New Cush Drive

There is now no need to offset the rim to the right the required 3/16", lacing the rim central on the hub places the position of the rim in the swingarm the same as before. So if you were fitting this to an Atlas then you would need to offset the rim 3/16" to the left to retain correct wheel alignment.

Looking nicer with the new hub cover fitted

A disc brake version of a rear cush hub might be a good go. Then we could use a Honda VFR750F style hub in the clutch where half the plates are attached to a sprag to give a bit of slip on back-off if you change down too quickly.

Or, could just use the stock Mk 3 Commando cush drive and disk brake !
Its more of a cush than previous - so why reinvent the wheel ? - quite literally.

Whereas it makes sense for a better cush drive for the earlier wheels,
those little blocks of hard plastic don't do much (?).

Rohan said:

Whereas it makes sense for a better cush drive for the earlier wheels,
those little blocks of hard plastic don't do much (?).

Click to expand...

Do they or Do they not do much? :shock:
I have been running this system, Pre 75 for many many years. Yes the plastic cushions are tight when new but can be adjusted.
I am not in any hurry to change with the original designer intent. This design seems satisfactory to me.
Most problems with this design are caused by improper assembly / tightening sequence.
You just got to assemble things correctly. Put your foot on the rear brake when tightening up the dummy axle if you disturb it.
Cheers,
Thomas
CNN

dunno, don't look like they do much cushioning in comparison to the now available option that is out there in spades,

and looks like it would do a way better job,

little plastic, wear out, fiddly bits vs massive rubber no maintenance chunks in comparison?

the original intent is prob one step up from nothing

84ok said:

dunno, don't look like they do much cushioning in comparison to the now available option that is out there in spades,

and looks like it would do a way better job,

little plastic, wear out, fiddly bits vs massive rubber no maintenance chunks in comparison?

the original intent is prob one step up from nothing

Click to expand...

84
Don't get me wrong. I like what Madass is doing but I would be more enticed if there was a disk carrier with the system and an option to change the rear sprocket.
Something like what cNw does for the front wheel. bring a Pre 75 bike brakes to meet the 21 century.

Cheers,
Thomas
CNN

no big deal, you may be correct that the original works well enuff, not making an easy decision, in terms of cost and changes,

i never got past mine being wore out to start with, back tire chirping faintly regularly then when i got new parts, couldn't get the wheel back in and thought hmmmm

think i ended up mixing old and new parts, that then easily fell out, or got in the way just fitting the wheel

Are brake hub/sprocket and the cush drive rubbers available separately?

This is a great looking product.

"Are brake hub/sprocket and the cush drive rubbers available separately"
of course but I doubt that you would ever have to replace the rubbers. the sprocket/drum is made from the same material as the original
so sprocket wear should be the same.
Don

The lumps of whatever they were that connected the brake drum to Dommy rear hubs which people INCORRECTLY refer to as cush drives were NOT cush drives / shock absorbers but a very cheap way of introducing a quickly detachable rear wheel with very little in the way of development and cost. To get the vanes on the drum to fit into the hub you have to apply a lot of grunt with a big hide mallet and once in use the lumps of 'plastic' / whatever compress and the vanes are rattling around within them introducing who knows what shock loads into the transmission system and the rivitted into the drum vanes then work loose ......
I would suggest that most / the greater majority of so called motor cycle 'shock absorbers' fitted to old British motor cycles are in fact shock increasers just like the ones fitted to Harleys for decades as The Gates Rubber Co found out when in conjunction with Harley Davidson developing an all belt driven motor cycle in the late 1970s . They had a belt failure problem that theory said should not be occurring and, probably after a lot of scratching of various body parts, took a look at the 'shock absorber' and found it was causing the problem as in use as the bike was accelerated the so called shock absorber wound up and once the throttle was closed or the clutch disengaged it unwound itself shoving a BIG shock load into the system. It was redesigned so it put smaller shock loads into the system over a longer time period which resulted in the belt problem being eliminated. You can read all about it by obtaining the S.A.E. technical paper series paper 800972.'the Development of a Belt Drive Motorcycle. I dread to think how much a copy costs these days...
A rather senior Meriden Triumph Gentleman once told me that the Triumph clutch shock absorber introduced after WW2 was simply a copy of one that had been around many years earlier and when I have over the years 'suggested' to people such as Mr Hopwood and Mr Hele 'In my opinion you spent more money on feeding the drawing office cat than you ever did on clutch and shock absorber development' no one ever contradicted my statement or given me any examples of development taking place apart from one Triumph Gentleman who remembered hanging weights from a clutch basket with the clutch centre locked off to determine how much movement was taking place for various loads. In fact one day talking to one clutch design Engineer he mentioned that while out in his new Japanese car just to amuse himself he did one of the clutch shock absorber tests they did when he was in charge designing and manufacturing clutches and he said the clutch would never of made it out of their factory gates! My fairly modern 12 year old dry warm 4 wheeled box clutch would also fail that particular slow speed in a high gear surge test.
If you are ever lucky enough to read one of Mr Jack Williams A4 design note / daily log books for the AJS 7R and E95 projects you will read he had requested a car type clutch shock absorber mounted on the crank as the clutch shock absorber did not have enough movement available within it to work correctly. Presumably Mr Williams had learnt a bit about the subject whilst previously at Vincent?? (Mr Williams also stated he had requested an oil bath chain case which would help lubricate the shock absorber and that a high linear speed primary chain with drip feed lubrication was probably no more than 90% efficient).
It would be interesting to see actual test results for that rear end shock absorber but as such testing would very probably cost a fortune and it is cheaper to say 'but it works OK' no matter how well or badly something works I doubt such testing will ever be done and I bet every similar one produced over the decades is simply a copy of a copy of a copy and that no real testing has ever been conducted to determine whether or not any of them actually work correctly....even changing the hardness (or whatrever it is called) of the rubbers must alter the shock absorbing characteristics of the unit.
I await with interest someone in Italy or Japan producing their test results from around the 1950s - 1960s or even earlier...just to prove me wrong and thus aid yet another of my rather uninteresting Engineering learning curves.

J. M. Leadbeater said:

The lumps of whatever they were that connected the brake drum to Dommy rear hubs which people INCORRECTLY refer to as cush drives were NOT cush drives / shock absorbers

Click to expand...

I agree that they factory system ('71-'74) doesn't absorb much shock but according to factory advertisements YOU are incorrect to regard their system as not a "cush drive":

http://cdn.silodrome.com/wp-content/uploads/2011/10/NGPersuaders540.jpg

1971: "New cush shock absorption drive in rear hub" :roll:

All this is very interesting. So far we have the no-cush drive and then the poor cush drive. Aftermarket we have
the Ludwig spring cush drive and now the madass modern bike like cush drive.
All I can say is I look forward to somebody doing some tests so I can make an "intelligent" choice.

Nortons themselves did a new bigger better cush drive for the disk brake hub on the Mk 3,
so they must have thought it an improvement....

J. M. Leadbeater said:

The lumps of whatever they were that connected the brake drum to Dommy rear hubs which people INCORRECTLY refer to as cush drives were NOT cush drives / shock absorbers but a very cheap way of introducing a quickly detachable rear wheel with very little in the way of development and cost. .

Click to expand...

This appears to be ignoring that the cush drive in ALL dommies IS IN THE CLUTCH HUB !

Of course it is an improvement. If nothing else it doesnt beat itself into goo in a few thousand miles.
It is such a bother putting the wheel and drum together madass's effort is probably worth the money.

Rohan said:

J. M. Leadbeater said:

The lumps of whatever they were that connected the brake drum to Dommy rear hubs which people INCORRECTLY refer to as cush drives were NOT cush drives / shock absorbers but a very cheap way of introducing a quickly detachable rear wheel with very little in the way of development and cost. .

Click to expand...

This appears to be ignoring that the cush drive in ALL dommies IS IN THE CLUTCH HUB !

Click to expand...

what year models was the clutch hub cush used? i'm not sure if the above "turns itself to goo quick" refers to this? was it reliable? doesn't sound like it's used at all on norton engines at some point?

I like the new cush and bummer sprockets can't be changed but then sure bet (way?) more money would be involved all around,

good to have modern/upgrade options tho prob mostly, or way more suitable right now to either low(er) mile riders or deep pockets,

also looks like there aren't any alternatives to the stock plastic bits, guessing that too small an area to go with or have tried something like rubber, or anything else(?)

i can't imagine how norton came up with that plastic bits hub setup but would be interesting hearing the thought process and decision making involved,

there must have been some basis that it did something positive to have moved forward with changes that
just seem ..............

cush?? had a look, didn't find an easy clear cut definition for it that i suppose is a short britt variation and has the same intent to what was much more familiar here - cushion ..but, hard plastic bits = cush ?!?! that turns into gooo?! how long do they even last? are they supposed to be replaced at the first sign of play? i don't imagine any play doing any good.....

trimming is involved for new parts? that is in a maintenance manual? as mentioned (things may have changed..), when i purchased new plastic bits the wheel/hub/drum wouldn't even go on/together?! too tight!

i suppose an interference fit holds the new bits in place, how long does that last? dunno, maybe not an issue but if they get loose which i think is likely (that then also creates another way of making mating difficult), but are still usable(?), a suitable glue or bonding agent could be used?

maintenance manual info and or lack thereof i suspect is quite interesting when it comes to the plastic bits

"Goo" refers only to the rear wheel tiny cush bits.
I agree that if you dont ride all that much or you dont ride very hard no cush drive at all
is probably not an issue.

My race bike tears up the small plastic/rubber items every other race meeting, I have a modified cast hub for quick change sprockets on an original three stud hub, will be looking at fitting one of Don's units if the cost is lesser than say a Maney cush drive system, although will still have to modify his hub to take my range of sprockets.
If it means protecting the drive line under those conditions with extra horse power delivered to it, I will be happy.
Regards Mike