheels are your drive wheels. Then you have to install the spare on the front. And this is only to prevent any serious damage to the rear end. Now imagine you're in the middle of nowhere, at night, with snow on the ground. Personally, I'd just buy one more tire that fits all the way around. My $0.02.

 

Agreed. Especially with a 4x4 and/or a LSD rear end. You don't want to run two different tire sizes for a long period. A short trip fine, but what if you have to drive 50+ miles?

Just buy 5 and murphy's law says you will never have a flat

 

Murphy and i are old drinkin buddies, and i am not a fan of flats "in the middle of nowhere, at night." especially "with snow on the ground". i'll just get the five.
perhaps i can get $20 for the unused goodyear.

Many Thanks to all.

 

if you wanna sell it ill buy it from you..ill give you more than $20.

 

I run the 275/55/R20 Nittos on my truck and kept the factory spare. I works fine and it doesn't damage anything. I've had to use it quite a few times times, and at one point had to use it for over a week due to my tire being a special order tire and they had to ship it in. I wouldn't worry about it too much unless you have the extra money that you want to spend on the spare.

Also, just an FYI but you wouldn't want your spare on your front you want to put your spare on the rear tire and move the rear to the front if you have to if the spare is larger than your tires cause of streering issues..

 

So long as you don't have the LSD OR use it in 4WD (if you have it) you'll be fine. The different drive axle speeds will cause the LSD to engage constantly going down the road and will destroy it and will cause axle bind in 4WD.

 

I cant really see it doing that though. The size difference from the stock 275/60's to the 275/55's is mabe a 1/2" - 3/4" difference in overall diameter. I could see it being a problem if he was going from the stockers to some huge mud grapplers or off road tires where there was quite a bit of a size difference between the two

 

True, I didn't realize the tires were that close in size. It all depends on the revolutions per mile and how big of a difference it is from side to side. Regardless, I'd rather buy a new tire or take the time to swap it to the front than to run the chance of the rear end going kablooey!

It is funny that this came up. I was at a Ford dealership a couple of years ago and overheard a customer that had his rear end tank from running a different size tire on each side. It seems as though his spare tire was swapped out for something smaller at either the factory or dealer. He had the factory 20's and his spare was a 17 with a different size tire. When he got a flat, he put the spare on. He continued home until his LSD grenaded. I'm sure that there was a bigger difference than 1/2" or so, but still interesting enough!