Upgrade to Max Tow Rear Brakes?

[imnuts]

W

here'd you see this?​

Had the weights off some, but the Ford parts website lists the shipping weight for the rotors. The light/medium rear rotor is 15.6#, the heavy rear rotor is 22.7#, so 50% heavier.

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[redline]

With 80% of braking is done by the front brakes a small upgrade to the rear will not be noticeable, you are better off looking at the front first for a real improvement.

start with fluid, pads, SS brake lines.

 

[Buyer2021]

Note that when towing a heavy trailer, the transfer of weight through the hitch during braking can significantly increase the tow-vehicle's rear brake role relative to the front (with or without a WDH, and the effect is similar when towing a 5th wheel or gooseneck trailer).

That effect is exacerbated on downhill grades, and is not mitigated by having trailer brakes (though trailer brakes will decrease the overall braking force required of the tow vehicle).

 

[EricR]

Does anyone know if the Tow/Haul mode changes the brake bias towards the rear?

If so, it's a good reason to stay in Tow/Haul when towing.

 

[Buyer2021]

Does anyone know if the Tow/Haul mode changes the brake bias towards the rear?

With the advent of modern ABS systems the old notion of 'fixed' or 'valve-adjustable' F/R brake bias is essentially no longer meaningful / applicable.

With modern ABS, no matter what the state of load in or hitched to the vehicle, and any weight-transfer dynamic that is in-play, each wheel's brake is applied independently to the best effect possible for the given brake hardware and actual road / traction conditions.

This is a much more effective and sophisticated approach than simply setting or changing F/R brake bias as it doesn't just estimate the different braking capability of F/R wheel pairs but constantly responds to the actual braking capability each wheel F/R/Left/Right independently.

No, the ABS does not 'change' in response to the tow/haul 'mode' setting, it doesn't need to do that, they are completely independent things.

 

[EricR]

With the advent of modern ABS systems the old notion of 'fixed' or 'valve-adjustable' F/R brake bias is essentially no longer meaningful / applicable.

With modern ABS, no matter what the state of load in or hitched to the vehicle, and any weight-transfer dynamic that is in-play, each wheel's brake is applied independently to the best effect possible for the given brake hardware and actual road / traction conditions.

This is a much more effective and sophisticated approach than simply setting or changing F/R brake bias as it doesn't just estimate the different braking capability of F/R wheel pairs but constantly responds to the actual braking capability each wheel F/R/Left/Right independently.

No, the ABS does not 'change' in response to the tow/haul 'mode' setting, it doesn't need to do that, they are completely independent things.

Makes sense.

Thanks!

 

[HammaMan]

the max tow brakes aren’t even all that lol.. my truck struggles braking with a 3000 pound trailer around town. i couldn’t imagine how bad it would be if i didn’t have max tow brakes lmfao

Well the "larger" brakes are imperceptible to a human. Total friction braking area increases by about 2%. While more mass in the rotor does increase the time it takes to heat them up, they stay hot longer / take longer to cool.

If you want better braking performance, leave the factory rotors all together.

 

[redline]

Note that when towing a heavy trailer, the transfer of weight through the hitch during braking can significantly increase the tow-vehicle's rear brake role relative to the front (with or without a WDH, and the effect is similar when towing a 5th wheel or gooseneck trailer).

That effect is exacerbated on downhill grades, and is not mitigated by having trailer brakes (though trailer brakes will decrease the overall braking force required of the tow vehicle).

maybe , but in my experience with towing heavy trailers that my rear brakes still last 2x-3x longer then the fronts and I would run better after market rotors and pads on the front and oem rear

 

[Eighthtry]

I had a 1985 Suburban. My factory front rotors were warping. I put a new set on, then warp. I put a new set on, they warp. So I got to thinking that if I continue this I will be running out of money and patience, overexercise my language skills, and still not solve the problem.

I called my mechanic (he turned down a full ride academic scholarship to Harvard to go racing). Explained the problem. He said to buy a fresh set of factory rotors and he would slot them for me.

I never warped a front rotor again.

All were the same factory part number GM Suburban front rotors as new.

Of course I think wheel size was 15", so that probably had a ton to do with it. But I believe in slots because of that experience. I do not believe in holes. That's for looks only. It reminds me of my first blind date.

 

[Eighthtry]

With 80% of braking is done by the front brakes a small upgrade to the rear will not be noticeable, you are better off looking at the front first for a real improvement.

start with fluid, pads, SS brake lines.

I have to know. Why does he need to go to SS lines?

 

[Eighthtry]

Well the "larger" brakes are imperceptible to a human. Total friction braking area increases by about 2%. While more mass in the rotor does increase the time it takes to heat them up, they stay hot longer / take longer to cool.

If you want better braking performance, leave the factory rotors all together.

I really like this guy. He's a thinker and communicator.

 

[redline]

I have to know. Why does he need to go to SS lines?

Improves paddle feel and reduced expansion, resulting in superior durability.

 

[Calson]

By law a trailer over 3500 lbs gross weight needs to have its own brakes, either hydraulic or electric. No need for the truck's brakes to be used unless the trailer brakes fail.

If truly concerned about braking with a heavy trailer it would be smart to buy a truck with a diesel engine and exhaust braking.

 

[mdomicolo]

the max tow brakes aren’t even all that lol.. my truck struggles braking with a 3000 pound trailer around town. i couldn’t imagine how bad it would be if i didn’t have max tow brakes lmfao

You may want to have your truck looked at.

I tow 10,000lbs frequently up & down the east coast and usually cruising at 85-90mph! 25k miles, and have zero issues. The truck brakes hard!

 

[FaaWrenchBndr]

Why is a different axle required?

Also, my understanding is that the max tow brakes have better cooling properties and are slightly larger in diameter. The larger diameter will give better braking despite an almost equal contact area, and improved cooling will keep them operating longer.

this ain’t a bolt on mod, you can’t just switch parts.

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