Stubby Legs

Danny Colyer said:

Are there any short people out there who've experimented with different crank lengths?

My wife is 5' with a 27" inside leg. She's currently using the 170mm cranks that the bike came
with, but I reckon she'd be better off with 150mm cranks (if I can find some).

165 are pretty common, sure to be better than 170 for stubby legs. TA cranks come in vast
array of sizes.

Quoted message said:

I haven't yet determined whether I can replace the right crank without also replacing the
chainring.

why not? rings separate on all but cheapest junk cranks. need to make sure bolt circle diameter the
same. or just go buy new, forget cost.

Either way wifey isn't convinced that it

Quoted message said:

will be worth the cost, particularly given that she only rides about 100 miles/year. However, we
intend to improve on that figure significantly this year.

too long cranks would make it less fun to ride. but best measure is not cost per mile, is about
health, fun, fitness, adventure, not transportation.

Danny Colyer said:

My wife is 5' with a 27" inside leg. She's currently using the 170mm cranks that the bike came
with, but I reckon she'd be better off with 150mm cranks (if I can find some).

That's a big, big difference. I've not got short legs but I find even 5mm makes a difference (175 v
170) to pedalling comfort & efficiency. I think it might be wise to try 160mm first.

~PB

"Danny Colyer" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

I haven't yet determined whether I can replace the right crank without also replacing the
chainring.

Remember that shorter cranks will give her less leverage, so you may be better to replace chainrings
anyway, to compensate.

Danny Colyer said:

My wife is 5' with a 27" inside leg. She's currently using the 170mm cranks that the bike came
with, but I reckon she'd be better off with 150mm cranks (if I can find some).

St John St Cycles offer their own cranks down to either 140 or 145mm - couldn't spot them on the
site but they're generally listed in their print ads.

They've also got some Suntour XR cranks listed in both 152 and 162mm - £29.99 with rings, so not
exactly bank-breaking.

150 seems an awfully big drop from 170 though - worth trying say 160mm first, to see how much of a
difference that makes?

John

SJSC's Thorn cranksets - sjscycles.comcat363.htmOpen ↗ - are available in 5 mm
increments from 140 to 175 mm lengths..Rings are 110 mm PCD outer / middle, 74 mm PCD inner. Seventy
of the BRITON'S pounds.

Dave Larrington - legslarry.beerdrinkers.co.uklegslarry.beerdrinkers.co.ukOpen ↗
===========================================================
Editor - British Human Power Club Newsletter
bhpc.org.ukbhpc.org.ukOpen ↗
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"Danny Colyer" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Are there any short people out there who've experimented with different crank lengths?

My wife is 5' with a 27" inside leg. She's currently using the 170mm cranks that the bike came
with, but I reckon she'd be better off with 150mm cranks (if I can find some).

Any difference in leverage caused by crank length variation can be compensated for by gearing, so it
seems perfectly reasonable that the ideal crank length will be mainly a function of the rider's leg
length. Shorten the cranks and you may have to gear down slightly to maintain the same speed for the
same effort on the same bit of road. This means spinning a bit faster, but this is just what the
smaller pedal circle promotes.

There are a couple of sites that explore the crank length issue in some detail.
cranklength.infocranklength.infoOpen ↗ is by Andrew Bradley. nettally.comCrankset.htmlOpen ↗ by
Kirby Palm is rather eclectic, also explaining why men should pee sitting down, how to build a
high-rise apartment for pond fish, and an improved version of badminton.

Sheldon also goes into this issue on his site and even gives an improved scheme for calculating gear
sizes that takes crank length into account. Of course as every 10th word is a link you will be
forced into spending several hours reading about Sturmey Archer gears or some other topic you had no
idea you were so interested in.

Changing the crank length will also mean adjusting the saddle height, which might mean an adjustment
in handlebar height is also required to get the ideal position. Increasing the crank length would
reduce the pedal clearance for cornering which is something tall people need to be aware of.

--
Dave...

"Martin Bulmer" <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

Remember that shorter cranks will give her less leverage, so you may be better to replace
chainrings anyway, to compensate.

They effectively increase the gearing right across the range. But she's hardly likely to run out of
low gears on the bike she has.

--
Dave...

Dave Kahn said:

They effectively increase the gearing right across the range. But she's hardly likely to run out
of low gears on the bike she has.

Quite - the bike's undergeared anyway, to the extent that on the flat she tends to ride on the big
ring and the 5th sprocket of 7 (42/15, roughly a 70" gear).

I'm aware of all the issues raised so far (but thanks for mentioning them). You don't spend long
doing Muni or riding a Coker without learning a little about crank length and effective gearing, and
I've spent enough time tinkering with riding positions on both our bikes to know what adjustments
are likely to be needed.

I think the biggest concern I have about fitting shorter cranks is that if I then put the saddle up
it'll become harder for Catherine to reach the floor. I shall take a closer look at her current
riding position with regards to that before I try shorter cranks.

The suggestion to try 160mm cranks first seems reasonable (Richard Ballantine suggests 165mm for
anyone with an inside leg of 29" or less, but I preferred the formula I found of leg length in
inches * 5.48 to find something that might allow her to spin comfortably at a decent cadence).

And thanks to those who mentioned SJSC, as well. I hadn't spotted anything less than 165mm when I
looked a couple of days ago, but if I know they do them then I can phone up and ask (after I've
asked at a couple of LBS'😉.

From the RHS it looks as though I should be able to separate the right crank and the chainring with
no problem, but I'll know for sure when I get round to lifting the bike off the wall, removing the
chainring and cleaning it up a bit! Which, come to think of it, I could probably do this evening.
(Bugger, maybe I won't, as it turns out that the retaining bolt is absurdly tight and my 10" wrench
doesn't provide enough leverage to shift it. Time for a squirt of GT85, methinks).

--
Danny Colyer (remove safety to reply) ( juggler.netdannyOpen ↗ ) Recumbent cycle page:
speedy5.freeserve.co.ukrecumbentsOpen ↗ "He who dares not offend cannot be honest." -
Thomas Paine

"Danny Colyer" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Are there any short people out there who've experimented with different crank lengths?

cut: Elderly overweight with an inside leg of 28" I occasionally get twinges in the knees when
riding (for me) long distances or after riding several days in succession. Normally use "standard"
170 long cranks that come with most bikes, but when fitting larger rings to a bike I increased the
crank length to 175 for the mechanical advantage longer cranks would give. Sharp increase in
occasions of and severity of pain, so did some research on the net that suggested 165 cranks might
suit me better. This is correct, pain now rarely happens and rather than a loss of power there seems
to be an increase in my ability to (slowly) grind up hills. peter

peter said:

"Danny Colyer" <[email hidden]> wrote in message "]news:[email hidden]...

Quoted message said:

Are there any short people out there who've experimented with different crank lengths?

cut: Elderly overweight with an inside leg of 28" I occasionally get twinges in the knees when
riding (for me) long distances or after riding several days in succession. Normally use "standard"
170 long cranks that come with most bikes, but when fitting larger rings to a bike I increased the
crank length to 175 for the mechanical advantage longer cranks would give. Sharp increase in
occasions of and severity of pain, so did some research on the net that suggested 165 cranks might
suit me better. This is correct, pain now rarely happens and rather than a loss of power there
seems to be an increase in my ability to (slowly) grind up hills. peter

Does anyone know where you might be able to "hire" cranks to try with. I've got an inside leg of
just over 29" which most websearches seem to imply would want a 165 crank.

In order to maintain the same speeds at the same cadence I would have to push harder. I'm limiting
my speeds because of the odd twinge in my knees and can't comfortably spin any faster on the
windcheetah. Do shorter cranks make it easier to spin a bit faster? Or mean that people with short
legs can push a bit harder without straining their knees? Or does it all depend on the person?
Hence why I would like to have a month to try shorter cranks. OTOH, it's only 70GBP to hopefully
limit the effects of arthritis in old age. Why do I find it impossible to limit my effort when
riding on my own? :-)

Regards,

Tim.

--
God said, "div D = rho, div B = 0, curl E = - @B/@t, curl H = J + @D/@t," and there was light.

tjw.hn.orgtjw.hn.orgOpen ↗ locofungus.btinternet.co.uklocofungus.btinternet.co.ukOpen ↗

Danny Colyer said:

I think the biggest concern I have about fitting shorter cranks is that if I then put the saddle
up it'll become harder for Catherine to reach the floor.

when you dismount you step down and magically one's foot teaches the pavement. surely you don't
expect to keep one's [censored] on saddle and touch pavement??

Tim Woodall <[email hidden]> wrote in message
news:<[email hidden]>...

Quoted message said:

In order to maintain the same speeds at the same cadence I would have to push harder.

The idea is to maintain the same speed and effort but spin a bit faster.

Quoted message said:

I'm limiting my speeds because of the odd twinge in my knees and can't comfortably spin any faster
on the windcheetah. Do shorter cranks make it easier to spin a bit faster?

Yes.

Quoted message said:

Or mean that people with short legs can push a bit harder without straining their knees?

Possibly. At any rate shorter cranks will reduce the amount by which your knees have to flex with
every pedal stroke.

Quoted message said:

Or does it all depend on the person?

To some extent, almost certainly.

Quoted message said:

Hence why I would like to have a month to try shorter cranks. OTOH, it's only 70GBP to hopefully
limit the effects of arthritis in old age.

If you don't get on with them you should be able to get some of your money back selling them on
eBay. If you do like them you may still be able to get some of your money back by selling the
original ones on eBay.

Quoted message said:

Why do I find it impossible to limit my effort when riding on my own? :-)

Because you are a cyclist.

--
Dave...

peter said:

so did some research on the net that suggested 165 cranks might suit me better. This is correct,
pain now rarely happens and rather than a loss of power there seems to be an increase in my
ability to (slowly) grind up hills.

Thanks Peter. I think I might try a set of 160's, then go up or down from there depending
how it goes.

--
Danny Colyer (remove safety to reply) ( juggler.netdannyOpen ↗ ) Recumbent cycle page:
speedy5.freeserve.co.ukrecumbentsOpen ↗ "He who dares not offend cannot be honest." -
Thomas Paine