Front brake upgrading

Thanks for your reply, Don. I've got the opportunity to by a second hand Lockheed caliper and carrier at a reasonable price.
(what a wonderful forum this is )
So I just (?) have to buy a 12" disk. Maybe I'll try it out with the Brembo M.C. first but a resleeving of the Norton MC will probably be better.

Thanks all of you for your help !
Paul.

I have a 12" floater with a Gimeca 2P (same as a Lockheed) caliper with a 11mm Grimeca master, which give me a ≈27:1 ratio. Excellent stopper. One finger will do. Very progressive.

JimC said:

I have a 12" floater with a Gimeca 2P (same as a Lockheed) caliper with a 11mm Grimeca master, which give me a ≈27:1 ratio. Excellent stopper. One finger will do. Very progressive.

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According to the "Front Master Cylinder Ratio Chart", 11 mm seems to be indeed the way to go. But where can I find an 11 mm. M.C. ?

As mentioned before, on the Brembo M.C. there is the # OK 03 16. Does anyone know if the "16" stands for 16 mm. diameter ?




If yes, can Brembo master cylinders be resleeved to 11 or 12 mm ?

I've got an answer from a Brembo service station right now: the M.C. on the photo has indeed a 16 mm. bore. Resleeving to a smaller diameter is not possible or done by Brembo.
Alternatives:
- Resleeving of the Norton M.C. I have. (It's not in a very good shape though )
Some dealers advise against that because of safety reasons :?:
- Other make. Were can I find a Grimeca 11 mm ?
Apparently, those are only sold by scooter dealers:
http://scooter-center.com/scoweb/pages/ ... f=adbutler

Is this the right type ?

I got the Gremica 11mm from a MZ dealer. A 250 cc MZ uses it. Don't remember what model or year. Of course, the dealer is long gone. It does appear very similar to the one on the link you provided, except mine has a mirror mount. I also have the matching clutch lever. You might try Michael Morris of Vintage Brake.

Odd thing about the stock Norton M/C, it's the correct size (26.68:1) for two 41mm two piston calipers.

Thanks Jim.

One more question: I read that the aluminum AP Lockheed caliper flexes too much. A Grimeca should be better.
Is this right ? ( the second hand caliper I can buy is a Lockheed )

the grimeca is a copy of the lockheed ,a bit heavier but as good as the original. Is the Lockheed a 3fin or a 4 fin? It beats the grimeca 100 times on looks and I think thats what you are after.The 3 fin are getting rare ,especially the handed ones but I do not like the 4fin aesteticly.Look at the pistons because the early ones had steel pistons wich tended to rust .I believe the grimeca has got alloy pistons wich can be used in the Lockheed .I use lockheed on the outfit with alloy pistons so they are around

Hi Paul,
I dont mean to sound picky or offend but is your Production Racer modified from a standard commando or do you think its always been a proddie Racer from new.
Its just that some things dont seem like the proddie racers I remember when they came out new.
Just an observation on my part.
I hope your not offended by this observation.
Cheers Don

Paul said:

Thanks Jim.

One more question: I read that the aluminum AP Lockheed caliper flexes too much. A Grimeca should be better.
Is this right ? ( the second hand caliper I can buy is a Lockheed )

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I have no experience with the Lockheed 2P. I do know from my experience the Grimeca, which is a copy of the Lockheed, works fine. I guess if the price is right I'd try the Lockheed. A new Grimeca can be had for $149.

@ Don :

Don't worry, I'm not offended at all. :wink: My bike is a replica, based on an MK III frame with a combat engine and quite some hand made parts. You can read the story here:

new-norton-and-new-this-forum-t3658.html

Paul said:

[
- Resleeving of the Norton M.C. I have. (It's not in a very good shape though )

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You can also buy them already sleeved. They may or may not take yours as a core.

Paul said:

Thanks Jim.

One more question: I read that the aluminum AP Lockheed caliper flexes too much. A Grimeca should be better.
Is this right ? ( the second hand caliper I can buy is a Lockheed )

Click to expand...

I have a pair of Lockheed racing calipers on my T140, and I don't experience flexing.
I do experience a grossly overbraked bike, and I fear that one day the headstock will give way
Seriously, it's a one-finger brake (standard Triumph M/Cyl & discs), and a bit too much for a road-going bike, but I'm not changing it!
I'm sure that the pad compound has a lot to do with it.
I just hope my sleeved-down standard Norton setup on the 850 is going to be up to snuff.

It took quite a while but finally, the "brake upgrading" is finished. (so time to upgrade this topic).



As often, anything that could go wrong, did.
After lots of delays, I received the ordered brake disk. When I opened the box, I saw it wasn't the right "semi floating" one, but a modern drilled "light" disk. Nice part but not what I wanted (nor ordened) for my Prody. So a new disk was ordered. This time it was the right type but not a 12" , only 11.5. The brake pads sticked out 5 mm above the disk. Eventually, the Norvil one was the one I needed. Still 5 mm. too small to be a 12" but I'm not that difficult and filed 1.5 mm away from the brake pads... :?

Next, I couldn't manage to bleed the resleeved MC. After a couple of hours I found out the MC leaked. The brass bushing turned out to be badly finished:




so I had to return it as well...

But in the end I had all the right and good working parts. As I wanted to compare the Norvil disk / Lockheed racing caliper with the Commando disk / standard caliper combination, I fitted the new disk with the present Brembo 16 mm. MC first. Braking was improved a bit but indeed not that much. Next, I replaced the Brembo by the 12.5 mm resleeved Norton MC and this was a big improvement: the bike brakes almost as good as a modern one now.
Conclusion: it is absolutely advisable to reduce the MC diameter ( if there's only one front disk).
The modification to the Norvil disk doesn't improve the braking performance much, but for a Production Racer, it looks of course much better.

I wonder how many brake conversions end up with the pads sticking out over the disc,I find the idea terriffying , imagine having an emergeny stop using the back retardent device.

Paul,

Thanks for sharing your experiences - It still amazes me that suppliers can maintain a 1970's level of service and remain in business - you'd thing that they'd have their products refined to the point of being fit for purpose by now!

The potential for the ignorant to fit one of these set-ups and have it go badly wrong doesn't bear thinking about.

It does look proper butch though

You didn't mention the vendor(s) you used.

swooshdave said:

You didn't mention the vendor(s) you used.

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That's right. The vendor who resleeved the MC mounted an Andover set, so I'm not sure who is responsible. Was the inner surface damaged when he mounted it or did he get it badly finished that way ? I don't know so I don't want to accuse him.
(allthough I think he should have tested it before sending)

Paul said:

swooshdave said:

You didn't mention the vendor(s) you used.

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That's right. The vendor who resleeved the MC mounted an Andover set, so I'm not sure who is responsible. Was the inner surface damaged when he mounted it or did he get it badly finished that way ? I don't know so I don't want to accuse him.
(allthough I think he should have tested it before sending)

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And what about the discs? Was that you ordering the wrong parts or them sending the wrong ones?

The first "wrong" one: no idea who made the mistake.
The second (11") one: seems to be the size of the disk sold by Mick Hemmings. The adapter piece for the front fork is made by Norvil (Les Emery) though and designed for a 12" disk (available also for 13 and 14"). I got this from Ludwig so I shouldn't blame the company who ordered the disk.
Anyway, all that was wrong was replaced without any grumbling so it's ok.

The next upgrade when you have a GOOD brake is a good tire. Old tires and new productions of the old tires, like k 70s' and SM ribs won't stand up under the stress of extra braking power, they came from an era when nothing had good brakes .

Next, I replaced the Brembo by the 12.5 mm resleeved Norton MC and this was a big improvement: the bike brakes almost as good as a modern one now.

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Having an incorrectly sized Brembo m/c is no better than an incorrectly sized stock Norton m/c. Size matters. In this case, smaller is better. A 16mm master is the right size for a 4 piston 41mm caliper setup.