Anyone here know of a way to improve front disc brake on '72 Commando and still be mostly stock ?

Stephen Hill said:

.. Seems like the piston would try to cock in the bore.

Stephen Hill

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Actually it will prevent the piston to cock in the bore .
If you look at worn brake pads , you may notice that they are worn thinner on the leading edge ,
especially if you used the brakes hard .
Concentrating piston pressure on the trailing side will counteract this .
That is also why most 4 piston calipers have smaller pistons on the leading edge .

Edit : Doing this mod will make piston orientation critical .
If in any doubt you can do it right , then don't do it !

I have a lot of the mods suggested. But didnt do them one at a time to evaluate each one. Probably not as good as complete modern setup
but heck of a lot better than stock.

When I brought my Commando new the front brake system worked like they should never had any problems locking up the front brake and lifting the rear end, but the more miles I clocked up they sort of started to fade away and even putting in new pads didn't make much differnts but then back in the 70s there wasn't that many improvements around and not having the internet to help source parts made things harder to source and the time differents world wide, waking up in the wee hours of the morning to phone orders to England, then sending a money order over to them and then waiting for weeks even months to receive your parts and what a nighmare if they sent you the wrong parts, life is so much easier these days, click, order, pay, sent and received in a few days world wide.
There are so many modern brake set ups for our old bikes these days I have no troubles at all modernizing my old bike and if you do spend the money modernizing your brakes you be thinking to yourself, I should have done this many years ago, remember your not riding back in the 70s there is a lot more happening on our roads today and it can be a dangerours place on our roads today, to many people are distracted while driving and the worst ones people on mobil phones (cell phones to my friends in the US) while driving is one of my biggest pet hates.
If you have the money then do it right instead of a 1/2 fix it might save your life one day.

Ashley

Tornado said:

Has any found improvement with a cross drilled stock rotor? These are common on modern bikes. Idea is to give gas venting from under the pads and should reduce disc over heating by giving a little more cooling area.

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I did have a drilled stock rotor once. The improvement is hardly perceptible. I you want a brake that’s up to snuff, start with a properly matched master cylinder to caliper. That’s the largest gain. Then pads, rotor and brake line.

The question at hand befuddles me....do you want to stop as fast as you can or do you want to look stock doing it...two different things.

W

Lineslinger said:

The question at hand befuddles me....do you want to stop as fast as you can or do you want to look stock doing it...two different things.

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While I like the sentiment in the proceeding I do think there is always room for compromise. If the only acceptable solution was best braking possible we would need full on dual disk, 6 pot setups with ABS. Why stop there and not go full traction control, air bag restraint, steel safety cage and throw in another two wheels and bucket seats with seat belts?!?
We each must decide where we want to make those compromises.

Its not sentiment, the concept and insight is real world, not ethereal.
I am talking about the best possible "solution" to stopping...when crunch time is in your face.... stopping in the shortest distance in the shortest amount of time is a big deal regardless of how many other additives you slap on your bike (or choose not to) regardless of the other applications you apply.
I choose modern day technology over 40 year old technology any time...better chance of walking away....and most riders appreciate that, so do their kids.

So why are you not riding a bike with ABS, dual discs, 6-pot calipers? My point is we all have to be comfortable with the risks we accept. I know guys who feel fine riding open face helmets and no other protective gear on bikes with front drum brakes. Gives me the shivers but I don't preach to them, they know the risks they are taking.

What I ride and its applications are my own...I have been doing so for more years than I care to share...you don't have a clue as to what I ride or how I ride it.
Preaching not on my radar, please don't misconstrue a basic observation. You can offer up all the high tech modern day applications available...I guess its a point you know those with"wind in their hair"...I did it...still do it sometimes...risks we accept? I have lived a very different concept of what that means...to each their own.
You be well.

Tornado said:

Has any found improvement with a cross drilled stock rotor? These are common on modern bikes. Idea is to give gas venting from under the pads and should reduce disc over heating by giving a little more cooling area.

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It is a widespread misconception that a drilled rotor improves braking power. The drillings are only ment to absorb water during braking when riding in wet conditions.

Come on boys this is about brakes, but for the record I have had my Norton of 43 years now with full brake upgrade, I also have a modern 2013 Triumph Thruxton with simlar brakes to what I am now running on my Norton, I also have a new 1200 S Thruxton with twin disc, ABS, TC etc etc and I can tell you my Norton stops as good as both, but then my Norton is much much lighter even a lot lighter than my orginal Commando while it was in that form, but then I hardy use my brakes when out riding even in the twisties or high speed straights, most times I only use my brakes to come to a full stop, but isn't it great to know when you really need them they are there, by the way I ride all my bikes pretty hard and push then to their limits, its the way I have always rode.

Ashley

Peter R said:

It is a widespread misconception that a drilled rotor improves braking power. The drillings are only ment to absorb water during braking when riding in wet conditions.

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Drill disc are more to cool the disc down from heavy braking quicker, a full disc will hold the heat longer and more brake fade.

Ashley

Tornado said:

Has any found improvement with a cross drilled stock rotor? These are common on modern bikes. Idea is to give gas venting from under the pads and should reduce disc over heating by giving a little more cooling area.

Click to expand...

Yeah but does a stock Norton set up have the oomph to generate enough heat to need any help dissipating it ?!

A drilled rotor may be a nice finishing touch to an uprated system, but on its own I doubt it would make any difference at all, apart from looking nice and saving a bit of unstrung weight.

I believe Worntorn on these forums told me he had his stock disc brake over heat, fade out on a ride...might have been a downhill or something like that. So, yes, our bikes can make too much heat for the stock setup to handle.
I've heard drilled (and even slotted) discs do several things...provide the gases generated under pads somewhere to escape, which helps prevent loss of friction. Better cooling. Better water dissipation. Lightens disc so less unsprung weight. All the above would seem marginal improvements at best to overall performance, so not likely something you'd notice on standard rides.
But I know of no modern bike running solid discs these days. Must be some reason manufacturers use them as a standard.

I once obtained some “racing pads” of unknown brand which were REALLY good but on a fast ride in the Sierras I cracked my drilled stock disc. That disc was drilled with many small holes, similar to the drilling pattern on the old Guzzi Brembo iron discs. There were many radial cracks

I have the 12” Miles conversion now

Yes, cracks at the drilled holes are a known concern. First heard they were a thing on car cross drilled discs. The brand I was looking to fit to my '84 VW GTi stated the holes were chamfered to reduce risk of stress risers at the hole edges. Seemed like a good solution.

If you want to use a braided steel brake line but want to keep the bike looking stock, have one custom made with heavy duty, black shrink tubing added before the ends are swaged on. I had a line like this made for my Commando 30 years ago. It works great and looks stock.

Thanks to all for your ideas. I did remove the chrome from my 79 Triumph Bonnie and it worked quite well. I have no chrome on the Norton so I suppose I will upgrade next spring when I can ride again. Thanks again for all the ideas !

I think the stock Norton disc setup is the worst front brake on the road. The faults of this system are too numerous to list. It has the feel of squeezing a 2X4 and needs 2 hands to stop. I replaced mine with a floating drilled disc, Grimeco caliper, SS lines and a properly sized master. (The Hyde fork brace looks sexy but I'm not sure it adds anything). The system doesn't look stock but I wouldn't brag about riding with the stock brake anyway. At an absolute minimum, re-sleeve your master. That will solve 90% of the design defects.

manxman said:

I think the stock Norton disc setup is the worst front brake on the road. The faults of this system are too numerous to list. It has the feel of squeezing a 2X4 and needs 2 hands to stop. I replaced mine with a floating drilled disc, Grimeco caliper, SS lines and a properly sized master. (The Hyde fork brace looks sexy but I'm not sure it adds anything). The system doesn't look stock but I wouldn't brag about riding with the stock brake anyway. At an absolute minimum, re-sleeve your master. That will solve 90% of the design defects.

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Have you tried a CB750 from the same era?