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Spare Tire Advice..what are most doing when running bigger tires?

Ready Go

Ready Go

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I recently realized I'm running a risk, I still have the OEM Spare setup even though I've upgraded my wheel/tire combo.

The OEM Spare is a 245/70-18 on a 18x8" (+19mm offset) wheel..31.5" height...⤵️
20251119_130845.jpg

I'm currently running a 285/60R20 on a 20x9" (+1mm offset) wheel..33.5" height (I'm running lower tire pressures 36F/33R, so my actual height equates to 33" (verified by GPS & JBV1, and AlfaOBD programmed to 2570mm for accurate speedometer readings, which is same as 275/60R20 for AlfaOBD programming).
20251119_130504.jpg

My 31.5" spare compared to 33.5"(33") tire setup is way off and needs to be corrected. Last time I needed to use a spare tire was ~25 years ago, but who wants to run the risk.

I'm curious what members are doing when they've changed tire sizes?

My two options are...
(1)..Just replace the 245/70-18 with a LT275/70R18..33.2" height (Only~$350 with M&B)
(2)..Buy a fifth combo of LT285/60R20 on 20x9"..~33-33.5" height (TireRack~$1020 shipped)
[Weight of either combo is almost identical]

I feel like getting the fifth combo is maybe best since it's the same as the other four, so no hurry to get flat repaired, but $1020 vs $350 makes me think is it really worth it for something I hope to never use. (My four combos are custom powder coat color matched and the fifth won't be, so I won't do a five tire rotation..and spare wouldn't stay on for long if needed).

Here's the specs...⤵️Screenshot_20251213_073209_Gallery.jpg

Thanks for any thoughts or advice👍
 
Other option, I did when I ran 37's, just buy tire and keep in the bed when traveling, or at home when local and hope you can get to it. The best would be to run the sale wheel/tire combo, but as you mentioned the cost factor. I still haven't figured mine out yet. I will probably just grab appropriate 18" size for the spare wheel. cheapest option.
 
CHeYeNNe71 said:
Other option, I did when I ran 37's, just buy tire and keep in the bed when traveling, or at home when local and hope you can get to it. The best would be to run the sale wheel/tire combo, but as you mentioned the cost factor. I still haven't figured mine out yet. I will probably just grab appropriate 18" size for the spare wheel. cheapest option.
Click to expand...
Yep, I know we discussed this need for both of us once before.

It'll be a while (when my tires wear out), but I love the look of your 285/65s even better than my 285/60s..and maybe in the future I'll be willing to forego a little more gearing to go to 285/65s..and then my spare would be off again.😋

A 275/70-18 would certainly work as a short term use spare, and is cheap basically, but a fifth combo would be better if on a long distance trip. 🤔
 
Ready Go said:
Yep, I know we discussed this need for both of us once before.

It'll be a while (when my tires wear out), but I love the look of your 285/65s even better than my 285/60s..and maybe in the future I'll be willing to forego a little more gearing to go to 285/65s..and then my spare would be off again.😋

A 275/70-18 would certainly work as a short term use spare, and is cheap basically, but a fifth combo would be better if on a long distance trip. 🤔
Click to expand...
Yeah, I'd love the 5th wheel option. Tires are just crazy expensive, plus both of us have custom powdercoat wheels making it more costly. UGH!! :ROFLMAO::ROFLMAO:
 
When I moved to 295/70R18's I bought the cheapest AT tire in the same size, had them mount it to spare wheel, then crammed it up under the bed. It'll fit if you jam it in and maybe kick it a bit. I didn't remove the heat shields, but if I go to 35x12.5 I'll probably have to and maybe grind the hitch receiver a bit. I'm not concerned about the spare wheel as I don't rotate all 5. It'll stay under the truck until it looks bad then I'll replace.
 
LaxDfns15 said:
When I moved to 295/70R18's I bought the cheapest AT tire in the same size, had them mount it to spare wheel, then crammed it up under the bed. It'll fit if you jam it in and maybe kick it a bit. I didn't remove the heat shields, but if I go to 35x12.5 I'll probably have to and maybe grind the hitch receiver a bit. I'm not concerned about the spare wheel as I don't rotate all 5. It'll stay under the truck until it looks bad then I'll replace.
Click to expand...
I feel like for me, the 275/70-18 on OEM Spare wheel is a cheap insurance policy for something I'll hopefully/probably never use.
A fifth combo is really just wasting money, in many ways.
 
Ready Go said:
I feel like for me, the 275/70-18 on OEM Spare wheel is a cheap insurance policy for something I'll hopefully/probably never use.
A fifth combo is really just wasting money, in many ways.
Click to expand...
Agreed. Think I got a Nexan or something like that from Discount Tire when I bought my Discoverers.
 
other threads has shown other members running spare 35 with deflating the tire and removing the heat shield and a little trimming on the back side of the trailer hitch
 
I have a 35x12.50 spare under mine. The heat shield is still there, but I did trim the back of the hitch, otherwise the tire was rubbing the track bar.
 
I do have the Vice Design LED Reverse Lights..which bolts to the backside of the hitch for support.
These do decrease the clearance between the spare tire and the hitch a bit..I measure that I should have ~34" with the heat shields in place, so either of my choices will fit..I'm leaning towards just swapping a 275/70-18" on the OEM Spare wheel..a $1000 spare really isn't necessary or better than a $350 spare that I hope to not need.
When my nearly new LT285/60R20s need replacement, I'll probably step up to LT285/65R20s (~34.6") at which point I'll remove the heat shields to fit a larger spare.

20251119_130355.jpg
 
**Side note..one thing I found out last night, I need to do a AlfaOBD Adjust Pressure Threshold for my TPMS settings.
I'm currently running 36F/33R (vs 39F/R OEM) and we went to a Xmas Party last night..outside temp was 0° and I was parked on yard in snow.
When we left, my Tires were 34F/31R and both Rear sensors kicked a red indicator on guage and yellow engine light.
By the time we got home, the psi was up to 37F/34R, but I don't think the lights will go out unless I juice the rears to 39, let it populate, then run back to 33 again.
My garage doesn't get that cold and my truck usually isn't sitting out in cold temp for that long, so may not happen again, but I have AlfaOBD so might as use it.👍
 
Keep what you got and make sure you only run the spare on the back axle, even if it means moving a good tire to the front. That should get you home or somewhere to fix the problem.
 
I did the AlfaOBD "Adjust Pressure Threshold" today..super simple to do.
Only odd thing, I set to 36F & 33R from factory setting of 39F/39R, and it propagated to 35F & 32R, so I redid it again and again it showed 35F & 32R..so I decided "f it" and left it.
I had readjusted the tire psi beforehand back up to 36/33, as it had dropped to 34/31 recently and kicked on the warning lights for low rear psi.
Once I backed out of the garage and half way down the street, the TPMS registered the 36/33 and both rear warning lights and the TPMS check light went out on their own.
Look like problem solved..love that AlfaOBD👍
 
2025 Ram Limited said:
Keep what you got and make sure you only run the spare on the back axle, even if it means moving a good tire to the front. That should get you home or somewhere to fix the problem.
Click to expand...
I thought since I have a posi rear and basically on open front diff, that if the spare is shorter it should be on the front not rear(??).
I'm pretty sure I'll pop the ~$350+ for a LT275/70-18" for my spare, which is basically the same height as my LT285/60R20s...⤵️

Screenshot_20251213_070747_Samsung Internet.jpg
 
Ready Go said:
I often needlessly burn through money..I feel like spending $350 instead of $1000 on a spare is a step in the right direction, but your idea is better yet..for something we hope not to ever use🤑
Click to expand...
Yeah after looking for a somewhat matching tire for the spare and that price is high, I'm going Cheap and put the other money for a direct replacement.
 
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