Drum to Disc brake (2019)

Early Commando with drum brake. Over the years, I've added the TLS stiffening kit and RGM high friction pads. The changes made some improvement, but the brake is very average in terms of performance. It was ok for every day riding as long as I kept my eyes focussed on the horizon. I had a car brake suddenly in front of me a couple of months ago. Gave me a fright as the car's rear bumper filled up the view in front very quickly.

Found an original rim, hub and disc on Flea Bay, in pretty good condition for $200. The correct fork leg also from there for $130. Used Nissin four pot caliper off a 2017 Kawasaki z900 for $100, and Nissin MC from Webike Japan for $120. Two new wheel bearings and the correct spacers were about $75.

Biggest challenge was the the bracket. Found a local guy with a CNC machine. He builds drag cars. His workshop is full of engines, custom parts and all the machines you can dream about. Three weeks and $150 later, all sorted.

According to the Vintage brake table for the pad area/piston ratio, the brake pad/piston ratio is 25:1 on this set up. Not the magical 27:1, but pretty close.

Performance is night and day. The spun iron rotor is obviously not as good as a 320mm modern EBC floating rotor, but is now like a modern brake and very confidence inspiring.

Definitely worth it. Now I understand and appreciate why after market brake kits are not cheap.

Still have to sort out the lower fender brace, but it's pretty much done.

To fix the rear mudguard stay get hold of 2 old ones, then cut them both on the disc side but about 2 inches different. Then take the longer piece from each one and mount on the bike still not connected overlapping by the 2". Bend them both so they clear the caliper and still run parallel, they should still overlap but if you now cut out the excess you can then insert rod to get them to join up and then have the joint welded.

freefly103 said:

Early Commando with drum brake. Over the years, I've added the TLS stiffening kit and RGM high friction pads. The changes made some improvement, but the brake is very average in terms of performance. It was ok for every day riding as long as I kept my eyes focussed on the horizon. I had a car brake suddenly in front of me a couple of months ago. Gave me a fright as the car's rear bumper filled up the view in front very quickly.

Found an original rim, hub and disc on Flea Bay, in pretty good condition for $200. The correct fork leg also from there for $130. Used Nissin four pot caliper off a 2017 Kawasaki z900 for $100, and Nissin MC from Webike Japan for $120. Two new wheel bearings and the correct spacers were about $75.

Biggest challenge was the the bracket. Found a local guy with a CNC machine. He builds drag cars. His workshop is full of engines, custom parts and all the machines you can dream about. Three weeks and $150 later, all sorted.

According to the Vintage brake table for the pad area/piston ratio, the brake pad/piston ratio is 25:1 on this set up. Not the magical 27:1, but pretty close.

Performance is night and day. The spun iron rotor is obviously not as good as a 320mm modern EBC floating rotor, but is now like a modern brake and very confidence inspiring.

Definitely worth it. Now I understand and appreciate why after market brake kits are not cheap.

Still have to sort out the lower fender brace, but it's pretty much done.

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Now your talking. Change out the drum for a disc brake. This was common in the late 70s early 80s. No one bought the used drums as no one wanted them. These days the drums are worth more than a disc setup. You should either hang on to it or you probably can get enough to early recover your disc cost.

Nearly rather than early...gotta watch that spell check.

Lookin' good!! I like that Idea for the Fender stay. Cj

This is the fender stay which is supplied with my brake kit. I made the right leg longer with a kink

There is only ever one excuse for using a drum brake - a race class requires it. When you use a drum brake, you put your life on the line. In racing the front brake needs to be there 100% reliably when you need it. I have never ridden a bike which had a reliable drum front brake. They are never enough. If you get into a corner too hot, you are faced with the situation that you need brakes in the middle of the corner. If you hold the brake on slightly, your bike will tend to run wide and all the time the brake is heating up. If it is a drum brake, the leader can become sticky causing the brake to lock and launch you. The other thing is, on circuits when there is lot of braking down from high speed, the sticky leader can launch you when you are braking down from very high speed.
Personally, I love the look of large drum brakes, however almost every racing crash I ever had, was due to one, so whenever I see one on a fast bike, I cringe. If you get them working well enough to race with, they are dangerous. With road bikes, riding with an inferior front brake, is like riding with an inferior helmet. For racing, a single disc is not enough. Chromed discs are useless. Cast iron usually comes in there grades - grey cast iron, meehanite and nickel bearing. Nickel bearing can be used to make gears. Do not use grey cast iron. My two front discs are high speed steel off a Suzuki. The rear is cast iron and one day, I will replace it.

When you need to stop your bike, IT MUST STOP ! - If there is any doubt in your mind about your front brake, do not ride the bike. With my Seeley 850, a handful of front brake is one finger. The rest operate the throttle. You can only ride as fast as you can stop.

Not sure why you didn’t go with the stock caliper and a sleeved master.

swooshdave said:

Not sure why you didn’t go with the stock caliper and a sleeved master.

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A commando is too heavy for a single disc.

acotrel said:

A commando is too heavy for a single disc.

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Uh. Ok. Well for those of us not on the race track and burning 100% methanol it’s just fine.

swooshdave said:

Uh. Ok. Well for those of us not on the race track and burning 100% methanol it’s just fine.

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I agree. No issue with my Norton Lockheed disc and caliper. However I’m not braking hard into any apex, just enjoying some mountain twisties.

A Commando on public roads is fast enough to need the best possible front brake. Anything less and you are probably kidding yourself. The problem is you find out the inadequacies in the worst possible circumstances

Nissin brakes work great on my modern Triumphs but with your set up I would have replaced the dics with something better if you want complete better braking, you are 3/4 there with the Nissin set up, when my stock brakes tired to kill me I replaced with a full Grimca front brake set up with semi floating dics, it brakes as good as my modern bikes.

Ashley

ashman said:

Nissin brakes work great on my modern Triumphs but with your set up I would have replaced the dics with something better if you want complete better braking, you are 3/4 there with the Nissin set up, when my stock brakes tired to kill me I replaced with a full Grimca front brake set up with semi floating dics, it brakes as good as my modern bikes.

Ashley

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I assumed you didn't try the sleeve master cylinder first?

swooshdave said:

I assumed you didn't try the sleeve master cylinder first?

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RGM kit, worked great till no warning and had to stop quickly lucky was only very slow speed the brake grabbed to much but it threw me over the handle bars, and applying my brakes just normal, my first broken bone and while recovering upgrade my whole front brake system, best thing I ever done, this was just over 7 years ago and full upgrade to Grimca set up for under $600, don't rely on 45 year old brakes and my old front brakes had been rebuilt a few times in the 44 years I have owned it.
I could tell you more what happened but I was concussed for a few hours after the accident and don't remember much after it.
My life is more important to me than to save a little bit of money and my Norton was a everyday rider till about 5 years ago, now its semi retired just like me.
I now have perfect brakes with one finger operation if I wanted to only use one finger lol.

Ashley

ashman said:

RGM kit, worked great till no warning and had to stop quickly lucky was only very slow speed the brake grabbed to much but it threw me over the handle bars, and applying my brakes just normal, my first broken bone and while recovering upgrade my whole front brake system, best thing I ever done, this was just over 7 years ago and full upgrade to Grimca set up for under $600, don't rely on 45 year old brakes and my old front brakes had been rebuilt a few times in the 44 years I have owned it.
I could tell you more what happened but I was concussed for a few hours after the accident and don't remember much after it.
My life is more important to me than to save a little bit of money and my Norton was a everyday rider till about 5 years ago, now its semi retired just like me.
I now have perfect brakes with one finger operation if I wanted to only use one finger lol.

Ashley

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RGM sleeved kit that grabbed too much and threw you over the handlebars? I'd like to know how that happened.

If it was me people would say I overreacted and grabbed too much brake (even though I convinced myself I hadn't) and stock system with a sleeve worked just fine.

Well till you have a bad experiecne with your brakes and it was the second time it done it in a few weeks apart and the first time it did it I was operarting my brakes the same as I have always done in 43 years of riding my Norton, so you can preach to me as much as you like but untill you have something go wrong with your old brakes.
I have no problems mobernizing my bike for better handling, better performance and better braking and if you want to stick with a brake system that is 45 years old, well then good on you and don't preach to me, I use to lock up my Norton brakes all the time in my younger days but when it did this without trying to there is something not right and to do it twice in a short time, make you think of better modern brakes systems, so you do what you want to do and I do what make me happy and a lot safer in my own mine.
By the way I am a fitter and turner by trade and do understad hydraulic systems and know when to replace is better than trying to save a few $$$$, things get to a point that one day it will let you down, is it worth the risk.
I know you think I might know everything, but I don't, but one thing I do know and thats my own Norton as well as my other bikes in my collection, at the time my old brakes had a fault with it and wasn't going to stuff around with old brakes and decided the upgrade was money well spent as I say my life is more important than relying on old brakes system.

Ashley

Sure. I don’t know much about hydraulics so I’d be super curious as to how a system could over pressurize.

Given it was a RGM sleeve kit and I’ve seen some questionable engineering you can’t rule out a mechanical failure. In assume you never did an autopsy? I hope you still have the parts because you might be able to save someone else if that’s what it was.

But the stock system, like most stock brake systems are meant to be reliable for a very good reason.

Best to know how to separate wheat from chafe when viewing this site.