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drilling holes in a read brake drum

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Pa

Site Admin

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Location: Ohio USA

Post Tue Sep 16, 2008 5:40 pm

Re: drilling holes in a read brake drum

I was thinking the same thing 44. Pa
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jib

Posts: 573

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Wed Sep 17, 2008 5:42 am

Re: drilling holes in a read brake drum

didnt manufactures start drilling motorcycle discs to help in the wet? i know that they are spinning [centrepetal force throw water off] but there is still a coating,which gets sqeezed into holes /bow waves gets broken by holes.
also surely the holes increase the coeficeint of friction ,as they would increase the 'bite' of the pads .
note only hi performance car discs are cross drilled, but virtually all motor cycle discs since the late seventies /early eigthies are.[some suzuke performance discs were grooved ala gsxr 1990 style]
and what about the wavey disc phenomonen what are they acheiving by having pieces missing from the periphery and inner edge as well as slots and triangles etc cut from the main brake friction surfaces???
regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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panic

Post Wed Sep 17, 2008 10:56 am

Re: drilling holes in a read brake drum

Drilled rotors are stock on bikes... because you can see them. It's bling, they'd do it even if it reduced performance because children buy them.

Holes increase cooling by radiation if the area exposed by the drill (a cylinder: the height is the rotor thickness, the diameter is the drill size) is larger than the surface area removed, otherwise not. Really big holes only save weight, and do bad things to the pads unless very carefully positioned. The best system is the late Buell, where the rotor is keyed to the rim (not the hub), so the wheel spokes need not transmit braking force.
Heat loss by convection currents through the holes really doesn't happen - the central radial holes work very well (with a big weight penalty), and some have directional vanes which point "backward" when rotating and expel air drawn into the hub center.
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jib

Posts: 573

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Wed Sep 17, 2008 11:21 am

Re: drilling holes in a read brake drum

Definition: Disc with friction surfaces which have been drilled with rows of holes to improve cooling, reduce weight and provide an escape route for dirt and gasses which can be wedged between the pads and disc. High-performance rotors can be both cross-drilled and slotted.
:idea: :arrow: :mrgreen:
somebody should rewrite that dictionary .to say kids love um...... :twisted:
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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jib

Posts: 573

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Wed Sep 17, 2008 11:46 am

Re: drilling holes in a read brake drum

quote from nitrac ''Grooves to give rapid gas expulsion and deglazing of the brake pad and improved resistance to distortion ''
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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jib

Posts: 573

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Wed Sep 17, 2008 11:55 am

Re: drilling holes in a read brake drum

quote from ebc ''Aeroplaning or Wind Noise on EBC GD series Sport Rotors under heavy braking
Provided you have the latest spec 3 slot version of EBC sport rotors the noise levels are as low as they will go with a sport rotor. We recently changed from 5 slot to 3 slot to reduce noise issues. The slots have a purpose of drawing cool air under the pad contact point and are therefore beneficial. On the 5 slot rotors experience shows us that noise gradually reduces over a period of driving but it can take up to 2000 miles use before this reaches its lowest point after which the noise is there to stay, some people like it, some people don’t. But if you are totally dissatisfied with the presence of this noise, please contact us again and we will come to a reasonable solution. There is ABSOLUTELY NO SAFETY ISSUE INVOLVED HERE.
EBC now also make their new Ultimax Black Dash series slotted rotors which feature narrower slots and no dimples. This design is significantly quieter. So why does EBC sell two types of sport rotor?
First the larger the slots (as on the 3GD series) the better the air cooling effect, tests on the UK Police Force Chase cars have shown the wide slots to be very helpful at speed at cooling the pad and rotor. Also the 3GD wider slots extend completely to the edge of the rotor and are better at removing dirt, dust, debris and water (making them ideal for off road uses).
On the other hand the narrower slots on the new Ultimax series provide SOME cooling and certainly degas the pads and are therefore a good upgrade option for street use at lower speeds.
People often ask … "Do sport rotors really do anything???” and our honest answer is … in most cases they do. First the cooling advantage is simple physics so YES they cool pads and rotors but the surface area reduction (again, simple physics) actually means LESS braking UNLESS you change the brake pads for a higher friction compound such as EBC to compensate. Every one of EBC pads offer significantly higher stopping than most aftermarket and OEM pads (according to our dyno tests) and one extensive independent vehicle test conducted on a closed race track in the UK on a Sport compact (Golf GTi) showed EBC pads to stop several car lengths faster than three popular USA aftermarket brands tested. Add this extra friction to the better cooling and you have better brakes.
Extra benefits of sport rotors are not often spoken about but are very worthwhile. This is the effect the slots have on maintaining a flat smooth pad surface during the pads wear life. The slots encourage the pads to wear with a more flat pattern and the “Ribbing” common with non slotted rotors does not appear. This removes the “Record groove” effect of pads on plain rotors, particularly around the outer edge and helps pads maintain better contact area with the rotor through their life. As far as EBC is concerned this is the MAJOR benefit of sport rotors over all others as honestly speaking EBC pads have such a high temperature rating they don’t NEED degassing. We test all pads to temps over 1000 degrees. ''
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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jib

Posts: 573

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Wed Sep 17, 2008 12:24 pm

Re: drilling holes in a read brake drum

ok last one ,read loads and now have to go and brick up a fireplace
quote AP racing ''Disc Cooling
A good source of cooling air should be supplied preferably through the upright to the disc throat. A typical venting cross section of 100cm² (16in²) is usually sufficient. The pick up should preferably be in an area of clean high pressure air flow and the ducting should be arranged to avoid sharp bends or changes in section which may choke the air flow.
Careful design of the Mounting Bell is important in achieving effective disc cooling and avoiding problems. Typically 80% of the airflow should be directed up the disc vents and 10% up each face of the disc. This ratio can vary considerably in practice but it is important that both disc faces are cooled equally by adjusting the air gaps. Unequal face temperatures can lead to disc distortion and a long pedal. Lightening holes in the bells should be avoided as available cooling air can be lost without cooling the disc.''
regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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45Brit

Posts: 1433

Joined: Tue Nov 27, 2007 2:29 am

Post Thu Sep 18, 2008 12:33 am

Re: drilling holes in a read brake drum

surely the braking forces in a rim-mounted disc still go through the spokes? The spokes connect the rims to the hubs and the hubs are mounted to the rest of the machine... and the brakes serve to disperse kinetic energy from the entire mass?
Shoot, a man could have a good weekend in Dallas with all that stuff...
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jib

Posts: 573

Joined: Sat Dec 10, 2005 3:36 pm

Location: devon,england

Post Thu Sep 18, 2008 5:24 am

Re: drilling holes in a read brake drum

road-tyre-rim-disc-pads-caliper-forks-headstock [front wheel only of course]
but there is the location of the wheel in space ,i.e. the hub bearings -spindle -forks .which all the above are pivoting on.
so in terms of motion about a point it would be....load-effort-fulcrum . but notice how close the load is to the effort on a rim mounted disc opposed to a hub mounted one,thus increasing the mechanical efficency of the brakes. for the same amount of effort more load can be handled .also the torsional loading between the load and the effort is tremendously decreased due to their closeness.
but the kids love um and so do all them custom boys out there cause they look rad man.... :twisted:

regards jib
Dude, check out that jibhead, he's crazy. Hasn't been sober for 40 years
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45Brit

Posts: 1433

Joined: Tue Nov 27, 2007 2:29 am

Post Thu Sep 18, 2008 7:11 am

Re: drilling holes in a read brake drum

Douglas built a rim caliper brake as long ago as the 1920s. Several other manufacturers have experimented with them, but they have never found favour. I have to suspect that if they were genuinely valuable they would be found in racing, and I am told that Honda looked at them very hard and decided that the problems with handling more than offset the benefits.
Shoot, a man could have a good weekend in Dallas with all that stuff...
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Chris Haynes

Posts: 2637

Joined: Wed Jul 05, 2000 12:01 am

Location: Los Angeles, CA

Post Thu Sep 18, 2008 11:38 am

Re: drilling holes in a read brake drum

Instead of spending a lot of time drilling drums why not use this product? :D
http://kalecoauto.com/index.php?main_pa ... ducts_id=1
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