"swiss cheesing" rear brake rotor

[COP TZR]

I've read about this in the Desmo Times book and that machining your rear brake rotor with bigger holes helps the cooling of the rear brake and also shaves unsprung rotational mass.

Has anyone on the forum done this with positive results?  Are the costs of machining at a shop worth it, or are you better off just buying an aftermarket rear wave rotor or something?

Any photos?

[NAKID]

What's a rear brake

[Popeye the Sailor]

I've read about this in the Desmo Times book and that machining your rear brake rotor with bigger holes helps the cooling of the rear brake and also shaves unsprung rotational mass.

Has anyone on the forum done this with positive results?  Are the costs of machining at a shop worth it, or are you better off just buying an aftermarket rear wave rotor or something?

Any photos?

Standard rule of thumb:

If someone makes it, just buy it. Life will be easier.

[Bizzarrini]

http://ducatimonsterforum.org/index.php?topic=32825.0

[COP TZR]

Standard rule of thumb:

If someone makes it, just buy it. Life will be easier.

I don't think it would be difficult for a machine shop to drill some oversized holes.  I'm not looking to cut the rear rotor into a "wave" pattern, just want to drill some oversized holes into it in an appropriate pattern

[Punx Clever]

Hmm... drill larger holes into an engineered piece of material that has been designed specifically to withstand a rediculous level of force and heat in order to keep you alive....

yeah, you COULD do it... but I wouldn't suggest it. go buy a set that is designed to be that way. 

lets put it this way... would you cut out the air vents on your helmet to provide more airflow?

[Popeye the Sailor]

I don't think it would be difficult for a machine shop to drill some oversized holes.  I'm not looking to cut the rear rotor into a "wave" pattern, just want to drill some oversized holes into it in an appropriate pattern

Sort of what I'm getting at. Who determines appropriate pattern? Size? If they do it wrong, and they may be unaware as to what "right" actually is, you risk having the rotor not perform as it should. That item you want to drill holes in was never intended to see the sort of thing you plan on doing to it.

You can also drill holes in your frame to shave weight. I still wouldn't recommend it.

There are real live, professionally engineered lighter rotors out there. Just buy one-it'll bolt right in.

[Goat_Herder]

Hmm... drill larger holes into an engineered piece of material that has been designed specifically to withstand a rediculous level of force and heat in order to keep you alive....

yeah, you COULD do it... but I wouldn't suggest it. go buy a set that is designed to be that way. 

lets put it this way... would you cut out the air vents on your helmet to provide more airflow?

What he said.  Your rotor is designed and manufactured to perform at its desired spec.  Drilling larger holes would weaken the rotor and potentially (very likely) throw it off balance.  It would also have less surface area to be in contact with the brake pads.  All in all, it's not worth it.  Get better wheels if you are that concerned about unsprung weight. 

[COP TZR]

I get the point that it "MAY" not be safe or designed for such alterations.  However reading about it and seeing photos of it done in the Desmo Times service manual made me wonder.

[junior varsity]

It would also have less surface area to be in contact with the brake pads. 

That's not a significant concern. There is already PLENTY of contact area in the lightweight, drilled rotors. Excessive amount of contact area in the stock.

Just buy an aftermarket rotor. They are cheap, especially relative to fronts. I've got a motomaster, and its the "flame" wave cut, just because.

[Punx Clever]

I get the point that it "MAY" not be safe or designed for such alterations.  However reading about it and seeing photos of it done in the Desmo Times service manual made me wonder.

I'm telling you that, as a mechanical engineer, it is NOT SAFE. it may still work, but it is NOT SAFE.

[junior varsity]

disagree. as a mechanical engineer.

Sure, They don't come that way, but its not because they "can't".

For another source, try DucPond: They have done TCM lightening, like this: http://www.peterverdonedesigns.com/600RRrearrotor.htm

[scott_araujo]

I remember many years ago reading about a brake shop that would drill or re-drill rotors, drums, and clutch plates.  I think the idea was basically to get an even distribution of open area across the face.  Taking any concentirc ring on a rotor, it should have similar or the same amount of hole area as any other.  They didn't give absolute specifics as to the pattens as that was part of the black magic they get paid for.  Part of the reason was not just more venting but to help break up and get rid of a super heated layer of air that tends to stick near the brake surface and reduce efficiency.  

The magazine that did the article had the drums on a VW bus drilled at the shop and said the braking was notably improved with just a slight hissing sound that hadn't been there before.

That said, buy a lightweight aftermarket rotor if you want light weight and get some aftermarket pads to help it stop better.  My stock rear brake was useless for anything but stabilizing the bike during stops until I got some Ferodo pads.  Now it's actually a functional brake, at least as much as any rear motorcycle brake.

Scott

[Punx Clever]

disagree. as a mechanical engineer.

Sure, They don't come that way, but its not because they "can't".

The way I look at it, the engineers who made the rotor to begin with were given (or came up with) criteria for the rotor.  Most likely acceptable safety margins, performance requirements, max weight, and a price point.  Strength of the material chosen and cost for that material would be considered.  The come up with a basic design (considering cost of manufacture, performance characteristics, etc), figure out the major stress areas, then apply that to a table of materials.  Lifespan is considered at the stress levels to come up with the cheapest material that satisfies that design, and go with it.

Those safety factors are probably large enough that you could modify the rotor to a large degree... but you are sacrificing safety.

At least in my opinion.

[Ducatl]

The way I look at it, the engineers who made the rotor to begin with were given (or came up with) criteria for the rotor.  Most likely acceptable safety margins, performance requirements, max weight, and a price point.  Strength of the material chosen and cost for that material would be considered.  The come up with a basic design (considering cost of manufacture, performance characteristics, etc), figure out the major stress areas, then apply that to a table of materials.  Lifespan is considered at the stress levels to come up with the cheapest material that satisfies that design, and go with it.

Those safety factors are probably large enough that you could modify the rotor to a large degree... but you are sacrificing safety.

At least in my opinion.

You know we're talking about Ducati here right?

That said, I like the ducpond design.  There's also Braking, several different eBay wave designs and I believe EBC used to or still does make a rear.