Renewing halfstep

[Jenny Brien]

I have a late-80's Cannondale tourer (Sugino AT chainset, bar end
shifters, 126 dropout spacing, 27' wheels and a screw-in hub) It had
''half step and granny" gearing which was a delight when it was newer,
allowing me to trim between the two close top rings to find *exactly*
the right gear.

But that was long ago. The original block and back mech is long gone,
replaced for now by a 14-28 six from a cheap mountain bike. That worked
surprising well with a middle chainring one tooth larger than the
original, but now the chainrings are also so worn that I tend to keep
to one or the other. I want that old feeling back!

Where is a good UK source for new chainrings - currently 48 45 28?
What would be a good modern replacement for the front changer?
As good tyres for 27" are getting harder to find would it be a good
idea to change to 700c?
If that is the case, could I fit a cassette hub with a 12-28 seven?

 

[Ryan Cousineau]

In article <[email protected]>,
"Jenny Brien" <[email protected]> wrote:

> I have a late-80's Cannondale tourer (Sugino AT chainset, bar end
> shifters, 126 dropout spacing, 27' wheels and a screw-in hub) It had
> ''half step and granny" gearing which was a delight when it was newer,
> allowing me to trim between the two close top rings to find *exactly*
> the right gear.
>
> But that was long ago. The original block and back mech is long gone,
> replaced for now by a 14-28 six from a cheap mountain bike. That worked
> surprising well with a middle chainring one tooth larger than the
> original, but now the chainrings are also so worn that I tend to keep
> to one or the other. I want that old feeling back!

> Where is a good UK source for new chainrings - currently 48 45 28?
> What would be a good modern replacement for the front changer?
> As good tyres for 27" are getting harder to find would it be a good
> idea to change to 700c?
> If that is the case, could I fit a cassette hub with a 12-28 seven?

Jenny: sounds like you have a bike with no indexing on the front
derailer, so any front derailer will work. I think whatever low-end
shimano road derailer is set up for a triple (probably Sora or Tiagra)
should work nicely.

Regarding the 27"-to-700c issue, I suspect it's easier to just find one
of the few enthusiastic suppliers of tires, calculate the number of
tires you use a year, the number of years you expect to keep the bike,
and buy a big order of the best tires for your needs. It will probably
be cheaper than the new set of wheels you will need, and whatever
solution you use for the brakes (new brakes, drop bolt, etc.)

Oh yeah: and if your tourer uses canti brakes, definitely just buy the
tires. You're into the ugly world of moving the canti posts in that case.

I had a fantasy at one point that the fast shifting of brifters meant
that the time was ripe for a return to half-step-plus-granny shifting
patterns on modern 9- and 10-speed drivetrains, until I realized that
compact drive setups offer most of the benefits with less shifter
fiddling.

--
Ryan Cousineau [email protected] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

 

[Chris Z The Wheelman]

Believe it or not, many of the "road" (a.k.a. "double" or "racing")
mechs have enough throw to handle a triple crankset, and the inner and
outer plates are even enough that they make half-step shifting a breeze.

I have an albeit old Shimano 600 double changer on my tourer which is
also equipped with a Sug. AT triple crankset, 26-44-48 / seven cog rear
and it works beautifully. I use Sh. Bar-Con shifters (index rear).

Just make sure the cage is long enough to accomodate the Granny.

- -
Comments and opinions compliments of,
"Your Friendly Neighborhood Wheelman"

My web Site:
http://geocities.com/czcorner

To E-mail me:
ChrisZCorner "at" webtv "dot" net

 

[[email protected]]

Jenny Brien wrote:
> I have a late-80's Cannondale tourer (Sugino AT chainset, bar end
> shifters, 126 dropout spacing, 27' wheels and a screw-in hub) It had
> ''half step and granny" gearing which was a delight when it was newer,
> allowing me to trim between the two close top rings to find *exactly*
> the right gear.
>
> But that was long ago. The original block and back mech is long gone,
> replaced for now by a 14-28 six from a cheap mountain bike. That worked
> surprising well with a middle chainring one tooth larger than the
> original, but now the chainrings are also so worn that I tend to keep
> to one or the other. I want that old feeling back!
>
> Where is a good UK source for new chainrings - currently 48 45 28?
> What would be a good modern replacement for the front changer?
> As good tyres for 27" are getting harder to find would it be a good
> idea to change to 700c?
> If that is the case, could I fit a cassette hub with a 12-28 seven?

I bought TA chainrings from Settle Cycles in the UK. TA makes almost
every conceivable tooth count in almost every bolt circle diameter.
Pretty sure you have 110mm bcd for the outer and middle rings and 74mm
bcd for the inner ring.

I use a Shimano Sora double 8 speed front derailleur on my half step
loaded touring bike. Shifts across all the rings just fine. I use bar
end shifters. I also recommend a third eye chain watcher type device.
Third Eye, N Gear Jump Stop, Deda Dog Fang, etc. Cheap insurance to
keep the chain from falling onto the bottom bracket shell when shifting
to the inner ring.

Stick with 27" wheels. Easier to just sell this bike and buy a similar
used bike with 700c tires and wider rear dropout spacing when you feel
the need to have 700c tires and 7 speed. Trying to put a 7 speed
freewheel onto your wheel will require it to be spaced to 130mm.
Usually you can just force a 130mm rear wheel into a bike with 126mm
spacing. But your Cannondale with big stiff seat and chainstays might
not take the spreading as well as steel bikes. So best to just leave
it alone.

48-45 or 45-42 or 42-39 outer and middle chainrings paired up with a 6
speed 14-16-18-21-24-28 freewheel makes an excellent half step setup.
With a 7 speed you would go 12-14-18-21-24-28 or 14-16-18-21-24-28-32
with the same chainrings. A 4 tooth spread in chainrings does not work
with the commonly available freewheels and cassettes. I run 45-42-20
rings with 14-32 or 12-28 7 speed cassettes on the half step plus super
granny touring bike.

 

[Jenny Brien]

Ryan Cousineau wrote:

> I had a fantasy at one point that the fast shifting of brifters meant
> that the time was ripe for a return to half-step-plus-granny shifting
> patterns on modern 9- and 10-speed drivetrains, until I realized that
> compact drive setups offer most of the benefits with less shifter
> fiddling.
>
I imagine it would be hard to figure out a 9 or 10 speed half-step
set-up to give anice even progression of gears. Compared with a 44-24
chainring and a 13-26 ten speed cassette, my present setup has about
the same range and gives away four gears below 45" to gain two. Works
for me!

 

[Jenny Brien]

[email protected] wrote:
>
> I bought TA chainrings from Settle Cycles in the UK. TA makes almost
> every conceivable tooth count in almost every bolt circle diameter.
> Pretty sure you have 110mm bcd for the outer and middle rings and 74mm
> bcd for the inner ring.
>
Thanks. I 've had good dealings with Settle Cycles back in the '80s, so
I'll try them again. Just a little unsure about all the pins and ramps
on chainwheels these days. Have they any advantage in this application
or will plain rings work just as well?

Your other advice is good too, so it's just new chainrings for now, and
I'll leave any other changes till the mext bike.

 

[[email protected]]

[email protected] wrote:
> Stick with 27" wheels. Easier to just sell this bike and buy a similar
> used bike with 700c tires and wider rear dropout spacing when you feel
> the need to have 700c tires and 7 speed. Trying to put a 7 speed
> freewheel onto your wheel will require it to be spaced to 130mm.
> Usually you can just force a 130mm rear wheel into a bike with 126mm
> spacing. But your Cannondale with big stiff seat and chainstays might
> not take the spreading as well as steel bikes. So best to just leave
> it alone.

I have a Cannondale touring bike of similar vintage to the OP's
(mine is 1988). It originally had 27" wheels, short reach caliper
brakes (unusual for a touring bike) and a sort-of-half-step gearing,
something like 50/46/28 Biopace in front and 14-28 6 speed in rear.
Because of the short reach calipers, converting to 700c wheels
was easy; I had to use an inexpensive Tektro long reach brake for
the front, but the rear short reach brake worked ok. If you have
cantilever brakes, converting is more of a nuisance.

7 speed road freewheel and cassette hubs are spaced at 126mm,
so one fits right into a 126mm Cannondale. I have a 7 speed cassette
hub in there now. I break freewheel axles on 7 speed (even without any
loaded touring), so a cassette hub is an improvement. A 130mm hub will
fit into mine with gentle spreading, but it does take more effort to
get the wheel in and out.

Ben

 

[[email protected]]

I wrote:

> 7 speed road freewheel and cassette hubs are spaced at 126mm,
> so one fits right into a 126mm Cannondale. I have a 7 speed cassette
> hub in there now. I break freewheel axles on 7 speed (even without any
> loaded touring), so a cassette hub is an improvement.

More precisely, I break freewheel axles every couple of years on
126mm spacing, whether the freewheel is 6 or 7 speed. This is
presumably weight and load dependent - I weigh ~175 lb and climb
a fair amount and sometimes ride off road. Somebody who weighed
120 lb might never have a problem.

Ben

 

[[email protected]]

Jenny Brien wrote:
> [email protected] wrote:
> >
> > I bought TA chainrings from Settle Cycles in the UK. TA makes almost
> > every conceivable tooth count in almost every bolt circle diameter.
> > Pretty sure you have 110mm bcd for the outer and middle rings and 74mm
> > bcd for the inner ring.
> >
> Thanks. I 've had good dealings with Settle Cycles back in the '80s, so
> I'll try them again. Just a little unsure about all the pins and ramps
> on chainwheels these days. Have they any advantage in this application
> or will plain rings work just as well?

I like pins and ramps on the rings to help front shifting. You do a
lot of it with half step. If you shift half steps instead of full
steps. I think TA rings only come with pins and ramps. Actually its
just pins on the TA rings I have. I'd definitely encourage pins/ramps
on the outer ring. Don't really need them as much on the middle ring
since you will not be going up from the inner ring to the middle too
often. Your bar end shifters can force the chain up since they give
you lots of control. Plain rings are cheaper of course.


>
> Your other advice is good too, so it's just new chainrings for now, and
> I'll leave any other changes till the mext bike.

Going to 7 speed, as suggested by the other person, doesn't gain you
too much. You have 6 speed 14-16-18-21-24-28 now. Going 7 speed
freewheel gets you 12-14-16-18-21-24-28. Is a 12 tooth cog useful to
you? Or 7 speeds come in 14-16-18-21-24-28-32. The extra 32 can be
useful. But you have a 28 inner ring now so you apparently don't use
or need really low gears. If you wanted lower gears you could easily
put a 24 inner ring on instead of the 28 you have now. And keep on
using your current 6 speed 14-16-18-21-24-28 freewheel.

 

[[email protected]]

Jenny Brien wrote:
> Ryan Cousineau wrote:
>
> > I had a fantasy at one point that the fast shifting of brifters meant
> > that the time was ripe for a return to half-step-plus-granny shifting
> > patterns on modern 9- and 10-speed drivetrains, until I realized that
> > compact drive setups offer most of the benefits with less shifter
> > fiddling.
> >
> I imagine it would be hard to figure out a 9 or 10 speed half-step
> set-up to give anice even progression of gears.

No its very easy. Outer and middle chainrings of either 48-45, 45-42,
or 42-39 paired with a 9 speed cassette such as
12-14-16-18-20-23-26-30-34, or 11-13-15-17-20-23-26-30-34, or
11-12-14-16-18-21-24-28-32. The 12-34 is becoming harder and harder to
find now days. Its the very best progression. The 11-32 is next best
except the 11 cog does not fit in, so you really have an 8 speed half
step cassette. And then add a very tiny inner ring to get a super
granny for mountain climbing.



Compared with a 44-24
> chainring and a 13-26 ten speed cassette, my present setup has about
> the same range and gives away four gears below 45" to gain two. Works
> for me!

 

[Michael Press]

In article
<[email protected]>,
[email protected] wrote:

> A 4 tooth spread in chainrings does not work
> with the commonly available freewheels and cassettes. I run 45-42-20
> rings with 14-32 or 12-28 7 speed cassettes on the half step plus super
> granny touring bike.

What is wrong with this 46-50?

46 50
----------
32 39 42
28 44 48
24 52 56
21 59 64
18 69 75
16 78 84
14 89 96

--
Michael Press

 

[[email protected]]

Michael Press wrote:
> In article
> <[email protected]>,
> [email protected] wrote:
>
> > A 4 tooth spread in chainrings does not work
> > with the commonly available freewheels and cassettes. I run 45-42-20
> > rings with 14-32 or 12-28 7 speed cassettes on the half step plus super
> > granny touring bike.
>
> What is wrong with this 46-50?
>
> 46 50
> ----------
> 32 39 42
> 28 44 48
> 24 52 56
> 21 59 64
> 18 69 75
> 16 78 84
> 14 89 96
>
> --
> Michael Press

The difference between 50 and 46 is 8.7%. The difference between 14-16
is 14.3%, difference between 16-18 is 12.5%, difference between 18-21
is 16.7%, difference between 21-24 is 14.3%, difference between 24-28
is 16.7%, difference between 28-32 is 14.3%.

Your 8.7% half step is good for the 18-21 and 24-28 full steps. Far
too high for every other shift. A 45-42 is 7.1%. Perfect for the
14-16, 21-24, and 28-32 steps. And in between the other steps. Look
at your shift pattern in the chart you provided. Going from the 46x16
to 50x18 is a decrease of 3 inches. Then your next downshift is to the
46x18, which is 6 inches. I like a lot more consistency in my half
step gearing. Your 50-46 is better than the garbage gearing Shimano
and Trek put on my 1991 Trek 520. 50-45-28 half step with 12-28 7
speed. Confirmation the idiots at both companies don't know anything
about riding bikes. Great at advertising bikes, but remarkably
pathetic at building them.