Coker crank length and risk of injury link?

Seat height makes a real difference to my knees, I find my knees ache if
I ride a long way with a too low seat..

Bear in mind that for shorter cranks, you want to raise the seatpost
slightly compared to long cranks too, as the bottom of the crank circle
is higher up.

Joe

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Cool, thanks Joe... just what I needed to hear. Might help to explain
why I have no problems on my racing bike. I just need a pipecutter to
get the new post rideable now.

Anyone had any injury/pain problems switching to shorter cranks or is
it just a coincidence?

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Things that might hurt your knees:

- Having your seat too low.
- Having your seat too high (less likely)
- Very sudden changes of load - riding a big wheel on short cranks
when you have to keep changing speed and direction - e.g. riding
muni, or idling.
- Long constant loads - riding up or down long hills. (As riding
down is a less natural movement it may be worse than riding up.)
- Very long rides without changing position or resting.
- Falling off and banging or scraping your knees - more likely on
short cranks.

For steady riding with no sudden stops or changes of speed, and no long
hills, you should be OK.

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The key is to have your seat at the right height. Too high and your
achilles tendons hurt. Too low and your knees hurt. The affectd can be
dramatic and quick. I remember a ride I went on in Tokyo with Roger in
2004. We both had borrowed Cokers with the seats too low. The figured
it would be ok since we were only going 5km or so. We were amazed to
both get sore knees in that short distance, almost completely flat.

Given that the seat is at the right position, I find the that shorter
the cranks are the LESS strain occurs on my knees and ankles. I saw it
just a few weeks ago when we did a 105km ride with a very experienced
unicyclist. He couldn't find his regular cranks and ended up doing the
ride with 170mm cranks. He kept up fine for the first 50km or so
(amazingly cruising at 12+mph), then his legs started cramping on a big
steep hill and he ended up having to sag back to the start after only
60km. This is a guy who has ridden 160km in a day and has ridden
probably 20000km, over many years.

I've done all-day 70+km rides on 152mm cranks, but have to be careful
to avoid going too fast which strains my knees and ankles. With 125mm
or 110mm cranks, that length ride and longer is no problem at all. The
larger the circle your legs make, the more your joints have to move. So
I always use the shortest cranks possible given the terrain.

---Nathan

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Thanks so much Mike and Nathan, that's really useful info!
I'll keep the shorter cranks on and raise the seat about as high as is
comfortable while making sure my lower leg is still slightly bent when
the cranks are vertical. I think that's how its meant to be on a bike
and judging by what you say I should be able to get it about right.
Then I'll change the cranks if it's still giving me gip, at least that
way I'll know if it was just one factor or another. I think that makes
sense, but there's only one way to find out.
I also have a brake from a road bike that I can fit next week which
should help. You're spot on about downhills, that's what really kills
me!
Cheers!

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yea, If you get brakes I think that wil also help a ton. I'm pretty sure
brakes are very useful on the big wheels.

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Quoted message said:

<>UNICYCLING FOR MYSLELF TOO<><

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Longer cranks mean your knees are moving through a larger range of
motion compared to shorter cranks. The larger range of motion means
that your knees need to bend more and your knees are in a different
position (angle) when applying the most force to the pedals.

If you have tendinitis type problems (ligaments or tendons rubbing)
with your knees then the larger range of motion from longer cranks
could cause problems.

On the other hand, longer cranks can mean that you put less force on
the pedals when climbing or descending and that can translate to less
force on the knee joint.

Twould depend on what type of knee problems you're trying to compensate
for.

Seat height is also a biggie. Riding a muni with 170mm cranks is a lot
different than riding a Coker with 170mm cranks.

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What Nathan said :p

You want to use the shortest cranks possible for the terrain if you are
going to be riding for hours on end. The shorter you go, the less your
joints move, the less strain you get. Not only that, you are going to
chafe less on the saddle.

During my 24hr Record ride I was using 100mm cranks and 110mm cranks.
The 100mm cranks were much smoother, faster and gave me less saddle
soreness than the 110's.

I remember going from 125's to 150's when I was riding in Cambodia
(which is pretty flat). I had been able to ride at least 20km without
stopping. After switching to 150's I had to stop every 5km's cos it
hurt so much. If I had to do that Unitour again I'd definitely be on
100's or 110's.

So for me- I use 100's on the flat, 110's for general riding, 125's for
hillly rides, and 150's off-road.

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100's? thats really short...

--
mornish

Quoted message said:

<>UNICYCLING FOR MYSLELF TOO<><

"LX seats are as comfortable as bricks." lildude2
"CX seats are bricks."
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You could go Brian MacKenzie style and ride 40mm cranks!!! I saw
them...They are so tiny

--
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TRIALS 4 LIFE !

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<>UNICYCLING FOR MYSLELF<><

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koebwil said:

I'm too hardcore to type. I just punch the keyboard and delete the
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are they actually usable?

--
mornish

Quoted message said:

<>UNICYCLING FOR MYSLELF TOO<><

"LX seats are as comfortable as bricks." lildude2
"CX seats are bricks."
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Yeah...Buy TWNR..Theres a few clips of him riding his Coker with 40mm
cranks in there.

--
trials_uni

TRIALS 4 LIFE !

Quoted message said:

<>UNICYCLING FOR MYSLELF<><

'Check Out The Newbie Guide' (http://tinyurl.com/99yez)

koebwil said:

I'm too hardcore to type. I just punch the keyboard and delete the
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w00t...i got reply # 60666 in MR
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Is TWNR training wheel not required? If so, where can I buy it and how
much is it?

--
mornish

Quoted message said:

<>UNICYCLING FOR MYSLELF TOO<><

"LX seats are as comfortable as bricks." lildude2
"CX seats are bricks."
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I think it depends on the nature of your injury. You just have to go
with what feels best. I'm sure the advice about seat height is very
important too.

I have knee ligament damage. I fully snapped two ligaments in the right
knee in a skiing accident in Feb 2005. I find longer cranks put less
strain on my knee, and I get more pain the day after if I ride with
shorter cranks.

I put it down to the stress on the knee being applied in a limited
range of movement, i.e. the knee is not being fully extended or flexed.
Also depending on the seat height, that narrow range of motion might
just be in the area that makes your knee worse.
While recovering from knee injury you are told that the more you can
use your knee (within reason of course), the better it is for regaining
full motion again. Infact unicycling was one of my rehab exercises and
works well because it exercises and re-educates the muscles without
impact, more so than conventional cycling or the other exercise
machines they put me on. I really think it helped me a lot (my doctor
agrees) and I have made an exceptional recovery.

Lack of motion is the worst thing for making the knee stiff and
painful. Infact even now if I'm laid up for a day or two my knee
deteriorates rapidly.

Of course I am not a doctor, I'm just telling you of my experience and
what I have learnt having been through a year of rehab, it may be
different for you.

Andy

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mornish said:

Is TWNR training wheel not required? If so, where can I buy it and how
much is it?

Yes it is. You can get it from e-bay and im pretty sure theres a link
in Brian MAcKenzies Sig that shows where to get it aswell.

--
trials_uni

TRIALS 4 LIFE !

Quoted message said:

<>UNICYCLING FOR MYSLELF<><

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koebwil said:

I'm too hardcore to type. I just punch the keyboard and delete the
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has anyone found that cokers with zero Q cranks are easier on the knees
for road riding? I've got prowheel 127s with relatively large/high??
Q-factor right now and wanted to try 114s with zero Q.

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I haven't noticed any issues with Q-factor. When I upgraded from a stock
narrow hub to a Tom Miller wide hub, I was worried that it would feel
funny at least or have some other problem. But it took about 1 second
to get used to it - just not a factor at all. I pretty much use Bicycle
Euro cranks in 110, 125 and 152 (and occasionally 170 for very steep
offroad riding). I have some Dotek 140s and Black Widow 165s that I've
used a little, but prefer steel cranks.

---Nathan

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brycer1968 said:

has anyone found that cokers with zero Q cranks are easier on the knees
for road riding? I've got prowheel 127s with relatively large/high??
Q-factor right now and wanted to try 114s with zero Q.

Q-factor on the Coker doesn't make a difference for me with regards to
the knees. I have used a narrow hub, a wide hub with straight cranks,
and a wide hub with wide (flared out) cranks. I haven't noticed that
one setup is better for my knees than another setup. But that is just
an individual observation. Could be different for someone else. Some
people may be more sensitive to Q-factor changes due to body geometry.

Proper cycling form and pedaling form is also important in minimizing
potential knee problems. Proper pedaling form means that your knees
are moving up and down in a plane and not making some kind of strange
elliptical pattern when viewed straight on from the front. The knees
should be moving up and down and not making any side to side movement
as you pedal. The side to side movement of the knees can cause knee
problems.

You can exaggerate the poor pedaling form by riding like a bow-legged
cowboy. You'll notice that the knees have to make side to side
elliptical circles as you pedal (when viewed straight on from the
front). That is bad form. Now move the knees in so they are in line
with your hips and ankles. Now when you pedal your knees will move
straight up and down in a plane (when viewed from the front). That is
good form.

Q-factor can make a difference for some people for how they can pedal
with good form with the knees moving straight up and down. For me, I
haven't noticed a difference with Q-factor affecting how well and how
comfortably I can pedal correctly with the knees moving straight up and
down. But I'm sure there are people who are more sensitive to Q-factor
changes due to their body geometry (hip width, joint orientation, leg
length, etc). If you notice that you have poor pedaling form you can
try experimenting with Q-factor changes to see what suits you best.

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