Knee hurting with 110mm cracks

I ride a 28 inch unicycle with 110mm cracks.
After +/- 30min riding my right knee start getting to hurt :frowning:
I don’t get this problemen on my 24 inch muni with 160mm cracks.
Are long cracks beter for your knees?
Do more people have this kind of problems.

Where does the pain come from? inside of the knee? it might help if you wear knee suports?


If anything, the shorter cranks ought to hurt your knees less.

The psychology of your situation is the thought that short cranks = more torque, equals more pressure on the knees. However, the leverage you are exerting is nothing compared to riding a bicycle in a normal gear.

If your knee is hurting, I would suggest:

  1. There may be a weakness there that the pedalling motion is aggravating.
  2. Your foot may be on the pedal at a funny angle.
  3. Or you may be doing a lot of hard-work pedalling - start, stop, idle, that sort of thing.
  4. Perhaps your seat is too low - or (less likely) too high.

You can reduce the movement of your knee by bringing the ankle into play - this will give a smoother pedal stroke too.

However, as all the torque exerted through the pedal has to find its way back through your knee to your pelvis somehow, this will not reduce the load on the knee - it will only affect how that load is applied.

One thing that is absolutely certain is that you do not want to develop long term knee problems. Do a warm up, bend and stretch, adjust your pedalling action, adjust your seat, but if it still hurts, rest. If it still hurts after a few days’ rest then seek medical advice.

A Tubigrip or similar may help, but it might simply camouflage the problem.

PS, 110 mm cranks are a good size for a 28.:slight_smile:

there IS the possibility that your cranks are bent. I rode a uni that was all bent up and hurt my knee, so that should be something to check.

My brother’s Coker came with a bent hub or cranks (not sure which)

You could try to change the height of your saddle, makes a great diference…

I agree. Did you raise your seat after putting on shorter cranks?

There seem to be arguments for both long cranks being worse for knees (bigger turning circle= more knee movement) and for shorter ones being worse (more force on the knee); it would be good to come to some solid conclusions on it.

Personally, as a unicyclist with less than perfect knees, I feel that riding my 24x3 with 150mm cranks, to be less hazardous to my knees than riding my 29-er with 125mm cranks (or worse, when I had 110’s on it).

I think it’s because with the extra control with longer cranks, there is less chance of an abrupt unexpected ‘jerk’ from the cranks, and it is those that I feel cause knee stress.

Maybe, however, there’s two types of knee damaging effects, and short cranks excarbate one type, and longer cranks, the other.

This would be par for the course for issues revolving around long vs. short cranks, which seem to vary according to each unicyclist with no definitive conclusions being possible :slight_smile:

I think your last sentence quoted above is close to the Truth, although I don’t think it’s just two. At least in my world, there are many motions that can lead to knee pain.

I think there is also a dependency on riding style/skill. While I’ve become more accustomed to shorter cranks, when I first switched, I was using an unnatural amount of “back-pedaling force” to adjust my balance or slow myself down. That particular motion makes my knees hurt a lot, especially when applied in short bursts of adjustment rather than consistently (as you might when going down a long hill). I noticed this even more during the time I had Harper’s Blueshift…the combination of the geared uni and my low riding skill was causing me to make panic over-adjustments, which was stressing my knees. As I got more used to the uni and started micro-adjusting rather than macro-adjusting, the pain in my knees decreased.

So back to rvs’s original problem…you might just give it a little more time and see if the pain decreases once you’re more familiar with how to handle the shorter crank length.

I’m not sure. The leverage should be quite a bit less than on a bike, PROVIDED that you have near-perfect control.

But if someone is relatively new on a 28" with 110 mm cranks, they may still be struggling with their balance, accelerating and decelerating to keep upright and/or have to much weight on the pedals. All of this is hardly an issue on a bike. So then the forces on the knees could be far greater than in the bike case.

1 ) I think my pedal motion is stable thats not the problemen.
Ridding a unicycle for few years now.
2 ) Can’t realy tell if my foot is at funny how can i check this??
3 ) With the 110 crack it’s harder to stop and to idle i can realy feel that.
4) I tried the seat at diffrent highed that does not help.

What do you mean by bringing the ankle into play??
I thinks of switching the cracks for 150mm and see if that helps.
Dont want to the 110 mm are so nice for the speed.

What about trying a “compromise” length, like 125/130? On my Coker, I had a noticable average speed improvement just going from 150s down to 140s. Maybe there is a length that will give your knee relief while also providing speed improvement over the 150s.

Well, if your knees hurt, then…:wink:

Seriously, your foot should be straight on the pedal so that if your knee were a hinge, the axis of the hinge would be parallel to the spindle of the pedal.

Put simply, make sure your foot isn’t on the pedal crookedly.

The way you expressed that could be a clue to the problem…

Slow down more gradually. Ride with the uni, don’t fight it. From high speed, it may take 5 or 10 complete revolutions of the wheel to stop under control. Plan further ahead. Think smoooooooth. You can dominate a 20, or a 28 on 150 mm cranks. You must co-operate with a 28 on 110s.

As for idling: the emphasis changes. Idling a 20, or a 28 on long cranks, is a “pump pump pump” movement of the bottom foot.

With short cranks on a 28, you need to find the two balance points: front of the idle, and back of the idle, and time your gentle pedal movements so that you are almost riding the short distance from one point to the other. Idling a 28 on 110s is like switching smoothly between two still stands.

Do you ride with the ball of your foot on the pedal, or with your instep on the pedal? If you ride with the ball of your foot on the pedal, then you can use the flexibility of the ankle to help to smooth out the pedal stroke and make it more circular. A clumsy rider pushes the pedals down hard, one after the other; the perfect rider would push the pedals round in a smooth circle. (I’m not a perfect rider!) Aim for a circular pedalling motion. Don’t fight the uni.

A 28 on 110s is a lovely elegant machine: a thoroughbred racehorse where the Coker is a warhorse and the 20 is a Thelwell pony. Ride it appropriately.:slight_smile:

I think if you get rid of your CRACK and replace it all with CRANKS you’ll make eveeryone much happier.

Err, is that right? The normal advice for setting up SPD cleats, which basically means foot position, is to walk along then stop. This leaves your feet in their natural position, which may be straight or may be slightly angled inward or outward. Remember where your feet are pointing. The ideal foot position on the pedals is one which keeps your feet at the same angle. This means that all the joints involved are at their natural angle so should be spared most of the twisting that cause problems.


I think my foot is straight have to check next time i ride.

I think also this can be the problemen idle this uni is something i still can do realy good.

I pedal with the instep of my foot.
I tried pedaling with the ball of my foot did not like it.
You say use the ball of the foot is beter i have to try that again.
An other problemen i thinks is de force on knee it get on up word motion.
I think that i fight the uni to much on the up word motion.
On normal bike that force is not so great.
And on a uni with longer cracks that force is also less.

Hmmm. So if your natural poosition is with your feet turned slightly out, then you fit these cleats, you catch your ankle on the crank with every stroke?

I wouldn’t be dogmatic about whether the feet should be dead straight or not - I shift mine about quite a lot as I ride anyway - but my point was that rvs might not have had his/her feet on the pedals in a good position.

rvs - In view of your later posts, maybe 110s are a bit ambitious at your present level of experience. I find 110s the natural length for a 28 and can ride it easily on 102s and fairly confidently on 90s. Some peopel regard 125s as “short”. The truth is, the shortest cranks you should use are the shortest you feel comfortable with. You don’t sound like you feel comfortable with 110s yet.