different size spare tire

Bill Gutman · July 28, 2020

.was under my 2018 truck today and noticed the spare is different size the truck came with the 20 in chrome wheels and the spare is 17 in.I called the dealer and asked if this was a mistake and they said no . I would have to buy a 20 in rim. I think this is BS. I think i will put the spare on the rear and let the limited slip eat the differential up as its under warranty. Anyone have the same problem?

LDM · July 28, 2020

26 minutes ago, Bill Gutman said:

.was under my 2018 truck today and noticed the spare is different size the truck came with the 20 in chrome wheels and the spare is 17 in.I called the dealer and asked if this was a mistake and they said no . I would have to buy a 20 in rim. I think this is BS. I think i will put the spare on the rear and let the limited slip eat the differential up as its under warranty. Anyone have the same problem?

Why do you care if the spare tire is not the same size? The purpose of a spare tire is to get you where you need to go if you get a flat, not to permanently replace a tire. Very few spare tires are full size tires, most are donuts that you are only suppose to use for 50 miles max. There is also limited space for most spare tires, which is why they are generally donuts or a smaller wheel size.

Also, if you think putting the spare on and running the tread off it to get it replaced under warranty will get you what you want, you are in for a surprise. It will not be covered under any warranty and you will be stuck buying a new tire.

newdude · July 28, 2020

40 minutes ago, Bill Gutman said:

.was under my 2018 truck today and noticed the spare is different size the truck came with the 20 in chrome wheels and the spare is 17 in.I called the dealer and asked if this was a mistake and they said no . I would have to buy a 20 in rim. I think this is BS. I think i will put the spare on the rear and let the limited slip eat the differential up as its under warranty. Anyone have the same problem?

No, its not BS Bill. They are all like this. The spare is a full size spare tire, and it is NORMAL for the spare to be the wrong size wheel.

The spare tire is a P265/70R17, which is 31.7" in diameter. The P275/55R20 that is on your truck is the same diameter, 31.7-31.9". Your differential won't "eat itself up", I promise. Unless you REALLY have to have a matching spare, there is NO NEED to run out and buy a match.

Edited July 28, 2020 by newdude

Salsa De Piña · July 28, 2020

A 31.7" tire at 60 MPH rotates at 636 RPM. A 31.9" tire would be 632 RPM. My understanding is the G80 locks up at a difference of 100 RPM. You're not going to do any damage with such a small difference in tire size.

rav3 · July 28, 2020

Ditto as above. Look at your RPO (RC4) or other literature. 17" spare is standard on my '17 LTZ too.

aseibel · July 28, 2020

I think he should buy a 20" chrome wheel and hang that under his truck. Then, next spring he can complain about how pitted it is.

Jglew82 · July 28, 2020

It’s normal. Go get a 20” wheel and tire if it helps you sleep at night.

djw88 · July 30, 2020

I bet you'd be real upset with what they give you in a car lol

its a spare, same tire diameter as the wheels on your truck and thats all that matters

14LTZ-1LZ · August 11, 2020

Hijacking thread,

Who has replaced their spare tire? Is it still safe to use? I just happened to take mine off to clean and air up. The Goodyear tire was made sometime in 2013.

Grumpy Bear · August 11, 2020

3 hours ago, 14LTZ-1LZ said:

Hijacking thread,

Who has replaced their spare tire? Is it still safe to use? I just happened to take mine off to clean and air up. The Goodyear tire was made sometime in 2013.

Is the rubber cracked? No? Does it hold air? Have you checked? Yes? All good for a spare.

rav3 · August 11, 2020

On 7/28/2020 at 1:27 PM, Bill Gutman said:

.was under my 2018 truck today and noticed the spare is different size the truck came with the 20 in chrome wheels and the spare is 17 in.I called the dealer and asked if this was a mistake and they said no . I would have to buy a 20 in rim. I think this is BS. I think i will put the spare on the rear and let the limited slip eat the differential up as its under warranty. Anyone have the same problem?

@ Bill.......I would pull it every year & clean it up. The dirt & salts will collect on the groove between the tire & wheel & will corrode the wheel to where it will leak air. My ole '96 did that. I was able to take it to a tire shop that removed the tire, cleaned the wheel & added a sealant to the rim to fix it. A little pre-emptive preventive care will get it to last longer.

14LTZ-1LZ · August 12, 2020

21 hours ago, Grumpy Bear said:

Is the rubber cracked? No? Does it hold air? Have you checked? Yes? All good for a spare.

Rubber still good no dry rot, yes. Checked it this morning.

Pearl2017 · August 13, 2020

get a plug n go kit and an air compressor and keep it in the back. If you get a flat throw a plug in and be on your way in 8 mins. You sound a bit OCD.