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Upon watching some YouTube videos of mudding/mud bog trucks out there, there seems to be a common brake being used, and was curious if someone here with many years of 4-wheeling experience can shed some light on what I guess is called a 'differential brake'. (that's the best word I can think of for it, because it looks to be mounted on the differential)
Looks something to the tune of this:
I've seen this used on Monster Trucks for years, and i'm curious why use only one brake rotor, instead of the two/four? Are the other brakes still being used, or do they rely on just one rotor to do the work of all of them? Pros? Cons? Street legal in most states? Hard to maintain? etc...
I want to get deeper into 4-wheeling and see what everything is and what everything does, and i've seen these things glow red hot on Monster Trucks sometimes, and i'm racking my brain trying to figure out why most of these guys out there that lift their trucks up so high, need/use what looks to be only one rotor on what looks to be a centered Dana front end. I'm guessing there will have to be some major modifications to make something like this work, but I'm just looking for the run-down. Any help is greatly appreciated!
Firstly that is called a pinion brake, as it is mounted to the pinion. Rockwells don't have discs, they have massive drums that don't perform particularly great from what I've heard. One major reason for using a pinion brake on Rockwells is for more tire options. 20" military wheels to clear the drums limit tire choices.
Pinion brakes are not very feasible for the street, particularly with very low gear ratios. Legality may vary, but with 6.x:1 or 7.x:1 gears that rotor will be spinning fast even at slow speeds. Things would get real hot real fast at speed.
Pinion brakes and transmission mounted parking brakes on big trucks work so well because of the gear ratio advantage. Yes they spin faster, but it's much easier to clamp and hold a driveline with say a 4 to 1 advantage if you had 4.10 gears.
Wheel brakes are better, especially if you are running an open diff.
Agreed. You see pinion brakes mostly on specialty rigs that are only used on race courses, rock crawling events, etc. In other words, places where stopping is a secondary consideration.
Consider this scenario. You're barreling down the road and a Prius pulls out from a driveway on your left and you have to swerve to the right and hit the brakes. Your two curbside wheels are now off the shoulder of the road, in the dirt, sand, snow, marbles, or whatever is there. Even though the two wheels on the pavement still have good traction, your braking action is now the same as regular brakes with all 4 wheels on the slippery surface. Your only option is to proceed to the scene of the accident.
No idea about what the law requires, but I sure wouldn't want to drive with pinion brakes on the street. I think they'd just be too squirrelly in many situations.
Agreed. You see pinion brakes mostly on specialty rigs that are only used on race courses, rock crawling events, etc. In other words, places where stopping is a secondary consideration.
Consider this scenario. You're barreling down the road and a Prius pulls out from a driveway on your left and you have to swerve to the right and hit the brakes. Your two curbside wheels are now off the shoulder of the road, in the dirt, sand, snow, marbles, or whatever is there. Even though the two wheels on the pavement still have good traction, your braking action is now the same as regular brakes with all 4 wheels on the slippery surface. Your only option is to proceed to the scene of the accident.
No idea about what the law requires, but I sure wouldn't want to drive with pinion brakes on the street. I think they'd just be too squirrelly in many situations.
That makes sense. I guess the factory uses them only for parking brakes.
