Arbitrary numbers?

[TwoManyToyz]

Hello, I'm new here. Just wanted to get your opinion on this?

https://rvlifemag.com/towing-half-ton-three-quarter-ton/

He ends the article with

"Is it worth possibly giving up independent front suspension, raising your centre of gravity and having a much heavier vehicle to stop and turn, just to satisfy an arbitrary number that does not actually matter when towing?"

[ib516]

TTCrewmax wrote:

ib516 wrote:

It's not just rotor size that determines brake capability.

It's the overall mass of the rotor for better heat load - heavier can absorb more heat - these are friction brakes after all. It's also determined by the calipers. Number of pistons, the hydraulic pressure used to actuate them, etc. There's also different materials used for the friction pads, with different coefficient's of friction in the material.

I think this is fluff answer...of course that all matters. But assuming that the main truck manufacture's don't have their heads up their a**. Then we can assume that the heavy 1/2 tons offered have huge disc brakes with big calipers and 4 pistons per.

If that's the case then there is nothing that says a 3/4 ton will stop a load better than a 1/2 ton.

Change my mind.

Nah, keep your opinion, I'll keep mine - and my engineering degree, 22 years of collision reconstruction experience as a LEO, and being a certified expert witness in numerous criminal trials.

[TTCrewmax]

ib516 wrote:

It's not just rotor size that determines brake capability.

It's the overall mass of the rotor for better heat load - heavier can absorb more heat - these are friction brakes after all. It's also determined by the calipers. Number of pistons, the hydraulic pressure used to actuate them, etc. There's also different materials used for the friction pads, with different coefficient's of friction in the material.

I think this is fluff answer...of course that all matters. But assuming that the main truck manufacture's don't have their heads up their a**. Then we can assume that the heavy 1/2 tons offered have huge disc brakes with big calipers and 4 pistons per.

If that's the case then there is nothing that says a 3/4 ton will stop a load better than a 1/2 ton.

Change my mind.

[mkirsch]

TwoManyToyz wrote:
I know and thats where I am with my overage. but its only a few hundred over.

I would imagine theres a safety buffer of 10-15% that i'm in.

You can "imagine" but you don't know for fact, and can't know because the manufacturer will never divulge that information. That would put them on the hook for any liability associated with the results of overloading, regardless of how remote the possibility of such a thing happening would be. They do not want to take ANY chance of being raked over the coals for saying, "It's okay to overload."

That said, if it works fine for you, what does any of it matter? Just drive it and be happy, until you aren't, then do something about it.

[ib516]

IdaD wrote:

shelbyfv wrote:
Well, if it can happen with a 3500 it's obviously something to think about!

All the newer diesels come with factory exhaust brakes. I've towed in the Rockies, Sierras and Cascades with my 2015 and coming down the big grades out here I rarely use the brakes other than slowing for corners or when I need to come to a stop. My setup isn't as heavy as some at about 20k combined, but having an EB that's able to hold a set speed without using the brakes at all is a pretty big advantage.

Yes my 5.9L was pre-factory exhaust brake. You could add one from Cummins to the late 5.9Ls, but here in Canada they were ~$1800 installed IIRC.

[IdaD]

shelbyfv wrote:
Well, if it can happen with a 3500 it's obviously something to think about!

All the newer diesels come with factory exhaust brakes. I've towed in the Rockies, Sierras and Cascades with my 2015 and coming down the big grades out here I rarely use the brakes other than slowing for corners or when I need to come to a stop. My setup isn't as heavy as some at about 20k combined, but having an EB that's able to hold a set speed without using the brakes at all is a pretty big advantage.

[shelbyfv]

Well, if it can happen with a 3500 it's obviously something to think about!

[ib516]

shelbyfv wrote:
It would also be interesting to hear from anyone who has experienced heat related brake fade while towing with any modern truck. With tow/haul transmissions and trailer brakes it may be uncommon.

I did. Towing over the Teton Pass in WY. Had smoke coming from both front brakes despite using 2nd gear and braking intermittently. The RV brakes may not have been doing their job as they were repaired the next season when one took a dive on me. The truck was a 5.9L Cummins 3500 SRW Megacab 4x4. Weight was about 21k combined. Had to pull over and let everything cool down. Stopping on the shoulder took 2 feet on the brake pedal. Scary stuff.

[Grit_dog]

^It is uncommon, unless a person is clueless, way overloaded, no trailer brakes, or just clueless.
FWIW, a 1990 1/2ton Chevy will tow 8000lbs through the mountains with no trailer brakes and not smokethe brakes.....if you know how to drive.
The dpwra (door placard weight rating anxiety) folks might say different.

[shelbyfv]

It would also be interesting to hear from anyone who has experienced heat related brake fade while towing with any modern truck. With tow/haul transmissions and trailer brakes it may be uncommon.

[ib516]

TTCrewmax wrote:

JIMNLIN wrote:


One big fib was 1/2 tons have nearly the same brakes as a 3/4 ton. Brakes are a axle rating function at a minimum... example;
A F250 Ford with a 6k fawr and a 6340 rawr = 12340 lbs of braking performance

A F150HD Ford has the heaviest specs with a 3750 fawr and 4800 rawr = 8550 lbs of braking performance.

Lots this guy simply doesn't know but he has a opinion like we all do.

I'd like to discuss this point further because I'm a 1/2 ton guy that tows heavy.

I've always been intrigued by this very point.

I drive a Tundra and it has, when it was originally designed in '07, huge disc brakes front and rear with a very capable front and rear axle.

So the question is how are the brakes on the new class of half tons - if equal in size - not as capable as an HD equivalent?

Thanks!

It's not just rotor size that determines brake capability.

It's the overall mass of the rotor for better heat load - heavier can absorb more heat - these are friction brakes after all. It's also determined by the calipers. Number of pistons, the hydraulic pressure used to actuate them, etc. There's also different materials used for the friction pads, with different coefficient's of friction in the material.

[TTCrewmax]

JIMNLIN wrote:


One big fib was 1/2 tons have nearly the same brakes as a 3/4 ton. Brakes are a axle rating function at a minimum... example;
A F250 Ford with a 6k fawr and a 6340 rawr = 12340 lbs of braking performance

A F150HD Ford has the heaviest specs with a 3750 fawr and 4800 rawr = 8550 lbs of braking performance.

Lots this guy simply doesn't know but he has a opinion like we all do.

I'd like to discuss this point further because I'm a 1/2 ton guy that tows heavy.

I've always been intrigued by this very point.

I drive a Tundra and it has, when it was originally designed in '07, huge disc brakes front and rear with a very capable front and rear axle.

So the question is how are the brakes on the new class of half tons - if equal in size - not as capable as an HD equivalent?

Thanks!

[rjstractor]

I wouldn't say the guy is an idiot. In fact, he brings up a lot of good points that many of us agree on here, like switching to LT-rated tires on 1/2 trucks, and axle ratings are the ones that really matter. I'm definitely not a fan of the idea of towing a huge Airstream with a Chrysler 300 (mostly due to drivetrain concerns) but I don't think he's as far out in left field as some do.

[ib516]

TwoManyToyz wrote:

shelbyfv wrote:
Another first post Can-Am RV plug? There was one yesterday on another forum.

No plug here, I'm just towing with a half ton and trying to get to the bottom of all this.

My big question is that my f-150 has as high or higher ratings than a 3\4 ton from 15 - 20 years ago, ( in HP and tow ratings). Those older trucks towed heavier RV's than we tow today based on construction Technics. So riddle me this? This bible of tow specs that everyone errors on the side of safety for, is it kind of "arbitrary"?

I realize there's a limit of ridiculousness, like I wouldn't tow a 15000lbs rig with a half ton. That being said , with better trailer brakes and modern half tons built today. Are the tow specs just a good guide line these days?

And I know your going to ask, I'm towing a 2015 Keystone Cougar 25rks 5er that weighs 6300lbs dry, 1125lbs pin weight. Its marketed as a "half ton towable 5th wheel" I'm only over some of my specs by 2 or 3%. It handles and stops just fine.

Your thoughts?

IMHO so long as you're under your GAWRs, a few hundred over GVWR isn't a big deal. I wouldn't worry about it.

[JIMNLIN]

And I know your going to ask, I'm towing a 2015 Keystone Cougar 25rks 5er that weighs 6300lbs dry, 1125lbs pin weight. Its marketed as a "half ton towable 5th wheel" I'm only over some of my specs by 2 or 3%. It handles and stops just fine.

Your thoughts?

If your happy with the way the truck handles the trailer thats what counts.
Top safety priority is stay under the trucks gawrs especially rawr as its carrying most if not all the load in the bed. Rawr = the lessor of a wheel/tire/axle/or rear spring pack.


The F150 comes in several gvwrs up to 7850 and rawr from the tiny 3800 lb up to 4800 lbs for the HD package. One size don't fit all with Fords F150
I see many folks happily towing around 10k lb trailers with their F150HD 7850-8200 gvwr and 4800 rawr. These trucks can have 2400-2500 lb in the bed payloads....but in no way can compare with the F250 10000 lb gvwr and 6340 RAWR. That 6340 rawr can have over 3000 lbs of real world in the bed payloads. In fact the F250 with the camper package or heavy service package has the same suspension as the F350SRW.
1/2 ton vs a 3/4 ton = apples vs oranges when we look at the numbers that count.