Regret 37s?

Some Random Guy

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so I want to know is my assumption that a lighter tire even if taller will accelerate and brake better.. or does the height of 1.74” taller make a bigger difference rotaionally and will matter more than the weight? My main goal is to achieve better driving dynamics.
I do remember that the rotational inertia is different than linear, so reduced weight alone may not improve anything. Vice versa, extra weight alone may not hurt. I think it has to do with radial center of gravity (is that a thing?) causing a new torque calculation when accelerating and stopping.





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SleepEatJeepRepeat

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I do remember that the rotational inertia is different than linear, so reduced weight alone may not improve anything. Vice versa, extra weight alone may not hurt. I think it has to do with radial center of gravity (is that a thing?) causing a new torque calculation when accelerating and stopping.
Ya I remember something about that too, hoping to hear some real world application experience
 

SleepEatJeepRepeat

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Also to the OP can we change the name of the thread to “37s Ragrets” officialy?
 

Steel8083

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First time jeep owner here. My question if Youre not a hard core offroader any advantages to bigger tires other than looks? Im trying to decide between 35's and keeping My stock 33's and just getting wheels. Thanks
 

SleepEatJeepRepeat

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First time jeep owner here. My question if Youre not a hard core offroader any advantages to bigger tires other than looks? Im trying to decide between 35's and keeping My stock 33's and just getting wheels. Thanks
Your axles get higher off the ground and you hit less stuff, plus the wheels can walk over much larger obstacles. Also the taller tires are wider giving the tire a bigger contact patch to the ground.
 

Kreepin1

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Ya I remember something about that too, hoping to hear some real world application experience
It's not a real world experience thing, it's a math thing. Bottom line, the larger, lighter tire will still be harder to start and stop because 1) the axle's leverage is reduced and 2) it stores more kinetic energy.

Tires contribute twice to the vehicle's kinetic energy. This is the energy the engine must supply or the brakes must remove. The first component is linear and depends on the mass - here the lighter tire will save some energy. The second is rotational and depends on the "moment of inertia" which takes into account how far the mass is from the center. A cylinder that has twice the diameter (but same weight) as another cylinder will have a moment of inertia four times larger. Point is, a fair amount of a tire's weight is in the tread (a cylinder).
 

SleepEatJeepRepeat

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It's not a real world experience thing, it's a math thing. Bottom line, the larger, lighter tire will still be harder to start and stop because 1) the axle's leverage is reduced and 2) it stores more kinetic energy.

Tires contribute twice to the vehicle's kinetic energy. This is the energy the engine must supply or the brakes must remove. The first component is linear and depends on the mass - here the lighter tire will save some energy. The second is rotational and depends on the "moment of inertia" which takes into account how far the mass is from the center. A cylinder that has twice the diameter (but same weight) as another cylinder will have a moment of inertia four times larger. Point is, a fair amount of a tire's weight is in the tread (a cylinder).
Ya will be interesting to see how it comes out, I want to go to 37s either way, so hoping cutting weight helps a bit.. especially because that weight is primarily on the putter spinning edge of the tire.
 

SleepEatJeepRepeat

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How much approximately does it cost to have a trained mechanic regear if I do have ragrets!
 

fjwagner

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I talked to Hauk Offroad and you can run 37s with their fenders if you want to go that route instead of a lift. Probably ends up being similar expense but it's an option.

I too am curious about the MPG with 37s vs 35s. I'm looking to stay around 17MPG and I'm guessing guys running 37s are seeing sub 15 but haven't heard any real world numbers.
You will need to change the gearing if you have not done so already.
 

ValB

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The question is, WHAT gears do you have? Are you planning on getting new gears?
 

C5er

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Currently running 35's Ridge Grapplers on a 18 Rubicon JLU with 4.10s. and 2" mopar life. Thinking of going to 37 KO2 D2's. Do 2-3 off road trips per year. The question is what are the other upgrades that need to happen to support the 37's.
1) New wheels -looking at getting the mopar gear wheels
2) Updates to tailgate to hold larger spare ? Any recommendations for use with factory steel bumpers
3) Are the stock Rubicon axles sufficient?
4) I aslso have a steer smarts front track bar i am about to install

Anything else?
 

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