40s or towing on factory rubber?

[Toro34]

Tires as a component of engine rpm at final speed, not as factor of rpms on initial start??


This would only apply from a stop where a different gear cannot compensate for additional load. If I'm going 30mph and the load calls for 2500rpm, the trans will find the correct gear.
We should be working from the beginning (initial and acceleration) rather than final (whichever the established constant speed is, where dynamic forces are minimized/ mitigated with inertia.)

Gear selection is the servant of engine power/ mph. I think you're trying to have the tail wag the dog here.

Again, acceleration/steady mph or rpm shouldn't be the concern. Braking should be the focus. I'm sticking with my very vague initial assessment. You can get up to 55-65mph no matter what gearing you have.

With 40s, I would guesstimate that you can safely tow 30% less than stock. Probably even less

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[Ironman 67]

I put 35s on my and towing it did not effect it.
I don't know if 40s is a good idea if you are towing.

 

[Pescatoral Pursuit]

I'm not sure there is a good answer to your question, at least without doing a great deal of dynamic modeling with sophisticated software unavailable to most of us. I was trained as a civil / structural engineer, and I can tell you for a fact there is no easy or satisfactory answer to your question. Just guessing but there are probably 50 or more variables that must be considered and without the modeling software, forget it. Having said that, I still get that you want some information here. Not being critical here, but if I were going to tow with what I assume is a more or less stock Jeep, I doubt I would ever consider putting 40" tires on it before doing so. Many of the commenters here have touched on the main issues already so not going to add anything other than if you intend to tow a relatively heavy (say 2000 lbs) load with a Jeep on 40"', at the very least I would regear to at least 5:12's, install significantly larger brakes, make sure the towed trailer had electric trailer brakes, and be gentle on the throttle while towing. Remember, 40" require a significant lift which increases your center of gravity and roll-over moment, among other things. Good luck to you and be safe.

Edited the initial post which is probably what caused so much confusion as "and" was used as "in comparison to." The title had the more clearly worded "or" in it.

It's a basic comparison of the dynamic load on the driveline between running 40s or towing a load. Not towing with 40s.

 

[Reddog]

Edited the initial post which is probably what caused so much confusion as "and" was used as "in comparison to." The title had the more clearly worded "or" in it.

It's a basic comparison of the dynamic load on the driveline between running 40s or towing a load. Not towing with 40s.

I just wasn't sure where you were going with it. But I get it.

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