Rear wheel speedo drive

Started by chrisx1, 18 May, 2023, 13:25:55

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chrisx1

Just fitted a new speedo cable, went for a ride and found the drive has moved round took the cable off again and the whole thing moves around when the wheel turns.
What holds the drive in place?

Bess

#1
Hi Chris,
            It should be sandwiched between the distance piece and spacer on the wheel spindle. Item 26 and 25 on the image.

Best wishes...

chrisx1

It seems that I don't have an A65 swingarm on the bike, so not sure if wheel is A65 or not.
Mine really is a bitsa it seems.

Spaceman

The type of swinging arm fitted shouldn't matter nor should the type of wheel provided it is designed to mount the Smith's speedo drive. The first thing to establish is whether the wheel is actually firmly clamped between the swinging arm brackets with the correct spacers fitted to ensure this is the case. If not, the bike will not be in a safe condition to ride as the rear wheel could move in the frame.

Assuming the rear wheel is firmly clamped between the swinging arm brackets then, logically, the only way the speedo drive can rotate is if the hole in the centre of the drive is larger in diameter than the spacers either side of it. A picture of what's fitted on the RHS of the rear wheel would be helpful.

chrisx1

Hope this shows it ok.

Spaceman

The rear wheel looks to be correct for an A65 but the swinging arm (SA) definitely does not. The A65 SA has a fully enclosed slot for the rear wheel axle but this one has a slot that is open at the rear. It does have the adjuster fitted in front of the wheel axle as per A65 but it also appears to have a second adjuster fitted behind the axle that shouldn't be there and obviously isn't needed!

The rear wheel axle appears to have a rear mounted adjuster fitted on to it and also what looks like a large nut, neither of which should be there. I suspect the rear wheel is not being clamped properly to the SA at the moment making it a safety concern and this might explain why the speedo drive is rotating.

The SA may be ok to use but the rear adjuster and nut need to be removed and a proper arrangement of spacers needs to be set up. As a first step, it would be a good idea to remove the rear wheel and to measure the distance between the axle brackets on the SA so it can be compared with a standard A65 which should be 7 25/32". It would also be a good idea to measure the length of the rear wheel spindle so it can be compared with a standard A65 one which I believe is about 7.5" measured from where it butts up against the outside of the swinging arm.





Ian C

#6
It looks like a correct A65 swinging arm (which has had the rear loop ground out perhaps?), but with pre-OIF unit single spindle and adjusters which is complete overkill (Is it possible a unit single rear wheel purchased and PO thought he had to use the adjusters with spindle that came with it?). As has been said before, you need to make sure that the body of the speedo drive is clamped by the spindle which means have the correct spacer between it's inside wall and the spindle tube that acts as a bearing spacer between both hub bearings. Then have the correctly dimensioned spacer between the speedo drive outer wall and the swinging arm.

Spaceman

As said, the length of the wheel spindle needs to be measured as does the width of the swinging arm to work out what is actually fitted. As far as I can see, the A65 spindle looks to be 7 3/8" long whereas the unit single's spindle is only 7 1/8".

chrisx1

Sorry for not replying guys. I have been out all day. Hopefully will get to pull it apart tomorrow and take some measurements.

Spaceman

Just for reference, the B44 swinging arm fitted with a similar QD wheel is 5/16" narrower than that on the A65 and the outer spacer is lightly shorter at 0.7" to partially compensate. The A65 outer spacer is 0.875" in length.

chrisx1

Distance between swingarm is 7 7/8"

chrisx1

It looks like the spacer that is on inside of drive unit in your diagram should be outside the unit. There is obvious wear on the edge inboard of the wheel

chrisx1


chrisx1

Looking at it it's a complete hodge podge done by the previous owner.
The speedo drive is almost seized the spacers aren't correct. I will have to identify the wheel and swingarm and try and get correct parts.

chrisx1

The spindle total length is 8 1/4" or 7" inside of swingarm fixing