Q-factor under 110mm for ISIS cranks

Hi everybody,

I have been thinking recently about the ISIS cranks selection available and I realized something:

=> Between 110mm and 165mm there is choice of zero-Q cranks (Nimbus, QU-ax…) and Q-factor’ed cranks (KH, Impact… )

=> Over 165mm, it is b*ke sizes and you find mostly Q-factor’ed cranks

But under 110mm, the only references I think of (Qu-ax alu & Venture) are zero-Q cranks :thinking:

Am I missing some other brand with Q-factor ?
Or is Q-factor no longer relevant with cranks under 110mm ?


Offset is added to cranks to minimize ankle hits, so unless you have very short feet your ankle will clear the center of the pedal circle with short cranks. Also, the longer the cranks are the lower the percentage of offset, and the less it will contibute to wobble.

So, yes the additonal Q is unnessary for short cranks.

use a 125mm hub ! result will be the same

Or Pedal extenders

I use 23mm and 27mm pedal extenders on my unicycles, whatever the crank length.
It’s more natural and comfortable for me.
the 27mm are on my 36er (137 spirit cranks) and the 23 are on my G26 (137/110 spirit).
Since I have only two pairs of PE I don’t have it on my 19er (125 qu-ax crank) and I find it a bit weird.

free mountings that involves a jump on the 36er is a bit harder because you have more chances to miss the pedal, but not so much.

I have already used the PE on 110 cranks, it’s ok too, but on 100’s it’s a bit strange.

Maybe the straight cranks + pedals extender combo is the source of the strange feeling…

Thanks for the input, it gives extra search topics :slight_smile:

I have just fitted 140mm long alloy cranks with about 23mm Q-factor to my 24" wheel.
The grippy 2.5 tyre used to work best on wet ground. On dry surfaces, it did it’s own thing and tried to straight line everywhere.

I tried out the new cranks on a dry pavement and the steering response is great.
There is a little bit more side-to-side wobble when pedalling, but the control is much better.
It means I don’t have to use higher PSI to steer. And as a beginner I can stay upright for longer, instead of being a passenger.

I wasn’t sure if the Q-factor had made the improvement, or the 140mm crank length.
A quick search threw up this post, and I think the Q-factor helps with sideways balance, the 140mm helps with forwards / backwards balance.
Put the two together and it is a winning combination.


The pedal end to pedal end measurement on this is the same as the Hatchet.
So maybe the Q factor isn’t as large as I thought.
The main advantage at the moment is the comfortable ride.
That advantage may diminish once my technique improves.

When you become a proficient rider you will be able to ride just about anything you want, but comfortable setups that work for your body will still be comfortable and work well for you.

Like you I like a bit of Q-farctor in my cranks when using a standard hub. It’s fortunate because it’s the same stance you get on a superwide hub and zero-Q cranks (you can set up nearly any unicycle to suit you!). I can ride wide cranks on wide hubs, and zero-Q cranks on a standard hub but don’t find them as comfortable.

I may be wrong about this, but I think the main reason most cranks flare outward is to clear chainstays. This obviously doesn’t apply to unicycle cranks, but now we have the KH Spirit cranks, which are designed to clear brake hardware.

Back when all unicycle racing was on 24" (or smaller) wheels, many riders preferred the narrow profile of zero-Q cranks, thinking they were faster, maybe because less Q meant less wobble. But the downside of zero-Q is the heightened possibility of catching your heel on the hub end of the crank on the front of the pedal stroke. Less of a worry in Track racing, but much more likely when riding over bumps or doing tricks.

The “wider stance” of flared cranks can be an ergonomic benefit for people whose knees are sensitive to pedal spacing, and can be very nice for that reason. But they still can increase the tendency for wheel wobble when pedaling fast.

Yep - these cranks had a chain ring attached when they arrived.
I would have bought Ventures if they made 140mm in square tapered.

My smaller 16" and 20" wheels don’t need the wider stance (102mm / 114mm).
But the 24 with a wide, grippy, heavier tyre does.
Maybe my muscles can remember the longer cranks and wider stance I used on my b*ke 40+ years ago - it feels “right”

Yes, mine, highly tailor made, costly materials, and time-consuming production. So I presume it’s unlikely you are willing to pay it’s price.
However I even can make you even pairs with a negative q-factor, in case you wished to hurt yourself.

It certainly is still relevant.

That are very nice cranks indeed ! Without mass-production savings it is difficult to get a comparable price. However, the estimate at the bottom of the page is quite close to the Triton frames. That would mean than labor cost is more expensive than Ti tubbing. :smiley:

Have you ever tried to make cranks with a cheaper material like CrMo or Aluminium alloy ?

Correct, although I work with a company that truly can obtain / truly supplies the best grade, labor is still ain’t cheap.

Compared producers of regular alu (or ergal) variants: they need large batches (and so large stock) to be cost effective, and neither can’t stock every possible combination. Secondly their CNC programs means input of a block of raw material, and output an end-product, so no extra work involved.

In my case attaching the tubing to the CNC’ed parts is still handwork, and requires precision. But the molds allow for any size or q factor.
Contrary I theoretically don’t need a finish layer, but for cosmetics it’s hand brushed also, costing more time than alu ones you just dip in an anodizing bath (or maybe just need a quick an easy bead-blast).

The owner of the CNC machine, with who I work, doesn’t like to do that. I assume alu kills his tools, but I think CrMo should still be a possible option, I in deed already asked before you raised your suggestion, but he simply never works with that, and doesn’t seem to be motivated to try.

I still could write a 1-piece CNC file, but the costs to realize that elsewhere for a single pair I estimated about nearly the same price, if it’s just for a one L and one R crank, and on condition you work with someone not asking too much lead costs.

I previously used Venture 165mm (almost zero-q) cranks on my muni. The low-q suited me fine, but I tended to “hug” the crank arm with my shoes, particularly my left foot. I messed up a few pair of shoes rubbing against the square profile of the Ventures. I’m currently using 170mm flared Quax cranks on my muni. After getting used to them, I switched back to my 165mm Ventures for a single ride, and I felt like I was about to step on the cranks.

I think flared cranks help slide my foot back into position when it starts hugging the crank. I still don’t know what Q-factor is right for me, but the flared cranks seem safer in the above regard. Maybe I could tolerate low-q cranks with a more rounded profile, so if I stepped slightly on the crank, I would slide off it.

On my 20" trials/street, I’m currently using Impact Eiffel cranks, 140mm. I prefer them to the 137mm Ventures I used previously. I think the reason is because there is not such a sharp edge on the Eiffel, compared to the Ventures.

Turns out I found an answer to my question while browsing the internet and finding the Qu-Ax Sale page:

Their CrMo ISIS cranks exist in 100mm and seems to have some Q-factor based on the pic.

At sale price, I placed the order with limited risks :stuck_out_tongue:

Pretty nice Q factor here!
Let us know, indeed for the price it was a no brainer!