Axle Ratio and Towing

[Darrow]

New to the forum, excited to be here.
Maybe someone can explain this…in the Ford towing guide it shows Broncos with taller gearing having slightly higher towing capacities. For example I wouldve thought that the greater torque from the Wildtrak Sasquatch 4.70:1 would tow more than it’s 3.73:1 counterpart. Does it come down to other mechanics of the sasquatch? Thanks!

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[Tricky Dick]

It's more of result of GVWR than gearing. Some of those high trim 4drs get real porky and it takes away from available payload/tongue weight.

 

[Darrow]

Awesome I was thinking that, thank you!

 

[isaacfinnegan]

It's more of result of GVWR than gearing. Some of those high trim 4drs get real porky and it takes away from available payload/tongue weight.

Payload makes sense. How would GVWR affect tongue weight?

 

[Fonz54]

It's more of result of GVWR than gearing. Some of those high trim 4drs get real porky and it takes away from available payload/tongue weight.

Who you callin' porky?

 

[Tricky Dick]

Payload makes sense. How would GVWR affect tongue weight?

~350lbs on the bumper counts against the tow vehicle's payload. When some of these configurations don't even allow for a roof rack it tells you how little you have to work with.

 

[isaacfinnegan]

350lbs on the bumper counts against the tow vehicle's payload

Sorry, I'm not following. I can see how weight on the hitch/tongue would reduce the overall payload, but not how the vehicle weight itself would affect tongue weight. Tongue weight, afaik, is based entirely on the frame/hitch strength. Not vehicle weight.

 

[Tricky Dick]

Sorry, I'm not following. I can see how weight on the hitch/tongue would reduce the overall payload, but not how the vehicle weight itself would affect tongue weight. Tongue weight, afaik, is based entirely on the frame/hitch strength. Not vehicle weight.

There isn't enough available payload to support the higher towing/tongue weights people want. Say your GVWR is 6000, and your curb weight is 5000. Add 4 occupants and luggage, you're left with say 300lb available payload. Adding 350lb of tongue weight now puts your curb weight over 6000. Theoretical numbers, but the basic reason a 4dr 2.7 Badlands isn't rated for the full 3500lb.

 

[isaacfinnegan]

There isn't enough available payload to support the higher towing/tongue weights people want. Say your GVWR is 6000, and your curb weight is 5000. Add 4 occupants and luggage, you're left with say 300lb available payload. Adding 350lb of tongue weight now puts your curb weight over 6000. Theoretical numbers, but the basic reason a 4dr 2.7 Badlands isn't rated for the full 3500lb.

Yes. I understand that, this is my point around GVWR is affected by weight on hitch (tongue weigth) but not the other way around. If I have an empty vehicle and a hitch carrier (not trailer), I'm towing nothing and the tongue weight defines how much load I can put on the hitch receiver. It's definitely NOT GVWR-current weight total: 800 lbs (1 driver, no luggage = 200lbs for this example). As the hitch will break because tongue weight is based on hitch/frame. Not GVWR.

 

[Tricky Dick]

Yes. I understand that, this is my point around GVWR is affected by weight on hitch (tongue weigth) but not the other way around. If I have an empty vehicle and a hitch carrier (not trailer), I'm towing nothing and the tongue weight defines how much load I can put on the hitch receiver. It's definitely NOT GVWR-current weight total: 800 lbs (1 driver, no luggage = 200lbs for this example). As the hitch will break because tongue weight is based on hitch/frame. Not GVWR.

I follow. I don't know how much weight the hitch can support before it breaks.

 

[isaacfinnegan]

What gets really confusing is the actual tongue weight varies per vehicle, and there is really no direct relationship between tongue weight capacity and towing. Towing capacity is almost entirely affected by braking power, NOT powertrain as is commonly misunderstood. Yes, powertrain is a factor (minor) as is suspension/wheelbase (medium). Some sites say 350lb, but that's based on the trailer tow limit (10% of tow) which is not really a great rule, although not too far off.
My wife's Range Rover Sport has a class III hitch rated at 750lbs, tongue weight and the vehicle towing capacity at about 8800lbs.

I bought the Rough Country class III hitch, which their site says is rated for 350lbs TW and 3500 towing. So clearly this is just copying the Bronco vehicle details as I believe the Ford factory hitch is class II.
So one is class II and the other is class III. Somehow different, but can't find specs that make it clear.
Types of Trailer Hitches and Hitch Classes - Towing 101 (curtmfg.com)

 

[Deleted User 5719102]

There isn't enough available payload to support the higher towing/tongue weights people want. Say your GVWR is 6000, and your curb weight is 5000. Add 4 occupants and luggage, you're left with say 300lb available payload. Adding 350lb of tongue weight now puts your curb weight over 6000. Theoretical numbers, but the basic reason a 4dr 2.7 Badlands isn't rated for the full 3500lb.

This is what towing capacity is all about, subtracting the curb weight from the GCVWR gives you the vehicle’s towing capacity.

This statement has nothing to do with a hitch class, I, II, III, IV, V. Tongue wt does factor into manufacturer suggested towing capacity. Occupants, gear, fluids such as a full tank of fuel, trailer wt all has to be configured in. Manufacturer tow capacities calculations are based on a driver occupant only, and most calculations are done with a dry vehicle, no fluids that a vehicle needs to drive. So if there is family, gear, etc, you the owner have to calculate the additional wt inside the tow vehicle. But again, has nothing to do with hitch specs. A hitch and receiver is nothing more than a coupler between tow vehicle and trailer to allow for your towing needs, hence the different classes. And calculations for hitches are based on type of tow vehicle, suspension and drivetrain (engine/transmission).

Tongue wt is not an absolute number either. Tongue wt can change each and every time you load your trailer, or fuel your boat etc, etc. If you load your trailer front heavy, then you are increasing tongue wt, if you load rear heavy your decreasing tongue wt. If you are towing a boat, and most fuel cells are aft, then when boat is full of fuel you are decreasing tongue wt. All these are factors in determining tongue wt. If you are tongue heavy, then you are decreasing your ability to drive the tow vehicle safely, if you are tongue lite, then you will most likely experience trailer sway left to right. Which in both cases are and can be extremely dangerous. Your tongue wt should never exceed 10-15% of trailer wt capabilities.

If you plan on towing a trailer with a 3500 lb capacity, and you want to install a class II hitch, which is rated max wt of 3,500 lbs, then you should install the class III rated at 5000 lbs. You never want to install a hitch that is going to be stressed at all times.

FYI, most manufactures of vehicle and towing attachments always error on the side of caution and suggest you stay 10% below vehicle towing capacity and towing attachment capacity.

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