warped rotors :(

[spongebob]

my 1 ton 4X4 had warped roters..at 45k.
i cant remember ever using the brakes that hard..
dood at the dealership said it want that uncommon..

anyone else had this??

[Mark Rinker]

Yeah. I got 'em from an employee with a heavy brake habit. I suspect he also forgot to run Tow/Haul mode when towing, which helps alot with downshifting to slow the load.

Spend the $$$ and put on some good stuff - not NAPA parts. I now have 1) a new driver, 2) ceramic pads and 3) Okebono rotors as suggested by a racer friend of mine who pulls a huge enclosed trailer behind his dually.

Mine were heat cracked and delaminating on the surface (NAPA crap parts) and the pads literally disintegrated and came apart in chunks at about 40K.

P.S. Your oversize wheels and tires don't help.

[killerbee]

P.S. Your oversize wheels and tires don't help.

How so? If anything the slower rotating wheel would be a benefit...in my mind that is. :)

[SoTxPollock]

I believe that if one could do the research, you would find the most common cause of warped rotors is inproper, (uneven) wheel torque. I've had to stand on the brakes pretty hard several times, but never warped the rotors yet. It used to happen pretty easy until I stopped trusting tire installers and brake repair people to torque the wheels to the right setting and started carrying a torque wrench in the truck. If I get the tires rotated I drive a few miles down the road and pull over at a safe place and retorque the wheel lugs. There are always a few that have loosened up.

Killerbee, I think Mark was commenting about the oversize wheels and tires not helping. The larger the diameter wheel and tire the harder you have to push the brake petal to stop, due to the increased distance from the center of the wheel to the road. Its called moment arm. The longer the distance the greater the moment reaction because of course the greater distance.
I've had discussions with my parts buddies that own the stores and they tell me the replacement rotors that most people sell and have made in China on them are so thin they won't last nor not warp. They are cheaper for a reason.
You sometimes get what you pay for.

[killerbee]

Mark,, sorry I doubted you. That makes perfect sense. Thanks STP. ;)

But still, slower wheel with more moment arm. sounds like they cancel each other out. Maybe not.

[Mark Rinker]

What SoTxPollock said. In my speak, its simply the increased torque that the larger diameter wheel excerts on the same braking surface area, as the wheel gets larger and the braking area stays the same (unless upgraded, or re-engineered altogether).

I am a farm kid, more seat-of-the-pants, experential knowledge than book knowledge, but do know that oversize wheels and tires reduces brake effectiveness and lifespan of brake componants. I have experienced it in lifted, 33" tire trucks and its not fun trying to stop with stock OEM brakes from highway speeds.

As an exaggerated example, picture yourself in 'Bigfoot' with the stock Ford F350 brakes in place...now stomp on the pedal after a 60mph jump over 5 cars...HERE COMES THE POPCORN STAND!!!

:)


....

"Something else we have that is unique in the monster truck industry is an internal planetary disk brake, also called a wet brake," Chandler said. "BIGFOOT trucks have one at each wheel. Ninety-nine percent of other monster trucks out there have disk brakes on the drive shafts. If they break an axle, differential, drive shaft, or a planetary, they have no brakes on two of the wheels." Although the truck still would have brakes on the other two wheels, it presents a hazard nonetheless, Chandler explained. After a jump, monster trucks often land on two wheels. If those wheels don't have the ability to slow or stop, the driver doesn't really have any control over the vehicle until the other two wheels touch down.

....

[killerbee]

interesting discussion.

Monster trucks also have 60% of total mass as rotating mass. So the brakes are overcoming angular momentum as well as linear on larger scale.

[Mark Rinker]

Wow! Are you really serious, or pulling my chain with all that?

Like I said, I am a farm kid. That being said, I am not easily baffled by BS...

[DmaxMaverick]

Vehicle brakes do one thing only. Only one. They decrease the rotational differential of the wheel and axle. The brakes don't care about angular momentum or vehicle mass. Greater mass or inertia only requires more friction to reduce this differential. Braking is kenetic energy converted to heat energy, via friction. Increasing the tire diameter decreases the rotational differential, with the same or more mass, allowing for less linear friction runout, requiring more clamping force to provide the same friction coefficient for distance (ground) traveled. Yes, changing tire size will effect braking operation. It will also effect the compression braking efficiency, as the engine RPMs are less for a given ground speed, and often, with an auto tranny, drop the compression braking below the torque converter's friction ability at lower speeds.

[SoTxPollock]

Well done Gentlemen, all that being said, Spongebob I hope you have the extended warranty so they can fix it right. Don't forget that torque wrench, pulling those lug nuts to 140 ft. lbs. will help build muscle for the mermaids to see.

[Mark Rinker]

Yeah Spongebob, thanks for queing up an interesting topic so we can all pontificate on our deep knowledge of brakes. ;)

"Damn, Leroy - ever since you put them big mudders on, ya got ta MASH on this thing to keep 'er on the road. I dern near ran over some lady in a Subaru wagon this morning, but all I did was scratch up her rainbow DEE-cal with my brush guard..."

Thats all I know, guys. :)

[Kennedy]

Killerbee, I think Mark was commenting about the oversize wheels and tires not helping. The larger the diameter wheel and tire the harder you have to push the brake petal to stop, due to the increased distance from the center of the wheel to the road. Its called moment arm. The longer the distance the greater the moment reaction because of course the greater distance.


Another example of how LITTLE this so called engineer (killerbee) knows about these trucks, mechanics in general and the real world yet he comment and collects/analyzes test data as a self proclaimed expert...

[killerbee]

Yep. Boy, did I really screw up a critical moment to shine! Upset the whole planetary balance! Better wear extra sunscreen today.

DmaxMaverick , good post about grade braking, the lower rpm reduces grade braking, and requires more brakes with larger tires. I wouldn't have thought of that

[spongebob]

thanks guys, my tire height is actually a bit shorter than stock..the wheel is 1" taller though..
and i have 140lbs written on the hub...im sure its been torqued to that spec....i hope.

when the rotors were reworked, the doOd at the dealship told me i would need new rotors next time....damn.

just seems a 1 ton truck would have some heavy duty rotors...i guess not. and the service writer told me chevy is having issues with the rear rotors/brakes and may go back to drum brakes..