a disc from another bike that fits ??

Given that many people including myself have problems with floating disc center wearing and becoming loose and that some bikes (Harley mostly) use 5 hole mounting pattern does anyone know of a disc ment of another machine that may fit a commando.
My thinking is most are cheaper than disc available and that if a solid or semi floating disc (where disc is riveted to center with none removable buttons) could be fitted to wheel then lose disc problem may be solve. (Yes i know nothing in life is ever that simply especially concerning Nortons :? )

when putting together my 320mm disc brake kits I searched for the same but ended up having made discs to suit the Norton hub, they dont have the large offset of the Norton disc. Riveted solid or floating.

I thought that would be the case Madass or someone would have found it by now and we would all have one or maybe even two :cry:

I haven't seen a car , van or truck that has floating discs. Probably because they would not last long. What's the be hang-up about having to have floating discs. I still run the original disc with 12mm modified original m/cy on my 850. I can lock up the front wheel. { that the quickest way to drop a bike that I kno
Dereck

I have to agree with that. I'm running a 12mm Brembo master cylinder and a new standard Norton disc and the braking is very very good. I remember the braking on my commando in the seventies was pretty bad. The 12mm Brembo has changed that. Why Norton ever used that original size master cylinder is difficult to understand. Put that on the list of "why didn't they ....."

If you need to have a large offset, you might consider using a disc with a larger centre and mount it in a carrier. On the Seeley, I use two rigidly mounted Suzuki discs on a Honda front hub, and use two Lockheed calipers with the old asbestos pads, It is easy to lock the front wheel with one finger, however I've always raced with a brake like that - one finger over the lever, the rest around the throttle. With a disc, you can always safely grab a handful and know it will come off again. Drum brakes should be banned for racing.

This is the type of aluminium carrier to which I was referring (sorry about the swarf and dust):

Why Norton ever used that original size master cylinder is difficult to understand.

Click to expand...

They considered that most new riders would be used to drum brakes initially and did not want there to be too big a step change from drum. In comparison to today's brakes they are of course inferior but in the mid 70's the UK bike mags were full of complaints about ineffective disc brakes on their Japanese bikes, wet weather was one issue, single piston with sliding pins on calipers were another (salt corroded the pins which seized). The recommended upgrade was AP 2 piston calipers with sintered bronze pads.

kerinorton said:

I haven't seen a car , van or truck that has floating discs. Probably because they would not last long. What's the be hang-up about having to have floating discs. I still run the original disc with 12mm modified original m/cy on my 850. I can lock up the front wheel. { that the quickest way to drop a bike that I kno
Dereck

Click to expand...

On the other hand, you probably haven't seen a modern race bike for years that doesn't have floating disks. You might be comparing apples and oranges here (or cars and motorcycles).

Ken

It boils down to mass to resist HI HEAT distortion and cost to sell... cars and trucks have thick enough dual surfaces with inner braced cooling space so a non issue to them even glowing bright cherry red. Thinner friction rim and smaller row of pads is to reduce the thermal differences between inner and outer friction surface as well as evening out the speed of translation on pad areas. Cycle front rotors have air flow and mass of wheel to help cool off so pretty darn hot to over heat even a old fashioned Norton. Dual rotors are only for spreading extra HI HEAT fad - not extra grip .............................


What is Full-Floating?Full floating rotors, such as were originally conceived, were designed to reduce the tendency towards thermal stress induced distortion due to uneven thermal expansion under load. Prior to the introduction (by Brembo) of this design, brake rotors in the motorcycle industry were simply round discs bolted solidly to the wheel. You may remember if you've been around long enough, the rotors on the early CB750 and Z-1's were nearly 7mm thick and weighed accordingly. This was in effort to keep them from warping. Now days, the only road bikes coming through with solid mount (front) brakes are the Cruisers and budget bikes.

Today's Sportbikes abound with trick features and hardware in every nook and cranny. Brakes too. The brake rotors on them work remarkably well considering their mass-produced (read: stamped) manufacturing process. These are technically semi-floaters as the outer SS blade is nearly bolted solid to the carrier via the stamped stainless steel rivets.

True full-floaters move on the carriers, this allows them to self-center in the caliper for reduced brake drag and "float" unimpeded for unrestricted expansion and contraction during repeated thermal cycling. The only serious down side is a bit of rattle that reminds you these are indeed full-floaters.

Does all this guarantee they won't distort under severe duty conditions? No, unfortunately, there's precious few guarantee's these days. But they do perform as advertised in improving overall braking performance while significantly reducing that distortion tendency.

BTW: All Superbikes, GP machines and the like unanimously have full-floating brake rotors

There are only two reasons I would not use floating discs. One is that they are not permitted in the type of racing for which my bike is eligible. The second is that my twin small fixed mount Suzuki discs with the Lockheed AP calipers are already almost too much brake for a light Seeley Commando. I'm used to riding with a 7R AJS drum brake with an extended actuating lever, if you grabbed it you would be dead. My current disc set-up is almost as savage, however much safer - you CAN actually grab a strong handful without crashing. It is the difference between rolling down the road knocking bits off yourself and outriding the guys around you.
With the drum brake, I used two grades of lining - a hard and a soft, so that at any time I always had some brakes - I don't do that idiocy any more.

If you have a look at this photo. I was trying to stop the bike for the next corner after coming down a long straight, and it was refusing to stop. About half a second later the leading edge of the brake shoe heated up and I was spat off over the front of the bike and slid on my back across the corner into the escape road. It was a very fast get-off. I think that brake was the cast iron GP Triumph drum with the extra fins outside the spoke flange fitted with a TLS backing plate. You don't need this stuff, especially if you are a beginner. The good thing about that crash is that my two sons were standing and watching where it happened and so I never had to watch them racing motorcycles.

acotrel said:

If you need to have a large offset, you might consider using a disc with a larger centre and mount it in a carrier. On the Seeley, I use two rigidly mounted Suzuki discs on a Honda front hub, and use two Lockheed calipers with the old asbestos pads, It is easy to lock the front wheel with one finger, however I've always raced with a brake like that - one finger over the lever, the rest around the throttle. With a disc, you can always safely grab a handful and know it will come off again. Drum brakes should be banned for racing.

This is the type of aluminium carrier to which I was referring (sorry about the swarf and dust):

Click to expand...

Would be interested in a bit more specific info about the Suzuki discs/Honda hub Alan....from which bikes?, what size discs? I have a Seeley style hub in my Rickman, single 11" cast iron....but my forks will take two calipers...I have a Suzuki kettle hub, a rim and a couple of kettle discs, but I think this is a heavy wheel...

Thanks


Steve

Alan you look like on a rocket sled with the acceleration and wind blast pushing your cheeks inward!

Who ever did my ole P!!'s Norton drum brake at Pagent's shop Tallahassee Fla. made it about perfect to me and was used often enough to pull down in time in big city and exiting freeway down ramps with a bit of curve to em. Wes's '69 Triumph drum would not slow well no matter how hard I gripped and almost crashed me at end of my drive way on THE Grade it had such poor grip. On the other hand Wes's '71 Cdo drum would about squeal front if gripped how enough but very shortly after ward it would self energize and lock front - which dumped me about 30 mph near edge of parking lot going straight but low sided us in a grass slide into big oak tree I mostly protected it with my body in between still seated holding grips.

Those who think the extra rotor in duals gives more grip should try them with only one rotor active and see for sure, until over heated. It does take a bit less grip to slow wheel with less spun mass.

Steve, I use the Lockheed master cylinder which was intended for use with the single caliper:



The hub is probably from a GS1000 Suzuki and the 250mm high speed steels discs are off something like a GT550 Suzuki. They cost virtually nothing :



There are not many mounting points on the Ceriani forks, so the mounting plates for the calipers are complex.
I previously used a single stainless steel disc off a 70s Suzuki big bike, and it was useless even with asbestos pads. I tried using carbon pads with the dual discs - also useless. I've now got asbestos pads in both calipers.
I get a bit confused about the source of the hubs, I think the rear one is Honda which has been cut up and a bit added to the middle, then a pattern taken and the final was cast in magnesium at Commonwealth Aircraft Factory. I know it is a bugger to try and buy sprockets which fit off the shelf.

'Alan you look like on a rocket sled with the acceleration and wind blast pushing your cheeks inward! '

That is not acceleration, it is top speed at the end of a third of a mile straight. I did worse that that at Phillip Island when I locked the brake and fell off onto the non-skid at about 90 MPH and rolled nearly every inch of the way. I belted the shit out of myself. At least in the get-off at Calder, I fell onto smooth-top. Thankfully I got past my crash and burn stage without getting killed. These days I go nowhere near that stuff. If you fall off enough you actually learn to stay on the bike. I don't think I am a good rider, however I know how to avoid crashing, and I still go fast enough.
When I first started riding the Seeley commando. I used the big single stainless steel disc in a race. I blew off a guy who was riding one of my old bikes. When I reached the end of the straight, I didn't have enough brakes and ended up running wide and having to climb off the bike to get around. After the race he said to me 'I thought you were gone' and I said to him 'so did I'. I was barely able to keep it on the bitumen, and if you run off with it all cranked over and going like buggery, you know what the answer is.

Might be worth trying these boys: http://www.bikehps.com/isr/isr_brake_di ... cgodkkEAhQ

lcrken said:

kerinorton said:

I haven't seen a car , van or truck that has floating discs. Probably because they would not last long. What's the be hang-up about having to have floating discs. I still run the original disc with 12mm modified original m/cy on my 850. I can lock up the front wheel. { that the quickest way to drop a bike that I kno
Dereck

Click to expand...

On the other hand, you probably haven't seen a modern race bike for years that doesn't have floating disks. You might be comparing apples and oranges here (or cars and motorcycles).

Ken

Click to expand...

I never had time to become interested in racing so my knowledge on these things is limited. I only acquired the disc brake 850 about 8 years ago, and decided shortly after that that the brake wasn't as good as the 750 drum. It sure was a dumb move on the Norton front to fit that sized bored mastercylinder.

Thanks for the update on the discs. It makes sense. 2 discs to disperse heat, and floating to try to help the warping situation. I mentioned some time a go I was talking to some racing supporters at Taupo about the time they "raced " over the Takaka Hill. So much heat built up in one of the bikes discs that it warped so much it jammed in the caliper. That's serious heat. [and insane riding]
Dereck

Dereck I too was disappointed-scared with Cdo disc, hard to squeal tire or lock up last few mph so upgraded past Peel to smaller m/c, 1.5 lb lighter rotor, ss braid hose plus RGM race lever for best braking cycle i've tasted yet. i noticed that the sleeved m/c didn't have any restrictor valve in it so red hot 6 penny nail removed the factory rubber pin hole restrictor in Trixie and got hwy speed squealing ABS like w/o lock up till upper 40's mph have to back off or lock up. Takes same manly grip squeeze as normal factory but by golly my panic grip would over come any tire afterwards, so had more brake power than tire traction success. Trixie has the first and the last 100 size tire on front that wearing flat in middle. I never had that happen before on Cdo or my SV650 that wear to a V shape and brake as often and hard on them too. I'll put back a 110 for its distinctly better tolerance of the nail holed factory brake. The more brake power you have the easier to over panic brake but in the end if tire limiting factor you got enough brake pad power.

The time I locked up my front brake the front tyre was a Meltzer 350.19 ribbed tyre. I got rid if that and fitted a TT100. I also reworked my rear brake so it worked as well. The 850 rear brake has never been as good as the rear brake on the 750. Its a puzzle I will solve some day. It works now but I suspect it is slightly out of true although it doesn't exhibit the problem while braking, It does wear out too quickly if adjusted up tooo much. I now have compensated by having my foot brake pedal as high as it can go. [ ie shifting the peg rubber out so the lever comes up and hits the steal peg. ]

next time the tsubaki chain wears out I will do another inspection then refit with the Iwis that will be arriving soon from U no Who. I have actually ordered quite a few of these chains so if anyone in NZ wants one quickly, I will be happy to supply.

Cheers Hobot and Andy.

Dereck

Time for a Malt


AAAAAHHHHHH Springbank, 15 year old, from Campbell town [ once home to Paul McCartney ] , my favourite small town in Scotland, and Andy Stewart wished the Loch was WHISKY.

kerinorton said:

The time I locked up my front brake the front tyre was a Meltzer 350.19 ribbed tyre. I got rid if that and fitted a TT100. I also reworked my rear brake so it worked as well. The 850 rear brake has never been as good as the rear brake on the 750. Its a puzzle I will solve some day. It works now but I suspect it is slightly out of true although it doesn't exhibit the problem while braking, It does wear out too quickly if adjusted up tooo much. I now have compensated by having my foot brake pedal as high as it can go. [ ie shifting the peg rubber out so the lever comes up and hits the steal peg. ]

next time the tsubaki chain wears out I will do another inspection then refit with the Iwis that will be arriving soon from U no Who. I have actually ordered quite a few of these chains so if anyone in NZ wants one quickly, I will be happy to supply.

Cheers Hobot and Andy.

Dereck

Time for a Malt


AAAAAHHHHHH Springbank, 15 year old, from Campbell town [ once home to Paul McCartney ] , my favourite small town in Scotland, and Andy Stewart wished the Loch was WHISKY.

Click to expand...

Surely you should be riding so smoothly that locking the brake is rarely an issue. I once locked the drum brake when an idiot mate of mine pulled a stupid at a club day when I accidentally over- braked for a corner and he popped in front of me and applied the disc brakes. I grabbed the lever that bit too hard and the bike when into the crashing lock to lock tank slapper after I broke the front tyre free, then it launched me. It was a killer incident and I dislocated my collar bone - very lucky to be alive and really my only serious racing injury.
I never use the brakes or accelerate in a jerky irregular manner, I always try to get the smooth high-speed flowing motion into my riding. I notice that the kids these days don't handle the rain very well - probably spoiled by good tyres. I sort of tip toe very quickly around a tight race circuit, the big ones are different. Phillip Island is great however I haven't raced there since about 1970, and I don't like the thought of riding the Seeley there. My theory is that however fast you go, that is the speed at which you have to be prepared to step off the bike. At my age I could end up as a skin bag full of bone chips.
I only seem to use the rear brake if I am in deep shit and have to stand the bike up and do a crash stop, at all other times I hardly touch it except to steady the bike a bit. In the olden days, you only had to chirp the rear tyre to get the crash and I still ride like that even though the tyres these days are superb.