cyclefit result

"Zebee Johnstone" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Thanks to those who recommended Steve at Pedal Pushers
http://www.cyclefitcentre.com/

Quoted message said:

I am using the sandals because I can't find shoes wide enough to fit
my feet, and adding 10mm of shim under the forefoot in the shoe isn't
going to make that any easier! Anyone have a line on shoes with
really really wide fittings? Shoes built for people with feet like
tennis rackets?

Another possiblity is to build up the pedal. I'm using SPD and MTB
shoes/cleats and Steve doesn't have shims for those. Anyone know of a
pedal that can be shimmed and be used with a shoe you can walk in?

The last possibility is to have a longer crank on the left side.
Sheldon Brown reckons this is a bad idea, anyone have any experience
with it?

Zebee
- off to the podiatrist to see if it's possible to make a 10mm shim
to glue to the sandal.

Possibly look to another socially marginal activity 🙂 The last SCA A&S
weekend I went to I did a shoe making workshop with a fantastic
shoemaker...I think his name is Duncan. He can make essentially any footwear
you care to name (his kids have the funkiest custom made sneakers
ever...they've never worn store bought shoes). If you ask around in the SCA
groups such as lochac, someone should be able to put you onto him.

"Zebee Johnstone" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

In aus.bicycle on 31 Aug 2006 18:21:39 -0700

Graeme Dods said:

Very bad idea! It may compensate for the leg length difference at one
position each rotation, but 180 degrees from that position it's making
the difference twice as bad. I'm not sure how you'd do it with clipless
pedals, but I've known of kids that are too short to reach unicycle
pedals put platforms on each side of the pedal (in a wood-pedal-wood
sandwich). That way it compensates for leg length all the way round.

Eh?

If they have their foot on one bit of wood, then the other bit of wood
is not doing a thing.

As for the longer crank, I can't see how that works either. If a
160mm crank is the right length for the long leg then how can it be
wrong 180 deg out?

The legs are more or less independent, so how on earth does 180 deg
get into it?

Zebee

Because lengthening the crank by 10mm won't put the pedal consistantly 10mm
further away. It'll be 10mm further away at the bottom of the stroke and
10mm *closer* at the top of the stroke resulting in excessive flexion and
[censored] biodynamics. If the carpet tiles are producing that dramatic a change
then I'd say you're on a winner with that. Shim out the cleats or get a 10mm
platform sole installed or something.

TimC said:

On 2006-09-01, Graeme Dods (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Zebee Johnstone said:

The last possibility is to have a longer crank on the left side.
Sheldon Brown reckons this is a bad idea, anyone have any experience
with it?

Very bad idea! It may compensate for the leg length difference at one
position each rotation, but 180 degrees from that position it's making
the difference twice as bad. I'm not sure how you'd do it with clipless
pedals, but I've known of kids that are too short to reach unicycle
pedals put platforms on each side of the pedal (in a wood-pedal-wood
sandwich). That way it compensates for leg length all the way round.

For clipless you'd need to raise the clip platform somehow. This would
require some hacking about and would probably be easier with single
sided pedals. At least you could use your usual shoes without making it
even harder to find new shoes every few years/months/weeks/milliseconds
(depending on where you are on the sliding scale of shoe rapaciousness)

What's wrong with a shim under the cleat (a few peices of sheet metal
with appropriately drilled holes?), and long bolts?

An engineering solution to an engineering problem? How novel.

Dave

In article <[email hidden]>,

Fractal said:

How did Steve measure this? I have heard the only way to do it reliably is
to have a full length hip to toe X ray.

Most people just measure it directly on an examination table. It's
pretty reliable. X-ray would have the problem of parallax. And then you
can go to a CT scanner which is just over-kill.
--

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

Quoted message said:

TimC said:

On 2006-09-01, Graeme Dods (aka Bruce)
was almost, but not quite, entirely unlike tea:

Quoted message said:

Zebee Johnstone wrote:

>The last possibility is to have a longer crank on the left side.
>Sheldon Brown reckons this is a bad idea, anyone have any experience
>with it?

Very bad idea! It may compensate for the leg length difference at one
position each rotation, but 180 degrees from that position it's making
the difference twice as bad. I'm not sure how you'd do it with clipless
pedals, but I've known of kids that are too short to reach unicycle
pedals put platforms on each side of the pedal (in a wood-pedal-wood
sandwich). That way it compensates for leg length all the way round.

For clipless you'd need to raise the clip platform somehow. This would
require some hacking about and would probably be easier with single
sided pedals. At least you could use your usual shoes without making it
even harder to find new shoes every few years/months/weeks/milliseconds
(depending on where you are on the sliding scale of shoe rapaciousness)

What's wrong with a shim under the cleat (a few peices of sheet metal
with appropriately drilled holes?), and long bolts?

An engineering solution to an engineering problem? How novel.

Dave

I say you could resolve it more cheaply and in a more user-transparent
fashion with a software solution.

*flees*

In aus.bicycle on Fri, 1 Sep 2006 18:16:12 +1000

Resound said:

Because lengthening the crank by 10mm won't put the pedal consistantly 10mm
further away. It'll be 10mm further away at the bottom of the stroke and
10mm *closer* at the top of the stroke resulting in excessive flexion and
[censored] biodynamics. If the carpet tiles are producing that dramatic a change
then I'd say you're on a winner with that. Shim out the cleats or get a 10mm
platform sole installed or something.

Why are people assuming the longer crank is for the shorter leg?

Zebee

"Zebee Johnstone" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

In aus.bicycle on Fri, 1 Sep 2006 18:16:12 +1000

Resound said:

Because lengthening the crank by 10mm won't put the pedal consistantly
10mm
further away. It'll be 10mm further away at the bottom of the stroke and
10mm *closer* at the top of the stroke resulting in excessive flexion and
[censored] biodynamics. If the carpet tiles are producing that dramatic a
change
then I'd say you're on a winner with that. Shim out the cleats or get a
10mm
platform sole installed or something.

Why are people assuming the longer crank is for the shorter leg?

Zebee

I wasn't. In that explanation I was working on the basis that it was for the
longer leg.

In article <[email hidden]>,

Zebee Johnstone said:

Why are people assuming the longer crank is for the shorter leg?

It doesn't work for either leg.
--

Artoi said:

In article <[email hidden]>,

Zebee Johnstone said:

Why are people assuming the longer crank is for the shorter leg?

It doesn't work for either leg.

Shorter crank for the shorter leg, at the bottom it works but at the
top your shorter leg has to stretch further - exactly what you don't
want. Or your longer leg is cramped. Either is bad.

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

Quoted message said:

In article <[email hidden]>,

Fractal said:

How did Steve measure this? I have heard the only way to do it reliably
is
to have a full length hip to toe X ray.

Most people just measure it directly on an examination table. It's
pretty reliable. X-ray would have the problem of parallax. And then you
can go to a CT scanner which is just over-kill.
--

Doubt if an accuracy of 10mm can be achieved except by scanning CT. And
Zeebee's was done standing, right? I guess if there is evidence of an out
of whack upper spine some work on posture and flexibility might also be
useful. Is there any evidence that correcting leg length difference would
make anyone cycle faster? Im a bit sceptical of the micro adjustment school
of bike fit, Ive heard of one bike fitter adding a 2mm pad to one side of
the saddle to adjust for a supposed hip misalignment.

fb

Zebee Johnstone said:

[left leg is] bit over 10mm longer than the right.

The result is that somehow I need to compensate for this leg length
difference when I ride.

The simple test was a couple of bits of carpet tile under my feet
in the sandals and wooo! I can't describe the difference very well,
but riding is easier. Lots and lots easier. Easier so that my speed
has increased by enough to mean I was panting a lot more today on the
ride in than I have been for some time. I don't notice going faster,
the computer tells me I am and I'm definitely doing more work. I seem
to be doing it easier until I run out of breath!

However, carpet tiles aren't the best solution.

I am using the sandals because I can't find shoes wide enough to fit
my feet, and adding 10mm of shim under the forefoot in the shoe isn't
going to make that any easier! Anyone have a line on shoes with
really really wide fittings? Shoes built for people with feet like
tennis rackets?

Another possiblity is to build up the pedal. I'm using SPD and MTB
shoes/cleats and Steve doesn't have shims for those. Anyone know of a
pedal that can be shimmed and be used with a shoe you can walk in?

The last possibility is to have a longer crank on the left side.
Sheldon Brown reckons this is a bad idea, anyone have any experience
with it?

Ok, you've invoked my name, so here I am. I do address this at
http://sheldonbrown.com/cranks

Here's a relevant excerpt:

"Mixing Lengths

"Riders who have one leg longer than the other sometimes attempt to
compensate for this by using a shorter crank on the side with the
shorter leg. I do not recommend this, however.
When one leg is significantly shorter than another, the shorter leg is
also usually weaker than the longer one. Since a short crank results in
a higher gain ratio, this setup would ask the the weaker leg to push
harder than the stronger one.

"A better way to deal with significant leg-length discrepancies is to
build up the sole of the shoe, or to use longer bolts and spacer
washers between the cleat and the shoe sole, or to build up the pedal
by some sort of add on attachment.

"Leg length discrepancy can also be somewhat accommodated by putting
the cleat on the foot with the longer leg farther back toward the heel.

"In some instances, deliberately setting the saddle slightly askew
might also help."

Note that you don't need to get all 10 mm from the same place.

You could get a couple of mm from shimming the cleat, maybe 3-4 more
from an orthotic or other insole, maybe another mm or two from moving
the cleat fore/aft.

Sheldon "Symmetry" Brown
+---------------------------------------------------------------------+
| It is amazing how much "mature wisdom" resembles being too tired. |
| --Robert A. Heinlein |
+---------------------------------------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

Resound said:

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

Quoted message said:

TimC said:

On 2006-09-01, Graeme Dods (aka Bruce)
was almost, but not quite, entirely unlike tea:

>Zebee Johnstone wrote:
>
>
>>The last possibility is to have a longer crank on the left side.
>>Sheldon Brown reckons this is a bad idea, anyone have any experience
>>with it?
>
>Very bad idea! It may compensate for the leg length difference at one
>position each rotation, but 180 degrees from that position it's making
>the difference twice as bad. I'm not sure how you'd do it with clipless
>pedals, but I've known of kids that are too short to reach unicycle
>pedals put platforms on each side of the pedal (in a wood-pedal-wood
>sandwich). That way it compensates for leg length all the way round.
>
>For clipless you'd need to raise the clip platform somehow. This would
>require some hacking about and would probably be easier with single
>sided pedals. At least you could use your usual shoes without making it
>even harder to find new shoes every few years/months/weeks/milliseconds
>(depending on where you are on the sliding scale of shoe rapaciousness)

What's wrong with a shim under the cleat (a few peices of sheet metal
with appropriately drilled holes?), and long bolts?

An engineering solution to an engineering problem? How novel.

Dave

I say you could resolve it more cheaply and in a more user-transparent
fashion with a software solution.

*flees*

And congratulations on your new job at Microsoft 🙂

Dave

Quoted message said:

In aus.bicycle on Fri, 1 Sep 2006 20:48:54 +1000

Resound said:

I wasn't. In that explanation I was working on the basis that it was for the
longer leg.

Still doesn't quite make sense to me.

If a 160mm crank is wrong for me if both legs were the same length
then I could see it.

But as my hips are straight and still against the back of the seat of
the bent, then I really can't see the problem.

If I'm using a 150 on the short leg and a 160 on the long leg, why is
the biodynamics of the 160 wrong if the 150 isn't?

If I had a 160 on both, would the biodynamics still be wrong?

Sheldon Brown talks about leverage and amount of work which makes more
sense to me.

Zebee

In aus.bicycle on Fri, 01 Sep 2006 21:36:20 +1000

Aeek said:

Artoi said:

In article <[email hidden]>,

Zebee Johnstone said:

Why are people assuming the longer crank is for the shorter leg?

It doesn't work for either leg.

Shorter crank for the shorter leg, at the bottom it works but at the
top your shorter leg has to stretch further - exactly what you don't
want. Or your longer leg is cramped. Either is bad.

Umm... I currently have 150mm cranks. If I adjust the bent seat so
that the heel is on the pedal and the leg is straight and relaxed,
that's the right seat length, correct?

If so, then *that* leg should be neither stretched nor cramped if the
cranks are of themselves the right length for me.

So, let us now do that with the other leg, but in this case let us not
adjust the seat, let us move the pedal. Now both legs are straight and
relaxed with the heel on the pedal at the furthest point of the
stroke.

Why is the short leg stretched and the long leg cramped?

IF the legs are the same length, why are they not both stretched and
cramped?

Are people visualising a 2" crank on one side and a 12" one on the
other or something?

Zebee

In aus.bicycle on Fri, 01 Sep 2006 13:43:32 GMT

Fractal said:

Doubt if an accuracy of 10mm can be achieved except by scanning CT. And
Zeebee's was done standing, right? I guess if there is evidence of an out
of whack upper spine some work on posture and flexibility might also be

I'm not sure how an out of whack upper spine would cause the hips to
be out.

Quoted message said:

useful. Is there any evidence that correcting leg length difference would
make anyone cycle faster? Im a bit sceptical of the micro adjustment school
of bike fit, Ive heard of one bike fitter adding a 2mm pad to one side of
the saddle to adjust for a supposed hip misalignment.

The 10mm wasn't a hard and fast, it was arrived at by eyeball and
fiddling with shims to correct pedal stroke. Look at the hip bones
and how they sit, shim up one foot, repeat till hips level.

Get on bike, play with shims, look at stroke and smoothness.

Problem with shimming the hip forward is that then I end up even more
twisted. Can't see the benefit, especially given the amount needed to
smooth the stroke.

Zebee

In aus.bicycle on 1 Sep 2006 08:22:21 -0700

Sheldon Brown said:

Ok, you've invoked my name, so here I am. I do address this at
http://sheldonbrown.com/cranks

Heh. Google strikes I suspect. Used to be you had to be 7333t enough
to grep the news spool...

Yes, I read the article, hence mentioning it.

Quoted message said:

Note that you don't need to get all 10 mm from the same place.

You could get a couple of mm from shimming the cleat, maybe 3-4 more
from an orthotic or other insole, maybe another mm or two from moving
the cleat fore/aft.

The cleat's as aft as it gets and has to stay there as otherwise I get
hot foot.

I might try shimming the cleat and some variety of sole, but getting
the sole is the problem...

Zebee

Zebee Johnstone said:

but getting the sole is the problem...

I'm not sure you can go past Sam & Dave when looking for soul

Parbs

In article <[email hidden]>,

Fractal said:

Doubt if an accuracy of 10mm can be achieved except by scanning CT.

10mm discrepancy can be easily measured manually. You don't need a CT to
do that. How do you think orthopedic surgeons operated before days of
CTs?
--

Artoi said:

In article <[email hidden]>,

Fractal said:

Doubt if an accuracy of 10mm can be achieved except by scanning CT.

10mm discrepancy can be easily measured manually. You don't need a CT to
do that. How do you think orthopedic surgeons operated before days of
CTs?
--

CT is overkill, an X-ray works fine as long as the subject is not rotated relative to the plate.

But sometimes, just going with the somewhat low tech "Mark I eyeball" works just as well.

Zebee Johnstone said:

In aus.bicycle on 1 Sep 2006 08:22:21 -0700

Sheldon Brown said:

Ok, you've invoked my name, so here I am. I do address this at
http://sheldonbrown.com/cranks

Heh. Google strikes I suspect. Used to be you had to be 7333t enough
to grep the news spool...

Yes, I read the article, hence mentioning it.

Quoted message said:

Note that you don't need to get all 10 mm from the same place.

You could get a couple of mm from shimming the cleat, maybe 3-4 more
from an orthotic or other insole, maybe another mm or two from moving
the cleat fore/aft.

The cleat's as aft as it gets and has to stay there as otherwise I get
hot foot.

I might try shimming the cleat and some variety of sole, but getting
the sole is the problem...

Zebee

Hi Zeebee

I am using Speedplay Frogs on my Shimano touring shoes. The cleat is built up about 10mm on the right shoe and the sole has been built up to match. These have lasted for over 7000kms so far and I am still on the second pair of cleats.
My road shoe uses an aluminium plate to get the right height and and the fore-aft position correct. Steve Hogg gets these made in a variety of sizes.
I had a chat to him about the possibility of puting a spacer in the Frog pedal to change it's thickness and he seemed interested to have a look at this.
I had pulled one of them apart with John Bosevski who has a couple of wonderful CNC mills to see if this was possible.
John's answer was yes, but to make the prototype would cost $1100, which is bit more that I was willing to spend.

A way a getting a shim made at the right price may be http://www.emachineshop.com/

Cheers

Geoff