35s to 37s with the same weight?

[lowmpg]

I'm currently riding on a setup of some 35" x 76lb Toyo open country RTs. on 39lbs wheels. Hypothetically if I keep the weight of the wheels and tires the exact same, but jump up to 37s will there be any change in performance? What about If I get a heavier tire but a lighter wheel to offset and keep the same overall weight? I'd prefer not to go up in unsprung weight from my current setup and ideally shed some weight in the transition to 37s.

Went from 35 MTs to 37 ATs, dropped from 79lbs a tire to 63lbs a tire. Acceleration improved as did fuel economy. I have a 60 mile a day commute with routine highway speed in the 70s. No issues, at all, what so ever.

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[Steph1]

Weight is indeed an important factor, but even more so is the circumference. The tire acts as the last gear in the chain of gears that propulse a vehicle. You logically cannot make them bigger without feeling the effects. Especially if you are on stock gearing and already undergeared with your current 35s.

 

[J0E]

MOST of those breaks, the vehicle has 0 inertia. The free spinning wheel coming to an abrupt stop is where the break happens. I guess if you look at it like the the sudden attempting to accelerate that 4500lb mass from 0mph up to the 10-30mph the wheel/shaft is spinning you could argue it is the vehicle and not the tire/wheel combo? Still doesn't explain why even the hp44 shafts and joints broke often under a heavy 35 in a rig that likely weighed 1500-2000lbs less than our JLURs though. Hugely less power and half the torque multiplication to boot. Obviously it's not proof of anything, but it's enough experience based evidence that you'll never find a set of nittos or other over weight tires on one of my Jeeps again.

MOST of those breaks, the vehicle has 0 inertia.

Right, and your trying to accelerate it.

The inertia of an object is a measure of its resistance to a change in the state of its motion. It is solely dependent on the mass of the object, with more massive objects having larger inertia and a greater tendency to resist changes to their motion.

The spinning wheel effectively increases the torque like a kinetic rope. So when bouncing, a heavier wheel is worse. 38" Nitto's with D44's on a 1,500 rig could do some bouncing.

I've got heavy Nitto 38x13.5R17's on heavy beadlocks, so I avoid bouncing like the plague.

 

[J0E]

Weight is indeed an important factor, but even more so is the circumference. The tire acts as the last gear in the chain of gears that propulse a vehicle. You logically cannot make them bigger without feeling the effects. Especially if you are on stock gearing and already undergeared with your current 35s.

Exactly, use my bt39.com/GearWheelSpeed to quickly compare two tire sizes.

 

[MVOffroad]

Went from 35 MTs to 37 ATs, dropped from 79lbs a tire to 63lbs a tire. Acceleration improved as did fuel economy. I have a 60 mile a day commute with routine highway speed in the 70s. No issues, at all, what so ever.

What tire did you go with and how do you like it?

 

[lowmpg]

What tire did you go with and how do you like it?

Went from 35x12.5x17 Wildpeak MT to a 37x12.5x17 K02 C. Thinner sidewall but I'm not rock crawling so that isn't important. Rolling at 32psi I'm averaging around 17-17.5mpg (up from 15.5 or less on the 35s). Performance feels great on my highway commute, which includes two times over the 4.5 mile bay bridge. My original tires from the factory were the standard 33" Wildpeak MTs which weighed 63lbs, the exact same as my current tire. The K02's aren't as tall as other 37's. Overall couldn't be happier. Getting around 1900rpms in 8th gear at 66mph. Glad I dropped the MTs.

 

[MVOffroad]

Went from 35x12.5x17 Wildpeak MT to a 37x12.5x17 K02 C. Thinner sidewall but I'm not rock crawling so that isn't important. Rolling at 32psi I'm averaging around 17-17.5mpg (up from 15.5 or less on the 35s). Performance feels great on my highway commute, which includes two times over the 4.5 mile bay bridge. My original tires from the factory were the standard 33" Wildpeak MTs which weighed 63lbs, the exact same as my current tire. The K02's aren't as tall as other 37's. Overall couldn't be happier. Glad I dropped the MTs.

Yeah I had my eye on the K02s for the weight but I'm gonna be wheeling in the rockies so I might need a thicker sidewall..

 

[lowmpg]

Yeah I had my eye on the K02s for the weight but I'm gonna be wheeling in the rockies so I might need a thicker sidewall..

You don't have to go with the C rated, you can go with D rated which are only 71lbs which is still pretty light for that type of tire. Just remember the sidewalls are all 3-ply.

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