How Significant Is A Change In Pedal Length?

I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

Thanks for your advice.

Best,

Joel Solomon

Solomander wrote:
I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

Thanks for your advice.

Best,

Joel Solomon

Remember that 5mm is about 1/6 of an inch..not much. make sure the BB
cenyter to seat height takes the 5mm less into account...raise the
saddle 5mm with the shorter cranks...otherwise it really isn't a big
deal at all. I had a customer that had two different crank lengths on
her bike for 4 years...and didn't know it....original builder did it by
mistake.

Qui si parla Campagnolo wrote:
Solomander wrote:
I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

Remember that 5mm is about 1/5 of an inch..not much. make sure the BB
cenyter to seat height takes the 5mm less into account...raise the
saddle 5mm with the shorter cranks.

Agreed. My three bikes have crank lengths of 165, 170, and 175 mm and
I switch between them without really noticing much of a difference. I
tend to have a slightly higher cadence using the 165s compared to the
175s, but am comfortable using any of the lengths.

On 13 Jul 2006 05:57:33 -0700, "Solomander"
wrote:

I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

Thanks for your advice.

Best,

Joel Solomon

My first long distance bike was 170mm and I put many thousand of miles
on it. My next one had 175's and just didn't feel right even after
several hundred miles. I put 170's on it and it just seems to spin
better. In my case, I think my legs just had gotten "worn in" with the
shorter crank.

Per Solomander:
I am happily riding a bike with 175 mm pedals.

Dem be some beeeeeeg pedals....
--
PeteCresswell

In article . com,
says...


I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

In the past week I have switched from bikes that have the followin crank
lengths:
160
170
172.5
175

I only noticed a difference when riding the 160's. The others were basically
unoticeable.
-------------
Alex

On 13 Jul 2006 05:57:33 -0700, "Solomander"
wrote:

I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

Thanks for your advice.

Best,

Joel Solomon

Dear Joel,

A normal rider's hips, knees, and ankles can easily handle whirling
his feet around a 3% smaller circle.

Most people don't even notice that their legs are different lengths
until the mismatch reaches 20mm:

http://www.orthoseek.com/articles/leglength.html

Ordinary riders from 5'4" to 6'4" are generally happy with 165mm to
175mm pedal arms.

This means that a group whose height and presumable leg length
increases from 64 to 76 (19%) is happy with pedals that increase from
165 to only 175 (6%).

I suspect that you didn't spot the shorter pedal arms on the bike that
you want to buy. It's far more likely that the owner mentioned the
length or that you peered at the markings.

Notice that you didn't even think to give your height when you asked
for advice.

Even if you can tell the difference (as opposed to just worrying about
it the way that we all do when we're mesmerized by numbers), you'll
probably get used to it within a week.

In the unlikely event that you're so tall that 175mm is the absolute
minimum that you can comfortably use, you can easily replace the dwarf
170mm pedal arms.

Cheers,

Carl Fogel

On Thu, 13 Jul 2006 20:29:42 GMT, Robert
wrote:

Solomander wrote:
I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.

Thanks for your advice.

Best,

Joel Solomon


Hi,

I'm also a recreational rider that's played with crank length, most
recently with 177,5 contra 172,5. My inseam length is 85 cm (33,5 in) so
I'm probably one of the shorter riders to try this longer length.

After about a year on the 177,5's I tried the shorter 172,5's for a
couple of days and found that
- I indeed spin faster on the shorter ones (cadence 105 instead of 92)
- I'm slower when climbing, sitting or standing, on the shorter cranks
- It's less effort to climb, standing, on the shorter cranks
- It is slightly less strain on the lower back and glutes, with the
shorter cranks.

YMMV but I'm now used to the longer cranks and will be doing *no*
serious riding with anything shorter, though I may settle on 175 as a
compromise.

Maybe you could borrow the used bike and do a day tour with it, swapping
over pedals and seat. Perhaps you won't notice any perceptible
difference, but then maybe you might.

/Robert

Dear Robert,

The crank length shrank from 177.5 to 172.5mm, about 2.8%.

Your cadence rose from 92 to 105, about 14%.

Unless you also dropped several gears, you would have been going 14%
faster.

For the same effort from the rider, this isn't a likely explanation,
unless your legs are so short that you were wretchedly uncomfortable.
(There has to be a length where a crank becomes awful.)

You may have been experiencing the well-known new-toy effect.

For a week or two, almost any change that we think is worth trying is
likely to show surprising improvement because we improve when we're
paying more attention than usual in hopes of noticing improvement.

If it still feels better and is still faster after a week or two, then
the effect is probably mechanical, not psychological.

But we're awfully good at fooling ourselves. A 14% cadence increase
from a 5mm crank change is startling.

Regardless, glad that you found something that you like better.

Cheers,

Carl Fogel

In article ,
Alex Rodriguez wrote:

In article . com,
says...


I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5
mm change in pedal length would be for a recreational/charity rider
such as myself and how changing pedal length would affect riding
comfort and efficiency.

In the past week I have switched from bikes that have the followin
crank lengths:
160
170
172.5
175

I only noticed a difference when riding the 160's. The others were
basically unoticeable.

That's consistent with my experience, too. I don't really notice the
difference between 167.5 and 175. I also didn't feel a difference with
180s but it sure aggravated the torn meniscus in my knee.

5mm change in crank length doesn't make much difference. I have a friend
whose Trek 520 tourer came with 175mm Shimano 105 cranks. He wanted to use
smaller chainrings (particularly the middle ring) than the 105 allowed, and
as I had a drive side XTR 170mm crank that was orphaned after the LH crank
was bent in a crash, I offered it to him, pointing out that he would be
riding with left and right cranks that were 5mm different in length. That
didn't worry him, and he has been riding for about the past 18 months on a
175mm LH crank and a 170mm RH crank without any problems.

Nick

"Solomander" wrote in message
ups.com...
I am happily riding a bike with 175 mm pedals. I am interested in a
used bike that has 170 mm pedals. I am wondering how big a deal a 5 mm
change in pedal length would be for a recreational/charity rider such
as myself and how changing pedal length would affect riding comfort and
efficiency.