On Jun 11, 12:01Â pm, fiddler crabby
ya-nospam-hoo.com>
wrote:>> Quick nerdy bike chain cog lesson:
>
>> back until the mid 80s, cogs were all flat and ya shifted by feel and
>> noise--the Italian stuff liked to be "overshifted " to pop onto the
>> next cog. The mid 80s brought "Uniglide" cogs from Shimano which had
>> every few cogs having a twisted shape which helped chain pickup quite
>> a bit. By the time 7-8 speed rolled around we went "Hyperglide" which
>> is a huge step forward because as Sheldon Brown explains, "it's system
>> of ramps and special-shaped teeth on Shimano rear sprockets that
>> permits much smoother shifting than older systems. HG sprockets are
>> designed so that, as the chain moves from one sprocket to the next, it
>> will engage the new sprocket before it has completely derailed from
>> the old one. This makes for smooth, silent shifting."
>
>> Basically, even without clicky indexing--if you use old friction
>> shifters with modern rear Hyperglide style cogs--which are available
>> as I linked to for old style bikes--you get a really positive feeling
>> shift. It pops into place because of the little ramps instead of going
>> kkkklunk.
>
>> In my opinion if you're gonna ride a geared road bike that's vintage--
>> running modern cogs with vintage shifters is the bomb--6-7 speed stuff
>> is really easy to shift via friction, not too fussy at all. It's a
>> stupid cheap upgrade to boot. Under $50 usually for freewheel and
>> chain--and you're suddenly shifting better than any bike that existed
>> at the time yours was built.
>
> Thanks for the lesson! I don't know how I missed that on Sheldon Brown's
> site.
>
> Still not sure if I want to go back to multi-gear. There's something
> really appealing about keeping things really simple, with little
> maintenance and almost no chance of a breakdown. But given that I
> haven't been able to bike in a while, I might not be physically ready
> for single gear, especially given all the hills in my neighborhood.
>
> You've really opened up the possibilities, maxo -- thank you for that.
> Maybe a few gears would be okay, and would avoid the weight and
> cumbersomeness of 10 or more. I looked at a 24 speed in a store the
> other day, a hybrid commuter/comfort bike -- who needs 24 speeds?!
> Either the rider's shifting constantly, or most of those gears aren't
> even being used.
>
There's a lot of similar overlap to be sure, but a 24 speed bike isn't
really a 24 speed bike. My utility monster with front and rear
platform racks and lights has a 8speed rear and a front triple. It's
perfect gearing for a do everything bike or a touring bike or
adventure bike--or whatever that bike of mine is. You basically have
your middle ring with 4/5/6 that are your three cruising gears in the
city, The same three with the big ring for tail winds and down hill,
and 2/3 are used for uphill. Gear 1 is a bailout gear on this
particular cassette (I need to get a closer ratio for my needs) and
7/8 are occasionally used when out for a fast ride. The small front
granny is rarely needed for monster hills, but a blessing when used.
So really--what I have are the 4/5/6 cogs that get used the most with
the two main chainrings--but the whole drivetrain does have its
purpose. With a cassette with smaller jumps between shifts, I'd
probably use more of the gearing.
Anyway--with 24 gears--unless it's alpine in your neighborhood, you're
usually only shifting between 2-4 gears most of the time. I'm honestly
a bigger fan of internally geared hubs like Sturmey's or even Shimano
Nexus or Sram for most riding--just that they're not widely
distributed in the states. You can easily build and use such a hub in
your frame. We discuss such magnificent monsters in rec.bicycles.tech.
Don't fear the derailleur these days, though--even the lower end
Shimano stuff, if set up right, shifts great. That's the beauty of
trickle down tech. I've set up some $300 "path" bikes for friends, and
they shifted as nicely and as silently as a bike would ever need to
shift--as long as you didn't mind the stamped finish on some of the
parts.
> So I'm trying to balance out simplicity with what'll work with my
> current physical condition -- but also keeping in mind that making a
> change isn't that difficult or expensive. I won't have to live forever
> with any decision that doesn't work out.
That's why I thought a freewheel and a chain might be a fun and cheap
step to get ya conditioned before you join the fixed gear velorution.
>
> This reminds me of using Linux on my other laptop. "Best" becomes what
> works for the individual, not necessarily what's most expensive or most
> standardized. Though it requires knowing how things work, and more
> personal effort, the system fits the user, not the other way around.
>
> I've got about two weeks to decide what to do, then the rebuilding
> begins. I'll post pictures as it happens.
>
> --fc
Have fun!
