back wheel 'clunk' 1955 g3lcs

[jimh]

Noticed with the bike on the centre stand and pressing down on the saddle so the wheel touches the floor there is a definite 'clunk' noise from the hub area and the wheel can be seen to actually jump up very slightly.

I had a word with the previous owner who said that just before selling the bike he had turned the Hub driving pins, 021607, 90 degrees which then puts the unworn area of the pins driving the brake drum, before delving further just wondered if the play on the worn pins has transferred from fore and aft to up and down and that's what I'm hearing, what do you think?

[Mick D]

Hi

I would have thought it more likely to indicate a bearing adjustment issue - do you have any significant play at the rim when you gently push / pull it?

Regards Mick

[Rob Harknett]

This was known as snatch, My 55 G3/LS did it from new at low speeds when not pulling. 55 was the first full width rear hub, metal pins in metal holes.
In 56 the design changed with rubber inserts.

[Mick D]

Hi

Snatch is a rotary movement of the hub in relation to the sprocket, caused by wear in the pins and their associated sockets in the sprocket, snatch will make a clunk as the play is taken up and you may observe the hub rotating slightly in relation to the sprocket, but should not cause the wheel to move up. The wheel is restrained radially by the correct adjustment of the bearings - look to the wheel bearings if the wheel is moving in any manner other than in rotation.

Regards Mick

[alanengineer]

The pins wear and the holes get enlarged, its what they do

[jimh]

Thanks for the prompt replies.
Mick, there is no play in the wheel that I can feel and the P.O. has fitted the Andrews Cassette bearing assembly in the hub, I first thought it was the bushes in the Jampots but they are fine.
With this being a common fix with regard to the worn pins I just wondered if anybody else had a similar problem, looks like I will have to take the wheel off and investigate further.

[alanengineer]

Im just building a 55 rear wheel with the steel pins. I had a choice of two sprockets, one fitted with a bit of slack, the other had about 35 thou ovality. So im going with the sprocket with the better fit, but i expect a bit of a clunk

[Duncan]

There is a bearing in the sprocket, has that been changed too?

[clive]

Jim the pins cannot affect up and down movement of the wheel as it is held in place by the spindle. Wear or poor adjustment in the bearings wpuld allow movement. As suggested there is a bearing in the brake drum although wear in this would allow movement in the drum not the wheel.

[56G80S]

Well

Just goes to show that even a machine acquired in the mid 70's isn't "original" my 1956 G80S has the steel pins in steel holes. It had clonked for years!

I fitted new oversize pins from Russell Motors and had the elongated holes bored out.

But Clive and others are right, the wheel is about the bearings on the spindle, cassette or not. It could be something other than the wheel?

Johnny B