Spare tire size-how much margin is acceptable?

[Highcountry]

I'm planning to go up one size on my 2020 2500 Crew to a 295 on the stock wheels. I see a lot of talk on here about needing to match the spare. I understand the principle with limited slips, I just don't know if an inch in height is enough to make a difference. It seems like if they were that sensitive, there would already be longevity issues. I've run slightly smaller spares on several rigs over the years that had posi, trac loc etc. and never had a problem, but nothing modern. Just wondering what peoples' thoughts are. I'm just trying to decide if I really need 5

 

[jsalbre]

The simple solution is to put the spare on the front axle. No limited slip up there.

 

[Rockcrawlindude]

I would say about 5% ish (approx two tire sizes 33-35 or 35-37 etc) as long as the tire meets the load rating and you wouldn’t really notice a difference.

It is the safest bet to put the spare on the front if you have a lsd rear but I am Not sure it’s needed. I don’t think I would do that extra work on the side of the road.

I don’t think you would tear up the lsd if you used your spare on the rear for a “spare tire” length of time. Meaning, fix the tire soon. You’re looking at a small amount of differentiation which is less than occurs every time you turn.

For example, if your stock spare is 275/75-17 like I believe mine is (33.2”)and you go up to a 35” that’s a 5.4% difference assuming both tires are true to size.

I haven’t tried it but my reasoning is this.. You’re looking at 609 rotations per mile on a factory spare vs 581 per mile on a true 35” that’s only 28 extra rotations every mile.

I have the factory spare on my rig and I would use it without hesitation.

 

[Icky]

Brand new deflated 295/65 R20 Toyo RT sits where my stock spare did on my 22 3500 megacab. A 35 fit on my 13 megacab 2500

 

[batman900]

I went up an inch & still have the factory spare. Would airing down the tire on the opposite side balance things out? Was just an idea but I may be wrong. Speedometer is off 1ish-mph on the hwy from OEM so they can’t be “too” much off from stock. I also keep a portable air compressor in our vehicles so unless it’s a blowout which I’ve “knock on wood” never experienced, I should be ok.

 

[ClawSS]

just an FYI....Spare storage options when running 37's suck unless you really want to change out a couple of 100lbs+ wheels on the side of the road due to only carrying a 35" for front duty only.

 

[Highcountry]

Thanks for your thoughts everyone.