Cast Iron Discs

[Mick Taylor]

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Hi all, when I picked up my Classic on Wednesday I had to load it onto the trailer in light rain, I stopped a few miles down the road just to check the straps and the brake discs were already red rust.

Having put it in the garage and dried it off, I went to take it out today and the pads had bonded themselves to the now properly rusty discs and took a bit of freeing.

I'm sure I have seen photos of Classics with what looks like stainless discs; it would not surprise me if the first owner requested cast iron discs as he also had the bike supplied with a right hand gear change conversion, very neatly done, but now reverted back to the left side.

Are these discs unique to the Classic?.....and does anyone know if stainless versions are available?

Mick.

[johnbirchjar]

As far as I know all Classics have Stainless discs as a standard fitting (perhaps IP2's did as well?)Weather they are still available?who knows,having said that, I seem to recall some time back, that a club member asked the same question and was told they were still avaliable,(some where in South London if memory serves)doubtless someone will answer on the forum, meanwhile,enjoy your Classic,they are a great bike ,ride safe,J.B.

[Mick Taylor]

Hi John, thank you, that pretty much confirms what I thought.......the only Classic I have ever seen with rusty discs is mine

I think the place in South London you mention might be All Bike Engineering.......I could take a couple of good photos and email them to see if they could fit new stainless discs to the carriers, it's pretty much their stock in trade......provided these are not special or uniquely difficult.

There are two things that I have never seen the point of on a motorcycle and that is cast iron discs and powder coating (except on sacrificial parts like crash bars etc)......one will cover your bike in corrosive red dust and the other looks fine until it fades, dulls or just peels off.....at which point the horror of getting the rest of it off safely becomes apparent.

Mick.

[kanonkopdrinker]

Mick,

We’re both of a similar vintage .... you must remember the discussions which took place in the 1970’s about cast-iron v. stainless-steel as brake disc material?

I think I would rather put up with this rusting you describe rather than have a pretty bike whose brakes did not work in the wet.

DC

[Mick Taylor]

But, given the right pads they do work in the wet, even bikes from the seventies.....and that's the whole point really, all modern bikes (I stand to be corrected) have stainless, low maintenance discs and stunning brakes.

I had a bit of a struggle to get the bike off the bench yesterday because the front wheel wouldn't turn, pads rusted to the disc in just two days and because the bench has a smooth surface the grip of the tyre was less than the grip of the rust; cast iron discs in modern usage terms are right up there with typewriters.

Does your Norton have iron discs?

Mick.

[kanonkopdrinker]

Mick, my IP2 is now living in Austria .... I’m not sure what material the discs were.

The RE5’s are certainly stainless-steel; the W2000’s are cast-iron beneath the chrome plating (which I have had skimmed off).

DC

[Mick Taylor]

Chrome plated discs........that's another mystery, there must have been a good reason, it's not a cheap process.

I did wonder if the Classic discs are unique to that bike or if anything else might fit, but I suspect I'm one of an extremely tiny number to have the problem so I will have to find out myself I guess....


Mick.

[johnbirchjar]

There are quite a number of IP2(or derivatives of )in the club, so I am sure one of them will answer my question whether said bikes have Stainless Discs fitted as standard,J.B.

[Mick Taylor]

Thanks John, looking at the discs a little closer today, the cast rotor seems to be mounted on an alloy centre fastened by Allen bolts.

The actual disc part seems to be a simple circle with a number of threaded holes, no complicated shapes......in an ideal world I would buy discs and bolt them to my carriers, but it's probably not that simple....I will give Graham at Startright a call to ask what if anything he might have.

Mick.

[mick695]

I have the same problem with my Hinckley Trident, if I put it away with wet disks they tend to have locked up by the next time I get the bike out the garage...

I find a good well placed whack with a rubber mallet on the caliper frees them up no problem

Cheers

Mick

[Mick Taylor]

A whack with a rubber mallet is the traditional cure.......but thinking about it, these are opposed piston, the caliper body is fixed in place, so whacking it won't do anything.......it might break something if I got a bit carried away though.

Stainless discs is definitely the way to go ......... if I can find some.......it must be a nightmare if you have iron discs on a bike that lives outside, the only upside is, it's a form of immobiliser.

[Richard Negus]

Mick,
In the world of Classic owners, there are lucky ones and unlucky ones.
The very first Classics produced had Brembo stainless discs with a cast aluminium centre.
Then Brembo discontinued that disc and offered the bolted cast iron one as a replacement. Snag was the offset was wrong so Norton made a nice anodised spacer between disc and carrier.
Predictably, Brembo then discontinued that cast iron disc.
Then Spondon came to the rescue and made a complete bolted-up stainless disc with anodised carrier and the correct offset. That is identifiable by round holes in the cast carrier.
EBC do very nice replacements for both front and rear F1 discs, so perhaps you might check their catalogue or ask a Moto Guzzi specialist what the options are.

[Mick Taylor]

Thank you for that, Richard.......it seems this was an 'unlucky' bike.......it definitely has the spacer ring you mention.

I will certainly look at EBC; failing that, because they look relatively uncomplicated, I will see what All Bike Engineering can do; I was hoping there might be a straightforward Norton stainless replacement disc to fit to my carriers, but it seems that is not the case.

I'll get there in the end......hopefully

[Richard Negus]

Mick,
If you do find a replacement, please let me know; there's a Classic in my workshop, unused for ten years, with very rusty discs.
I was planning to use a Scotchbrite mop to get the worst off and hope a bit of heavy braking will make them look better.
As Classics weren't built in numerical sequence, but "he who shouts loudest gets the next one" order, it's impossible now to know when the changes occurred.
R.

[Mick Taylor]

Will do, I'm going to try Allbike Engineering first, they are set up to make discs and claim they will make pretty much anything.

I guess when these parts were not made in-house, Norton were always at the mercy of their suppliers.

Mick.

[Interpol2471]

I spotted a pair of discs in my little shed the other day I will have a look

[GeoffD]

I've got classic number 11 and it has got cast iron discs with anodised spacers. I know these were original fitment to this particular bike, as I have a photo of it when it was nearly new. I turn the wheels a bit every week or so over the winter and don't have a major problem with rusting.

Interesting note about the build order. Is there a record of when the bikes were actually built/despatched?

I'm sure that I'll enjoy riding it as soon as I can get the engine running smoothly.

Geoff.

[Mick Taylor]

As it happens I have an update on my cast iron disc problem; I picked up a set of three stainless rotors from Allbike Engineering in Greenwich late last week and got them all fitted today.

Before:

20180325_141320_resized (1280x720).jpg

There are 27 M6 screws holding the rotors to the alloy carriers, the head of the very last screw just fell off as soon as I put the slightest pressure on it, look carefully at the break and the damage through corrosion (I think) is obvious.....you never know what these things are hiding.

20180325_153010_resized (1280x720).jpg

Here it is with the new stainless rotors fitted......it may be that the problem with the pads sticking to the discs is worse than it needs to be on my bike as I am using sintered pads, but just getting it wet on the trailer on the trip home caused them to stick quite badly and I do recall getting a bit fed up with the amount of red oxide dust on the wheels when I owned it previously. The iron discs which were much rustier than anticipated where they meet the anodized spacer ring will be brushed off, greased and stored so it can always go back to original if need be. Bear in mind this is a bike with less than 5,000m on the clock from new that will have spent almost it's entire life in dry storage.

Here are the new front discs fitted, hopefully they will be a little more user friendly.

20180326_172057_resized (720x1280).jpg

As an aside to this conversation, I was at the National Motorcycle Museum last week, they have a very original looking Classic, still wearing it's Pirelli Phantom tyres (I wish they would re manufacture them).....I took a couple of photos from several feet away of the engine number which looked like LE032 (or maybe not) and that bike was fitted with the later production round hole Spondon stainless discs which looked very neat.

The stainless replacements are not as nicely manufactured and finished as the originals, but if they do the job I'll be happy.

Mick.

[mickm]

Hi Mick
How much were the discs from ABE is LE 032.

[mickm]

Hi Mick Sorry that last post should be
How much were the discs from ABE? as I may well have to get some for my Classic. Which is LE 032 Thanks Mick

[Mick Taylor]

The discs were £100 each, but if I had bought four or more then they would have been £90 each.....I guess once they have the machine set up and programmed, the more they make, the more economical it becomes.

The number written on my job sheet was 2063......I believe (but don't hold me to it) that should allow them to remake the same thing again without having to create a program which they had to do for mine.

If that is the case it should also mean you might be able to order them without having to go there and leave a disc to copy as that has already been done.

Mick.

[johnbirchjar]

My Classic is LE029 and is fitted with the Spondon S/Steel discs(which I had a biker buddy drill holes in for me some years back,purely for aesthetic reasons ) "You didn't tell me the discs were Stainless,"was his comment,"Broke about six drill bits "I professed ignorance and gave him an extra tenner,truthfully though I didn't know back then.J.B.

[mickm]

Hi Mick Taylor can you put up a picture of your new discs? the old picture isn't available to me anymore. I am off to ABE on friday the 3rd to get a new set of Spondon Stainless? discs. i question the word stainless as my discs whilst still bright and look like stainless must be a very low quality stainless as they are magnetic! Thanks Mick M

[Clive603]

Actually most types of stainless steel are magnetic in greater or lesser degree.

Only Austenitic types are always non magnetic. Ferritic, Martensitic, Duplex and some Precipitation Hardening types are generally at least weakly magnetic. The common grades that folk like us usually encounter eg 303, 304 (18/8), 316 are austenitic but other types are frequently better for engineered applications.

Austenitic grades are generally known for being vulnerable to corrosion related stress cracking and for being a pain to machine or drill because they work harden very quickly if the tool stops cutting. I've had frequent reasons to be glad that my Pollard 15 AY pillar drill is a proper industrial size brute so I can lean on things to keep the drill cutting in stainless.

Clive

[mickm]

Thanks for that Clive. It was just I was supprised as to how strong it is. I took my discs up to ABE on Friday 3rd, and have ordered a new set of three. They also offer a face grinding service. So as mine have only a minimal run out of 0.005 & 0.007 on the other disc I have requested that the front pair be cleaned up. Whilst the rear is NFG, and will be replaced. This's now means that ABE now have the ability to manufacture both types of discs for the Classic. So if anyone should need a new one or three it's just a phons call away. Mick Taylor has done the legwork for a cast replacement whilst I have sorted the stainless version.