Spare Tire Alternatives for a 285/70/r17

[bsquaredMTB]

I have a stock wheel, running a 285/70/r17 on my truck. I haven't upgraded the spare with the same tire as I have on my truck because I've read that a full size spare really impacts the rear clearance. I'm wondering if there's another size I should be looking at to use as a spare that is good enough but won't hang down so low. Does anyone have any suggestions? Pictures of alternate solutions would be great!

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[ejosesa]

Also interested in a solution with the same wheel/tire spec

 

[bsquaredMTB]

I did find this by googling but I don't know enough about trucks to know if that's ok to run, even if just for a few miles as a spare. This is the closest size in Nitto Terra Grappler G3 which is what I'm currently running.

Width Comparison

• 285/70R17 Width: 285 mm (approximately 11.2 inches)
• 235/80R17 Width: 235 mm (approximately 9.3 inches)
• Net Difference: 50 mm wider for the 285 specification (285 mm - 235 mm = 50 mm, or ~1.97 inches)

The diameter difference is .19685 inches from the 285/70/r17.

Interestingly enough, the width difference in width between stock (265/70/r17) and my current tires (285/70/r17) is only .78 of an inch. Maybe it's not as big of a difference as I though. If I go "skinny" with the 235/80/r17, it's only 1.18 inches thinner.

 

[Dutchman4]

I recently had a similar situation and I can suggest that you look at a 255/75/R17 for a spare.

A tire size comparison calculator wills show your tire as 32.7" height vs 32.06" for the spare with a difference of -0.64" smaller for the spare.
Tire Height: 32.7'' 32.06'' -0.64''

The revs/mile will be 12.31 more for the spare since it is smaller.
Rev. / Mile: 616.76 629.07 12.31

I don't think that small difference in size will cause any problems with the traction control system (A-Trac) but maybe some of the experts on this site will chime in to confirm. Just to be safe, you would probably not want to engage a locking differential when using this spare.

I chose a "Westlake SL369 All Terrain 255/75/R17" with a price of $140, for my spare since my four other tires are Toyo Open Country AT3 255/75/R17 at $315 per tire and I didn't want to spend that much for a spare.

From what I have read, you can fit up to a 33" tire in the spare tire location under the truck so this 32" high and 255 width tire fits under there nicely behind the hitch.

Regards, Ceril

 

[Dutchman4]

I did find this by googling but I don't know enough about trucks to know if that's ok to run, even if just for a few miles as a spare. This is the closest size in Nitto Terra Grappler G3 which is what I'm currently running.

Width Comparison

• 285/70R17 Width: 285 mm (approximately 11.2 inches)
• 235/80R17 Width: 235 mm (approximately 9.3 inches)
• Net Difference: 50 mm wider for the 285 specification (285 mm - 235 mm = 50 mm, or ~1.97 inches)

The diameter difference is .19685 inches from the 285/70/r17.

That might be a good option as well and they also come in low cost all terrain configuration.

 

[bsquaredMTB]

These are the current calculations. Diameter diff and Width diff are the differences to my current spare (245/75/r17). I'm thinking that 255/75/r17 seems reasonable with a possibility to 235/80/r17 as an alternative. It looks like the full size spare drops rear clearence by only 1.5 inches so that's not nothing. the 235/80/r17 option is actually thinner (-0.39 inches) than the current spare with the 255 only increasing the width by .39 inches.

I'd like for more knowledgeable people to comment because this is just the math. I'm sure there might be more real-world things we should consider

Type                        Diameter Diff               Width Diff
SPARE 245 75 17          0                            0
OEM 265 70 17            0.137795276                  0.787401575
235/80/r17               0.334645669                 -0.393700787
255/75/r17               0.590551181                  0.393700787
Current 285/70/r17       1.24015748                   1.57480315
235/85/r17               1.25984252                  -0.393700787

 

[TacoBirdinNW]

Will be interested to hear what you go with. My 285/70r17 spare barely fit, I'm talking by a hair, after my track bar relo kit. At the end of the thread you can see some photos of how low it hung too. If I ever got rid of the camper I'd want it back underneath v.s. the Trailswing so I would like to see how yours fits when you come up with one.

 

[Will721]

I can't say how much larger of a a tire you can fit in the stock location. Best bet is to crawl under there with a tape measure. Mine doesn't fit at 285/75r18 but I seen someone say they deflated theirs and got it up there.

However a bit of advice, use this site for finding like sizing for tire:
https://tiresize.com/calculator/

Also, a very important detail; tire manufacturers do NOT run true to size. There are wide variations between manufacturers and even models of tire in a given size. So, once you've decided on a size you want, you need to check the actual measurements of a given tire. I like to use @simpletire check true sizing. Once you've selected a tire on their site, scroll down to Specs and it will show true sizing. This is very important, because there can be a full inch or more difference in diameter between two of the same size tire.

 

[bsquaredMTB]

I can't say how much larger of a a tire you can fit in the stock location. Best bet is to crawl under there with a tape measure. Mine doesn't fit at 285/75r18 but I seen someone say they deflated theirs and got it up there.

However a bit of advice, use this site for finding like sizing for tire:
https://tiresize.com/calculator/

Also, a very important detail; tire manufacturers do NOT run true to size. There are wide variations between manufacturers and even models of tire in a given size. So, once you've decided on a size you want, you need to check the actual measurements of a given tire. I like to use @simpletire check true sizing. Once you've selected a tire on their site, scroll down to Specs and it will show true sizing. This is very important, because there can be a full inch or more difference in diameter between two of the same size tire.

I appreciate the links! I think I'm settling on 255/75/r17. We'll see if anyone else has input

 

[DinnyJon]

I liked the idea of having a perfectly matching spare. Failed to do any research before buying (5) 285/75/17s. I don't bother with the spare for day to day travel and something about having that spare area underneath the bed just feels great. Unfortunately, when I hit the trails this is what I'm stuck with doing. Not the end of the world but tough to pack around that.

Good luck with your search for a more practical solution!!

 

[TacoBirdinNW]

I liked the idea of having a perfectly matching spare. Failed to do any research before buying (5) 285/75/17s. I don't bother with the spare for day to day travel and something about having that spare area underneath the bed just feels great. Unfortunately, when I hit the trails this is what I'm stuck with doing. Not the end of the world but tough to pack around that.

Good luck with your search for a more practical solution!!

Trailswing dude ! Or Ultraswing.
Can take it on and off. And you can do some good ol fashioned cooking and have your bed space back. Can find used ones here or there for under $1k

 

[DinnyJon]

Yeah that looks pretty sweet. I fucked up and got the oem trd lift not realizing it doesn't handle added weight very well. My rear springs are constantly compressed almost 2 inches more than they should be. Adding a swing out will just make this problem even worse not only adding more weight but pushing out the center of gravity.

Planning on waiting for warranties to expire before swapping out all the suspension for something that can handheld handle all the weight. I got the smartcap, roof rack, full skids, sliders, bumper, winch, Dual battery setup. The trd suspension can't handle all that and adding more weight is just gonna make it worse..... did it to myself, should've done a lot more research on all this. Lessons learned

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