72 Commando Cush Drive Question

phillyskip · Oct 31, 2013

I've purchased the Andover Norton cush drive "rubbers" for my 72 Commando project bike. I was taken back by how "hard" they are and I did notice that they were tapered and can only go in one way. No problem.However, I've had to "trim" or thin down the paddle contact surfaces of the rubbers in order to get the wheel hub onto the brake drum. Is this normal,or just a case of crappy replacement parts? Thanks,Skip

concours · Oct 31, 2013

phillyskip said:
I've purchased the Andover Norton cush drive "rubbers" for my 72 Commando project bike. I was taken back by how "hard" they are and I did notice that they were tapered and can only go in one way. No problem.However, I've had to "trim" or thin down the paddle contact surfaces of the rubbers in order to get the wheel hub onto the brake drum. Is this normal,or just a case of crappy replacement parts? Thanks,Skip

Usually is a tight fit, once run a bit they wallow out, slip right in.

mikie3117 · Oct 31, 2013

The cush rubbers are hard to get in and still leave room for thedrive paddles. An option is to lube everything up and drive the assembly together while off the bike. gets pretty frustrating trying to do it while on the bike.
Mike

Hobot · Oct 31, 2013

I found the easy to fit softer cushions need to be glued in to stay in place once vertical or interfere with the paddles slip in and then don't hardly last a gas tank worth of Commando torque. Ya get to check the AN set again in 4-5000 miles of next tire change and think about hobot slicing the side wall section of old tire for next set. Also I found if the DS set of cushions is not about twice as thick - tough as the brake side then they last about half as long.

Hobot · Oct 31, 2013

deleted repeated post

Matt Spencer · Oct 31, 2013

If you sit the wheel across two 4 x 4s on the lawn , and stand on the drum , with a car battery under each arm , it useually goes in o.k. :mrgreen:
sorry , didnt videotape it . Is literal load & technique . Wear good boots . And have breakfast first . :wink:

you sort of arange them 1/4 to 1/3 in , and get the tangs started , all even . And rely on the drag & ' theres no place else to go ' factor .
Should go in easy after a bit of use . The new ones might even still be o.k. after 10.000 miles .

phillyskip · Nov 1, 2013

Thanks all for your response. I'm going to use what I have ,but next time I'll cut them out of an old tire as suggested. No disrespect to Norton ,but this cush drive set up leaves much to be desired.

Brooking 850 · Nov 1, 2013

And you think you have problems These are what are left of some high impact Shutex rubber cush drive rubbers I made. This is after a practice day and 6 races. I have since replaced them with a stock set and use an old drum to align them before I fit up to the bike.Now you know why they need to be such a hard compound
Regards Mike

Dances with Shrapnel · Nov 1, 2013

phillyskip said:
I've purchased the Andover Norton cush drive "rubbers" for my 72 Commando project bike. I was taken back by how "hard" they are and I did notice that they were tapered and can only go in one way. No problem.However, I've had to "trim" or thin down the paddle contact surfaces of the rubbers in order to get the wheel hub onto the brake drum. Is this normal,or just a case of crappy replacement parts? Thanks,Skip

These really are not a cushion in the more common undersatnding of "cushion drive" but more a few bits that keep the metal to metal fretting from occuring. This is the price you pay for a quick release rear wheel. If it were not for the hard plastic bits it would be metal to metal clacking and pounding and metal to metal wear.

I would fit them in, run them on the street and you will find that they will loosen up to the point that removing and installing the wheel is not a problem. I don't recommend going with softer smooshier material as these pound out in time anyway.

madass140 · Nov 1, 2013

Here is the castings before machining of the sprocket/drum for my upcoming new rear hub assembly

madass140 · Nov 1, 2013

and here is the freshly molded new cush drive rubbers

concours · Nov 1, 2013

ROCK IT Madass!!! Looks good!

Dances with Shrapnel · Nov 1, 2013

madass140 said:
and here is the freshly molded new cush drive rubbers

Nice work there. Starting to look like the cushion drive on a Ducati GRIMECA hub. The GRIMECA has a large rubber spider. See the link below for a good example. http://www.google.ca/imgres?sa=X&bi...dsp=59&ved=1t:429,r:13,s:0,i:118&tx=129&ty=61

I ran this on the back of my Commando racer as have a few other Vintage road racers. It is relatively light weight with lots of yield at the right rate.

madass140 · Nov 1, 2013

my aim is to have a replacement hub assembly which looks identical (exterior) to the original hub
but have the benefit of a proper cush drive and one piece axle.

nortriubuell · Nov 3, 2013

madass140 said:
my aim is to have a replacement hub assembly which looks identical (exterior) to the original hub
but have the benefit of a proper cush drive and one piece axle.

Most excellent Don

Count me in for one when they are completed

Brooking 850 · Nov 3, 2013

Don, may have asked you before, will the new drum and cush drive system have a removable/replaceable sprocket?
Regards Mike

madass140 · Nov 3, 2013

unfortunately not. I know that will not please everyone,especially racers, I figure that probably 95% or more Commandos use the existing hub and may or may not be happy with that but thats what they use. My hub has the benefit of having a decent cush drive,decent axle setup while retaining the
original exterior appearance. it wont be for everyone.

Lars.Elvik · Nov 3, 2013

Looks like another improvement I'd be interested in for my '73 850 just now getting the JS motorsport lightened internals in a rebuild.
Please put me on the list for one when you start producing units.

rx7171 · Nov 4, 2013

Dances with Shrapnel said:
phillyskip said:

I've purchased the Andover Norton cush drive "rubbers" for my 72 Commando project bike. I was taken back by how "hard" they are and I did notice that they were tapered and can only go in one way. No problem.However, I've had to "trim" or thin down the paddle contact surfaces of the rubbers in order to get the wheel hub onto the brake drum. Is this normal,or just a case of crappy replacement parts? Thanks,Skip

Click to expand...

These really are not a cushion in the more common undersatnding of "cushion drive" but more a few bits that keep the metal to metal fretting from occuring. This is the price you pay for a quick release rear wheel. If it were not for the hard plastic bits it would be metal to metal clacking and pounding and metal to metal wear.

I would fit them in, run them on the street and you will find that they will loosen up to the point that removing and installing the wheel is not a problem. I don't recommend going with softer smooshier material as these pound out in time anyway.

That makes sense to me. I never could figure how chunks of plastic as hard as they are could flex to any degree under impact, especially since they are trapped in their holes.

72 Commando Cush Drive Question

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