Inboard Brakes, what they are and how they work.
What are they?
Inboard not mounted to any external component ie wheels, this type of braking system is mounted to the differential or a brakeshaft on the front of the vehicle.
What are they?
Inboard not mounted to any external component ie wheels, this type of braking system is mounted to the differential or a brakeshaft on the front of the vehicle.
Why?
The purpose of inboard brakes is to reduce unsprung mass within the suspension system on the vehicle, alot of old English sports cars used to have this arrangement, most noteworthy older JAAAGGs. And subsequently used in the back of hotrods, as they came on a subframe of sorts.
The lotus F1 car above car uses inboard brakes to improve centre of mass and inertia, as well as cooling, this is a compromise as it means running a small driveshaft to the brakes on the car.
Advantages
PACKAGING, a larger brake disc can be used without it being inside the wheel as a result less rotating mass as the wheel can be smaller.
Heat: brake dust and higher temps can be separate from the tires
improved roll centers, improved inertia, improved front brake cooling
solid fixed brake lines can be used.
SPRUNG MASS is lowered meaning ride can be softer, less time is spent overcoming inertia of the suspension and more is put on the tires.
Disadvantages of this system
HEAT: rear brakes where notoriously bad at cooling, not aided by poor aero of the time as well as the fact that it is mounted in a confined space under the vehicle
PACKAGING, area around the rear differential will need to be bigger.
TORQUE: the distance from the tire to the brake disc has significantly increased, meaning that any force will cause distortion in the drive/half shafts,however we are talking Nm here so there is a difference so the drive shafts need to be stronger
SERVICE: lower a diff to just do the brakes, hahahaha NO.
#GiveMeABrake #builtnotbought , #inboardbrakes . #oldstillgold
why not now? on modern cars?
I genuinely have no answer, well other than the diff thing.
Comments
Nice little write up!
Thanks!
When you make editors pick and your like
It’s your day!
Military Humvee (HMMVW) uses the same kind of brakes setup.
yes it does, so does the Jaguar e-type
I was just about to say this. I was quite confused the first time I looked under one and saw this setup for the first time.
i feel sorry for alfasud owners haha
they work brilliantly, briefly
i think Hummers H1 used inboard brakes aswell, their aim was to have rotors away from dirt and rocks.
rotacional inertia may be improved, no when braking but under steering inputs
strength and removal of wear was the goal in creating the HUMMER they wanted it to never break, so they used this system. Also there is the advantage that brake lines can’t be cut with a knife, and are nowhere near breakable suspension components
Yep they are inboard on the H1, tucked away nice and high
A big downside you overlooked in your (rather nice :)) article is the fact that you need axles that can handle much higher amounts of torque. (Braking torque is a lot higher than engine torque).
Also, shouldn’t “The purpose of inboard brakes is to reduce sprung mass within the suspension system on the vehicle,” be “The purpose of inboard brakes is to reduce UNsprung mass within the suspension system on the vehicle,”?
thank you for the correction, i don’t know what? What’s sleep?
Wow, this article deserves way more upvotes.. Here have mine as a start! I really learnt something today…
you should see my other stuff.
Great info. the more you know
and knowing is half the battle
Interesting, having seen this on an Alfasud on wheeler dealers I was intrigued.
that’s where everyone is from, i just wanted to know what the best way of building a car for performance.
I’ve seen brake discs mounted to drive shafts before weirdest thing I’ve seen working on cars