Sprockets sizes ,purposes

cf160 · Post by **cf160** » Tue Sep 11, 2012 4:19 pm

Does anyone know the various sprocket setups for the Model 18?
The crankshaft sprocket, the gbox mainshaft and the final drive sprocket are the only ones that can be altered to produce different
road speeds with a standard B52 Burman gbox and clutch chainwheel right? So , in order to increase road speed , I need to change the sprockets to ones with greater numbers of teeth,right?
Mechanically challenged member (cf160)

bigwol · Post by **bigwol** » Tue Sep 11, 2012 4:55 pm

general rule is bigger sprocket at the rear wheel = more acceleration less top end, smaller sprocket less vroom more speed. Other way round for the front end.

cf160 · Post by **cf160** » Tue Sep 11, 2012 6:09 pm

Thanks ,Big Wol , but that means if the sprocket is larger at the front and smaller at the back I should get
more speed on the road , right?
Did you see this thing? Pix in the New Photos dept.
My new old G80 coming home to roost.

bigwol · Post by **bigwol** » Tue Sep 11, 2012 6:55 pm

I did see the pics David, very nice, shame you couldn't get it back for what you sold it for though!
Yes, the closer the sprocket sizes are the more top speed, but the poor old engine will be working harder to get it there! As always there are pros and cons. With a big enough rear sprocket it will go up the side of a house, just not very fast, small enough it will have a great top end but won't go up any hills. Be careful how much you change things from standard.

edited for school boy (spelling) errorsEdited by - bigwol on 11 Sep 2012 5:56:51 PM

SPRIDDLER · Post by **SPRIDDLER** » Tue Sep 11, 2012 8:22 pm

quote:
So , in order to increase road speed , I need to change the sprockets to ones with greater numbers of teeth,right?
Mechanically challenged member (cf160)

You must be awarenessally challenged if you've never noticed the effect on your legs, lungs and road speed when riding a bicycle with gears!

cf160 · Post by **cf160** » Tue Sep 11, 2012 9:00 pm

Yes dear Spridler, but it somehow seems a little different when it comes to sprocket teeth numbers . I
wasn't born with implicit understanding of sprocket sizes and teeth numbers , but now that you mention it,
it does seem rather elementary ,Watson.

wilko · Post by **wilko** » Wed Sep 12, 2012 1:00 am

If you're a lightweight like me you can go to a 23 tooth engine sprocket.But you can't buy them, you have to get an original one rebanded like i did for 45 bucks.

cf160 · Post by **cf160** » Wed Sep 12, 2012 3:11 am

Well , Douglas, I just bought a 21 tooth engine sprocket for this crank , so it will help a lot as the one on there
now must be a 19 or smaller...
What sort of craftsman can make a 23 tooth sprocket for $45? Perhaps I could order one from you... This is a 1953 crank, mind you, and I haven't
even seen it yet. I will look tomorrow or the next day...
David (cf160)

wilko · Post by **wilko** » Wed Sep 12, 2012 11:27 pm

They just machine the old teeth off and weld a blank on.

cf160 · Post by **cf160** » Thu Sep 13, 2012 1:00 am

Who makes the blanks ?
The welding is fairly straightforward, but where to get the blanks?
Dave(cf160)