Now that you mentions it, it reminds me of the asym(atrical) cranks that were sold a while back as they were apparently more convenient for some tricks…
It is a good reminder that anybody with foot placement sensitivity should take into account this growth the same way Q-or-no-Q-factor could help or not 
I have only had minor issues with this, and it’s probably just me making beginner’s mistakes. How do you place your feet on the pedals? Mine are pointing more or less directly forward.
It would certainly be detectable if the measurements by a particular scale were consistently different in the same direction from other scales.
You forgot to mention the difference depending on the phase of the Moon.
I think it’s unlikely that there’d ever be enough volume to work out issues with specific scales, so I’d just go with a weighting system for scale precision (and for complete unicycles, perhaps stock or not), and provide something like the high, low, median and mean.
It could also inform someone inputting data that it suspects there might be an issue based on how far off their measurement is from the existing weighted average.
This might be getting a bit off topic from Q-Axle though 
I’m not sure I’ve had an issue with this, perhaps due to crank length or shoe size, but I’d have thought that zero-Q cranks with sharp corners would be worst, whether or not they’ve got an extra bit at the end or not.
I definitely had moments when my cranks pushed my feet off when I was learning, but it was just down to dodgy foot positioning rather than crank specifics.
OK that would work if there are ‘many’ entries from that particular scale, AND there are many entries from other scales for the same parameters.
No, my remark was in response to newuser’s comment about moon tidal forces, which are directly related to phases of the Moon. And otherwise you may consider it covered by ‘and whatnot’.
Since we are talking about the Q-Axle Crank Interface. I have a question from a friend. he recently discovered that one of his “Adjustment Caps” is missing. He is ordering a new one and wondered if it was safe to continue to use the unicycle in the mean time.
I have no idea, since I have never owned a unicycle with this crank interface, so thought I would ask here.
I can confirm that he’s asking for a friend and not a “friend”. I pointed out that his crank (to the right) seems to be further out on the axle than the crank in the Qu-Axle video. Is the crank out of place?
So they’re also known as pre-load caps.
The idea being that before you really tighten up the pinch bolts, you tighten the cap to seat the crank correctly on the hub against the spacer and the bearings.
It does look rather like it is. I’d be double checking that the crank is snugged up against the spacer, and undo the cap from the other side to see if the axle seems to have shifted.
It’s not out of the question for the axle to shift from side to side, but less likely than on something like an older KH or Nimbus hub with pressed flanges where you’re putting an insane amount of force on the end with the ISIS crank bolts. The Q-Axle caps shouldn’t ever be done up really tight, definitely not to the point where they’d start pulling the axle out of the hub shell.
Back to the original question of whether or not it’s fine, so long as the cranks are in the right place and the pinch bolts are tight then it should be fine to ride, but it appears something may be amiss.
Thanks, I (or @UniMyra 
) will pass this on!
P.S. I recall a discussion where it was stated that this system is basically Shimano Hollowtech. Does this mean a Hollowtech cap would work?
That uni has wrong spacers. Better change tothe slimmer spacers before loosing caps again
Maybe, but the spacer difference is only 1mm. That picture looks more than 1mm off what it should be.
And from that picture I’d presume that they’re as supplied with the unicycle so I wouldn’t expect them to be wrong.
Yep, Hollowtech caps work fine too.
So something like this
https://www.bikester.no/kcnc-veivbolt-for-shimano-crank-arm-igjen-M125893.html
and this tool to install it?
https://www.bikester.no/shimano-tl-fc16-kranklagerverktoy-M174962.html
P.S. Our friend is impatient and also wants to save on shipping. 
Personally I would probably have gone to UDC UK bought the official Q-Axle equivalents, swallowed the shipping (or bought some other stuff I wanted, since there is always something) and waited.
What @mowcius said. On Shimano Hollowtech II cranks, the cap isn’t holding anything in place. In fact, the Shimano cap is hollow (surprise!) and made of plastic. There is no problem with riding without the cap for a while.
Yes, but you should keep away from Bikester. They pretend to be a Norwegian store, but they’re not. Go for this tool and this cap.
Edit: See this document, pages 17–19. That’s where Qu-Ax stole the design from
I have heard from people where riding without it worked, but on my uni it didn’t and I lost one crank twice (crank is still rideable, the other crank just moved further out) (I only adjusted the crank and removed the caps right afterwards since at this point I had only one pair and that was on my Freewheel uni). I would be careful, looks already if the crank is sliding out and your friend will soon loose it.
The caps are mainly for adjusting the position but also for preventing sliding.
Edit: I found the reason for that caused/enhanced the sliding: I greased the interface
I had one of my cranks do that yesterday. It felt like my pedal was coming loose, just a tiny bit of wobble. I stopped and inspected it to find the end cap missing and the crank backed off 7mm or so from where it should be. I walked it home, reseated the cranks and replaced the end cap with a spare I had from when I switched cranks. No damage so far as I can tell. I usually torque bolts pretty tight, so I’m not sure what happened. I’ll make a habit of rechecking the tension on those bolts every few days.
On Shimano Hollowtech II there is a small stopper plate which fits into the slot in the cranks where the bolts go through. The stopper plate has a small pin which fits inside a hole in the axle. (See step 8 on page 19 here.)
I always thought the pin was just there to position the crank correctly, and that the main purpose of the stopper plate was to ensure you didn’t overtighten the bolts. But I just checked my Q-Axle cranks, and they don’t have the stopper plates!
So perhaps the plate and pin also prevents the crank from coming loose? Perhaps the end cap plays a different role on Q-Axle than on Shimano Hollowtech II? Perhaps this is why the Q-Axle cap is beefier than the Shimano cap? Perhaps it’s time @qu-ax helps us out here?
I’m really surprised that the crank can walk along the spindle at all with the pinch bolts properly tightened. The stopper plate and end cap on Shimano cranks are both plastic, and don’t look sturdy at all. I always assumed that all of the load was taken up by the cranks clamping onto the spindle.
I also assumed that the stopper plate was to aid installation. Or some kind of lawyer device.
