3 speed gearing

[12boy]

Been searching a bit and trying to count teeth on pictures of 3 speeds but can't figure it out. What were the sprockets and chainrings on the club, sporty and utility SA 3 speed bikes? Were all 3 the same? My 700c bike has 48/18 and I've been curious as to what the old ones had. Thanks for your help.

 

[mjr]

Whatever you liked, I think. IIRC my 1990s Polish clone of a 1950s Raleigh came with 46/16 to a 26x1⅜" wheel. Not very useful, even in the fens.

I think the only restriction was that ratios under 2:1 were discouraged, but much less commonly ruinous on SA than Shimano, especially early ones.

 

[12boy]

I have 54, 72 and 96 gear inches respectively.. close to what I have now. Why don't you like that?

 

[classic33]

The SA 3-speed hubs accepted 13 - 22 tooth sprockets

 

[12boy]

There are a lot of combos possible but I was wondering what was typical gearing bback in the day.

 

[rogerzilla]

60" for the middle gear works well (41 x 18). Club riders may have used an AM rather than an AW. The AM has medium, rather than wide, ratios and is ideal for stronger riders or flatter terrain. The lowest gear with a 60" middle comes out at about 52". This sounds pretty high but we used to climb everything with a lowest derailleur gear of 42 x 21 back in the early 90s, and that's the same.

 

[mjr]

60" for the middle gear works well (41 x 18). Club riders may have used an AM rather than an AW. The AM has medium, rather than wide, ratios and is ideal for stronger riders or flatter terrain. The lowest gear with a 60" middle comes out at about 52". This sounds pretty high but we used to climb everything with a lowest derailleur gear of 42 x 21 back in the early 90s, and that's the same.

Yes, but look at the state of my knees now, possibly as a result!

I also tend to lug heavy stuff on the 3speeds. So they're set as about 42+54+72".

 

[rogerzilla]

I do set a lower middle gear on slower bikes like the Brompton. Spinning a 60" gear at 100rpm on a Brompton is a lot more diffucult than on something lighter, with 700c wheels and racing tyres.

 

[12boy]

Thanks for this info. Makes sense, too. The utility bikes I've seen on your tv shows set in the past with rod brakes and fully enclosed chainrings look like they were heavy. Very heavy.

 

[rogerzilla]

On the bright side, if you're riding one of those and someone opens a car door on you, the door just gets ripped off its hinges as happens to the red Jag in "Get Carter".

 

[mjr]

Even some modern three speeds are pretty robust. This one merely wobbled a bit when hit by a road biker doing a daft unsafe overtake:

View: https://m.youtube.com/watch?v=sp3rIHjTRBE