Bicycle Mechanics - Sturmey Archer 3-Spd Hub - Cog change?
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02-07-09, 03:35 PM
I have a terratrike path (recumbent trike) with the sturmey archer 3 spd hub, and I am wanting to change my gearing to something higher. My highest now is 55 GI with 46x22. I am wanting replace the 22t with a 18t or 19t cog. I have seen the SA replacement cogs online, but am not sure what is involed in this. Are there any special tools needed to replace the cog?
Thanks in advance.
02-07-09, 03:44 PM
Changing an SA cog is very easy... snap ring pliers are the ideal tool but a small thin screwdriver can also serve to remove the spring clip that holds the cog and spacers in place.
Exercise caution when removing the clip as it can fly away... covering the clip with your free hand during removal is prudent.
After you have done this a few hundred times it gets really easy and can be done in minutes... if you are unfamiliar with setting up the shifter you should review that too.
A massive change in cog size will also warrant a change in chain length and a smaller cog will probbaly require you to reduce your chain length as you may not have room in the dropouts to adjust the chain tension.
Sheldon Brown's site has all the information you would ever want on SA hubs.
02-07-09, 03:52 PM
Thanks Sixty Fiver..
I read your braking 101 thread in the SS/FG forum.. very good.
Sixty fiver did a good job on the tools and eject risk. One other thing is that there are Shimano sprockets that'll fit the S-A hub, and these can take a narrower chain than the S-A sprocket. But if you use one of those you also need a spacer to keep the sprocket from wobbling on the hub.
02-07-09, 05:16 PM
dabac - I should have mentioned that... thanks.
I have used Shimano cogs on SA hubs and they can even be used to set up a dual drive system... that might even be an option for a recumbent so it retains it's lower gearing for climbing.
I can be a bad influence... :lol:
02-07-09, 08:40 PM
Thanks.. Ive ordered a SA replacement cog.
Take into account SA cogs come in flat, dished,and deep dished variants to adjust chainline. With the original AW, this is not as much of a deal, as there were 3 available cog positions due to spacers, but with some of the modern 3spd hubs this comes into play.
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