Weight of front disc brake(s)

There has been some threads on weight of the front wheel, and the desire to reduce unsprung weight. It seems weight of the braking system has been left out of the discussion entirely. How does the standard disc brake fare weightwise vs. the TLS stopper?
And how much does the available upgrades from CNW (Matt), Madass140 (Donald), Norvil (Les), Andover Norton and maybe some others actually weigh? Weight of parts from these vendors are rarely listed.

Another question succeeds, if the hub and braking system attached to the slider is heavier than the corresponding F/W hub and TLS brake, shouldn't the internal springs have a different spring rate? N-V kept the same springs right up to the last Commando. Weight distribution left/right may change as well and what are the implications?

I'd like to hear from those who have weighed their hubs and brake parts. I will post some weights myself.

- Knut

My Commando front end (with TT100s) gives better feedback than my Kawasaki Ninja 1000SX. So I'm not going to worry. The brakes aren't as good though.

I don't have any science to share, but a single modern disc is going to be a lot lighter weight than an aftermarket affordable 4LS drum. A lot lighter.

I'm not sure about the need to add spring rate for more unsprung weight. Still more unsrpung weight does add to the overall weight of the motorcycle. Adding a little more pre-load would probably be sufficient to help compensate for the additional weight of a heavier brake when braking hard. I doubt there is more than 5 lbs difference though. The numbers you and others come up with will tell the real story.

To be painfully honest, I don't think what NV did with any part of the Norton Commando toward the end of life is an example of doing the right thing. It is an example of doing what it took to try and keep the business afloat. Sorry not a fanatic. I just happen to have a Norton left.

If you can stop faster, you can ride faster, safer.

I use two discs on the front. One rotor for the bike, the second rotor to stop the first rotor.

Acknowledging the weight, it's worth it.

Some weights (update 07/09):

10.7" STD disk 061885 - 2.39 KG
10.7" lightened disk 061885L - 2.25KG
10.7" Girling floating disc 061885G - 1.990 kg
12" floating lightweight disc 050015 - 2.14KG
12" floating lightweight disc by Brembo for KTM/BMW hubs - 1.76 kg
12.5" floating lightweight disc (Don) - 2.01 kg
11.5" floating lightweight disc by Brembo/CNW - 1.50 kg
13" floating lightweight disc (Norvil 069813) - 2.0 kg

Drum brake plate compl. 063280 - 2.08 kg
Drum brake plate compl. RGM3281 -
Drum brake plate compl. 063280/Don - 2.11 kg

STD Locheed 061926 caliper - 1.2 kg to be verifed
AP Lockheed CP2696 caliper - 0.9 kg
Brembo P4 30/34 caliper - 0.9 kg
Brembo P4 (CNW) caliper - 0.84 kg
Brembo XX caliper for KTM/BMW F800GS - 1.06 kg
Nissin 44SC440L1/R1 30/34 caliper - 1.07 kg
Tokico 6-piston caliper (Don) - 1.24 kg

Drum brake hub 060364 - 4.37 kg

Disc brake hub 062867 - 1.5 kg
Disc brake hub 050146 - 1.8 kg
Disk brake hub (KTM/BMW F800GS for twin disks) - 1.17 kg
Disk brake hub (Woody's for twin disks) - 0.91 kg

Drum brake Ceriani 230mm 4LS aluminum/magnesium complete - 8.3 kg

All caliper weights include weight of pads!
Hub weight does not include axle/spindle and external spacers.

I have the AP Lockhead calliper and a lightweight floating disc. But it also has a thick alloy adapter plate for the calliper, so in my case, not sure there's any difference.

Not sure of all the physics in play, but unsprung weight should not be a factor affecting braking performance, as the wheel/its weight are in full contact with road. Forks are pushing it harder into road contact. More or less spring force should have no effect on the wheel, just on how much the suspension compresses, correct? Where unsprung rate likely comes into effect, is when the tire leaves the road over a bump. Fork springs need to force it back down sufficiently fast, which will be a combo of spring force and inertial momentum of the wheel weight.

The drilled and slotted stock Norton Rotor that I have on my bike weighs 1.9 kg - just happened to have a spare one handy...



The 4 piston caliper I use weighs 635 grams without pads, 907 grams with pads.

For what it's worth...

My Seeley has two Lockheed calipers with two Suzuki steel discs on a Honda hub. My front forks are Ceriani off a 450 Ducati. I use a master cylinder which is intended for use with two calipers, so I can operate the brake with my right fore-finger. I can fly into any corner of a race circuit on a lean while braking, regardless of how rough the surface might be. The front never gets out of control. A single chrome plated disc is not enough brake for racing.
My first race bike had 7R AJS drum brakes. On the inside of the backing plate, there were steel snail cams, rollers and pins. It was heavy, and even with Norton forks the front end never got out of control

Derek Wilson said:

The drilled and slotted stock Norton Rotor that I have on my bike weighs 1.9 kg - just happened to have a spare one handy...

The 4 piston caliper I use weighs 635 grams without pads, 907 grams with pads.

Click to expand...

Thanks for weighing these parts. Your brake disk/rotor is surprisingly lightweight!
The caliper weight matches the Brembo P4.

- Knut

Tornado said:

Not sure of all the physics in play, but unsprung weight should not be a factor affecting braking performance, as the wheel/its weight are in full contact with road. Forks are pushing it harder into road contact. More or less spring force should have no effect on the wheel, just on how much the suspension compresses, correct? Where unsprung rate likely comes into effect, is when the tire leaves the road over a bump. Fork springs need to force it back down sufficiently fast, which will be a combo of spring force and inertial momentum of the wheel weight.

Click to expand...

Correct. Let me emphasize that this thread is about weight, not retarding force. Low unsprung weight benefits gross weight (-> faster acceleration and retardation) as well as the time it takes to restore wheel to ground friction, which may help reduce the braking distance under unfavourable conditions.

Edit: For large brake discs, or double disks, reducing moment of inertia is another objective, in the interest of minimizing gyroscopic torque reactions.

- Knut

There is a lot of info on the wheels/parts at https://www.accessnorton.com/NortonCommando/what-do-wheels-weigh.21895/post-365182

Stock Commando brake rotor – 5 lbs 4.4 oz.
CNW Brembo rotor - 3 lbs. 8 oz.
Bare front hub (disk brake)– 1501 g. (3 lbs. 4.9 oz.)

Not so much info about calipers.

mdt-son said:

Thanks for weighing these parts. Your brake disk/rotor is surprisingly lightweight!
The caliper weigth matches the Brembo P4.

- Knut

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I am kind of surprised myself - I had never weighed it before. It was more of an attempt to make it a bit more stylish than anything - lol

BTW - the caliper is a Nissin from a Honda CBR600F4 - frugal man's Brembo

mdt-son said:

Correct. Let me emphasize that this thread is about weight, not retarding force. Low unsprung weight benefits gross weight (-> faster acceleration and retardation) as well as the time it takes to restore wheel to ground friction, which may help reduce the braking distance under unfavourable conditions.

- Knut

Click to expand...

Does that mean that the wheel will get back to road contact quicker due to the heavier weight?

Ian James said:

Does that mean that the wheel will get back to road contact quicker due to the heavier weight?

Click to expand...

No. Lower unsprung weight allows the suspension to react more quickly.

mdt-son said:

Low unsprung weight benefits gross weight (-> faster acceleration and retardation) as well as the time it takes to restore wheel to ground friction, which may help reduce the braking distance under unfavourable conditions.

Click to expand...

Hey Guys,

My new cNw/Brembo system has changed a bit recently with a design change.

Disc / 3.307 lbs (1500 g)
Caliper with pads, bracket and hardware to mount / 1.86 lbs (844 g)
Master cylinder / 0 .68 lbs (309 g)

Matt

I wonder if the stock Norton front end is so primitive that making marginal changes in front brake (unsprung) weight will make no real difference in the front end suspension performance.
Holding aside braking efficiency, which is a separate issue entirely.

I think it's remarkably good for a 50 year old machine. I found 20weight fork oil improved the front end performance, as per the manual.

gortnipper said:

View attachment 94515

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Are those caliper weights with or without brake pads and small hardware?