My Qu-Ax RGB - Build quality and design concerns

So I just got a shiny new unicycle. A lovely (completely stock base spec) Qu-Ax RGB 27.5" in red.

However as soon as I built it up I noticed a few things that had me concerned.

  • Firstly what’s up with the bearing holders? Why on earth is Qu-Ax obsessed with having the bolts centred to the clamp rather than centred to the bearing? When you tighten up the bearing holders they visibly stop being perfectly parallel to one another; the gap being slightly narrower on the crank side which puts uneven pressure on the bearing. This was an issue on the older Qu-Ax QX series but I had presumed that they would have changed this on the RGB series.
    The bearings already felt somewhat gravely out of the box (not even in the frame, just rotating by hand to apply a light grease) like some of my other unicycles feel after a few years, so I’m not expecting they’ll live a long life!
    Also, a blasted surface as a bearing surface? I’d expect this to be a flat machined finish, but perhaps this isn’t an issue at all.

  • Secondly the zero Q cranks and the space in between them and the frame is pretty small. Now I understand that their goal here was to have a super narrow setup, but having ~4mm between the frame and cranks (145s - on a related note UDC, your page for the 27.5 says 137s on the spec and 145s in the description - I was rather expecting 137s!) seemed a bit small. This issue then revealed its ugly head on my second ride out with the dog where I fell off the thing (still training the dog - he went for a sprint) and apparently put enough force on something for the frame and crank to smash into one another.
    Getting home I presumed that I had done something wrong with the setup, but I couldn’t find anything. The bearing holders were tight (if anything erring on too tight), and the cranks were tight onto the splines, bottoming out on the spacers with the caps properly locked in as they’re meant to be. I’m doubtful this is user error but I’m open to the possibility if anyone has any ideas, especially as this is my first Q-Axle unicycle.
    I also a bit over 60kg so if I’ve somehow managed to do this while having a UPD onto my feet on a flat grass field then it doesn’t seem impossible for others to have this issue.

  • Thirdly quality control/build quality…
    People say that the build quality/QC of KH unicycles has been going downhill, but how good is everyone else?
    -The bearing caps appear to possibly have been cast (which is fine), but then not machined/finished afterwards - there’s unevenness on both of them in places. It’s not on a mating surface, a purely aesthetic issue, but I guess I expected better.
    -The anodising on the seat post is weirdly uneven. It’s all been blasted in some manner for the matte finish, but there are streaky lines near the top that again I just didn’t expect. If it was a discolouration in a paint finish, it probably wouldn’t/shouldn’t have passed QC.
    -There’s a tiny bit of raw aluminium visible on the frame near a weld where it looks like cleaning may have not been perfect so the anodising hasn’t gone quite right and there’s some visible bubbling next to it too.
    -Metal shavings fell off the hub splines as soon as I took off the cranks. There’s no damage so it’s swarf left over from machining, and now it’s in my carpet. They were a fraction of a mm in diameter/size and maybe 10mm long - a good dozen of them on one side and a couple on the other. I own a vacuum, but they could have easily been missed and end up in a human or animal foot.
    -The brake mount doesn’t fit in the handle without filing the corners. This is close, and you could force it to fit, but I’ve seen so many people strip inserts in saddles forcing things so this could perhaps do with being machined to better fit the shape of the saddle handle of the QX Eleven.
    -The top of the frame where the seat post goes in is slightly oval with the edges of the clamping slot having a tendency to mar the seatpost. This is something I’ve seen a lot, and is a far bigger issue with steel frames, but why is this the case here? Are they all like this? Is there any post-processing done to try and mitigate the issue once the clamping slot is machined?
    I noticed the issue and mostly managed to ensure the tube was circular and everything was well greased up for seat post insertion, but others may not know to be so careful.

  • Fourth minor thing, why such crap pedals?
    It’s a MUni. Ship some pedals that are grippier than an ice skating rink.
    They’re obviously cheap pedals which is fine, and composite is a good option these days, but anybody who keeps these pedals doesn’t ride offroad, or just thinks that having almost zero grip is normal.
    The Nimbus competition ship the version with metal pins on them at least.

I’d love to hear anyone else’s thoughts on the matter - is your RGB everything you ever dreamed of? Have you noticed anything similar?

I’m really not trying to just throw a load of negativity towards @qu-ax here as despite these issues it is a lovely unicycle. It’s fabulously lightweight (if seemingly a few hundred grams heavier than they say on the website, after chopping the seat post down a few inches), and I think that the spec they’ve put together is well considered and very practical for most riders.
I’m just a little disappointed having spent a big chunk of money here and it’s not as I expected.

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A picture of the crank-frame collision aftermath:

and the seat post anodising weirdness (it’s like this all of the way around):

The other things mentioned are much harder to photograph!


I’ve found the offcentered bearing holder thing weird too, but they seem to work just fine, so I’m not to bothered by it. Same with the bearing surfaces, but since the machined ones on other unis don’t fit too tightly either, I don’t find it a problem. (Bearing clamps on all unicycles are an engineering nightmare anyway)

That is weird indeed, I haven’t seen anyone else have an issue like that. Is the gap even on both sides? I don’t own an RGB frame, but I know a good amount of riders that have one, and they didn’t experience clearance issues (I think I would have heard of them). I’m interested in Qu-axs opinion on this.

The crap pedals (and brakes) are something I hate too, but for me, I’d probably replace them with something I personally prefer anyway, so I guess I’m happy they deliver it with the cheapest possible. (On their website Qu-ax has options for metal pins, I’m not sure why that isn’t the standard on UDC.)

The rest seems like pretty “normal” quality control issues that happen with overseas manufacturing, although you have gotten an example with quite a lot of them. I’d generally lean toward sending an email to the manufacturer/supplier first to give them a chance to resolve it before making it public, but maybe that’s just my own opinion. (And send them an email before ordering if you find conflicting information…)


my 24 Qu-Ax aluminum from 2006 already has such design … I was a very big issue and the wheel could not turn freely. Triton as well but I told them and they modified the design, no more issue with Triton

Yes, the gap is even on both sides.
I suspect in this case I may just have been unbelievably unlucky when I had my UPD as the marks on the frame suggest that the crank was also perfectly inline with the frame leg.

I agree to an extent, but the majority of riders that I know use the stock components for not knowing any better. I don’t think a MUni like this shouldn’t be offered with these pedals as an option.
On the brake, I’m OK with that one as it works and with the 4 finger lever it’s surprisingly functional. For most riders it will be enough. I’m not bothering to change it yet.

On the conflicting information, I didn’t realise until I went back to check why I’d received 145s - that has been fixed on UDC’s website this morning.
On emailing the supplier/manufacturer, I didn’t email UDC with these other issues because they simply opened the box, added some additional parts that I ordered and then sent it on to me.
While I accept that some of it is perhaps a typical QC issue, some of it is clearly not. How the bearing holders look is down to how they manufacture/process them. The fact the brake mount doesn’t fit properly is because they didn’t design/make it quite right.

Am I expecting too much at this price? It is the single most expensive unicycle I’ve purchased, and although I accept that inflation is a thing, almost all of my other unicycles have been KH, and practically perfect in fit and finish.

I recognize this too, but forcing it into place was not too hard.

I ordered directly from QX and had the option to choose out of 6 different pedals of which at least one set has metal pins. So I’m not sure where you bought it, but this is a configurable option.

I have it setup with 137mm cranks and weigh 1,5 times your weight, yet I had no issue at all with the cranks being able to touch the frame. I can’t remember the cranks even being that close to the frame… Maybe the wrong spacers were used?

I don’t have my frame anymore, but the only thing I didn’t like about it was the color range. For the rest it’s very light and compared to my M41 frame I would place the M41 frame in a downhill uni and the QX frame as a XC uni (at least for someone with my weight).
But that’s ok I guess. You can’t expect every manufacturer to have the same targeted audience…

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So on the frame-crank collision I’m still having a hard time believing it myself!
Putting it on the floor and applying a moderate amount of pressure, it’s definitely not out of the question that it could happen during a fall (flex wise), but just the fact that the stars seemingly all aligned is hopefully the worst luck I’ll have this year.

With 137s it would be even more unlikely as the frame obviously flexes out more as you go up it.

The spacers are definitely there and correct (I believe they only supply one length - they’re stock as Qu-Ax supplies).

On the pedals it’s perhaps more down to UDC choice as to what they specified in the ones they got shipped over, but I remain unconvinced that these slippy plastic things should be an option. Even the cheap £5 plastic Wellgo ones I just got from UDC have more grip.

Depends on what you mean by that. Should Qu-ax to take care of some of your issues (the crank hitting the frame, and the anodizing of the seatpost being visibly weird)? Yes, absolutely.

Can you expect to never ever get a unicycle with minor quality issues? No, I think (unfortunately), it’s just a problem that you are going to encounter with mass produced products, especially at the sort of mid level where unicycles live - big enough to be manufactured in relatively large quantities, but by far not big enough to have a seperate Quality Control departement.

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So after a day of thinking about it, some sleep, and some time spent pondering while repairing a pile of other unicycles I’m going to admit that I think I’ve perhaps been a bit too harsh here.

The crank-frame issue I think I can only put down to bad luck. The zero-q side of things definitely has its advantages, and without widening the whole stance (or having more than one model of frame), it was always going to be close here in order to support the width of tyre that you can get in an RGB.
I can still count the number of rides I’ve had on the unicycle on one hand but I’ll be sure to update everyone if it happens again!

On the surface imperfections - it’s a shame but I’m again going to put it mostly down to bad luck, and it doesn’t sound like issues are widespread from others I’ve spoken to here and elsewhere. Anodising is tricky to get perfect.
Qu-Ax has also moved to machined bearing caps on their QX RGB square crown 19" frame but David assures me it’s significantly more expensive to do - which seems clear from the €20 bump in price! I guess time will tell how well the off-centre mounting affects the bearings on my wheel.
I have grabbed by feeler gauges and calipers to see if I can quantify the apparent change in parallelity or if my eyes are just playing tricks on me.

The brake mount was apparently made for a different seat initially, hence the non-ideal fit into the KH handle on the Qu-Ax Eleven saddle - production run sizes no doubt stopped this being redesigned again for this saddle as you can make it fit.

On pedals, I’ve moved to my old faithful Nukeproof Electrons and the whole unicycle is a completely different beast.

And just to be transparent, David from Qu-Ax has emailed me directly regarding this thread.


Insane the crank touched the frame. Is the frame that flexible?
I’ve been pondering getting a 27.5 RGB for a while but that puts me off.

I definitely wouldn’t call it flexible, but there is some flex like all frames. Most unicycles however don’t have the end of the crank within a distance of a few mm of the frame.
It also does seem like I’m the first person to do such a thing…
Riding it, it feels stiff and responsive, especially with how lightweight it is.

If I had another 27.5 I’d do some side by side testing. Perhaps I can take a look at my old KH29 frame some time and see how they compare - they’re probably pretty similar in height.

I’ve got three gripes about mine.

  1. I don’t like the seat. There’s way more curve there than I’d like and the boys don’t like it.
  2. Mine came with 137mm cranks and no option for 145s. For me, I think 150’s would be ideal, but you’d think they’d have a bigger variance in crank options.
  3. Yeah, the pedals suck. I’m just getting used to repositioning my feet as I ride, so originally I liked the way I could just slide my feet around as I rode and get them in the right position. With the metal studs on the Nimbus it seemed like my feet were glued in place. Unfortunately, having only recently learned to freemount, they usually seemed to be glued in the wrong place.

Other than that, I was impressed with it. It’s very light, the crank setup does seems to be an improvement over ISIS and the seatpost also seems very solid and very light. So far the brake has worked fine for me. It’s much better than any mechanical disk brake I have ever used and better than any rim brake I have used with a wide rim.

Oh, interesting. And changing the angle didn’t help at all? What size RGB did you get?
I quite like the seat despite normally riding a Fusion One, but I’ve ridden for quite a lot of years on classic Fusion Freerides and similar KH seats so perhaps I’m just more used to the shape.

Are you in the UK?.. :wink:
They have a pretty large selection if you buy from Qu-Ax directly, but that wasn’t practical for me due to the import duties I’d have had to pay.

Have you replaced them now? If so, what have you gone with?

From looking on the Qu-Ax website, seeing as most of the options are no additional cost - I think the basic option should be the QX-Series Cross with nylon pins. That’s a genuinely good pedal and although not quite as grippy as the metal pin version you could happily ride that off-road (and I do on identical shape pedals from elsewhere). Although UDC no doubt pay less buying in bulk with the Qu-Ax cross option as the pedals themselves are sold for half the price.

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I’ve adjusted the angle of the seat, but I still don’t like it. All the way tilted up seems to be the best aa I can ride with my butt more hanging off the back of it. I find the Nimbus stadium saddles to be more comfortable, at least for short rides.

I’m in the US and the only cranks I was aware of here were the 137 and 145s and 137s are what come with it.

I haven’t yet replaced the pedals as they’re currently adequate. As I get better at repositioning my feet while riding I imagine I’ll switch them out. The Nimbus pedals with the metal studs do an excellent job of keeping my feet planted, but I have to actually lift my feet from the pedals to move them which is something I’m still clumsy at. On the Quax I just wiggle my feet around until I’ve got them in the right place. So for the time being, the Quax pedals are easier for me to use.

That’s interesting, but just shows how difficult it is to please everyone. I’m not a huge fan of the Stadium saddles!
I long for a time where unicycling is popular enough that I can pop into a local cycle shop and try different unicycle saddles…

By the sound of it, the 137s are the standard and mine with the 145s is more unusual and built up that way because Qu-Ax was short of 137s at the time.
No doubt in the future as UDC everywhere gets in more stock of Qu-Ax parts and the Q-Axle hubs become more popular more options will be available locally. In the UK I can weirdly only buy 89mm and 100mm separately right now - both of which are just a little too short!

What shoes do you ride with? I find that grippier pedals with pretty smooth somewhat flexible soled shoes (5.10 freeriders with a stealth sole here) works better than less grippy pedals and shoes with lots of grip.

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I’m not sure I really like the stadium saddles either as I notice that after about 2 miles on one they also aren’t very comfortable, but its a different kind of discomfort. With the stadium saddles its more a matter of pressure and numbness after 15 minutes in the saddle. The fusion saddle feels better in that regard, but it seems to frequently crush my testicles.

I’m using specialized 2fo mountain bike shoes and they seem pretty grippy.

I’m not sure this can help but regarding the spacers Qu-ax website states that the grey ones (4.8mm wide) are dedicated to ZeroQ cranks (which are black) and the black ones (5.8mm wide) dedicated to Q-Axle cranks (which are grey).
The matching colors is a bit counterintuitive and I wonder about the fact that the spacers for ZeroQ cranks are intended to be 1mm narrower than the ones for Q-Axle cranks. This makes perfect sense in order to reduce the Q factor but could also marginally create a too small gap between the cranks and the frame.

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I’ll measure later and report back!

There are a few more problems: These unicycles are very badly spoked (mad4one and nimbus too, by the way).

QAxle unicycles have loose spokes on one side, they are far too little tightened. The wheel is also not exactly in the middle, but slightly offset. The ball bearings are not good either and the plastic pedals are a joke.

But as far as I know you can configure the unicycles yourself and choose other pedals if you buy them directly from QUAX. I have the feeling that the unicycles (various brands) have gotten worse in terms of quality.

The fork is way too flexible. You can easily squeeze the fork ends together a little at the bottom. This means that the frame twists when driving uphill and, under certain circumstances, a tire touches the inside of the fork

I think it’s best if you assemble a unicycle yourself from individual parts and spoke it yourself.

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So I can’t say I’ve noticed any specific issues with the wheel. It’s pretty true, pretty evenly tensioned (in a dished wheel one side is always going to be less tight than the other), and pretty close to the centre of the frame.
Unless you pay for either UDC or your local bike shop to build your wheel you’re not going to get anything other than a hastily built up wheelset though. They’re probably all machine built and trued.
It’s something that I always check and re-true after a few weeks of ownership anyway. It’s not something I think we can complain too much about for the price.

I do wonder how good a set of bearings you can get for reasonable money in 24x42x12. No ball bearings that come with unicycles are particularly good quality, but perhaps due to the lower volume production of this size cost is prohibitive for nicer units.

Is there a frame where you can’t do this?