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Aluminum brake rotors
http://www.kawi2strokes.com/forum/viewtopic.php?f=16&t=12337		 Page 2 of 4
Author:  Ja-Moo [ Sun Dec 18, 2016 12:08 pm ]
Post subject:  Re: Aluminum brake rotors
Not exactly in line with your "stock" look, but not far off, is the tried and true EX caliper conversion. You can thin and drill your stock disc to about half the weight, and you only need one caliper and disc for all the stopping power you need. Jim sells the simple adapter and you can get pads anywhere unlike the specialty aftermarket calipers and such. :thumbup:
Author:  husson73 [ Mon Dec 19, 2016 6:07 am ]
Post subject:  Re: Aluminum brake rotors
6 holes on the Brembo
Image
Image
Author:  oxford [ Fri Dec 23, 2016 8:36 pm ]
Post subject:  Re: Aluminum brake rotors
If drilling your own holes in the rotors, go with....hole diameter=2 times the rotor thickness. With that you can get the biggest hole possible without loosing any surface area on the rotor.
Author:  Jim [ Fri Dec 23, 2016 9:25 pm ]
Post subject:  Re: Aluminum brake rotors
Yes, but why not go with more smaller holes to increase the surface area, the theory being that cooling will be helped?
Author:  RODH2 [ Fri Dec 23, 2016 9:43 pm ]
Post subject:  Re: Aluminum brake rotors
I have always been a small holes are better kind of bloke, unless you are drag racing or scared of the rear brake!! (stirring.....!!)
Author:  H2RTuner [ Sat Dec 24, 2016 1:34 am ]
Post subject:  Re: Aluminum brake rotors
When Steve and I did the first drilled H2R discs, (decades ago, this time of year in 1972), we used the pattern Porsche used on their 1965 Can-Am cars, three rows, holes twice the thickness of the rotor (72 holes),. It has worked well over the years, and so have other hole patterns. To each, their own preference.
Author:  ALTERED IMAGE [ Sun Dec 25, 2016 10:52 am ]
Post subject:  Re: Aluminum brake rotors
Just wanted to thank y'all and I am hoping you have a splendid Holiday.

72 holes?
Diam. at 2x thickness?

Doing the math..............at 7.8 specific gravity................... :crazy:

7mm initial rotor thickness
Author:  ALTERED IMAGE [ Sun Dec 25, 2016 11:16 am ]
Post subject:  Re: Aluminum brake rotors
Just by drilling stock stainless steel rotors...


mm inches
7 0.275590551 thick
72 72 number of
14 0.551181102 diameter = 2x thick
each hole
area 0.238604238 sq in
vol 0.065757073 cu in
sg 7.8 g/cc
sg 0.475987063 g/cu in
total hole
vol 4.734509284 cu in
vol 77.58440363 cc
mass 605.1583483 grams
mass 1.332947904 lbs


20.20% mass reduction

Looks like surface area for cooling is the main reason for the effort.

Then again, heat flux from hot zone band to cooler areas may turn the rotor into a pretzel if pressed hard.

Auto-Retracting pads if bad enough! :eh:
Author:  ALTERED IMAGE [ Sun Dec 25, 2016 11:27 am ]
Post subject:  Re: Aluminum brake rotors
JP,
Where would I find such brakes in the pix of the Brembo's?

Looks OK but I did this set-up on my bike to neutralize the mass moment of inertia from the calipers when the steering is turned.

Best is the leading side of the forks, to keep the moment from unloading the tire in bumps. Marginal at best I know..... :think: ..

cliff
Author:  H2RTuner [ Sun Dec 25, 2016 12:49 pm ]
Post subject:  Re: Aluminum brake rotors
We used off the shelf stock street bike rotors, .480 inch thick, drill holes double the thickness, rounded off to the next drill bit size we had, .500,. One half inch.

The swept area of the disc was measured, then divided in half (center drill hole center), then divided the 1/4th and 3/4ths distances for the other two rows. 1/4th and 3/4ths lines had one hole each per row on the same rotary table center, the 1/2 had one hole, exactly half way between the two outside holes.

Each hole set was 15 degree apart, all 3 rows, with the center row offset 7- 1/2 degrees from the outer rows. This gives 24 holes per row, 24 x 3 = 72.
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