At 2/21/2006 12:32 PM -0500, Sheldon Brown wrote:
>Those are good, but we actually sell a lot more of the SRAM 24 tooth
>sprockets, which also work for both types of chains.
Those are nice, but most of my friends don't want to go that
large. I use some homebrewed 24s and 26s
>I've toyed with the idea of making a close/medium ratio 3-speed from
>an S5 or FW by removing some of the internal parts. I suspect this
>could improve the efficiency, if one didn't need the range.
Should work, I've read of someone turning one into an ultra wide
ration 3 speed for use with multiple cogs.
>>You can put the guts of any pre April 1984 5 speed into any pre
>>April 1984 AW or FW shell.
>What happened in '84? All of my Sturmey-Archer hacking has been
>with older models.
Darned if I know, but I've read it in a few places. Like you, I've
hacked the old stuff.
>By the way, almost all of the parts of an S5 are interchangeable
>with FW. I used to regularly convert FWs into S5s.
Me too, but now I think functioning FWs may be rare enough that they
should be kept for vintage bikes.
>You REALLY don't want to use an SA shifter on the left.
You don't, and I don't, but I've a friend who has 2 SA shifters on all 8 of his 5 speed equipped bikes. His are all S5/2s, or have /2 axle assemblies, so that might be the difference.
I've never used 2 SA shifters with the bellcranks. What sort of problem would I encounter?
Both of my wife's 5 speed bikes have S5/2s and she much prefers the
SA shifter for the left. I intend to convert hers to S5 spec. I'm
curious to see if the spring on the bellcrank will allow her to keep
her shifters.
>It is my impression that S5s generally have less internal friction.
I agree. Fortunately I have a friend who hates the bellcranks, so
we've swapped 3 sets of axle assemblies.
>The key to this is to only shift the left side
>_while_pedaling_forwards_. They work quite smoothly if you do this.
I still seem to have the occasional problem. The spring is also the
easiest way to mate the Sturmey adjustment rod to the Shimano bellcrank.
>One used to be able to buy cable anchorages with a built-in spring.
>These were great for this application, also for using as a
>"pre-selector" for the right side cable.
That's where I got the idea.
>I don't believe that's correct. Springs don't "lose pressure"
>unless they are extended/compressed past the yield point.
You're probably right. But I've had shifting problems that I traced
back to weak clutch springs.
>>FW
>>The problem with the FW 4 speeds is that it takes quite a bit of
>>cable tension to engage low gear against the extra springs, which
>>can sometimes overpower a worn shifter. Another is that the
>>indicator rods are rare and delicate. Also shifters are harder to find.
>
>Those are some of the main reasons for upgrading them to 5-speed.
That's why I did it, but now I have a small stash of shifters and rods.
>I have a bunch of technical/historical material on my Web site about
>older British bikes. See:
> http://sheldonbrown.com/
> http://retroraleighs.com
> http://sheldonbrown.com/
> http://sheldonbrown.com/
> http://sheldonbrown.com/
> http://sheldonbrown.com/
> http://sheldonbrown.com/
> http://sheldonbrown.com/
> http://sheldonbrown.com/
Thanks, I hadn't seen some of those.
Mark Stonich;
Minneapolis Minnesota
http://mnhpva.org
http://bikesmithdesign.com