Crank length on a Coker

Hi Everybody
I am considering purchasing a second-hand Coker. The seller says he has a selection of seat posts and cranks and I can pick the ones I want. I am about the same height as him (1.75m or so, if that makes any difference), which should make things easier, but as I have never ridden anything like this before, I’d like a bit of advice before I go to have a look.

So - what is a good crank length for a first time Coker rider? I know that I could always take my time and try them all but that seems a bit nasty. I know the crank length debate usually oscillates between the power / speed choice, but what’s a good midpoint for a novice?

Thank you


150mm should be fine for starters.

They come as standard with 150mm cranks (or mine did, anyway).

150mm is ideal. When I bought my Coker, I could only freemount my 26 about 3 times out of 4.

It took me 7 goes to freemount the Coker then I was able to ride it with reasonable confidence.

Since then, I have ridden on road and off road on 150s.

125s are rideable with care, but I still prefer the versatility of 150s.

The standard 152mm 6" cranks they come with are the best for a novice and are a good all around choice. Depending on your riding style and terrain and body size, you may end up with anything from 110mm to 170mm or even longer. I am now using 125mm for most rides, sometimes 152 and sometimes 170.


I have 170mm cranks on my coker for the hills but they are slow on the flats, I am wanting to try a set of 160s or 165s but I don’t have any, some smaller road bikes use them so I am keeping my eys open for a used pair

Re: Crank length on a Coker

I’ve been using 102’s for the last 9 months. It took more than a month to
get comfortable with them. They were quite a step down from the 125’s that
I ordered with the Coker.

Last night I changed them out for 110’s because I found myself avoiding
rides when the wind was up. High winds (Oklahoma) and mild hills became a
struggle. I did a very short ride tonight and can feel a considerable
difference. I think the 110’s will be just right but will miss the near BC
wheel effect of the 102’s when going down hill.

The 102’s were a good experience.

Start with the 152’s, and as soon as you are comfortable with them, get some 127’s. The effeciency upgrade is very noticeable.

I will be switching from 127’s to 110’s when the snow melts.

I use 170’s or 152’s for Coker Muni. I am using 152’s in this MuniCoker video and you can see they are a quick offroad size, and many steep hills can be negotiated with lots of momentum.

(it’s the Coker wheel bending/unbending video)

Re: Crank length on a Coker

being her normal, reticent self, jayne failed to mention that she’s planning on learning to ride on a coker

does that affect the recommendations?

OK Dave, sully my reputation why don’t you!
Reticent my foot!
I wasn’t even sure this had gone through thanks to my ISP.

SO - here are the edited highlights:
Due to hassles in getting anything on a single wheel in the unicycling backwood where I reside, I will probably be learning to ride on this monster.
I am not a raving loon, I am a mathematician and statistician with great dedication to the ideal of “take more samples”.
This will not only be a challenge for me, it will provde Klaas Bil with an extra point of data for his “Hours to learn to ride” model.
The model claims I should be riding in 5 to 10 hours, depending on how long I practice every day and how much instruction I have.
I consider this an opportunity to verify the algorithm.
On a lighter note, if I get this right, I will have unquestionable bragging rights for the rest of my life.

If this changes your suggestions, let me know, otherwise I’ll go with the 152’s and let you know what happens.


If you really want bragging rights, learn to ride on Sem’s 115 footer. I suggest having a fence to hold onto unless, of course, you are a quick study and can freemount right away.

With out any possiblity at all of falling, it would probably be easier to learn on. Why lean on a fence when you can dangle from a cable?

Also, some people look good wearing a crane.

Learning to ride on a Coker is an admirable feat. Scott Kurland is the only one I know of who has done this. Matching Scott’s feat would be very impressive indeed. If you want to know something of his learning history just search using his name and maybe some other keywords. If you’re going to learn on a Coker, stick with the stock 6" (150mm) cranks. If you have long legs, longer cranks might be helpful. I have a 35" (89cm) inseam and 6" cranks are easy for me because they don’t seem long. For people with shorter legs, longer cranks will be more cumbersome and awkward.

Good luck and please keep us updated on your learning curve. There is only one other datum in this demographic.

I think learning on a Coker would be easier.

I am basing this only on the non riders I have seen making more progress after 10 minutes or so on the Coker than on the 24".

My thoughts: A unicyclist already comfortable on a ‘normal’ one has to almost relearn it to an extent.

A complete newbie who has absolutely no idea what they are doing yet can benifit from the slow motion of the Coker…how the pedal doesn’t get away from you when you put your weight on it.

Sure he has to jump up on to it, but that’s no harder than straddling something that’s gonna wack you in the shin before it throws you off as soon as you lift up that second foot.

I was shocked to see the guy making better progress on the Coker, but then after I thought about it, it makes sense.

edit: not easier to learn, but not any harder I bet

That may be true in a way Sofa. I was teaching my ex girlfriend on my 20’’ norco, with slow progress she started to get it. But when she jumped on my coker, she seemed to be more comfortable and able to go further while assisted like on the 20’’.

OK. I’m glad to see that the suggested crank length doesn’t change.

The crane sounds like a good idea. I’m not exactly dainty so I think I could pull off wearing a crane in public. However, it would take a while to get Sem’s 115 footer and crane to South Africa and I already have a perfectly good wall. Also, the crane might limit my choices of where to practice.

I also pulled out a pair of my trousers and measured the inseam. It’s not something I’ve done before as inseam length isn’t really a big deal in women’s clothing. It was 84cm. Does that give me long legs?

I’ll do some searching and see what is out there about learning on a Coker. I’m aiming to be riding fairly well by the convention, which is 20 to 22 March.


Re: Crank length on a Coker

On Tue, 10 Feb 2004 03:00:31 -0600, Jayne ZA wrote:

>This will not only be a challenge for me, it will provde Klaas Bil with
>an extra point of data for his “Hours to learn to ride” model.

Hurray! And a valuable point at that. Scott Kurland never supplied his
learning data and so the largest wheel in the dataset was 26". One
point will be way too little to base conclusions on but together with
some narrative it might give an indication whether Sofa was right when
he said that learning on a Coker would be easier.

Klaas Bil - Newsgroup Addict

I have a feeling you might need two points of contact with the ground for such a thing to work? Or at least training wheels on the front and rear. - John Foss commenting on a picture of a one-wheeled vehicle he saw on RSU.

(For the USA that’s 33inches) That’s certainly long enough for 6" cranks. I would recommend NOT using shorter cranks for learning to ride a Coker.

Note, a more accurate measure of the inseam you want to know is, put on shoes typical for riding, put feet flat on ground (do not stand on toes), measure from ground to firmly against riding area of groin. You also want to initially set your seat this high (less maybe a cm or two) - measure seat height from top of a pedal (in it’s lowest position) to low spot on seat (the center of the seat).