RGM 12" disc and OEM caliper ?? (2017)

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Your brake looks like it provides serious braking effort. Can the forks and the front end, indeed the rest of the bike, handle
all this?
 
Onder said:
Your brake looks like it provides serious braking effort. Can the forks and the front end, indeed the rest of the bike, handle
all this?
Click to expand...
Yes It can handle it, maybe not a good Idea on a widowmaker frame though
 
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BrianG said:
Modern brake rotors are stainless steel, to avoid that ugly rusty look of the old cast iron rotors, as well avoiding rust contamination of the caliper pads.
Click to expand...
Modern rotors are also made of iron. Quality modern organic pads are made to work on iron rotors and don't get "rust contaminated". Some of us actually way prefer iron rotors. I think you were getting some good input on a RGM 12" rotor and AP/Grimeca caliper set up. I doubt you could tell the difference between a 12" rotor and a 320mm rotor on a Commando, and it bolts right on the hub. RGM and Clubman Racing both sell caliper adapter plates for the AP/Grimeca calipers. I got the Clubman Racing version and an 11mm Magura master cylinder. A 12mm master would be my second choice. Clubman Racing can also make up new hoses for you if necessary. This set up, while not the only good one, is tried, true, and in use by forum members recommending it. There is something to be said for not reinventing the wheel when it comes to something as critical as front brake systems, especially if you are not experienced setting them up.
Bill
http://clubmanracing.com/nortonbrakes.php
 
Modern rotors are also made out of steel- not stainless but still containing chromium. Stay away from cast iron. There are three main types - grey cast iron, meehanite in which calcium is added to the melt to precipitate calcium silicide and iron containing nickel.My friend was killed when grey cast iron discs exploded off his RG500 Suzuki at the end of Conrod Straight at Bathurst in the 70s.
 
Brian, I did a cast wheel modification and used the stock lockheed caliper on the yamaha cast wheels with it's 11" yamaha disk. I had a machinist make me an offset bracket to move the caliper further out to use the bigger disk. It actually works very well. The norton disk is much heavier than the larger diameter yamaha disk, so I increased braking power and removed some unsprung weight from the front wheel.

With certain modifications you have to decide where to go from stock to custom parts. Sometimes it's cheaper to buy something that bolts up, than have a machinist make you a custom part. The bracket you see below in the picture cost me $350. I designed it and actually make it out of wood, then I brought it to my machinist who milled it out of an aluminum billet.

RGM 12" disc and OEM caliper ?? (2017)


that rubber brake hose was replaced with braided one, and I swapped the stock Master cylinder for the one Madass sells for commandos and my brakes are excellent...
 
o0norton0o said:
Brian, I did a cast wheel modification and used the stock lockheed caliper on the yamaha cast wheels with it's 11" yamaha disk. I had a machinist make me an offset bracket to move the caliper further out to use the bigger disk. It actually works very well. The norton disk is much heavier than the larger diameter yamaha disk, so I increased braking power and removed some unsprung weight from the front wheel.

With certain modifications you have to decide where to go from stock to custom parts. Sometimes it's cheaper to buy something that bolts up, than have a machinist make you a custom part. The bracket you see below in the picture cost me $350. I designed it and actually make it out of wood, then I brought it to my machinist who milled it out of an aluminum billet.

RGM 12" disc and OEM caliper ?? (2017)


that rubber brake hose was replaced with braided one, and I swapped the stock Master cylinder for the one Madass sells for commandos and my brakes are excellent...
Click to expand...


That is a nice looking conversion, but my goal is to sneak in some extra braking power without altering the vintage appearance too much. To that end, I'd like to get the largest rotor that would reasonable fit (320mm) while maintaining the wheel and the master cylinder sleeved to 13mm or not (at 15mm)

and using a like-sized caliper like this nice compact 4 piston unit that is easily rebuildable with easily found parts, and won't look too foreign when stripped of the paint and anodized:

RGM 12" disc and OEM caliper ?? (2017)


Here is how the last similar project went, albeit on a sounthpaw.

RGM 12" disc and OEM caliper ?? (2017)
 
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madass140 said:
this is my pre MK3 brake kit Tokico 6 piston caliper and bracket, kit comes with mastercylinder which accepts the Lucas switchblock and brake light wires, hose, fittings , lower fender stay. EVERYTHING is supplied to convert from stock.
cant change the center color sorry. purchasing from me directly $450 + shipping
silver, gold or black caliper.
Click to expand...


Very impressive kit. I have sent you a PM to discuss.
 
I had a thread on a stock caliper with a 12" Ninja disc, but photobucket wiped all the pictures out. You can see a small pic in my Avatar.
Jaydee
 
I see several bikes here with the brake rotor on the LH side, what did you guys do to prevent the bearing lockring from coming loose ?
 
Peter R said:
I see several bikes here with the brake rotor on the LH side, what did you guys do to prevent the bearing lockring from coming loose ?
Click to expand...
I'm betting you have a few people worried with that one ;-)
 
the brakes you see on the left side are MK3's, Norton changed to a circlip to retain the bearing instead of the lockring for MK3's
 
Can anyone tell me if the Grimeca caliper 12" disc conversion will work with the stock fender stays? The Grimeca looks just a bit smaller than the AP.
 
No it won’t.
The calliper will definitely be in the way of the stay. Also, the adaptor bracket / plate mounts on the stay mounting point.
It may be possible to do something, a custom stay, bend the stay, etc. But the stock set up won’t work unmodified.
 
For my 320mm x 6 piston brake kits I made new fender stays. the right side being a bit longer to account for the kick
and also a 1" long spacer (5/8" OD) and longer 5/16" bolt to hold the stay out off the caliper.
RGM 12" disc and OEM caliper ?? (2017)
 
Thanks Fast Eddie & madass140! Not what I wanted to hear but what I needed to know. I will have to think about this some more.
 
I made a small block of 1/2" alloy about 1.25 inches out from the bottom lug and a second threaded hole about 1" back. this alloys the stay to be bent out far enough to clear a Lockheed calliper. It is screwed to the bottom lug from the inner side through the adaptor plate. Bending the stay down and back up is going to require a longer stay.
 
On my Alton install thread (Here) some folks have asked me for some details of my brake upgrade using an RGM disc as a starting point, which is why I've tagged it to this thread.

So like I said it's an RGM disc, a Yamaha V-Max Sumitomo 38mm twin piston caliper powered by an 11mm Nissin master cylinder from a Honda Silverwing 600 (which to my disgust I later found out is a scooter). The reason I chose that caliper apart from size was that the pads have something like 55% more friction area than those in the standard caliper.

I really don't like some of the adapter plate offerings so set out to make something which blends in a bit better. Here are some pics of what I came up with..

Prototype adapter made of clear acrylic (helps to get the holes in the right place).



Adapter plate fitted ( I ran it like this for a while to make sure everything stayed tight).





Here you can see the 5mm spacers which are required to centre the caliper.





More in part 2 ( I can only add 5 photos)

Cheers,

cliffa.
 
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Part 2..


Master Cylinder ( with all the instructions filed off)



The adapter cover (styled to look like Z plates).






And a final touch - the Norton logo.





I took it to a quiet place and performed dozens of emergency stops to make sure it was safe.

The brake works pretty well !!

I still have that piece of acrylic so if anybody wants I can trace out the pattern and send it to you.

Cheers,

cliffa.
 
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