Lou Holtman wrote:
I asserted:
Quoted message said:Quoted message said:Quoted message said:>A part I already own is always going to be 100% cheaper and more
>available than a part I need to buy.
Lou Holtman said:
Not in my case ;-)
When I buy/put together a new bike I think things over well and stick with
my choices until I sell/trade in the bike for a new one. Till then you just
have to suppress marketing driven upgrade urges.
There is no need to put a mismatching a crank with the wrong BB taper.
All generalizations are false.
That sort of consumerist by-the-book ethos works for lots of folks, with
normal store-bought bikes, but some of us are of a more experimentalist
turn of mind.
For this sort of approach, trial and error is often the only way to go,
since the "specs" do not exist or do not apply to the application.
I gave three examples of "mismatched" tapers in a previous message, but
perhaps some details will help explain my rationale:
•I had long desired a fixed-gear tandem, and when I had an opportunity
to buy some older 105 cranksets in the 165 length I favor for fixed gear
use, VERY cheap on closeout, I snapped up a few sets.
Some years later I came upon a used Picchio tandem frameset, which I
acquired by barter. It came with two nice Campagnolo Record bottom
brackets installed. I decided to try installing the 105 cranks on the
existing bottom brackets and see how it worked. As it turned out, the
chainline came out basically perfect for this application, so why would
I want to discard the nice Campagnolo bottom brackets?
http://harriscyclery.com/picchio
•When I built up the Hetchins frame I bought on eBay, I wanted to use a
wide-range double, specifically a TA 50-28 setup that I already owned.
For this type of a double setup, you don't want the normal chainline
that puts the cassette in line with the space halfway between the rings.
Instead, I wanted the 50 tooth ring to be usable with all 9 sprockets
of my 12-28 cassette. The idea is to run on the 50 tooth ring 99% of
the time, but to keep the 28 chainring available for unusually tough
climbs, or for when I am seriously tuckered out.
This is not a setup that could be sold on a commercial bike, because it
depends on the rider understanding that the 28 tooth chainring is not to
be used with the smaller rear sprockets.
http://sheldonbrown.com/hetchins
•My Thorn Raven touring bike uses a Rohloff hub. I had a low end
Campagnolo double crankset, maybe a Mirage, maybe Veloce, not sure
which, that came off of a bike that I had converted to a triple.
The stock Campagnolo bottom bracket would have put the 53 tooth
chainring at about 46 mm, but the Rohloff hub wants a 54 mm chainline.
I don't think there is any Campagnolo bottom bracket that is long enough
to provide that chainline. The Raven came with a Shimano clone bb. I
installed the Campagnolo crank onto that bb (I think it was a 110) and
measured the chainline. It was too close in, but that bottom bracket
provided me with a point of reference, so I was able to calculate what
length Shimano BB would give the desired chainline. I installed it and
it has been working great.
http://sheldonbrown.com/thorn
Sheldon "Custom" Brown
+-----------------------------------------------------------+
| Always listen to the experts. |
| They'll tell you what can't be done, and why. |
| Then do it. --Robert A. Heinlein |
+-----------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com
