Upgrading from double to triple crankset

Yumi- However, I
found that I need to work much harder with this road bike when climbing a
hill even at the lowest gear selection.
So, I would like to replace the double crankset to triple if possible, but
I'm not sure what I need to get.
Can I simply replace with pretty much any crankset, or do I need to get some
specific type ? BRBR

A bike shop can probably help you on this. Probably only need a bottom bracket,
a matching triple crank, a triple front der and perhaps a new, longer cage rear
der. With a few exceptions, this all will work on your bike.


Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

On Sun, 28 Sep 2003 00:08:57 -0700, "Yumi"
may have said:

I recently got an old road bicycle with 12 speed. Before this, the only
bike I rode was a cheap ATB, the kind you can buy at Walmart. However, I
found that I need to work much harder with this road bike when climbing a
hill even at the lowest gear selection.
So, I would like to replace the double crankset to triple if possible, but
I'm not sure what I need to get.

Swapping to a triple front will almost certainly require replacing the
front derailleur; your luck would be astounding if yours were the
exception. It will probably require replacing the bottom bracket
(generally called BB, it's the bearing and pedal shaft assembly) since
the triple crank will most likely need a longer BB in order to avoid
having the small ring too close to the seat tube. Your shifter lever
most likely will work OK with the new derailleur, but that's not
guaranteed. The rear derailleur, however, is probably one of the old
short-cage types, and may have problems taking up the slack of the
small ring; if that's the case, you'll need to replace it as well.
There's a distressingly good chance that this will end up costing you
more in parts than you want to invest in an old bike, unless the local
bike shop has a pile of used stuff that can be had cheaply.
Alternately, you might be able to pick up most of the items on eBay if
you know what to look for, but you're probably still looking at
punching a big hole in a hundred bucks, even with much of it being
used stuff.

I would suggest, though, that there's an alternate path which might
give you close to the same result with less hassle. Shimano makes
replacement 6-speed freewheels with a larger low gear than what's
probably there now; count the teeth on the big rear cog that's
present, and if it's 28 or less, a $20 (plus shipping) freewheel with
a 34 tooth low gear might solve the problem adequately with a lot less
work. You'll almost certainly have to replace the chain or add some
links if you go this route, but there's a good chance that the old
chain is worn anyway. In rare cases, it's necessary to replace the
rear derailleur to get enough slack take-up capacity, but the chances
are good that your existing der will be up to the task. A lot of
older touring bikes came with gearing very much like this, so the ders
generally had the capacity. You may need to clean it thoroughly,
though.

For the megarange 6-speed freewheel, here's one source:

http://www.sheldonbrown.com/harris/freewheels.html#6

--
My email address is antispammed;
pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.

Hi all. Thank you for excellent suggestions. They are all very useful
information for me.. I'll probably go for a freewheel upgrade approach
suggested by couple people. It probably makes more sense for an old
bicycle. Yumi