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THE "How much do H-Series Discs REALLY weigh?" Thread!!!
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Author:  scrambler73 [ Wed Jan 11, 2012 6:51 pm ]
Post subject:  THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Digging through my "disc box" I realized I had enough variety to do a Comparo....

The scientific equipment consists solely of this circa 1950 "antique" scale that I stole from my wife about 12 years ago. It was once proudly displayed on our kitchen counter, but she now refuses to accept it back into the house as it has been tainted by Garage Grime.... Good! I need a scale!

Disc #1 (the "control" disc) is a bone-stock (other than the pretty blue smurf paint) 7mm thick, 6 Hole H1/H2 disc.
Weight 6lbs 10oz. :shock:
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Disc #2 is one of John Aylor's "Moo-dified" EX500 compatible discs.
This Disc has been thinned to 6mm, and is Undrilled. (One could shave another pound off of this by drilling holes and/or thinning to 5.5mm, which IMHO is still safe)
Weight 4lbs 10oz.
Image


Disc #3 is a KH500/KZ 4-hole disc that has been thinned to 5mm and is drilled to a pattern Denco used back in the day..96 holes increasing in size as you move out from the hub.
For those of you who think 5mm is too thin in a single disc application, I would have to strongly disagree.
I had two of these done, and one has now been on the KH750 for well over 10,000 miles with zero problems... (warping, etc)
This particular disc is going on my current 4/5 hybrid project. 8-)
Weight 4lbs 7oz.
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Disc#4 is standard thickness (7mm) H1/H2 disc with 48 large holes drilled
Weight 5lbs 14oz.
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Disc #5 is a "Hyperlite" Roadrace disc correct for KH500 and KZ 4-hole wheel. Disc has an aluminum carrier with bolt-on rotor.
I had this disc fitted on the KH750 for a year or so with EX500 caliper, but it warped due to it being too thin (4mm) for use in single application. Hindsight being 20/20, I should have used it as a dual set-up as I have (er, had) 2 of them... :roll:
Weight 3lbs 14oz.
Image

Disc #6 is also a "Hyperlite" Roadrace disc correct for the H1/H2 6-hole wheel. It too is 4mm thick. (I also have 2 of these... just waiting for a bike to use them on :thumbup: )
Weight 3lbs 12oz.
Image

So, in a nutshell, by thinning a standard disc to 5mm and drilling holes similar to Disc #3 (96 hole Denco Pattern), you can shave about 2lbs 3oz from stock.

John's "moo-dified" disc if drilled and thinned even further to 5.5mm, which I think would still be fine, could get you easily into "Hyperlite" territory, without having to worry about warpage in a single disc application. Couple that together with a slightly lighter caliper (EX500), and you have a pretty sweet front brake.....

The End.

Author:  RODH2 [ Wed Jan 11, 2012 7:12 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Great stuff, thanks! I have, (and have used) dual Hyperlites with stock (reversed)calipers. The current build gets the same, with the inside of the calipers "shaved" 2mm, and an aftermarket M/C, 5/8ths of course.

Author:  Jim C [ Wed Jan 11, 2012 7:40 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Thanks for doing this Cody; really helpful for decision making.
It's easier for me to see the cost/benefit values when the weights are all in ounces:

Disc 1 106 ounces
2 74
3 71
4 94
5 62
6 60

Author:  Mikepdutton [ Wed Jan 11, 2012 8:07 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Must have been bored today? :think:

There goes our nice weather we were having. :thumbdown:

Maybe some day I should come down and help you go thru those bins??? :clap:

Author:  Ja-Moo [ Wed Jan 11, 2012 8:35 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Hey Cody, did you get the disc yet? :lol:

Author:  Zambia [ Wed Jan 11, 2012 8:36 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Hmmm. I like these, but the guy wants $175 for the pair....

Image

Author:  scrambler73 [ Wed Jan 11, 2012 8:40 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Ja-Moo wrote:
Hey Cody, did you get the disc yet? :lol:



I figured this post would pretty much answer that question...

Author:  scrambler73 [ Wed Jan 11, 2012 8:43 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

Zambia wrote:
Hmmm. I like these, but the guy wants $175 for the pair....

Image



wow... I just realized those are factory discs! That looks like $175.00 worth of work to me all day long. I wonder what they weigh? :lol:

Author:  Ja-Moo [ Wed Jan 11, 2012 9:00 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

They look a bit scary to me, but I guess using duals would cut the load in half.

Author:  RODH2 [ Wed Jan 11, 2012 9:11 pm ]
Post subject:  Re: THE "How much do H-Series Discs REALLY weigh?" Thread!!!

It's interesting to see how "flimsy" modern sports-bike rotors are, and they have a lot more work to do..............! (Granted, they are duals.)

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