Cush drive rubbers don't fit

My 850 hub has new cush drive rubbers. They look like the correct parts, as far as I can tell (they resemble the drawing in the parts book), but they seem to be a little too thick and it's almost impossible to get the wheel on.

I was wondering if I have bad ones, or maybe they're cheapo Asian pattern parts and I should replace them with Genuine ones. Or are they all like that? If so, perhaps I could cut these down a bit with a sharp knife?

The ones in my 750 hub look a little different and fit perfectly. I'm guessing they're original.

Debby

I have a 750, but the theory must be the same.
Think I remember that the new ones I installed, back in the 70's, were almost too thick to get the brake drum back on the hub. The stubs on the back of the drum are tapered to help push between the hard rubber blocks. Remember that these have to take up a whole lot of torque from the motor and they can't be loose or you will have slop in the drive train. I had a battle to get the hub on, but once on, they take on a form and the next time it is really much easier. I have somewhere brand new originals I could perhaps find and photograph, but more than likely, what you have is just what I have and you will have the same problem getting the drum on the first time.... next to impossible as you say. Cutting with a knife might make it easier to get on the first time, but the blocks will be then too thin, and you will get slop between the drum and the wheel...better to fight one time and have good blocks in there, than trim and find you wish you hadn't.
:wink:

Try a little lube - silicone or dielectrical grease (like isolastics like) - and a rubber mallet. They are a PITA.

Debby, I found the rubbers to be very tight also. I wedged them towards thecorners of the slots with a large screwdriver, put a bit of rubber grease on them and stood on the sprocket with the whole assembly off the bike and lying on the floor (the wheel, not me!)

Debby,

What Brian and dave said! I did them a few months ago and found the same thing. Definitely, a PITA! But rubber grease, patience and persistence will get them in. Good luck.

bang em in!

I sent my rim for re-spoking a few weeks ago (75 Mark III), and it came back with the rubbers in a bag. At first I was sure I wasn't going to get them back in, but after a bit of lube and some persistent tapping and cursing, it worked.

The first couple are relatively easy, its the last batch that are tough - when the spaces get smaller.

Keep working it - good luck.
Keith

Hi Deb

Ditto to the above. I sprayed the rubbers and wheel with WD 40 and drove them in with a soft face hammer.

Ok, so they do fit after all!

The problem wasn't getting the rubbers into the hub, but rather getting the wheel and brake drum paddles to engage. Some CV Joint Grease to lube the rubbers, working from the drive side so I could pull rather than push the wheel on, and that Bob guy is now my uncle! 8)

I have a 110/90-18 rear tire, and I have to say it's a pretty tight fit getting the wheel in past the fender and brake drum paddles. Definitely wouldn't want to go any larger on the rear tire. 100/90 might be a better size for the bike.

Debby

Uggh! I hear you Debby. I dread taking off the rear wheel. It's such a PITA to get back on.