The reason they cool better is because of the directional airflow and not the mass, there are dozens of white papers on this.
Are drilled and slotted rotors worth the cost?
- Thread starter kitchbow
- Start date
The reason they cool better is because of the directional airflow and not the mass, there are dozens of white papers on this.
Correct, it could be heavier but it's not because there are other requirements at play. It's as heavy as necessary with regards to it's intended use.
Ok I am going try to break it down because the logic is germane to this discussion. The heavier the barrel is the better it can deal with the heat. Same goes for the brakes. This is is proven out mathematically.
See the formula below. Make your disc 500 grams now make it 1000 grams which gets hotter?
The reduced mass is part of it. A single piece can't reject as much heat as quickly as the lighter two-piece because the iron rotor hat of the one piece doesn't reject it as fast as the aluminum hat on a two-piece.
It's as you way simple thermodynamics.
Re-read what I said.
You do realize that the outer iron ring transfers little to no heat to the aluminum part ? It keeps the heat off the hub and the bearings acting as an insulator.
Also look at the formula again Cp is how well it dumps the heat. You can plug aluminum and iron rates in there and you still will come out with mass on top.
Yes and consequently you should realize that is not the case with a single piece iron. Right?
Correct. single piece iron heats up the brakes more because it conducts the heat to the caliper. The aluminum hate acts as an insulator. This has nothing to do with mass.
edyvw
$50 site donor 2025
My God, what did I miss 
How can aluminum act like an insulator when aluminum has ~5x the thermal conductivity of iron?
Because of surface area and most of them are free floating on top. Look at how the aluminum hat is connected. Minimum contact.
BITOG at it's finest !My God, what did I miss
The rotors with better cooling has better cooling, very surprising. Who would have thought that.
Now make the stock rotors 10% larger and heavier at basically the same cost and do it again.
They convert kinetic energy into heat energy, which is then dissipated into the air.
The contact area of the hat is very small, the aluminum dissipates the heat very quickly.
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Also the free floating helps with runout.
You gonna safety wire the last 2?
I'm assuming safety wire because of heat melting thread locker ?
You gonna safety wire the last 2?
I'm assuming safety wire because of heat melting thread locker ?
I was still working on it, I changed the pic. Not the best application for thread locker with the heat.
Whats it going on?
Panther
