New Rotor?

Manu · Friday at 2:36 PM

the rotor on my new-to-me sat-for-10-years '72 750 is fairly pitted and might even have a small crack or two. Thinking about getting a new one. I see Andover has stock-looking ones. BCS has Gerling for about the same price. Wondering if one is better the the other or if there are any better sources?

And then there is the cnw/brembo kit for a mere $1400.
Thanks

Torontonian · Friday at 6:34 PM

Always replace any doubtfull rotor with a brand new one . Not cheap , but you will be buying full magnetism and no worries about the center working itself loose . When the older type let go it's not pretty .

ashman · Friday at 7:06 PM

I still run with the original rota but the centre did let go about 40+ years ago had a new centre pressed in and still working today.

batrider · Friday at 7:14 PM

Front disk rotor

Torontonian · Friday at 9:27 PM

O.K. , brake rotor .
Good brakes are your life . Other lives too . Replace . Mine came from Walridge Motors , has many holes drilled into it and was not expensive .

Dedubyah · Friday at 11:19 PM

Might as well go with an RGM 12" disc then, increase braking power and easy enough to make up a new bracket

gortnipper · Friday at 11:23 PM

Manu said:
the rotor on my new-to-me sat-for-10-years '72 750 is fairly pitted and might even have a small crack or two. Thinking about getting a new one. I see Andover has stock-looking ones. BCS has Gerling for about the same price. Wondering if one is better the the other or if there are any better sources?

And then there is the cnw/brembo kit for a mere $1400.
Thanks

It all depends on how important stopping is for you.

For me, it is everything.

kommando · Saturday at 12:48 AM

New rotor plus smaller dia master cylinder is best bang for bucks.

cliffa · Saturday at 12:50 AM

Manu said:
the rotor on my new-to-me sat-for-10-years '72 750 is fairly pitted and might even have a small crack or two. Thinking about getting a new one. I see Andover has stock-looking ones. BCS has Gerling for about the same price. Wondering if one is better the the other or if there are any better sources?

And then there is the cnw/brembo kit for a mere $1400.
Thanks

Or you could fit one of Don Penders kits…

Norton Commando | tritonmotorcycleparts.com

ashman · Saturday at 4:22 PM

ashman said:
I still run with the original rota but the centre did let go about 40+ years ago had a new centre pressed in and still working today.

Wrong rota.

Dedubyah said:
Might as well go with an RGM 12" disc then, increase braking power and easy enough to make up a new bracket

When my stock front brakes let me down badly, and at the time the RGM full Grimca front brake system was a cheaper system at the time for me the 12" semi floating disc, Grimca caliper, Grimca MC and SS brake line and longer brake lever that was 15+ years ago for just over $500 at the time, my Norton has good brakes up front now, they all work together and can also be 1 finger operation if you need to, the brake system has worked a treat ever since installing it, so much better than the useless stock front brake and looks so much better as well, great stopping power, the caliper came with a mounting bracket so no need to make one, and it looks good on the bike.

Ashley

Torontonian · Saturday at 4:51 PM

Dedubyah said:
Might as well go with an RGM 12" disc then, increase braking power and easy enough to make up a new bracket

Yeah , that's what in on my machine . Came with bracket .

Manu · 2026-07-19T10:46:59-0600

that Don Pendor kit at $450 looks pretty good. Especially since it claims to not require other mods. How well does it perform compared to stock?

Onder · 2026-07-19T12:42:11-0600

Pender brake works well. I rode with it yesterday. When I first put it on I had issues with one of the pots not releasing.
Don sent a replacement caliper complete directly. It is more brake than most of need.

Dedubyah · 2026-07-19T17:12:49-0600

RGM 12" disc, brembo caliper and home made bracket plus 13mm m/c and braided line work a treat. Don't care for the looks of the 320mm disc on the front of a Commando and don't think it would perform better.

concours · 2026-07-19T18:51:35-0600

Torontonian said:
Always replace any doubtfull rotor with a brand new one . Not cheap , but you will be buying full magnetism and no worries about the center working itself loose . When the older type let go it's not pretty .

The Commando rotor is a one piece casting. The center does not work itself loose.

As for magnetism...

some hipster buzzword application?

concours · 2026-07-20T06:11:20-0600

Manu said:
the rotor on my new-to-me sat-for-10-years '72 750 is fairly pitted and might even have a small crack or two. Thinking about getting a new one. I see Andover has stock-looking ones. BCS has Gerling for about the same price. Wondering if one is better the the other or if there are any better sources?

And then there is the cnw/brembo kit for a mere $1400.
Thanks

How about you post some good clear, close-up images of the rotor, and point out the cracks, some pitting, would not be a dealbreaker so long as the overall surface is level.
If you are not interested in cleaning, and thoroughly inspecting, then by all means, get a new rotor, and be glad that they are available. As mentioned, thinking through the big picture, about where you end up with the bike, how much modern breaking that you want on this vintage bike...

New Rotor?

Manu

Torontonian

ashman

batrider

Torontonian

Dedubyah

gortnipper

kommando

cliffa

ashman

Torontonian

Manu

Onder

Dedubyah

Attachments

concours

concours

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