Front brake upgrade..........

Fast Eddie said:

I know it might sound like more blah-blah... but I’d argue it’s important to remember that ‘feel’ and overall set up is almost as important as outright braking power.

People often say they have all the brake their bike can handle cos it’ll lock the wheel, or make the tyre squeal. Well, a bicycle can lock the wheel, but we don’t fit bicycle brakes to motorcycles!

Suspension, tyres, correct stance of the bike all help to ensure the tyre is correctly loaded and is able to handle the braking forces. As does correctly applied lever pressure, and the squeezing a brick feel of stock based set ups certainly doesn’t help with this.

So, actually, increasing the braking power at the caliper end without increasing the feel at the lever end can create an unpleasant brake.

A huge benefit to the Brembo master cyl assembly as sold by cNw is that it has a dog leg lever, this provides more feel, it also has an adjustable span, so it can be adjusted to give max bite at a point most comfortable to the rider. All of this stuff is important in getting good braking.

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You are right about the feel of the brake being important. I think it has to also have great braking power without fade in order to have good feel.
I recall the first real test of the Madass brake on the Commando was on a twisty Mountain highway, doing a good clip. As happens, some of the corners were tighter than anticipated so hard braking was required.
I found that I could scrub off 20 mph in a couple of seconds just using a light touch with two fingers on the brake. It was more of an automatic response rather than a deliberate " I'm going to apply the brakes now" operation as with the stock brake.

This gave a smooth but rapid deceleration.
The smooth part is pretty important to getting around the corner safely and not going down the 1000 foot dropoff at side.
Contrast this to the same trip a couple of years earlier, still with the stock brake. Yes it was possible to slow the bike enough, but the effort required made it a very deliberate and clunky operation. After three or four fairly fast corners, there was some brake fade, which adds to the choppiness of the operation.
After it fades once you worry about it on every corner and tend to overdo the braking, just in case.
The Madass brake has several advantages over stock. To my mind, the biggest advantage is the relative size of the brake pads
Those tiny round stock pads just can't handle repeated hard braking.
I really dislike that stock brake, glad it's stuck in a drawer somewhere!

Glen

acotrel said:

You can only go as fast as you can stop. A mediocre front brake will slow most riders - the survival instinct is psychological. When you know stopping the bike is reliably at your finger tip, you will always be faster. If the brake is unreliable and you know it, you can suffer from severe anxiety. When I used a drum front brake, I had nightmares before every race meeting. And the single chromed disc was not much better.
When you find yourself in a corner at high speed, running out of road, at full lean with the front brake hard on - what do you do ?

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Wish you opted for boots and leathers rather than flip flops and shorts

Had a similar situation, but in a car. At the track going into a 90+ deg left at 80+ mph. Hit the brakes, nothing! Turned out i boiled them and a couple pumps brought them back, but in those couple of milliseconds, it was definitely a hair raising experience.

commandofastback said:

Daytime with main beam in use, red helmet and a jacket with neon yellow applications.
Like a parrot.
But i was still invisble to him.

Yes. Equal pressure on both pistons.
But that doesnt matter.
Its about even distribution of the brake forces and compensating the heat expansion of the disc.
If both components are fixed the expanding disc will try to push back the pads into the caliper resulting in fading brakes.

EVERY modern brake has a floating component.
You wont find one with both caliper and disc fixed.
Why would brake manufacturers make an effort about making expensive inner rotors with float rings instead of making cheap solid disks ?

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Glad you weren’t hurt worse. I call them “assassination attempts”. All the right technique, and sometimes they get one in on us.
Please, re-read my posts. I made them short because I’m very busy.
Not challenging MOST of what you say. I am VERY familiar with brake designs.
The point is, a performance increase comes from a LARGER DIAMETER ROTOR (simple lever/mechanical advantage).
Now, MANUFACTURABILITY and resistance to warping come into play as the size goes up. To make a large diameter rotor, with a dished hub, and axial runout less than .001”, can be done, but we can’t afford it. Also, when heated, it’ll change shape. The “floating rotor” really just a simple, cheap attachment to the hub (carrier) method that allows the rotor to move in a controlled fashion. In and of itself, it is not a “performance upgrade”. The BIG ROTOR is.
Back to Commando brake. The PADS & PISTONS seek their own place relative to the rotor & caliper which are hard mounted. Works fine. No longer used today, granted, but kind of like a Chinese scooter in cost conscious engineering. (Sorry kids).
Your comment of substituting a “floating rotor” in place of the stock iron hat rotor as a means to improve the brakes performance simply isn’t true.

The moto journalists regurgitaed what they were told, just like flat slide carbs. A MANUFACTURABILITY upgrade (read cheap) rolled out as a performance latest great thing.

BIG rotors will improve brakes.

Cheers

acotrel said:

How did you overbalance ?

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I', guessing the wheels were not in line, so the rear pivoted on the headstock, snapping the bars hard left & down I went like a sack of potatoes!

Longest graze on the bike was 2 1/2", no scrapes to gear, so minimal forward velocity.

Mike Sullivan said:

I', guessing the wheels were not in line, so the rear pivoted on the headstock, snapping the bars hard left & down I went like a sack of potatoes!

Longest graze on the bike was 2 1/2", no scrapes to gear, so minimal forward velocity.

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Sounds very unusual. Do you align your wheels with a string line ? Usually if the wheels are out of line, the bike tends to feel heavy as you steer it in slow corners. There is a thing about Guzzis which I dislike - the direction of the torque reaction of the motor. If you have a differential at the rear hub, can you still turn the wheel to get alignment ?

Perhaps you lifted the rear wheel by braking too hard and the bike turned ?

acotrel said:

Sounds very unusual. Do you align your wheels with a string line ? ... Perhaps you lifted the rear wheel by braking too hard and the bike turned ?

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Ah sorry, misunderstanding, the bars were slightly to the left (turning), wheels are in line (fore & aft); I suspect that your final suggestion may be a likely contender - as I did it I realised I'd put all my fingers on the lever , usually just 1 or 2 fingers enough for braking on the Guzzi (which I've had for a couple of Lockdown months).

Mike Sullivan said:

Ah sorry, misunderstanding, the bars were slightly to the left (turning), wheels are in line (fore & aft); I suspect that your final suggestion may be a likely contender - as I did it I realised I'd put all my fingers on the lever , usually just 1 or 2 fingers enough for braking on the Guzzi (which I've had for a couple of Lockdown months).

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I never use more than one finger on the front brake and NEVER grab a handful unless I really need to crash the bike to the ground -( that situation can actually happen when racing ). My brake feels slightly spongy when I use it, so the pressure you apply to the lever is progressive. If everything is rock hard, your brake can become effective too suddenly.

concours said:

Glad you weren’t hurt worse. I call them “assassination attempts”. All the right technique, and sometimes they get one in on us.
Please, re-read my posts. I made them short because I’m very busy.
Not challenging MOST of what you say. I am VERY familiar with brake designs.
The point is, a performance increase comes from a LARGER DIAMETER ROTOR (simple lever/mechanical advantage).
Now, MANUFACTURABILITY and resistance to warping come into play as the size goes up. To make a large diameter rotor, with a dished hub, and axial runout less than .001”, can be done, but we can’t afford it. Also, when heated, it’ll change shape. The “floating rotor” really just a simple, cheap attachment to the hub (carrier) method that allows the rotor to move in a controlled fashion. In and of itself, it is not a “performance upgrade”. The BIG ROTOR is.
Back to Commando brake. The PADS & PISTONS seek their own place relative to the rotor & caliper which are hard mounted. Works fine. No longer used today, granted, but kind of like a Chinese scooter in cost conscious engineering. (Sorry kids).
Your comment of substituting a “floating rotor” in place of the stock iron hat rotor as a means to improve the brakes performance simply isn’t true.

The moto journalists regurgitaed what they were told, just like flat slide carbs. A MANUFACTURABILITY upgrade (read cheap) rolled out as a performance latest great thing.

BIG rotors will improve brakes.

Cheers

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Thanks for your warm word regarding my accident.

Of course big rotors improve braking.
At least when you you use the right components.

Braking once or twice with the stock caliper and disc wont hurt it and the braking power (at least with a 13mm master cylinder) isnt so bad.
I know that. I have it.
But if you go down something like this ...

https://3.bp.blogspot.com/-cIPBUM_P...AABaI/2jd2h-Sk_rY/s1600/Anstieg+aufs+Joch.jpg

.. its COOKED !

Happened to me twice. The discs were blue and the brake was squealing like hell.

The cnw brembo kit has a modest solid 12" (or was it 13") disc and floating caliper and as afaik nobody has complained about a lack of braking power, feel or fading.
Good choice of components.

On the other hand you dont hear much good about those hideous, monster double floating disk kits from Norvil with cheese inner rotors.

commandofastback said:

The cnw brembo kit has a modest solid 12" (or was it 13") disc and floating caliper and as afaik nobody has complained about a lack of braking power, feel or fading.
Good choice of components.

On the other hand you dont hear much good about those hideous, monster double floating disk kits from Norvil with cheese inner rotors.

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The cNw kit has a solid mounted caliper and floating disc.

Yes, the disc size is modest, Matt specced that intentionally as bigger ones just look wrong to his eye.

I have noticed some fade at the end of a long track session, and I’ve had the disc blue, but functionality is still good. I’ve never experienced that on the road. I agree it’s a very good selection of complements, it’s also very nicely made. But, if Matt made a slightly bigger rotor as an option, I’d have one!

I can’t imagine the huge twin Norvil discs fading much! But they just look wrong on a Norton to me.

I fitt

commandofastback said:

Thanks for your warm word regarding my accident.

Of course big rotors improve braking.
At least when you you use the right components.

Braking once or twice with the stock caliper and disc wont hurt it and the braking power (at least with a 13mm master cylinder) isnt so bad.
I know that. I have it.
But if you go down something like this ...

https://3.bp.blogspot.com/-cIPBUM_P...AABaI/2jd2h-Sk_rY/s1600/Anstieg+aufs+Joch.jpg

.. its COOKED !

Happened to me twice. The discs were blue and the brake was squealing like hell.

The cnw brembo kit has a modest solid 12" (or was it 13") disc and floating caliper and as afaik nobody has complained about a lack of braking power, feel or fading.
Good choice of components.

On the other hand you dont hear much good about those hideous, monster double floating disk kits from Norvil with cheese inner rotors.
I fitted two Norvil 14 inch discs to the fastback I rebuilt in 2002, and rode it to the top of Norway and back from London(4400 miles!!), using the stock m/cylinder, which was a good enough match. Haven’t done many miles since, but so far no complaints, and very useful descending fiord -side hairpin bends.....

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This set up has been working well on my Roadster. It uses the standard size disc which looks more original on the bike than a large floating disc set up (which I have on my other bike):

olympus said:

I have fitted AP calliper and drilled cast disc from RGM, calliper carrier from Norvil (As I don't like the elongated holes in the unit from RGM
Magura master cylinder
Everything fitted a dream
As I'm yet to road tsst, I cannot confirm efficiency & feel

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Hi
im just about to upgrade the front brake on my commando and I’ve decided to go RGM disc and caliper but I note what you say about the slotted bracket. The Norvil site is v unfriendly, do you happen to know if the caliper to fork leg adaptor for the RGM 12” disc and Grimeca caliper is the Norvil part 069189?

I have just taken receipt of a package from Madass140, a 320mm disc, adaptor bracket and 6 pot caliper. I already have a 13mm master cylinder.
Very good delivery service, ordered last weekend and posted Monday. I received it first thing this morning. All the way from the Philippines - 4 days only. Terrific.