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Old September 6th 19, 06:26 PM posted to rec.bicycles.tech
Tim McNamara
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Posts: 6,863
Default 50.4 BCD TA vs. VO

On Mon, 02 Sep 2019 11:16:46 +0700, John B Slocomb
wrote:
On Mon, 2 Sep 2019 03:19:15 +0000 (UTC), Ralph Barone
wrote:


And, of course, the important measurement when discussing Q factor is
how far apart the ankles are when doing a similar exercise like
walking or running.


I wouldn't argue except to say that over the years I've owned quite a
number of bicycles which undoubtedly had varying BB width... and I've
never been able to tell the difference. I've never jumped on a bike
and thought "Gee, those pedals are a long ways apart" or conversely,
"Gee those pedals are really close together".


I prefer narrow pedal spacing which seems to make my knees feel better.
I have had patellar inflammation in the past and have had a torn
meniscus scoped so wider cranks make my left knee hurt. People with
healthy knees might not notice Q factor differences much. My bikes are
mostly set up with old style Ritchey Logic cranks (110 mm BCD) on Campy
Veloce BBs which gives me a Q factor of 142-144 mm; my bike with
Truvativ ISIS cranks has a Q fctor of 140 mm; my old Raleigh Sports has
a Q factor of 145 mm. I don't notice the miniscule differences between
those. My tandem has Shimano cranks with a Q factor of 170 mm and that
is very noticeable and feels noticeable throughout the ride. I lost out
on a set of Ritchey Logic tendem cranks a number of years ago through
inattention; still bummed about that.

My wife- with wider pelvis than me and a bit knock-kneed- prefers a
wider Q factor of 160 mm or so. She sets her SPD cleats as far in as
she can and complains of discomfort if the Q factor is too narrow.

For that matter, I see people running and their stride seems wider
with running shoes on than when barefoot.


I have read claims that when running people's effective Q factor is less
than zero- their feet overlap along the centerline of their stride.
I've never bothered to verify that but suspect that this is true for
some folks and not true for others. Contrary to Tom's claim, pelvic
and leg geometry vary widely (no pun intended).

As always, I may be wrong, but like many of the things that seem to be
of such major concern, I just can't believe that pedal width (within
reason) is THAT important. --


For people with normal healthy knees and average body geometry, it is
probably not important and usually not even noticeable. People who are
outliers- especially with very short legs, bowlegged or knock-kneed,
etc.- Q factor differences might be noticeable. The hips move in all
dimensions to accommodate movement- otherwise we'd only be able to walk
or run of certain kinds of terrain.
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