Looking for advice from tire specialists/mechanics on here:
I want to go up a size tire on my 4x4 truck but that will require going up in size on my spare as well. I am going to purchase a spare full size rim but only want to put the cheapest same size tire on it and not the tires which will be on the other 4 tires.
Will it matter if I have a different brand same size tire on spare rim if I only plan on using the spare as an emergency if needed and switching back to regular tires asap? I hope the question makes sense.

Thanks in advance

If "go up in size" means a bigger wheel (like from 17" to 18") ignore the following.

I'm no expert, but I would just keep the old spare as is and call it good. It's only to limp home or to the tire shop.

If I really wanted to get another spare, I would go all the way and get five matching (brand and size). That way, you can do a 5 tire rotation and get more miles out of the set. You're going to buy another wheel anyway, so all you would save is the difference between a cheap tire and your choice tire.

Match them all and do a 5 tire rotation.

That is the correct answer for a true 4x4.

You don’t want a few 1/32” difference to screw up your tranny one day.

-Rob

If you end up with the same overall circumference wheel/tire combination, then it shouldn't matter except for aesthetics.

I have yet to find a vehicle that could tell what brand tires were on it.

It might be possible to keep the current spare rim and just upsize the tire to get the same overall circumference. For example, a 275/70/R16 could be replaced with a 275/65/R17 giving you a 1" bigger wheel and pretty dang close to the same overall circumference.

If it is all confusing, go find a tire size calculator see if it helps. The mystery of the equation is that the "275" is your sidewall height. The "75" is your tire width in percent of sidewall. The "R17" is a 17" rim.

Pmetric vs LT is a whole different discussion. If you are swapping from Pmetric to LT, please be sure to inflate properly for the LT NOT the Pmetric or you run the chance of tire separation. Most buy LT tires and run them under inflated because a lot of tire people don't even bother to understand...

quote:

Originally posted by BurtonRW:
Match them all and do a 5 tire rotation.

That is the correct answer for a true 4x4.

You don’t want a few 1/32” difference to screw up your tranny one day.

-Rob

This.

quote:

Originally posted by BurtonRW:
Match them all and do a 5 tire rotation.

That is the correct answer for a true 4x4.

You don’t want a few 1/32” difference to screw up your tranny one day.

-Rob

This is the correct answer. I will add Transfer case, differentials.

Okay. Thanks for the advice as always.
I will find the exact same rim and get same exact tire for the proper rotation.

Who actually does a 5-tire rotation anymore?

I'd get the same size cheapo tire in circumference (wheel size is irrelevant), mount it an carry as spare expecting never to put it on the ground. After 7 or so years if you have the same truck still, replace the tire only.

The advice to have a different size tire for a limp home, assuming this is a different circumference, is awful. Bad for tranny and if its a newer truck with any stability control it will complete jack that up.

The plus/minus one calculator tool at Tire Rack will get you the answer to a same sized tire that will match the new ones and mount on your current smaller spare wheel.

For the record, it would have been the same exact size rim AND tire on spare, just a different brand

I'm driving an old Jeep. my spare tire is a full size but I have a cheapo Walmart tire on it to get me home. It's old so I'm not too worried about it.

I know my brother had a flat one day in his awd car. No spare and he got rid of his runflats. He called me to bring him all four of his snow tire/wheel setup and we swapped them all out on the road so he can get home. He didn't want to risk anything. Probably overkill but he babies his bimmers.

5 wheel rotation is the best way to do it.

No it won't hurt anything as long as it is the same diameter and you're only going to use it temporarily. Long term a different brand on 1 wheel might create some weird driving characteristics in inclement weather.

You gents talked me into doing it the right way. I just ordered a factory rim from Ebay for a great price.
Now, I just need to buy my wife flowers on the way to the tire shop!
Anyone try the new Cooper AT3 XLT tire yet?!

5 wheel rotation here. I see you went that route. Much better peace of mind, in my opinion.

Factory puts donut spares as original equip when they even give you a spare and they aren't the same diameter as the regular tires. Full size is better but for emegency use manufacturer sanctions smaller diameter spares or they wouldn't include them.

I'm approaching the point where I need to rotate the 4 new tires and buy the spare for rotation.

I have the K02 right now but will likely switch to the Falken next time. So, deciding whether to buy the K02 or the Falken for the spare.

If K02, I can use the spare in the rotation; if I get Falken, should I just keep as spare only or okay to use in the rotation? I'd get the same size as the K02.

quote:

Originally posted by doublesharp:
Factory puts donut spares as original equip when they even give you a spare and they aren't the same diameter as the regular tires. Full size is better but for emegency use manufacturer sanctions smaller diameter spares or they wouldn't include them.

Wow. I’ve never seen a donut as standard equipment on a 4WD vehicle.

And yes, I do a 5 tire rotation. And I do it myself because I don’t trust my dealer’s tire monkeys to get the pattern right.

-Rob

I may be talking out my ass but my 08 Honda Ridgeline AWD has a donut spare. I've never had it out of its storage compartment so it could be same diameter. That's the talking out my ass part because I'm not going to measure it but it is a skinny donut no doubt.

Wouldn't it be the same kind of potential transmission problem if you had unequal diameter tires, like with a mini donut, on the front axle of a front wheel drive?

quote:

Originally posted by whododat:
You gents talked me into doing it the right way. I just ordered a factory rim from Ebay for a great price.
Now, I just need to buy my wife flowers on the way to the tire shop!
Anyone try the new Cooper AT3 XLT tire yet?!

Check out the Falken Wildpeak AT3Ws. I just bought a set for a fair amount cheaper than the Coopers. I have read nothing but good things about them.
https://sigforum.com/eve/forums...0601935/m/7050070554

I just bumped up my tire size and need to figure out if a bigger tire will fit under there.
You just want them do be close in diameter.
I have 18” factory wheels but a 17” spare. I stepped up to 33.5” tires so need to get as close as I can for the 17” spare. I may end up grabbing an 18” steel wheel as they are cheap and get the same tire.
Eventually I’d like to do a spare tire carrier and I’ll get 5 aftermarket wheels.

I second the motion of purchasing the Falken Wildpeaks.