Full-size spare tire: largest / biggest size (diameter) that fits is 285/70/R17 (33's)

[Gastan]

I've been lurking often on Tacoma4g to pick up knowledge and answers that should apply to the 4Runner also. Here's helpful info about the largest spare tire (by diameter) that fits in the spare wheel / tire location in underbody.

285/70/R17 is the biggest spare tire size possible. This is essentially a 33" tire (32.71" to be exact).

From the owner:

I installed a full-size 285/70 r17 under the bed. It fits. The tires are wider but honestly I think it kinda looks badass with the bigger spare. It looks like it might impact my departure angle, but the tires are built to support the weight of the truck and they might even protect my trailer hitch a bit. Definitely it will get me home if I ever need it. Stock suspension and wheels, no mods to exhaust. Nitto Ridge Grapplers.​

And here's another full size spare tire used that's not as wide as the one above.

255/75/R17 (32" spare tire)

From the owner (of a TRD Off-Road):

I did a tire swap at dealership at time of purchase. They gave me $500 for OEM tires.​

​

I had them install Nokian Outpost nAT 255 75 R17 onto OEM wheels AND the spare wheel. Convenience spare was 245 75 so getting the new tire to fit on spare wheel wasn't an issue.​

​

This tire size is a tad larger diameter than factory tire about 1/2"..also known as a true 32" whereas factory tires 265 70 17 measures closer to 31.5".​

​

Image of spare. Sits close to tow hitch receiver level and well above rear diff.​

​

Is ground clearance affected..i think a little yes but it sure is nice to have a proper full size spare that I can trust vs that convenience spare crapola.​

 

[Gastan]

Added another spare tire size -- 255/75/R17 (32") to first post above.

 

[DustyLens]

I'd be concerned about departure angle as well. And I don't think the spare should be visible under there.
Having said that... I was behind a 4Runner the other day which had its spare tire mounted to an after-market swing-out system -- bumper-mounted I expect (after-marker bumper as well?). Which makes a lot of sense if you ever have a flat out in the wilds and can't access the underthing.

 

[TRD_GUY]

I've been lurking often on Tacoma4g to pick up knowledge and answers that should apply to the 4Runner also. Here's helpful info about the largest spare tire that fits in the spare wheel / tire location in underbody.

285/70/R17 is the biggest spare tire size possible. This is essentially a 33" tire (32.71" to be exact).

From the owner:

I installed a full-size 285/70 r17 under the bed. It fits. The tires are wider but honestly I think it kinda looks badass with the bigger spare. It looks like it might impact my departure angle, but the tires are built to support the weight of the truck and they might even protect my trailer hitch a bit. Definitely it will get me home if I ever need it. Stock suspension and wheels, no mods to exhaust. Nitto Ridge Grapplers.​

And here's another full size spare tire used that's not as wide as the one above.

255/75/R17 (32" spare tire)

From the owner (of a TRD Off-Road):

I did a tire swap at dealership at time of purchase. They gave me $500 for OEM tires.​

​

I had them install Nokian Outpost nAT 255 75 R17 onto OEM wheels AND the spare wheel. Convenience spare was 245 75 so getting the new tire to fit on spare wheel wasn't an issue.​

​

This tire size is a tad larger diameter than factory tire about 1/2"..also known as a true 32" whereas factory tires 265 70 17 measures closer to 31.5".​

​

Image of spare. Sits close to tow hitch receiver level and well above rear diff.​

​

Is ground clearance affected..i think a little yes but it sure is nice to have a proper full size spare that I can trust vs that convenience spare crapola.​

I would never run a spare of that size as it simply doesn't fit underneath based on your photos. I would be mounting that on the rear door of a 4-runner unfortunately. Toyota didn't do well with their measurements....also on the inside of the new 4-Runners with the dip in the floor that ensures the rear (inside) isn't flat. Really disappointing engineering.

 

[TRD_GUY]

I'd be concerned about departure angle as well. And I don't think the spare should be visible under there.
Having said that... I was behind a 4Runner the other day which had its spare tire mounted to an after-market swing-out system -- bumper-mounted I expect (after-marker bumper as well?). Which makes a lot of sense if you ever have a flat out in the wilds and can't access the underthing.

I honestly feel this is gonna be the only real option unfortunately for anyone running non-OEM tires (which is a lot of 4Runner owners in the West.

 

[TRD_GUY]

285/70/R17 is the biggest spare tire size possible. This is essentially a 33" tire (32.71" to be exact).
And here's another full size spare tire used that's not as wide as the one above.

255/75/R17 (32" spare tire)

From the owner (of a TRD Off-Road):

I did a tire swap at dealership at time of purchase. They gave me $500 for OEM tires.​

​

I had them install Nokian Outpost nAT 255 75 R17 onto OEM wheels AND the spare wheel. Convenience spare was 245 75 so getting the new tire to fit on spare wheel wasn't an issue.​

​

This tire size is a tad larger diameter than factory tire about 1/2"..also known as a true 32" whereas factory tires 265 70 17 measures closer to 31.5".​

​

Image of spare. Sits close to tow hitch receiver level and well above rear diff.​

​

Is ground clearance affected..i think a little yes but it sure is nice to have a proper full size spare that I can trust vs that convenience spare crapola.​

How does this help when your truck is running the larger tires? Gonna feel pretty weird running an odd size tire for one of your wheels when you need to swap them when you get a flat.

 

[TRD_GUY]

Of course this is info for someone who's deciding to upgrade to bigger tires sizes all around, and wants to know what's the largest matching spare tire size they can fit in the underbody spare tire area.

But the wheel showing in the pic underneath is too big to carry there. It's simply too large and hangs too low. So this size clearly won't work. I wouldn't drive around with that huge tires hanging so low. Are Toyota engineers challenged with measuring things out? Serious question as this is a big oversight, IMO.

S

 

[Gastan]

This info is helpful regarding what's the maximum tire diameter that fits in the spare tire space in the undercarriage. I updated the title to clarify that.

What an acceptable width is (how much lower the spare tire hangs down compared to stock) is going to a subjective decision by each individual owner. This particular Tacoma owner (including others) is ok with it.

 

[TRD_GUY]

This info is helpful regarding what's the maximum tire diameter that fits in the spare tire space in the undercarriage. I updated the title to clarify that.

What an acceptable width is (how much lower the spare tire hangs down compared to stock) is going to a subjective decision by each individual owner. This particular Tacoma owner (including others) is ok with it.

Fair enough, but that's just flat out wrong and telling of Toyota's engineering efforts.