Deciding crankarm length?

If I were you, I'd get 172.5mm cranks. For someone your height that
sounds about right. Even if it's the wrong choice, you'd only be off by
2.5mm.

Art "Com se, com sa" Harris

Strayhorn said:

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a method
of discovering if there was a better length for my size.

There are a lot of opinions, but any time any testing has been done
they find that most people can perform optimally with a crank length
*anywhere* between about 140mm and 185mm. You are more likely to have
problems (joints, etc) with a crank that is too long than one that is
too short.

See: http://www.sheldonbrown.com/cranks.html

I'd recommend getting what you had before, if it's available, and if
not, then get the closest that is available... 170-175 is a very tiny
range anyway.

Ron Ruff said:

Strayhorn said:

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a
method of discovering if there was a better length for my size.

There are a lot of opinions,

Here's mine.

Quoted message said:

but any time any testing has been done
they find that most people can perform optimally with a crank length
*anywhere* between about 140mm and 185mm. You are more likely to have

Maybe if you don't have muscle memory, or if one never rides. My old bike
had 172.5s. I had 165s on my new bike. I thought that they might solve my
hot toes problem. They definitely did not, and they were far, far slower
than my old cranks. I felt like I was pedaling molasses the whole time, and
I struggled to keep up with the group.

Quoted message said:

problems (joints, etc) with a crank that is too long than one that is
too short.

See: http://www.sheldonbrown.com/cranks.html

I'd recommend getting what you had before, if it's available, and if
not, then get the closest that is available... 170-175 is a very tiny
range anyway.

Noticeable back-to-back, but agreed.

--
Phil, Squid-in-Training

Strayhorn said:

Friends -

How does one go about deciding which crank arm length will be best for a
particular person?

I'm looking at an upgrade to a 105 crankset for my road bike - the chain
rings are worn and the previous owner apparently rode in combat boots,
the crank arms are so nicked and scuffed. So I thought I would replace
the whole unit since they are on sale at my LBS.

Anyway, the 105 set comes in 170, 172.5, and 175. I've looked around the
web at all the usual places for sizing info but have come up blank.

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a method
of discovering if there was a better length for my size.

I generally ride 10-miles a day after work and do at least one ride per
weekend of 40 to 50 miles. The bike fits me well otherwise (58 with a 55
top tube).

I don't think it makes any difference, unless you have knee problems or
something. I'm 6' even with a 34' inseam, and I've ridden everything from
165-180mm cranks without incident. I've settled on 175mm, just to have my
bikes the same. So yes, I can feel a difference, but once I've been
riding on one or the other for awhile it doesn't matter.

The human body is incredibly adaptable, and the difference we're talking
about is tiny. Remember the last time you went on a hike -- was every
step the same, for hours and hours?

Matt O.

Howdy.

The readily available sizes of 170, 172.5, and 175 can be thought of as
S, M, L. If shoes or pants were only available in sizes small, medium,
or large, what size would you choose? At 6 feet, I'd guess you'd fall
into the large category. My vote goes for 175's.

As others have said, crankarm length is probably "just" a matter of
personal preference. But it makes sense that larger folks would use
larger cranks.

Joseph

Strayhorn said:

Friends -

How does one go about deciding which crank arm length will be best for a
particular person?

I'm looking at an upgrade to a 105 crankset for my road bike - the chain
rings are worn and the previous owner apparently rode in combat boots,
the crank arms are so nicked and scuffed. So I thought I would replace
the whole unit since they are on sale at my LBS.

Anyway, the 105 set comes in 170, 172.5, and 175. I've looked around the
web at all the usual places for sizing info but have come up blank.

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a method
of discovering if there was a better length for my size.

I generally ride 10-miles a day after work and do at least one ride per
weekend of 40 to 50 miles. The bike fits me well otherwise (58 with a 55
top tube).

Thanks in advance,

--
Strayhorn

³Excuse me, brother, who you jivin' with that cosmik debris?" - F.Z.

Put three people in a room and ask about crank arm length, get four
opinions. It really matters little...get a 172.5...good for you and
your height.

Quoted message said:

Howdy.

The readily available sizes of 170, 172.5, and 175 can be thought of as
S, M, L. If shoes or pants were only available in sizes small, medium,
or large, what size would you choose? At 6 feet, I'd guess you'd fall
into the large category. My vote goes for 175's.

As others have said, crankarm length is probably "just" a matter of
personal preference. But it makes sense that larger folks would use
larger cranks.

Joseph

I agree that it makes little difference but 6 ft isn't 'large', IMO. I
think of a large rider as somebody 6'2-3" or taller. The gent would be
fine with any mentioned cranks. I raced for years on 170s(6ft tall),
now have 172.5, have used 175...all work.

Strayhorn said:

Friends -

How does one go about deciding which crank arm length will be best for a
particular person?

I'm looking at an upgrade to a 105 crankset for my road bike - the chain
rings are worn and the previous owner apparently rode in combat boots,
the crank arms are so nicked and scuffed. So I thought I would replace
the whole unit since they are on sale at my LBS.

Anyway, the 105 set comes in 170, 172.5, and 175. I've looked around the
web at all the usual places for sizing info but have come up blank.

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a method
of discovering if there was a better length for my size.

I generally ride 10-miles a day after work and do at least one ride per
weekend of 40 to 50 miles. The bike fits me well otherwise (58 with a 55
top tube).

Thanks in advance,

--
Strayhorn

³Excuse me, brother, who you jivin' with that cosmik debris?" - F.Z.

Zinn recommends that you check this out:
http://www.nettally.com/palmk/crankset.html

/s

http://www.cranklength.info/

This calculation puts a 32" inseam on 175's. But as mentioned 2.5mm
either way is pretty insignificant. I'd say 175 if he likes mashing,
and 172.5 if he is a spinner (or wants to be one).

Joseph

Disclosure: I'm a "true believer" (aka nut-case) who now has switched
to 195mm cranks for my 37" inseam.

Strayhorn said:

Friends -

How does one go about deciding which crank arm length will be best for a
particular person?

I'm looking at an upgrade to a 105 crankset for my road bike - the chain
rings are worn and the previous owner apparently rode in combat boots,
the crank arms are so nicked and scuffed. So I thought I would replace
the whole unit since they are on sale at my LBS.

Anyway, the 105 set comes in 170, 172.5, and 175. I've looked around the
web at all the usual places for sizing info but have come up blank.

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a method
of discovering if there was a better length for my size.

I generally ride 10-miles a day after work and do at least one ride per
weekend of 40 to 50 miles. The bike fits me well otherwise (58 with a 55
top tube).

I'm 5'11" tall. 34.5" inseam. Not pant length. Total distance from
the floor to the crotch. I had 170 cranks on my first Schwinn 23"
frame bike in the early 1980s. When I replaced that bike in 1992, the
21" frame Trek 520 came with 175 cranks. I used them many years.
Still do use them in fact. In 1998 I bought a new racing 58 cm c-t
frame and build kit. I chose 175 cranks. In 2000 my 20" Raleigh
mountain bike came with 175 cranks. I use 167.5 cranks on my fixed
gear because that is what my brother gave me. The 167.5 cranks came
off his 50 cm 1991-2 OCLV. In 2003-4 I put together another bike and
bought 175 triple cranks for the 58 cm c-t frame. So I've sort of
standardized on 175 mm crank lengths by choice and happenstance.

The measurements you give are somewhat odd. 6' tall and a 32" inseam
suggests extra short legs and an extra long torso. Assuming your 32"
inseam is measured correctly and not your pant length. A 58cm c-t
frame seems correct but the 55 cm top tube is extremely short if your
legs really are 32" long. That means your extra long torso is
scrunched up on a 55 cm top tube. Are you using a 15 cm stem to get
stretched out?

Art Harris said:

Art "Com se, com sa" Harris

ITYM "Comme ci, comme 'ca", where the 'c symbolises the c-cedille this
keyboard won't let me do right now. French, and all.

Jasper

Quoted message said:

The measurements you give are somewhat odd. 6' tall and a 32" inseam
suggests extra short legs and an extra long torso. Assuming your 32"
inseam is measured correctly and not your pant length. A 58cm c-t
frame seems correct but the 55 cm top tube is extremely short if your
legs really are 32" long. That means your extra long torso is
scrunched up on a 55 cm top tube. Are you using a 15 cm stem to get
stretched out?

I'm with Russ here... My torso is shorter than the OPs if he's 6' tall
and has 32" pants inseam. My preferred top tube length is around 58-59
cm, and I use longish (~13 cm) stem. If the numbers given by the OP are
correct, I think he might want to try out a bigger frame instead of
different cranks.

There's another $0.02 for the piggy bank.

--
Dave
dvt at psu dot edu

Matt O'Toole said:

Strayhorn said:

How does one go about deciding which crank arm length will be best for a
particular person?

I'm looking at an upgrade to a 105 crankset for my road bike...

I'm 6-ft, with a 32-in inseam. I suppose I could just measure the old
crank and replace it exactly, but I wanted to see if there was a method
of discovering if there was a better length for my size.

Quoted message said:

I don't think it makes any difference, unless you have knee problems or
something. I'm 6' even with a 34' inseam, and I've ridden everything from
165-180mm cranks without incident. I've settled on 175mm, just to have my
bikes the same. So yes, I can feel a difference, but once I've been
riding on one or the other for awhile it doesn't matter.

The human body is incredibly adaptable, and the difference we're talking
about is tiny. Remember the last time you went on a hike -- was every
step the same, for hours and hours?

My dimensions are similar to Matt's, and I've ridden cranks from 165-175
mm. I like the 165s best, but since they don't come on bikes my size
(~60 cm), I generally ride 170s. The difference is pretty small. My
preference goes against any of the recommendations I've found. Note that
I haven't tried any extra-long cranks, so I can't pretend to know about
all of the possibilities. And also note that I like to spin small gears
and climb long (>10 minute) hills.

Summary: you don't know until you try.

To reinforce Matt's theory about the human body's adaptability, I once
had a bike outfitted with one crank shorter than the other (it's a long
story). I rode a few hundred miles over the span of a few weeks, and I
forgot about the difference most of the time. I noticed the difference
when I first hopped on the bike, and occasionally thereafter. It was
most noticeable after I had ridden another bike with matching cranks,
then hopped on the bike with mismatched cranks.

--
Dave
dvt at psu dot edu

On Fri, 28 Oct 2005 17:11:04 GMT, Jasper Janssen <[email hidden]>

Quoted message said:

Quoted message said:

Art "Com se, com sa" Harris

ITYM "Comme ci, comme 'ca", where the 'c symbolises the c-cedille this
keyboard won't let me do right now. French, and all.

Ce n'est pas si difficile que ça...try alt-0231 !

Andrew Price said:

On Fri, 28 Oct 2005 17:11:04 GMT, Jasper Janssen <[email hidden]>

Quoted message said:

Quoted message said:

Art "Com se, com sa" Harris

ITYM "Comme ci, comme 'ca", where the 'c symbolises the c-cedille this
keyboard won't let me do right now. French, and all.

Ce n'est pas si difficile que ça...try alt-0231 !

Didn't work. I was VNCing from my mother's laptop to my own PC, which I
suspect has something to do with it. Even producing the ç locally and then
c/ping it into the VNC session failed.

Jasper

In article <[email hidden]>,

Jasper Janssen said:

Art Harris said:

Art "Com se, com sa" Harris

ITYM "Comme ci, comme 'ca", where the 'c symbolises the c-cedille this
keyboard won't let me do right now. French, and all.

US English keyboard and preference settings, no typing of
numeric codes:

Comme ci, comme ca.
Accent acute: e
Accent grave: e
diaeresis : u o

--
Michael Press

Michael Press said:

In article <[email hidden]>,
Jasper Janssen <[email hidden]> wrote:

Quoted message said:

Quoted message said:

ITYM "Comme ci, comme 'ca", where the 'c symbolises the c-cedille this
keyboard won't let me do right now. French, and all.

US English keyboard and preference settings, no typing of
numeric codes:

Comme ci, comme ca.
Accent acute: e
Accent grave: e
diaeresis : u o

So what you're saying is, ignore the funny characters, they'll recognise
it anyway? Incidentally, in French, there is no acute accent. Just an
'accent aigu', which is spelled the same as an acute accent (at least on
the computer), but which can only happen over an e. The diaeresis I find
myself using very rarely, although I regularly use Umlauts in
german-derived words, which are spelled the same (on the computer, again.
I believe typesetters might still know the difference.). Überhaupt typ ich
regelmässig aksenten.

Jasper

Jasper Janssen said:

Michael Press said:

In article <[email hidden]>,
Jasper Janssen <[email hidden]> wrote:

Quoted message said:

Quoted message said:

ITYM "Comme ci, comme 'ca", where the 'c symbolises the c-cedille
this keyboard won't let me do right now. French, and all.

US English keyboard and preference settings, no typing of
numeric codes:

Comme ci, comme ca.
Accent acute: e
Accent grave: e
diaeresis : u o

So what you're saying is, ignore the funny characters, they'll
recognise it anyway?

Us English-typers butcher our own English with horrible misspellings (not so
much in this NG than in others) so the answer is sure! 😉

--
Phil, Squid-in-Training