Author Topic: Spacer width required (Dragonfly)  (Read 605 times)

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Offline Sgtbiro

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Spacer width required (Dragonfly)
« on: 19 Jan 2021 at 20:11 »
Hi all by any chance does anyone know the width of the spacer collar in the back wheel between the speedo drive and a washer, part number 31553 item number 14 on page 39 of the parts book.

Cheers Kevin..

Offline Roys rider

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Re: Spacer width required (Dragonfly)
« Reply #1 on: 20 Jan 2021 at 21:27 »
Hi
I have just had a look at mine and there is a nut to hold the speedo grearbox but no spacer. Nut goes against the swing arm. There is a 10.5mm spacer outboard of the brake plate on the otherside. Does your chain line up OK?
Cheers
Peter

Offline eddie

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Re: Spacer width required (Dragonfly)
« Reply #2 on: 20 Jan 2021 at 22:18 »
It depends on which wheels you have fitted. Early Dragonflies had Douglas wheels - later models had 'British Hub' wheels.

  Eddie.

Offline Sgtbiro

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Re: Spacer width required (Dragonfly)
« Reply #3 on: 21 Jan 2021 at 20:27 »
Hi guys thank you for your help.
Eddie my Flys frame number is 1207/6 not sure if is an early or late one, but it does look like someone has been messing with the back wheel in the past .

Cheers kevin

Offline Roys rider

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Re: Spacer width required (Dragonfly)
« Reply #4 on: 24 Jan 2021 at 22:12 »
Hi Kevin
I took a couple of photos of the brakes on ROY. These are the Brit. Brakes which Eddie mentioned. The cover plates are pressed aluminium with a sort of angular stepped profile. Douglas brake plates are spun and cut aluminium and much thicker with rounded edges. The spacer is shown on the rear brake. I have shown the front brake because it photographs better, not so much clutter.
Cheers
Peter

Offline Roys rider

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Re: Spacer width required (Dragonfly)
« Reply #5 on: 24 Jan 2021 at 22:15 »
OK only one photo made it so here is the front brake. Peter

Offline eddie

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Re: Spacer width required (Dragonfly)
« Reply #6 on: 25 Jan 2021 at 08:33 »
As Peter has said, the 2 photos show British Hub brakes (they are the ones with spun sheet alloy brake plates). The earlier Douglas brakes have cast alloy brake plates. It was easy to swap early for late rear wheels, as they were the same width. That is not the case with front wheels - the British Hub wheel is wider than the Douglas wheel, so later bikes have a front fork that is wider between the wheel bosses.
  Also, from Peter's photos, I have noticed that his front wheel has been fitted with the wrong rim - it is one from an early wheel (or a rear wheel). As the later brake plate covers the front wheel spoke flange, all spokes (leading and trailing) have to be laced from the outside inwards. In order that the leading and trailing spokes shouldn't bend around each other (and chafe), the piercing and dimpling on later rims was changed from the normal staggered pattern to 'one left and 3 right'.

  Kevin, As far as I am aware, the change from Douglas brakes to British Hub units originally took place around frame number 1278/6 - of course, that doesn't mean subsequent changes haven't taken place!

  Hope some of this helps,
                                          Regards,
                                                         Eddie.

Offline Roys rider

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Re: Spacer width required (Dragonfly)
« Reply #7 on: 25 Jan 2021 at 21:40 »
Thanks Eddie
Is that front wheel lacing a hazard?
Many years ago my father bought a complete Dfly from club spares by ordering every part number. I assume he had hub and rim put together, however neither he nor the spares boss at the time would have known they were not really compatible.
Sorry to pinch your message Kevin.
Cheers
Peter

Offline Sgtbiro

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Re: Spacer width required (Dragonfly)
« Reply #8 on: 26 Jan 2021 at 20:32 »
Cheers thank you for the pictures Peter the brakes on my Fly are definitely the Douglas type going of your photos .
So Eddie does help you identify the thickness of the spacer for my Fly.

Regards Kevin..

Offline eddie

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Re: Spacer width required (Dragonfly)
« Reply #9 on: 27 Jan 2021 at 09:49 »
Kevin,
          I can't say exactly what the thickness is without removing the wheel from my bike, and measuring my spacer. From memory, it is about 1/4" thick. If you have the wheel out of your bike, it is easy to check the thickness - slide the speedo drive onto the spindle (with no spacer, and having fitted and tightened the bearing locknut)making sure the drive engages with the slots in the end of the hub, carefully check (and note) the distance from the end of the spindle to the face of the speedo drive. Repeat the exercise with a thick spacer(say 3/8") fitted, and again note the distance. The spacer then needs to be thinned down until the distance to the end of the spindle is about 1/16" less than your original measurement. That will then leave 1/16" clearance between the end of the hub and the drive gear. Make the overall diameter of the spacer large enough to fit fairly snuggly inside the plate that retains the speedo drive gear in it's housing. (Smiths speedo drives were always made of a zinc based alloy that easily crushed under the load of the wheel spindle, so making the spacer as large as possible reduces that problem)

  Regards,
                  Eddie.
 

Offline Sgtbiro

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Re: Spacer width required (Dragonfly)
« Reply #10 on: 28 Jan 2021 at 17:50 »
Thanks for the information Eddie . I have the wheel off at present and the spacer measures 0.272 so I think it might be the original one, I will try the wheel on at the weekend and let you know how I get on.

Regards Kevin..