Gear ratios and sprocket size recommendations

[ScottyH]

I’m new to Scott squirrels so I’d like to canvass other riders thoughts and recommendations on gear box ratios and sprocket sizes for a 600 Flying squirrel ridden solo?

Any thoughts would be appreciated,

Regards
GH

[BRIAN MARSHALL]

How many teeth have you got on the rear wheel sprocket ?

[PaulR]

Scotts are normally under geared as standard with a final drive sprocket on the gearbox
s.haft of 20T. However 21T is often used . A lot depends on your local terrain, flat or hilly.
Sidecar gearing is 18 / 19T for a 600cc machine. If the factory set up has been altered,
this is were Brian requests sprocket sizes

[PaulR]

Scotts are normally under geared as standard with a final drive sprocket on the gearbox
s.haft of 20T. However 21T is often used . A lot depends on your local terrain, flat or hilly.
Sidecar gearing is 18 / 19T for a 600cc machine. If the factory set up has been altered,
this is were Brian requests sprocket sizes

[ScottyH]

Hi,

One bike has a 45tooth final drive sprocket,

The other bike has a 35 tooth sprocket – this bike was originally fitted with a sidecar, but no longer is.

Regards,
GH

[PaulR]

Simple question, what year are the bikes. Thanks

[BRIAN MARSHALL]

We also need to know the rear wheel size, 19″, 20″, or 21″ ? A 35T rear sprocket would be VERY odd for a sidecar machine !?

[ScottyH]

1927 has 45 tooth sprocket and 21″ wheels

1930 has 35 tooth sprocket and 19″ wheels

[ScottyH]

Any advice / recommendations from those of you with the knowledge?

[BRIAN MARSHALL]

I suspect that the pregnant silence is caused by the odd rear sprocket sizes that ‘we’ are not familiar with. What are the bikes fitted with ? 8″ Enfield rear brake/hub/sprocket assembly, or the 7″ Webb brake/hub/sprocket ??

[scott596]

It would be fairly normal for a 600cc flyer to have a 40 tooth rear sprocket and 21 tooth gearbox sprocket regardless of wheel sizes as the overall diameter of the tyres is fairly similar. Alan Noakes. scottworkshop@hotmail.co.uk

[ScottyH]

Brian,
I’ve very limited knowledge of Scott’s and wouldn’t know the difference between an Enfield or Webb hub,

But on both bikes the sprockets are bolted to the hubs

Regards
GH

[BRIAN MARSHALL]

Are your sprockets dished or flat plate type ?

[ScottyH]

The larger of the two sprockets is dished whereas the smaller sprocket is plain in-dished

[BRIAN MARSHALL]

OK, without photos I’m guessing that the dished one is on an Enfield cush-drive rear hub assembly. That ought to be the 40T size used on Flying Squirrels from 1927 to 1939. There are 2 or 3 on eBay at the moment. As Alan Noakes has stated, that would have been driven as standard by a 21T gearbox sprocket. A ‘larger’ rider, or someone living in a very hilly area might specify a 20T or even a 19T sprocket. This assumes a 19″ back wheel. In the past Alan has retoothed worn sprockets for me, but he isn’t taking on any more work at the moment.

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