11 inch (283mm) brake rotor.

[liveforphysics]

It's good to see what the best ever created of a device looks like to know which directions to proceed when making your own designs.

Here is a standard F1 brake. Full floating rotor (this is a good thing always, I love floating rotors). The disk is plain and round with no holes or slots, but internal vents, which are an extremely beneficial way to extract rotor heat. The disk itself is an extremely high temp carbon ceramic composite material (kinda like a modern racing brake pad).

If you are looking for the best brake design ever created yet to copy, this is it. A marketing department guy would cringe about how plain-Jane it looks.

 

[Thud]

hmnn.
I must be a victom of marketing...
I did taco 2 stock honda rotors in the spring of 86 from over heating (they just warped & made a real anoying rub when they cooled) after the 2nd one warped I bought the hot new thing (a wavy rotor) & it lasted the remainder of the seaon...& I ran that front & rotor wheel on my 89 for 2 seasons without a hick-up or unreasonable amount of wear. That bike still has the same rotor on it (and is still raced 12 times a year). Made a beleiver out of me &
I have been an advocate of the wavey rotors for off roading ever since.

Just my experiance.

looking the units I have in hand, all my chepo magura bicycle rotors have a slight champher on all the holes....I will defo be looking at them closer in the future.
(all my motorcycle units have too much wear to make a determination ATM) :|

 

[recumpence]

The best rotors I have ever used are my Hope floating rotors. All slots and holes are sharp edged.

Matt

 

[bobc]

Interesting discussion, & very relevant because any high power ebike (1kW or more) is going to be supplying braking energy WAY outside the system's comfort zone. In level terrain a cyclist can supply <200W - that is all the heating that could possibly go into the brakes, and is essentially what the system is designed for; guys with 3kW motors can supply 10x this..... Every trip out the brakes feel like they're descending an alp....
Even with my 20mph ebike, I brake FAR more than I do when under pedal power.
We use bike disc brakes in the greenpower race cars - these go up to over 40mph, but typically only use the brakes in emergencies or at the end of the race....

 

[amberwolf]

Silly irrelevant question: When the rotors "fold" at the spokes, does it ever leave the disc part (braking ring) intact (flat)? If it does, those could still be re-used as floating discs, or ones mounted on a hubmotor cover bolt-ring.

 

[liveforphysics]

Silly irrelevant question: When the rotors "fold" at the spokes, does it ever leave the disc part (braking ring) intact (flat)? If it does, those could still be re-used as floating discs, or ones mounted on a hubmotor cover bolt-ring.

Negative. Total warped destruction.

 

[RWP]

You guys are awesome - I keep learning and learning.
Maybe one day I can learn my motors to run cool :lol:

 

[hydro-one]

I would buy one of these!!

 

[tedcs]

I too, would buy one of these!!

 

[MitchJi]

Hi Luke,

Tell them, straight spokes! They can come off the hub at an angle, but if the spokes have a curve, its asking for the rotor to fold.

Not like this?:
http://www.zeromotorcycles.com/shop/index.php?main_page=product_info&cPath=5&products_id=37

Brake Rotor Front or Rear
Zero X/MX [2009-10]
$29.99
Does not include local shipping or applicable taxes.
This high performance rotor is 9 inches in diameter and fits either the front or the rear of the 2009-2010 Zero X or MX.

 

[Farfle]

heres my shot at a good rotor for the Rotor design gurus out there, this will be the front rotor for my bike. It is a 210mm rotor, so don't let the proportions fool you.

 

[amberwolf]

Wouldn't those rows of holes between the ring and the arms create potential weak points? Maybe it will never see stresses along them that would matter, but it doesn't look right to me.

 

[Farfle]

Wouldn't those rows of holes between the ring and the arms create potential weak points? Maybe it will never see stresses along them that would matter, but it doesn't look right to me.

It shouldnt, first, the torque moment at that radius is fairly low, and the holes closest to the edge are omitted to prevent a stress riser at that point. And second, The total amount of materiel left in the holed sections, Is greater than the amount of material in the "spokes". So that holed section will actually be stronger than the spokes. If you think about it, the typical floating bicycle rotor only has six trailing-edge flanges on 6 half-bolt holes to hold it on.

 

[GITech]

Yeah, they look like break-off perforations to me.

Those holes would go a long way towards isolating the heat in the outer ring, thus greatly increasing the temperature differential contributing to warp, and reducing the heat dissipation ability as a whole.

Also, I know why you have those ~half circle cutouts in the outer edge of the ring..to reduce the breaking area further from the moment of rotation..evening out the break surface to even out pad wear and heat generation, but why do you have them..at least the same size..on the ID of the outer ring?

Later,
Jay

 

[Farfle]

Im in over my head here, but my train of thought, is that The half circle cutouts are there to help shed debris, and increase the surface area of the rotor, and about the "perforation" holes, If you can confine the heat to the outer ring, you don't let the heat affect the shape of the spokes, which try to warp the rotor.

 

[GITech]

I'm just going off my train of thought too bassed on my reading/researching of brakes lately.

Anyone with more experience in this area willing to chime in?