"Realistic" towing ratings

[ratdude747]

AOD. 3rd gear is the innermost shaft to the direct clutch. It is splined to the front of the torque converter and is driven directly by the crank, in OD it is split 60% direct and 40% converter if I remember correctly. The AOD towing in 3rd is exactly like towing with a manual transmission. This is also why the throttle rod or cable adjustment is so critical to preventing damage, too much either way can burn it up or break something.

The AOD is unique in that it does not have a lock-up torque converter. And yet it can run without torque-converter action. Unlike all other transmissions, the AOD has TWO input shafts. They are concentric, one inside the other.

The smaller, removable secondary input shaft is tied directly to the torque converter’s shell and forward clutch. The larger, hollow primary input shaft is driven by the torque converter’s turbine (torque multiplication) in First, Second, and Reverse gears. Full torque converter action is available in 1st and 2nd gears, and is always there, like a C6 for example.

However, 3rd and 4th gears use the direct input shaft, so there is absolutely NO torque converter action in 3rd or 4th, no matter what. In other words, the smaller, direct input shaft connects THROUGH the converter, bypassing converter action completely. This is good for gas mileage. And since there is no clutch in the torque converter nor need to control one, the AOD is simpler.

Ford called this design "split-torque" because 40% of the engine’s torque goes through the torque converter as torque multiplication (via the impeller, stator, and turbine), while 60% goes through the smaller input shaft in Third gear. When the transmission shifts into Overdrive or Fourth gear, 100% of the engine’s torque goes through the smaller secondary input shaft as straight drive and lock-up in the gear-train and clutch pack. Tip in the throttle and the AOD goes into Third gear with the split-torque pattern. At WOT, 100% of the torque goes through the torque converter and hollow primary input shaft.

Capiche?

Here's a good read on how the AOD's torque split works:

https://ateupwithmotor.com/terms-technology-definitions/split-torque-lockup-converters/6/

It's a lot to comprehend, but Ravigneaux based automatics aren't exactly the simplest transmissions in the world.

My understanding (going back to my original "AOD not good enough" post) was that since the AOD replaced the C4 and C5, it wasn't as strong as a C6 and thus on a torquey motor like my 300, is the weak link (and thus bottlenecks towing performance). Ford didn't specify on the chart though... perplexing.

[Rusty_S85]

I've used trailers with surge brakes, including my boat trailer. I don't mind them on a relatively lightweight trailer on a relatively heavy truck (like my 2500~3000 lb boat/motor/trailer behind my 6600 lb truck). But when the trailer weight is approaching the truck weight I really prefer electric.

But with electric, make use you get a brake controller that's not the cheapy timer-based style. It costs more to get the kind that use an accelerometer to decide how hard to apply the brakes, but it's well worth the extra $20.

It costs a lot more, like $40,000 more, to get the kind that are integral to the truck's braking system. But you get a free truck with it, so it's not that bad really.

The unit I installed at work that stressed it had to be level was one of those, it stated that it cant be more than I think it said 5* for the accelerometer to work properly.

All the trailers I ever had were without brakes except for the latest for the new truck that has electric brakes and it pulls good and stops good. Down side is you have to adjust the controller constantly where as with a surge brake its automatically adjusted if you unload the trailer and then tow a empty trailer home.

I personally looked at the electric over hydraulic before but it requires a unique controller and you cant simply use any electric trailer brake controller.

[Nothing Special]

The unit I installed at work that stressed it had to be level was one of those, it stated that it cant be more than I think it said 5* for the accelerometer to work properly....

That's odd. I've set up several brake controllers (and none of them has been a very expensive one). All of them have had a way to compensate for being mounted at just about any "pitch" angle (the one in my truck is closer to vertical than it is to horizontal).

What is fairly important is that they aren't mounted with much "yaw". They need to be aligned parallel to a line running front-to-back.

.... Down side is you have to adjust the controller constantly where as with a surge brake its automatically adjusted if you unload the trailer and then tow a empty trailer home....

True. So far all of the trailers I've towed with electric brakes have had a fairly consistent weight (a couple different travel trailers and flat-towing my Bronco or the CJ5 I had before it) so I haven't had to deal with that. But I still think I'd prefer electric brakes. If you know what setting you need it's really quick and easy to change it.

[ratdude747]

The unit I installed at work that stressed it had to be level was one of those, it stated that it cant be more than I think it said 5* for the accelerometer to work properly....

That's odd. I've set up several brake controllers (and none of them has been a very expensive one). All of them have had a way to compensate for being mounted at just about any "pitch" angle (the one in my truck is closer to vertical than it is to horizontal).

What is fairly important is that they aren't mounted with much "yaw". They need to be aligned parallel to a line running front-to-back.

.... Down side is you have to adjust the controller constantly where as with a surge brake its automatically adjusted if you unload the trailer and then tow a empty trailer home....

True. So far all of the trailers I've towed with electric brakes have had a fairly consistent weight (a couple different travel trailers and flat-towing my Bronco or the CJ5 I had before it) so I haven't had to deal with that. But I still think I'd prefer electric brakes. If you know what setting you need it's really quick and easy to change it.

Reviving this thread due to recent events.

My father-in-law is selling me his car hauler for "cheap". He's upgrading trailers, and I had to snap at the oppertunity.

The trailer is overkill (7000lb rated, one of two axles has brakes). Obviously I'll need to get a class III receiver and a brake controller. Any suggestions?

[FuzzFace2]

Reviving this thread due to recent events.

My father-in-law is selling me his car hauler for "cheap". He's upgrading trailers, and I had to snap at the oppertunity.

The trailer is overkill (7000lb rated, one of two axles has brakes). Obviously I'll need to get a class III receiver and a brake controller. Any suggestions?

What do you have again? I see it in your sig.

I got my receiver off CL its a Reese TowPower fit all.

The brake controller I got through Northern Tool along with the pig tail that plugs into the controller and you splice the other end to the truck side.

Dont cheap out on the controller and get a timed one as they are junk in my book.

I have 2 that have a pendulum, the harder you brake the more it swings and applies more trailer brakes.

They also have a hand over ride so you can apply the trailer brakes with out touching the trucks pedal.

If I did not get the controller & receiver the way I did I would have gone thru https://www.etrailer.com/

That is were I got my other controller from, truck came with tow package so had the hitch and wiring.

I have not pulled my car trailer yet but the truck is all set up to do so if needed.

I use a weight distribution hitch (WDH) with my other truck (02 Durango) I ordered to pull my trailer.

I for see needing to use the WDH on the pick up as it is only a F100 and no over load springs out back.

The WDH also helps control sway but you still have to make sure the load (car or truck) is placed right on the deck of the trailer.

To far forward and even with the WDH you can drag the hitch.

To far back and you can get a lot of swaying that you cant control and the next thing you are on YouTube!

Dave ----

[Gary Lewis]

What do you have again? I see it in your sig.

I got my receiver off CL its a Reese TowPower fit all.

The brake controller I got through Northern Tool along with the pig tail that plugs into the controller and you splice the other end to the truck side.

Dont cheap out on the controller and get a timed one as they are junk in my book.

I have 2 that have a pendulum, the harder you brake the more it swings and applies more trailer brakes.

They also have a hand over ride so you can apply the trailer brakes with out touching the trucks pedal.

If I did not get the controller & receiver the way I did I would have gone thru https://www.etrailer.com/

That is were I got my other controller from, truck came with tow package so had the hitch and wiring.

I have not pulled my car trailer yet but the truck is all set up to do so if needed.

I use a weight distribution hitch (WDH) with my other truck (02 Durango) I ordered to pull my trailer.

I for see needing to use the WDH on the pick up as it is only a F100 and no over load springs out back.

The WDH also helps control sway but you still have to make sure the load (car or truck) is placed right on the deck of the trailer.

To far forward and even with the WDH you can drag the hitch.

To far back and you can get a lot of swaying that you cant control and the next thing you are on YouTube!

Dave ----

I have a Tekonsha 90195 P3 on Big Blue, and Clay probably does on Rusty as I put it there. They have worked well for me.

[ratdude747]

What do you have again? I see it in your sig.

I got my receiver off CL its a Reese TowPower fit all.

The brake controller I got through Northern Tool along with the pig tail that plugs into the controller and you splice the other end to the truck side.

Dont cheap out on the controller and get a timed one as they are junk in my book.

I have 2 that have a pendulum, the harder you brake the more it swings and applies more trailer brakes.

They also have a hand over ride so you can apply the trailer brakes with out touching the trucks pedal.

If I did not get the controller & receiver the way I did I would have gone thru https://www.etrailer.com/

That is were I got my other controller from, truck came with tow package so had the hitch and wiring.

I have not pulled my car trailer yet but the truck is all set up to do so if needed.

I use a weight distribution hitch (WDH) with my other truck (02 Durango) I ordered to pull my trailer.

I for see needing to use the WDH on the pick up as it is only a F100 and no over load springs out back.

The WDH also helps control sway but you still have to make sure the load (car or truck) is placed right on the deck of the trailer.

To far forward and even with the WDH you can drag the hitch.

To far back and you can get a lot of swaying that you cant control and the next thing you are on YouTube!

Dave ----

Found a similar one on FB Marketplace. Will be looking at it after work. $40, has some surface rust (and supposedly came off an '85 bullnose!).

[85lebaront2]

Found a similar one on FB Marketplace. Will be looking at it after work. $40, has some surface rust (and supposedly came off an '85 bullnose!).

Unfortunately, I don't think I have a picture of the complete receiver setup on Darth. He has a V5 rated receiver that is integrated into the rear step bumper. Result being a massive chunk of bolted together steel on the back end of his frame. Original owner haul large horse trailers on that setup. I used a bed mounted 5th wheel hitch.

[Jstas]

Hankook Optimo. Marked "Extra Load", rated for 2183lbs @50PSI Max (per the tire stamp).

Not trying to be pedantic here or step on toes but load ranges are different for passenger vs. light truck tires.

If you have tires that have a load range rating of XL or "Extra Load", they are passenger car tires and XL is the top load range rating for them.

Light Truck tires have load ranges from A to F and if you have anything with a GVW of 8500 pounds or higher, your tire spec often dictates a load range of E. Stuff like a new F450 chassis cab will often come with tires rated in the load range of F. After F you get into medium duty truck tires which are commercial level stuff and the rating ranges change again.

This site from Tire America explains it pretty simply: https://www.tireamerica.com/resource/guide-to-tire-load-range

But the biggest reason you want to shy away from passenger car tires, even if they are rated XL and have load ratings that exceed your GVW or GCWR is sidewalls. Not because they are more stiff like someone else mentioned but because they have more materials and belting in the sidewalls.

That's important because as tires load down, the sidewalls bow out. This is a design feature that allows the tread block to stay square with the road offering the largest contact patch for traction and control surface area. The extra belting and materials in LT sidewalls helps control the tire's contact patch under heavy load. If you load the tire down too much, the sidewalls bow out too much. The only draw back is that your nice, cushy new F350 King Ranch might need load range E tires on it and unloaded, those E tires are going to be like basketballs running 45-65 psi. It'll make your squishy King Ranch bounce around like a 1950's Land Rover.

But back to overloading, at the point where the sidewalls are bowing exceesively, instead of having a vertical bow to transfer the vehicle load to the road, the load is sitting on the air pocket sandwiched between the two sides of the sidewall U. When that happens, as the tire rolls down the road, the carcass and rim bead will get stretched and then relax at a very frequent rate. They are not designed to do that.

So that means that layers of the tire carcass are now rubbing against each other inside the tire and that causes excessive heat to build up. Enough heat that the tire layers soften and melt enough that they will delaminate. That delamination leads to catastrophic failure (aka: a blow out) and at highway speeds with a heavy load, that's crazy levels of dangerous.

Infrequent use of the truck as a heavy hauler you can get away with slick looking, smooth riding, quiet passenger car tires. But if you plan to do any kind of heavy load hauling or towing then you should consider light truck tires with an adequate load range rating.

Side note, when you drive down the highway and see those huge chunks of tires and rubber on the sides of the road that was caused by the same type of load as exceeding your load rating on your tires. Those failures happened, though, from under-inflation. The truck drove down the road dragging a trailer that had a tire go down in pressure and as it heated up, it caused the tread plate to separate from the carcass which then whipped around until it disintegrated and the carcass blew open. It wasn't overloaded when it was properly inflated but it did get overloaded when the air pressure in the tire dropped to the point where the tire was now longer capable of supporting it's rated load and the sidewalls bulged just as if it was overloaded.

If you are driving down the road and passing an 18-wheeler, you can hear that separation starting to happen. It usually sounds like one tire is perpetually rolling down a rubber gravel road despite being on smooth pavement. Don't hang around next to that tire too long because it can, honestly, let go at any minute once it's making that sound. Those tire chunks are heavy and they will damage your ride or even you.

BTW, over-inflating a tire can cause it to stretch in the wrong way too which will also lead to failure.

So, TL;DR, tire load range ratings are important and so is the difference between passenger car tires and light truck tires.

[kramttocs]

Not trying to be pedantic here or step on toes but load ranges are different for passenger vs. light truck tires.

If you have tires that have a load range rating of XL or "Extra Load", they are passenger car tires and XL is the top load range rating for them.

Light Truck tires have load ranges from A to F and if you have anything with a GVW of 8500 pounds or higher, your tire spec often dictates a load range of E. Stuff like a new F450 chassis cab will often come with tires rated in the load range of F. After F you get into medium duty truck tires which are commercial level stuff and the rating ranges change again.

This site from Tire America explains it pretty simply: https://www.tireamerica.com/resource/guide-to-tire-load-range

But the biggest reason you want to shy away from passenger car tires, even if they are rated XL and have load ratings that exceed your GVW or GCWR is sidewalls. Not because they are more stiff like someone else mentioned but because they have more materials and belting in the sidewalls.

That's important because as tires load down, the sidewalls bow out. This is a design feature that allows the tread block to stay square with the road offering the largest contact patch for traction and control surface area. The extra belting and materials in LT sidewalls helps control the tire's contact patch under heavy load. If you load the tire down too much, the sidewalls bow out too much. The only draw back is that your nice, cushy new F350 King Ranch might need load range E tires on it and unloaded, those E tires are going to be like basketballs running 45-65 psi. It'll make your squishy King Ranch bounce around like a 1950's Land Rover.

But back to overloading, at the point where the sidewalls are bowing exceesively, instead of having a vertical bow to transfer the vehicle load to the road, the load is sitting on the air pocket sandwiched between the two sides of the sidewall U. When that happens, as the tire rolls down the road, the carcass and rim bead will get stretched and then relax at a very frequent rate. They are not designed to do that.

So that means that layers of the tire carcass are now rubbing against each other inside the tire and that causes excessive heat to build up. Enough heat that the tire layers soften and melt enough that they will delaminate. That delamination leads to catastrophic failure (aka: a blow out) and at highway speeds with a heavy load, that's crazy levels of dangerous.

Infrequent use of the truck as a heavy hauler you can get away with slick looking, smooth riding, quiet passenger car tires. But if you plan to do any kind of heavy load hauling or towing then you should consider light truck tires with an adequate load range rating.

Side note, when you drive down the highway and see those huge chunks of tires and rubber on the sides of the road that was caused by the same type of load as exceeding your load rating on your tires. Those failures happened, though, from under-inflation. The truck drove down the road dragging a trailer that had a tire go down in pressure and as it heated up, it caused the tread plate to separate from the carcass which then whipped around until it disintegrated and the carcass blew open. It wasn't overloaded when it was properly inflated but it did get overloaded when the air pressure in the tire dropped to the point where the tire was now longer capable of supporting it's rated load and the sidewalls bulged just as if it was overloaded.

If you are driving down the road and passing an 18-wheeler, you can hear that separation starting to happen. It usually sounds like one tire is perpetually rolling down a rubber gravel road despite being on smooth pavement. Don't hang around next to that tire too long because it can, honestly, let go at any minute once it's making that sound. Those tire chunks are heavy and they will damage your ride or even you.

BTW, over-inflating a tire can cause it to stretch in the wrong way too which will also lead to failure.

So, TL;DR, tire load range ratings are important and so is the difference between passenger car tires and light truck tires.

Thanks for that info Jstas

In my 86 I have a Reese hidden controller but in the 80 and my dad's 00 2500HD we have Tekonsha 90160 Primus IQ's. No complaints with either.