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Biggest tires on stock suspension/stock 20 inch rims

kobra said:
Sorry but not true. On my 2020 3500 ltd, the tires are 285/60R20 and the spare is 275/70R18.

B
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A differential doesn’t care what size rims are on both sides, it only cares that the diameter of both tires are the same. Like mentioned above, both of the tire sizes you mentioned are roughly the same size in diameter so they would work fine. If you carry a spare, it certainly needs to match the other tires in this one category.
 
H3LZSN1P3R said:
Take a second to calculate the diameters they are the same diameter thats all that matters they use 18s for all the spares but change tire sizes to match the tires that get put on the truck
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I did use tiresize before I asked the question and got similar results to you. I'm not sure why you would say they are the same diameter as you've just shown that they are not.
So, that's why I asked the question about how much the size difference matters. Obviously RAM thinks that about 1% difference is not an issue.

I didn't mean to derail the OP thread here, but I guess maybe it's still relevant. Maybe part of deciding how big of a tire to run will include how much of a difference between your tires and your spare. The offroad guys realize you cannot put a much larger spare in there, so they start to need brackets to carry the full size spare in the bed or bumper. I suspect most of us - like the OP who is asking about stock suspension - will want to keep the spare where it is.

So again perhaps my question is still valuable to the thread - if you go to larger size tires, how much larger can you go before you may have issues if ever needing to use the factory spare?

Hope that makes sense and that is still helpful to the thread,
B
 
kobra said:
I did use tiresize before I asked the question and got similar results to you. I'm not sure why you would say they are the same diameter as you've just shown that they are not.
So, that's why I asked the question about how much the size difference matters. Obviously RAM thinks that about 1% difference is not an issue.

I didn't mean to derail the OP thread here, but I guess maybe it's still relevant. Maybe part of deciding how big of a tire to run will include how much of a difference between your tires and your spare. The offroad guys realize you cannot put a much larger spare in there, so they start to need brackets to carry the full size spare in the bed or bumper. I suspect most of us - like the OP who is asking about stock suspension - will want to keep the spare where it is.

So again perhaps my question is still valuable to the thread - if you go to larger size tires, how much larger can you go before you may have issues if ever needing to use the factory spare?

Hope that makes sense and that is still helpful to the thread,
B
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The difference needs to be within 5% so its not a problem.....
 
A .3" difference is not going to kill the diff. 6 more revolutions per mile traveled between those two. Going to 35x11.50s compared to the stock spare is farther than I would go though. I'd be looking to put a 305/70R18 or 285/75R18 on the spare rim to match a 35x11.5R20.

Problem is there doesn't look to be much room under there. I swear my stock spare is already touching the hitch receiver as is.
 
Epsilon Plus said:
A .3" difference is not going to kill the diff. 6 more revolutions per mile traveled between those two. Going to 35x11.50s compared to the stock spare is farther than I would go though. I'd be looking to put a 305/70R18 or 285/75R18 on the spare rim to match a 35x11.5R20.

Problem is there doesn't look to be much room under there. I swear my stock spare is already touching the hitch receiver as is.
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Ya, that's the problem isn't it. I think it would be much better if there was room for a ~35" spare.
And, while at it, I actually think the RAM HD's should come with about 35" size tires from the factory. To me, from 4th gen and up, all of the factory options look too small in the wheel wells, and actually 37's look even better than 35's.

So, give us 35s (including spare) from the factory, and those who want can upgrade to 37s. Boom! mike drop :D

B
 
kobra said:
Ya, that's the problem isn't it. I think it would be much better if there was room for a ~35" spare.
And, while at it, I actually think the RAM HD's should come with about 35" size tires from the factory. To me, from 4th gen and up, all of the factory options look too small in the wheel wells, and actually 37's look even better than 35's.

So, give us 35s (including spare) from the factory, and those who want can upgrade to 37s. Boom! mike drop :D

B
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35s are fine for people who dont use their truck for plowing but if i put my 35s on with the plow it would rub bad unless you level or lift it then it starts ruining functionality thats why i run the 35s in the summer and stock size in the winter... these trucks are work trucks and built as such
 
H3LZSN1P3R said:
35s are fine for people who dont use their truck for plowing but if i put my 35s on with the plow it would rub bad unless you level or lift it then it starts ruining functionality thats why i run the 35s in the summer and stock size in the winter... these trucks are work trucks and built as such
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Of course and I guess I wasn't totally clear either. I don't necessarily mean a 35x12.5 flotation tire, but rather a larger tire than what the factory ships; examples could be 285/75R18 or 295/70R18.
But it's a good point; these trucks are very versatile and extremely capable, and folks use them for all sorts of things. Including actual, you know, and I hate to say it; work ;)

B
 
Considering back when 3rd and 4th gens started they regulary came with 31s (265/70-17) i think the stock 33s are a pretty decent improvement for the 4.5gens... i remember my 2001 dually had 2 options from factory one bieng 215/85-16 30” tall and you can put 35” tires without lifting on that truck too so you can just imagine how ridiculous looked

i was pleasantly surprised when i was shopping for my 19 that they came with 33s stock even if it was the transforce garbage
 
I have Cooper Discover S/T 35X12.50LT on stock rims. They have not rubbed at all. Stock height 2020 2500 Mega Cab 4x4 Off-Road. They have been great so far in snow and on icy roads. The middle strip has been siped from side to side to help on ice.IMG_5590.JPG
 
Graphxdesigns said:
I have Cooper Discover S/T 35X12.50LT on stock rims. They have not rubbed at all. Stock height 2020 2500 Mega Cab 4x4 Off-Road. They have been great so far in snow and on icy roads. The middle strip has been siped from side to side to help on ice.View attachment 11346
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I am thinking about getting 35" as well, what did you do with the spare? did you change the spare, and what size of the spare. I am not sure the location would fit 35" spare. Thanks.
 
If I was on a long tow, I carry a separate jack for the trailer so I'd probably put a steer tire on the back and put the spare on the non LSD front if I had a mis-match. PITA but would solve the problem.
 
I probably need to pick up a spare for a long tow...
 
Also I found this a useful resource for tire fitment. Short answer that I am picking up is 35 x 12.5 is no problem at all, I'll leave the caveat that it will probably depend a bit on tread aggressiveness as well.

4wheeldriveguide.com

Biggest Tires On Stock Ram 2500 4WD: Perfect FIT - 4-Wheel Drive Guide

Discover the biggest tires you can fit on a stock Ram 2500 (W/Without a Lift)
4wheeldriveguide.com 4wheeldriveguide.com
4wheeldriveguide.com

Biggest Tires On Stock Ram 2500 4WD: Perfect FIT - 4-Wheel Drive Guide

Discover the biggest tires you can fit on a stock Ram 2500 (W/Without a Lift)
4wheeldriveguide.com 4wheeldriveguide.com
 
Listen Karen. If you flat a rear and your spare is considerably smaller in diameter, swap a front to the rear and put the small spare on the front. Front diff (and t-case in 2wd) is open and there is zero issue.

My 295/65-20 right front rubbed lightly at full lock on the sway bar. 2.25" Thurens changed that for now. Will see after alignment. (3500 air ride btw)

Will try 37x11.50R20 Ridge Grapplers next....
 
Blackbrush said:
Listen Karen. If you flat a rear and your spare is considerably smaller in diameter, swap a front to the rear and put the small spare on the front. Front diff (and t-case in 2wd) is open and there is zero issue.

My 295/65-20 right front rubbed lightly at full lock on the sway bar. 2.25" Thurens changed that for now. Will see after alignment. (3500 air ride btw)

Will try 37x11.50R20 Ridge Grapplers next....
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This sounds like the awesome addition to your family vacation. If you don't use your truck as a truck who cares what size spare you run, ruin your clutches in your diff who cares. If you are towing though good luck with a 35 on one side and a 33 on the other.
 
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