Tire Size, Gear Ratio, Affect on Payload/Towing

[Oscar Indy]

Look at the GCWR
12,800 for the sport max
12,450 for the Rubicon

Using the explanation of GCWR from the screenshot it can be inferred the lower combined weight of the Rubicon is due to the increase in tire size. This 350 lb loss in combined capacity needs to be removed from the Rubicons tow capacity loss to come up with roughly 300lbs of additional curb weight. The max tounge weight difference is 65lbs. The springs don't really factor into the tow capacity.

But if you want to look at what springs do affect look at the difference between the max tow and Rubicon as far as payload.

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[Oscar Indy]

But that's where the confusion comes in - nowhere does the tire say "I'm a 33" tall tire". Nowhere on the Gladiator specs showing tire size for any of them, Overland included, does it say "these are 31" tires".
No, they say 18" rims, 255/70R15 so where the heck is anyone getting the DIAMETER out of that?
Looking at that - where does it say it's a 31" tire? Where does the guy that's saying the tires he has are 33" tall - where on the tire does it say 33" tall?

https://tiresize.com/converter/
Use that to convert a metric tire to an inch equivalent

 

[ShadowsPapa]

https://tiresize.com/converter/
Use that to convert a metric tire to an inch equivalent

using that the Overland actually has 32" tires - so a 33 is only an inch taller total.
The Overland stock tire size is 255/70R18

So no wonder he said they'd fit with no lift - it's only an inch difference and that means that above the axle, or hub to fender is only a half inch difference. They would raise the truck a whopping half inch up.

18" Wheel Size
255/70R18 = 32.1X10R18

 

[Oscar Indy]

using that the Overland actually has 32" tires - so a 33 is only an inch taller total.
The Overland stock tire size is 255/70R18

So no wonder he said they'd fit with no lift - it's only an inch difference and that means that above the axle, or hub to fender is only a half inch difference. They would raise the truck a whopping half inch up.

18" Wheel Size
255/70R18 = 32.1X10R18

It's actually worse than you think.

https://www.tacomaworld.com/tirecalc?tires=255-70r18-285-70r17

 

[ShadowsPapa]

If these are 285/70R17 as you predict then there's hardly any diameter difference, it's mostly width or footprint in that respect. More aggressive tread for sure.
Interesting! Thanks.

 

[Uparms]

I used one of the tire-size calculation pages and my Sport Max tow with 4.10s would become a 3.69 gear when I put 35s on it.

3.69 is not bad gearding for a daily driver. Not a bad gearing at all. Combine that with the 8 speed. I am looking forward to it.

I have read 1-2 MPG loss going to 35s form the stock 245/17.

You don't have to build it in black ( Heavy strong off road capable) or white (damn cream puff -stock -in my driveway with max tow and funny wheels and tires) but you do get to make the decision what gray areas are acceptable for you and your most common use.

Build it your way. Anyway!

 

[ShadowsPapa]

I used one of the tire-size calculation pages and my Sport Max tow with 4.10s would become a 3.64 gear when I put 35s on it.

3.564 is not bad gearding for a daily driver. Not a bad gearing at all. Combine that with the 8 speed. I am looking forward to it.

I have read 1-2 MPG loss going to 35s form the stock 245/17.

I am curious... is the tow rating related to just the suspension, frame and weight of the vehicle or dose the HP and Torque changes affect that number also ( down if I lose gearing or even up if I supercharge it.). I will have to check that answer somewhere else here.

You don't have to build it in black ( Heavy strong off road capable) or (white damn cream puff stock in my driveway with max tow and funny wheels and tires) but you do get to make the decision what gray areas are acceptable for you and your most common use.

Build it your way. Anyway!



PS. Almost sounds like someone above has has some life coaching about grey areas in life........

As has already been stated, the COOLING of the engine and transmission and other factors come into play for towing and payload. NOT just suspension, axles and so on. Yes, the HP curve, how much the transmission will be shifting and in which gears, how hard the engine will be working, how many BTUs will be generated vs what can be dissipated...... off a dead-stop launch will be impacted by higher gear numbers - larger tires. When pulling a load, or having a payload on board, you'd not expect to pull away from a stop as easily.
Since I've been involved with performance builds for decades, gear ratios and so on for muscle car use - I can attest to what some folks can expect in some areas. What they DO with the information is up to them. But the idea is to let people know the side effects of what they do. Not TELL them "DON'T DO IT" but say "IF you do, here's what to expect".
So why does it sound like you are dissing the warnings or the education part?

 

[PyrPatriot]

 

[ShadowsPapa]

Absolutely disagree with his statement that the wider wheels with the offset doesn't bother handling, etc. It is a major thing. You change the scrub angle, you change the intersection of the tire center-line compared to the SAI line and you can run into big trouble with brake steer and other handling issues. You change how hard or easy it steers and how it handles under heavy braking - and with a load behind you, braking could be pretty heavy in an emergency. Apparently they haven't been towing a load and had to stop suddenly on a road that's wet or rough. It can jerk that truck to the side awfully fast.
It's too bad that people make massive changes, take it down a nice road, typically straight, maybe through town, then claim it's fine, no problems, handles like a dream. That is until you run into trouble........... then you are trying to rope a wild stallion.

Otherwise he was pretty much on target - you can tow, it will reduce capacity some, "depending".........

Covered before - and like he said in that video - you change tire size, you change final ratio. And we can easily see what Jeep put into the trucks that have max tow and the highest towing capacity/rating - right? Yeah, the 4.10. It was the same with the Silverado I had - to get more towing capacity I needed lower gears. My truck had the middle option for gears. No other changes but gear ratio got the truck a higher trailer towing rating. So bigger tires means lower towing capacity due to engine loading, transmission shifting, more BTUs put out and needing to be taken away.

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