On 01/02/2017 06:37 PM, ted wrote:
John wrote: "46-11 = 113GI, pretty high for all but pros". When I see
the term "pro" there I think of somebody who makes a living racing a
bicycle. I was never a pro, never even really competitive as a middle
aged local cat 4 racer wana be, but I did find a 116" gear (53-12 with
700c 23mm tires) useful on group rides with a local racing oriented
group. So I think John seriously over stated how high a 46-11 gear is.
It wouldn't surprise me if competitive local cat 3 racers (a long way
from pro caliber) found a 50-11 combination (yielding ~120GI) useful.
Use cases for 50x11 (or gears that high in general):
- tandems
- sprinting at the finish of a race
- very strong riders riding fast in a pace line
- pedaling while going down several mile long hills
Making your living riding has nothing to do with it.
Veering onto antique standards, John wrote: "... from 52-14 130BCD days"
I had no idea 130BCD cranks with 52t big rings and 14-xx
freewheels (emphasis on the 130BCD) were ever a common thing. I take
it thats what 70's Schwinns had.
1970s Paramounts had Campagnolo Record cranks. 144mm BCD, I think.
Learn something new every day.
I always thought the Campi 144BCD was standard back then and that the
130BCD standard emerged much later to allow the 39t small ring (as
opposed to the previously prevalent 42) of the 53/39 cranks that were
ubiquitous on "racing" bikes before 50/34 110BCD "compact cranks" came
on the scene. By that time I believe cassettes typically started at
13, 12, or even 11 teeth. So I didn't think there was ever a time when
52-14 top gears and 130BCD cranks went together. Not that that is of
any importance, just saying thats what I thought.
If anybody is still reading, I apologize for the impending snarkyness
but it seems I can't help myself.
Work on it.
John recommends 98-100 inches which is 99" plus or minus 1". He also
says 2" is insignificant, and says 103" is too high. I find all that
rather inconsistent. If 3" too many is too much, I wouldn't think 2"
is insignificant. Does the transition from insignificance to excess
occur in a delta of <1%? If 2" is insignificant, why not 97 to 101"?
If the target is 99" why all the talk about a magic and recommended
100" value that he seems to treat more like an upper bound than an
actual target?
All snarkiness aside, I had a 104" top gear on my 1972 P-15 Paramount as
originally delivered. I found it way too high. I changed the freewheel
(had no choice, really: the shop destroyed the Regina Oro when trying to
remove it for the first service) to one with a 15T that brought the top
gear down to a 97" and found that it made a huge difference: top gear
was now usable. It made as profound a change in the usefulness of the
bike as switching the granny to a Merz 31. That was a 27 x 1 1/4"
wheel, 54T big ring. Make of that what you will. And back then, I
lived in the Catskills, where we did have some big long mountains to
ride down, unlike now where most of my "downhills" are stream-cut gorges
no more than 150' deep and 0.3 - 0.6 mi.
These days, everything of mine is in the 96 - 99" range (except the
Moulton, which is in the mid-80s).
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