5thGenRams Forums

Register a free account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members through your own private inbox!

Biggest Spare Tire that Fits?

ColoradoCub

Ram Guru
Joined
Jul 6, 2019
Messages
559
Reaction score
553
Location
Calirado
I see a lot of guys running 34 and 35 inch tires, curious what you are doing for a spare and what will fit under there?
 

DavidNJ

Well-Known Member
Joined
Aug 3, 2019
Messages
343
Reaction score
135

There is another one where someone fit a 34" and it was concerned about the distance to the muffler. In another forum I recall some shaving some bolt heads to increase the space, but I think that was for a 4th gen. In any case, all real full size spares (the same size as on the truck) are going to be among the lowest points on the truck. A 12.5" wide tire (305mm r 12.5) would probably be the lowest point.

How do you like the 275/65-20s? I'm beginning to think they are the best size, at least for a truck with 20" wheels. Actually just over 34" at 34.1", very high load rating so 35psi is an ok pressure (maybe 40 or 45 for towing heavy) and articles/videos I've seen are indicating narrower is better except in sand/mud where floatation could be an helpful...except that a 6000+ lb truck isn't likely to see much difference between 11.2" (275 on 9" rim) and 12.5.
 

ColoradoCub

Ram Guru
Joined
Jul 6, 2019
Messages
559
Reaction score
553
Location
Calirado
Looking at those pics it sure seems like a 34 would be stuffed in there pretty tight. I have the 18” spare, might have to just pick up a 275/70/18 to mount on it and play with air pressure to offset the 3/4 inch if I ever need to mount it.

I like the 275/65/20’s, ride is smooth , fuel mileage doesn’t appear to have taken much of a hit and its even lowered my highway rpms a little with the 3.92’s. Fills the wheel wells better than the 33’s did. I’m running 38 psi in the fronts snd 36 in the rear, seems about right.
 

DavidNJ

Well-Known Member
Joined
Aug 3, 2019
Messages
343
Reaction score
135
Looking at those pics it sure seems like a 34 would be stuffed in there pretty tight. I have the 18” spare, might have to just pick up a 275/70/18 to mount on it and play with air pressure to offset the 3/4 inch if I ever need to mount it.

I like the 275/65/20’s, ride is smooth , fuel mileage doesn’t appear to have taken much of a hit and its even lowered my highway rpms a little with the 3.92’s. Fills the wheel wells better than the 33’s did. I’m running 38 psi in the fronts and 36 in the rear, seems about right.

Which tires do you have? With the higher GAWR in the rear, I would have thought that would have the higher pressure.

This the thread where the bolt was shaved on a 4th gen to fit: https://www.ramforumz.com/threads/oversized-spare-tire-what-sizes-fit.249477/post-2170349

With ORG a 34" has the same distance between the fender and tire as a 32" without ORG/Rebel. With your 2" level, a 35" would have 1/2" more. But the larger diameter brings inner fender interference issues closer, although it appears with the 285/65 they don't yet occur. But I guess those owners haven't had a flat yet.
 

ColoradoCub

Ram Guru
Joined
Jul 6, 2019
Messages
559
Reaction score
553
Location
Calirado
Which tires do you have? With the higher GAWR in the rear, I would have thought that would have the higher pressure.

This the thread where the bolt was shaved on a 4th gen to fit: https://www.ramforumz.com/threads/oversized-spare-tire-what-sizes-fit.249477/post-2170349

With ORG a 34" has the same distance between the fender and tire as a 32" without ORG/Rebel. With your 2" level, a 35" would have 1/2" more. But the larger diameter brings inner fender interference issues closer, although it appears with the 285/65 they don't yet occur. But I guess those owners haven't had a flat yet.

Running around empty the rear end is pretty light hence why I run a couple psi less than the front where the motor,front diff and tranny is.
 

DavidNJ

Well-Known Member
Joined
Aug 3, 2019
Messages
343
Reaction score
135
Running around empty the rear end is pretty light hence why I run a couple psi less than the front where the motor,front diff and tranny is.

Makes sense. Have you tried even lower pressures? If you're empty, with those tires, you probably could drop to 30psi or even less. At 35psi, the lost on the LT load table, they still are about the same place as the OE tires at load capacity.

BTW: Have you the ORG and have you considered adding balancing beads?
 

ColoradoCub

Ram Guru
Joined
Jul 6, 2019
Messages
559
Reaction score
553
Location
Calirado
Makes sense. Have you tried even lower pressures? If you're empty, with those tires, you probably could drop to 30psi or even less. At 35psi, the lost on the LT load table, they still are about the same place as the OE tires at load capacity.

BTW: Have you the ORG and have you considered adding balancing beads?

I could drop down some more, not every tire openly lists an inflation table, but using Toyos chart even at 35 psi each tire is rated at over 2000 lbs and we both know the rear axel of an empty ram 1500 is not carrying 4000 lbs. That’s why it blows my mind to see guys inflating their rear tires to 45-50 psi which is so much more air than these tires need to be at. I ran my 2500’s at 45-50 in the rear when empty.

Never have considered balancing beads
 

carpram1500

New Member
Joined
Jun 25, 2020
Messages
2
Reaction score
0
Just fit a LT285/75R-17 COOPERDISCOVERER AT3 XLT into the spare tire location without any fabrication work. The nearest points are the exhaust on both sides with it being about 3/4 inch of space. Hoping it is far enough away for the heat not to negatively impact the spare tire. I got a 1500 Classic.
 

rzims

Active Member
Joined
Dec 17, 2019
Messages
99
Reaction score
98
I just ordered a 285 70 18 to put on the spare rim. Ordered a Suretrac AT off walmart.com so we'll see how it works. I have 295 60 20s on the truck so that size seemed to be the closest I could get with the spare
 

Zoompastu

Well-Known Member
Joined
Apr 13, 2020
Messages
225
Reaction score
111
Suretrac AT is 33.74 NItto Ridge grappler is 33.98 in 285/70/18
Of course there’s a price difference between the two LOL
 

rzims

Active Member
Joined
Dec 17, 2019
Messages
99
Reaction score
98
yeah, I saw those, but for my spare I figured I would try to pinch some pennies....hopefully the cost/value tradeoff doesn't bite me in the butt at some point
 

Zoompastu

Well-Known Member
Joined
Apr 13, 2020
Messages
225
Reaction score
111
yeah, I saw those, but for my spare I figured I would try to pinch some pennies....hopefully the cost/value tradeoff doesn't bite me in the butt at some point
I hope you never have to use it
 

Jwa73

New Member
Joined
Dec 30, 2018
Messages
1
Reaction score
0
I just ordered a 285 70 18 to put on the spare rim. Ordered a Suretrac AT off walmart.com so we'll see how it works. I have 295 60 20s on the truck so that size seemed to be the closest I could get with the spare
We’re you able to fit that size in the spare tire area?
 

rzims

Active Member
Joined
Dec 17, 2019
Messages
99
Reaction score
98
We’re you able to fit that size in the spare tire area?
The tire from walmart.com never came so I picked up a practically new 275 75 18 which is slightly bigger than the 295 60 20s I have on. It fits snuggly and will work in a pinch. Still need to figure out a longer term solution
 

Techguy2000

Active Member
Joined
Jun 9, 2019
Messages
102
Reaction score
58
Location
Dallas, Tx
@rzims Did you keep the metal shield installed around the spare? I have a 285/75r18 which is half an inch taller than your tire that I'd love to get under the truck but from quick measurements it seemed like there was no chance. It felt like even without the shield the tire would touch the hitch on one end and rub the track bar on the other?
 

rzims

Active Member
Joined
Dec 17, 2019
Messages
99
Reaction score
98
I did not have to remove the metal shield to fit it up there, but it is definitely a tight fit
 

Attachments

  • spare.jpg
    spare.jpg
    131.8 KB · Views: 311
Last edited:

Techguy2000

Active Member
Joined
Jun 9, 2019
Messages
102
Reaction score
58
Location
Dallas, Tx
Thank you for the picture that is helpful, on second look maybe it's because you have the longer bed that you gain more room to the hitch. I have an issue where my spare tire winch seems to be missing a piece from the factory so I haven't been able to test fit yet.
 

rzims

Active Member
Joined
Dec 17, 2019
Messages
99
Reaction score
98
yeah, the longer bed gives us a little more room. My main goal was to get as close in size to the rest of the wheels/tires without buying a new rim.
I ended up getting the used tire, which was a take-off from another truck, from the tire place we use at work for 20 bucks.....couldn't say no
 

dwalme

Active Member
Joined
Nov 1, 2020
Messages
117
Reaction score
114
Does anyone know the RIM width of the factory spare wheel? Looks like an 18" aluminum wheel.

I went to 275/60R20 tires on my RAM 1500 and figured I would just throw a 275/70R18 tire on there as a spare. But I have a feeling the wheel may be narrower than 7" wide.
 

Users who are viewing this thread

Top