New Cush Drive

hi Don, this is what I did to get the removable,changeable sprockets to work on the cast drum to retain the drum brake, although due to clearance problems, I could only run a 44 tooth. With my current TTI gearbox sprocket, this has proved to be the highest gearing I would want/need to run, so at present there is a 46 tooth on there with , 48 and 50 available.
Regards Mike

Yep , thats fine for one offs but not really practicable for a look like original, production run.
99% of Norton owners are using the standard sprocket so............

Nice item, Madass. I use the same cush rubbers in the rear wheel of my race bike which has a 70's Suzuki rear wheel- they can really take a pounding and are massive compared to the tiny Norton cush rubbers. Well done, keep up the good work.

Hi Don, yes understand, was just posting as an example of what can be done using the stock drum, backing plate etc. After market bit is your one piece axle.
I use Shutex rubber for cush drive inserts. Your new system would work great on my Roadster as you say, production based items.
Regards Mike

the raw hub casting

the new sprocket/drum

Great stuff, and looks good,

Brooking 850 said:

hi Don, this is what I did to get the removable,changeable sprockets to work on the cast drum to retain the drum brake, although due to clearance problems, I could only run a 44 tooth. With my current TTI gearbox sprocket, this has proved to be the highest gearing I would want/need to run, so at present there is a 46 tooth on there with , 48 and 50 available.
Regards Mike

Click to expand...

good point , time will tell. thats the first I've ever heard of the rubbers melting, you sure must of been riding that brake to get it that hot.

Les, how did the sprocket/drum bearing handle the heat when you cooked the rubbers? under normal operating conditions I would expect the bearing not to get to warm that it would be affected hence I doubt the rubbers would also be affected. zooming down Pikes Peak only using your rear brake would not be considered normal operating conditions.

I have seen the new vendor sold, tab type cushions that are pretty hardened, turn to chewing gum in one ride [50m] after a flat caused a look in yet I never used the rear brake at all. This was on an initial break in timid ride but the normal throttle power pulses still did the dirty deed. I cut next set out of tire side wall and with a new tire so took off to see if I could break my new rebuilt Combat for 100 miles mostly WOT to upper 6000's to return and notice hub/drum gap too wide, so went in again to discover heat had melted grease out the dual bearing and screwed with rollers so circlip has come out, but also the tire side wall cushions had turned to chewing gum with fiber cob web embedded. Replaced new dual row bearing and cut more tire cushions and ain't looked in again but also gave up on pressing Trixie much so expect tabs at least half gone after few 1000 miles of pretty normal mundane touring use. The tire cushions I cut were fairly snug fit and glued in place with the paddles set inside so the beating/heat wear was not from excessive slack banging, just poor design over loading the amount of rubber old 750's provide.

I'm fairly versed in rear brake use to point of lock up to ride a skewed upright slide to side of road or a jab instant to help upright a front slip out while leaned [mostly fear reflex reaction that happened to work that time] but generally avoid all rear break use as it wears the rear tire faster and my fronts all wear out sides before the center so it more economical not to use engine drag or rear brake unless so steep or slick I must use both brakes or just hang on for front roll steering control into the impact stop at bottoms.

I've cut big lightening/cooling holes out of 2 drums back walls and got to thinking I could also drill cooling holes out of the friction surface too like the front brakes but ain't done so yet. I don't know if friction surface holes would need a tape over to keep grit or grease out but think would work fine just leaving open to environment. First drilled drum also had 520 chain teeth milled which wore out so fast that ended my 520 teeth desire as pretty annoying to give enough throttle to climb steeps and it just makes a grinding noise before it threw chain. I'd pull over and reach down to set chain on teeth then roll back to put on sprocket again.

On that particular ride on Ms Peel early days tri-linked I stopped at big gathering to yell out for a hot shot to contest/compare with my old clunker - everyone pointed to a Duci and Truimph Speed Triple riders but the Duci guy dropped out of the rates we were running so just me and the Triple diced it up - me mostly following him on his home ground roads. Pleased me that even w/o ability to accelerate much I had no trouble keeping up with him as he couldn't take turns like Peel but was one the best riders I've played with and we parted after slapping hi fives with trembling adrenalin high. Then on way home solo decided to run into a truck gravel pit at 40 mph, for one of the most intense long lasting handling extremes I've ever done on Peel but only got up to 2 mph. No cushions left on next tire change.

machined a couple of hub castings, all looks good, will machine a batch over the next few weeks at which time I'll have the new sprocket/drums in my hands.

Looking good Don, so when do you start building Commando frames???? !!!
Keep up the good work, regards Mike

Machining of new style hubs is well under way.
Unfortunately when cast, the spoke flanges were slightly oversize meaning I had to machine the flanges to
retain original dimensions, therefore losing the original cast finish. So now I have to determine the final finish.
Pic (1) machined finish or Pic (2) polished finish, only talking about the outer faces of the spoke flanges.
the space between the flanges looks best as in Pic (2) which has had a scotchbrite wheel finish
Which would be your preference?

If I were to purchase for myself, Polished, as I think it would look best with the standard chrome rim or polished shouldered rim.

but that's just my personal .02

JD

Was a cost determined ?

Not yet , but expect between $500-$600, this will consist of
Complete hub minus brake.
Hub, bearings, axle spacers, speedo drive ring,alloy cover plate, Stainless one piece axle and nut, 42t sprocket drum, set of 6 cush drive rubbers. supply your own brake or buy my finned alloy brake which will be discounted to $200 if purchased with new hub assembly, also can include standard size polished flanged alloy rim and stainless spokes (assembled) add $200.
apart from the machined spoke flanges it will look standard.

Sounds good.
What about a 520 and WM3 option.

no 520 and I dont have stock of WM3 rims sorry

Looking good, another 2 weeks they will be fitted with new right side alloy cover plates , the stamping dies are now made and the samples are beautiful.

once again you've out done yourself my friend ! Damn fine work and big kudos for making the effort in the first place.