Oversized Spare Tire Question (1 Viewer)

[100d ua]

Not sure if this has been covered in this forum and I couldn't find a comparable thread to bump so I figured i'd ask here.

I'm mounting a tire carrier soon and currently I have the stock size OEM tire on my spare that is underneath the rig.

My question is;

Will I cause damage to the drivetrain running my spare even though I have AT tires? (incase of a tire blow out or trail damage)

I currently have 265/75's KO2's but want to upsize to either 275/70 or 285/75... With that being said, I would like to proactively upgrade my spare to the size I decide on... OR... is that a bad idea and should I stick with a 265/75? I have maybe 1 or 2 more seasons on the tires.

Thanks all.

 

[awesomeissquid]

I believe damage can be caused by running non-same sized tires. Regardless a 285/75R16 fits under the truck in the stock position.

 

[jLB]

1.) I believe that you’ve got the mechanical issue of working the differentials harder than normal.

2.) From your signature, it would appear that you have a 2000 model year. This would indicate that we’re talking about a VSC/A-TRAC equipped vehicle. I’d be more concerned about the “electronic nannies” trying to “fix” a perceived issue, and putting me in a ditch, than the mechanical issues.

In my opinion, a mismatched spare allows you to limp to the nearest tire store, but it is less than an ideal situation. In addition the cost savings of a mismatched spare seems pretty trivial compared to the potential costs incurred dealing with it in the middle of a trip.

And why do people insist on listing only partial tire sizes (Metric width and aspect ratio in this case)?

Technically wouldn’t the subject “Undersized spare” be more accurate?

 

[100d ua]

1.) I believe that you’ve got the mechanical issue of working the differentials harder than normal.

2.) From your signature, it would appear that you have a 2000 model year. This would indicate that we’re talking about a VSC/A-TRAC equipped vehicle. I’d be more concerned about the “electronic nannies” trying to “fix” a perceived issue, and putting me in a ditch, than the mechanical issues.

In my opinion, a mismatched spare allows you to limp to the nearest tire store, but it is less than an ideal situation. In addition the cost savings of a matched spare seems pretty trivial compared to the potential costs incurred dealing with it in the middle of a trip.

And why do people insist on listing only partial tire sizes (Metric width and aspect ratio in this case)?

Technically wouldn’t the subject “Undersized spare” be more accurate?

Two part question to satisfy my curiosity on the subject of running mis-matched tires.

Not sure what you mean in regards to "partial tire size". You were able to determine my LC was a 2000 with A-Trac, so you can probably conclude from the avatar picture i'm running a factory size LC rim

In either regard, I think you are both correct and the cost of a $200 spare is not worth the risk damaging electrical / mechanical components.

 

[jLB]

Not sure what you mean in regards to "partial tire size". You were able to determine my LC was a 2000 with A-Trac, so you can probably conclude from the avatar picture i'm running a factory size LC rim

A "265/75", "275/70", or "285/75", seems to be missing a critical element (rim diameter), which makes a bit of difference
I can guess that we're talking about 16" tires on a 2000 model year, but that may or may not be accurate.

 

[100d ua]

A "265/75", "275/70", or "285/75", seems to be missing a critical element (rim diameter), which makes a bit of difference
I can guess that we're talking about 16" tires on a 2000 model year, but that may or may not be accurate.

They're all 16x8 in that year range

 

[oakback]

You can extend the useful life of your tires by having a matching spare, and rotating it in with your other tires.

 

[waynegro]

So what are most of you guys doing for a spare that have upgraded tire size? I went to a 275/7018 vs the stock LX size that's 265/65/18 or something close to that. Tire shop says the bigger tire wont fit, or if they can cram it in its gonna hang really low.. would limping the truck to the tire shop really damage the diffs?

 

[GTV]

Tire shop says the bigger tire wont fit, or if they can cram it in its gonna hang really low.

Stock is 275/60R18
You have 275/70R18
They are the same 275mm width so it won’t hang lower. If you don’t have an OEM hitch it may not fit because of the diameter.

 

[2006 LX470]

I have a 295/75/16 spare in the stock location on my 06

 

[dpeshkin]

I have a 295/75/16 spare in the stock location on my 06

That's good to know. About to swap to 275/70 R18 on a stock LC.

 

[MountaineerLC]

I think having the correct size spare is important. You could probably limp along to a shop to get a tire, but I wouldn't want to drive too far that way. To save some $$ you could always try to find a used tire to mount up as a spare. 265/75 is a very common size.

 

[Live to Ski]

I believe damage can be caused by running non-same sized tires. Regardless a 285/75R16 fits under the truck in the stock position.

I second that opinion....that's what I run (including spare under rig).

 

[newbielx470]

If my installed tires' size is different from the spare, and if the spare has to be used after one blows out, would it be safe (for driving and for the truck mechanically) if I air down the larger ones a little bit to make all 4 to have the same outer diameter and drive a few hours slowly on pavement?