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Anyone Running 37’s on a Max Tow???

RH 67

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A couple local owners I have met who put 37s on their Max Tow JTs said the loss of power/towing was felt to such an extent that they abandoned the idea of tow capacity ratings, put in Mopar lifts, and now use them as off-roading vehicles with more (but an unknown amount) of towing capability. I picked up an entire suspension system from one of them for $50 because they said the 37s were just such a drag on the engine and they didn't feel they could tow the same 7650lbs as before

I went ahead and sent an email to Jeep asking what the documented affect would be from their engineers
Jeep themselves run 37" tires, go to any event, SEMA, LA Auto Show, Off Road Expo, MOAB events. In person i asked the people who R&D the JT`s and the comment was that stop and go and break wear would be most affected while towing with 37".
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Jeep themselves run 37" tires, go to any event, SEMA, LA Auto Show, Off Road Expo, MOAB events. In person i asked the people who R&D the JT`s and the comment was that stop and go and break wear would be most affected while towing with 37".
You asked the Jeep/FCA folks who R&D the Gladiator or 3rd party/aftermarket folks? If you have their contact, could you provide a writing? Once I get a response back from Jeep on tire sizes, lifts, and towing capacity effect, I'll post it here. I do hope you are right, I'd love to be able to tow the same or close to it with 35s. However, from a pure mechanical/geometry perspective, you change out too much to do that. For example, the Max Tow has different rear suspension springs from the non-Max Tow Sports. The angles of control arms, shocks, etc is changed with a lift. The amount of power needed to move the larger wheels is greater and the JT is already engineered to its limits on cooling to allow for the Max Tow rating. I don't see how it could be physically possible to change the JT and still keep its engineered properties.

And can you do it? Yes.

 
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RH 67

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You asked the Jeep/FCA folks who R&D the Gladiator or 3rd party/aftermarket folks? If you have their contact, could you provide a writing? Once I get a response back from Jeep on tire sizes, lifts, and towing capacity effect, I'll post it here. I do hope you are right, I'd love to be able to tow the same or close to it with 35s. However, from a pure mechanical/geometry perspective, you change out too much to do that. For example, the Max Tow has different rear suspension springs from the non-Max Tow Sports. The angles of control arms, shocks, etc is changed with a lift. The amount of power needed to move the larger wheels is greater and the JT is already engineered to its limits on cooling to allow for the Max Tow rating. I don't see how it could be physically possible to change the JT and still keep its engineered properties.

And can you do it? Yes.

I said JEEP and why would i have anyones contact and if i did it`s not my place to quote anyone. I said i talked to them you know us Jeep people like to shoot the breeze.

You must be new to lifts a proper lift will keep your axles and drive train geometry within factory specs. and can make the Jeep handle better when not in the wind. What a lift does is take away mpg because the poor Jeep is even less aerodynamic.

I believe that you have bought the wrong truck, if your primary goal was towing this is the wrong truck
 

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I said JEEP and why would i have anyones contact and if i did it`s not my place to quote anyone. I said i talked to them you know us Jeep people like to shoot the breeze.

You must be new to lifts a proper lift will keep your axles and drive train geometry within factory specs. and can make the Jeep handle better when not in the wind. What a lift does is take away mpg because the poor Jeep is even less aerodynamic.

I believe that you have bought the wrong truck, if your primary goal was towing this is the wrong truck
primary goal is not towing. I just want to know what I can/should do with it. I dont want to lift it, need to tow something, and overdo it because parameters changed
 

RH 67

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primary goal is not towing. I just want to know what I can/should do with it. I dont want to lift it, need to tow something, and overdo it because parameters changed
A good 3" and below lift should not be an issue, i bought a RK 3" lift and the tow and payload ratings are as stock each lift manufacture should be contacted as to their specs. As i mentioned before lifts and tires are a give and take, if 90% of the time your not towing and like a lift and bigger tires why let the 10% dictate the 90%.
 

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A good 3" and below lift should not be an issue, i bought a RK 3" lift and the tow and payload ratings are as stock each lift manufacture should be contacted as to their specs. As i mentioned before lifts and tires are a give and take, if 90% of the time your not towing and like a lift and bigger tires why let the 10% dictate the 90%.
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That’s cool. It is opposite what everyone else on this and other forums have told me. There are a couple threads on lifts/tire size and towing. A couple things I learned from them.

The Max Tow package has different rearsprings from both the standard Sport and Rubicon. They are bigger, as I have compare the two from takeoffs side by side.
Someone claiming to have been told from the engineer for FCA responsible for designing the towing features said (and thus heresay) that the tire size plays the biggest role in tow capacity
https://jalopnik.com/the-engineering-behind-the-jeep-gladiators-tow-rating-1833657453

Not hearsay. This is an interview of one of Jeep's former engineers working on the Gladiator. Perfectly matched gear ratio to tire size and additional cooling (more powerful fan and larger front grill holes) combined is what got the Gladiator to have the "Class leading towing" numbers.
 

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https://jalopnik.com/the-engineering-behind-the-jeep-gladiators-tow-rating-1833657453

Not hearsay. This is an interview of one of Jeep's former engineers working on the Gladiator. Perfectly matched gear ratio to tire size and additional cooling (more powerful fan and larger front grill holes) combined is what got the Gladiator to have the "Class leading towing" numbers.
And rear springs as max tow springs are beefier. I am familiar with that article; good read.

Larger tires then definitely decrease towing. An article I posted earlier estimated 10% per inch increase
 

RH 67

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voiding warranty
That was the thinking 20yrs. ago. Today it`s the manufactures burden to prove that an aftermarket part caused a failure and not the consumer to prove that it did not. There was a time that if you took a lifted truck into a dealer for service they would not even look at it, times have changed and so have the laws. Most dealers that i`am aware of (at least SoCal) sell lifted trucks in fact it`s rare to see a truck not lifted, my local dealer has a new Gladiator with a 6" EVO lift and 40" tires i asked if it was covered under factory warranty and was told as long as a lift comes from a reputable company it`s covered.
 

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That was the thinking 20yrs. ago. Today it`s the manufactures burden to prove that an aftermarket part caused a failure and not the consumer to prove that it did not. There was a time that if you took a lifted truck into a dealer for service they would not even look at it, times have changed and so have the laws. Most dealers that i`am aware of (at least SoCal) sell lifted trucks in fact it`s rare to see a truck not lifted, my local dealer has a new Gladiator with a 6" EVO lift and 40" tires i asked if it was covered under factory warranty and was told as long as a lift comes from a reputable company it`s covered.
Good point. Here in so cal/nor cal you will be hard pressed to find a gladiator without a lift (they are charging 10,000 for those lifts). I have a feeling everyone commenting on this issue (who don't have 37's) are falling back on their experiences with a Jeep wrangler. Let me reiterate as many have on here "THIS IS NOT A JEEP OF THE PAST". Not comparable. Im not a mechanic or pretend to be one, nor am I an engineer. But....I have a Gladiator on 37's, with 8 gears, and 4.10's. I have been in jeeps since a baby. I just got rid of a jk on 35's lifted. This gladiator with 2 in lift, on 37's feels better than any stock jeep I have ever driven off the lot. I absolutely feel no loss in power what so ever. It is completely capable of handling the 37's with very little difference in feeling than stock off the lot. Is it going to tow max capacity? Probably not. Would I tow max capacity with a stock max tow? No way. Can you tow 6,000 pounds with 37's and 4.10's? I would be super comfortable doing it. Your mpg is gonna go down for sure, breaking is gonna feel a tad different, and all the other obvious things. But everyone thinking this is such a big deal are completely living in the past.
 

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DylanR

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Went with 37’s... looks much better. Performance wise no real noticeable decrease. At least not enough to worry about. Still a lot of torque... still gets up and goes. I have the bigger brakes with the max tow so that helps... I also have the fox shocks so the MT’s don’t ride bad at all. The 37’s look exactly like they are supposed to be there with my set up the way it is... I’m happy.
 

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An automotive engineer explained to me once that the only time large tires really hurt you is when you're accelerating from a stop or when you're trying to stop from highway speed. He said that while cruising, the added leverage and weight of the tires actually is the force that helps them keep spinning. Makes sense to me. It's physics. "An object in motion wants to stay in motion." So the additional horsepower required to spin 37s down the road at 55 MPH vs. 33s is not nearly as much as you might think. Very little actually.

Taking off or trying to stop...that's where it hurts.
It is true that Newton’s first law of motion states that an object in motion will remain in motion UNLES ACTED UPON BY AN OUTSIDE FORCE. The outside forces when going to larger tires are increased wind drag, increases rolling resistance and my personal favorite gravity. It takes a whole lot more energy to move 75 pounds up a hill than it does 50 pounds. Now multiply that by 4. My argument is that the 3.6 and 8 speed do such a good job of compensating that it is barely, if at all, noticeable
 
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DylanR

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Had some interstate time this past weekend... it cruised at around 80mph at 1900-2200 rpm give or take depending on the grade of the highway.. I had plenty of room left in the throttle and it still felt like it had the torque. Very pleased with the top end torque actually. It’s no corvette obviously but very well pleased. I know I was passing cars and other jeeps and they had to of been like... :crying::like:

Like a have said before these trucks are super capable.
 

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Had some interstate time this past weekend... it cruised at around 80mph at 1900-2200 rpm give or take depending on the grade of the highway.. I had plenty of room left in the throttle and it still felt like it had the torque. Very pleased with the top end torque actually. It’s no corvette obviously but very well pleased. I know I was passing cars and other jeeps and they had to of been like... :crying::like:

Like a have said before these trucks are super capable.
Stock gears, 4.10?
 
 







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