There we are 
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Thanks. As i said, i was really lucky. It was very close to disable me but only the muscles were affected and they are fast to heal (tendons canât). My main aim in this post is to raise awareness to the dangers of this rotor. It may be better to open a new thread as it seems to me the message will soon get lost in this thread,
I managed to move the lower half of my rib cage while hopping down some stairs at university a few weeks ago. My eighth rib and the ones below it on my right side are now resting slightly behind the ones above them. The doctor said I would just have to let them work themselves out, but didnât tell me to stop riding. So far I havenât had any negative side effects from the daily riding I get around to.
Oooouuuch! That sucks! Just make sure youâre taking full breaths so you donât get pneumonia! Broken ribs suck.
That rotor looks like it was made from a circular saw. Aught to be recalled for being dangerous.
Damned right.
Udiron, your injury is a hell of a price to pay for a manufacturer attempting to be stylish. Looking at the severity of your wound, the potential for it to have been significantly worse and the extent of medical repair, Qu-Ax are wide open for possible law suits.
I hope the OP sent the details on to Quax. Until I saw it I would never have believed it, and now itâs so obviousâŚ
Thinking about it there is no reason for the outside edge of a disc to be anything but rounded, no 90 degree edges at all, (talking about the cross section of the disc)let alone teeth 
When I made a dinghy years ago (Opti) I read one boat builder never had anything less than a 10mm radius on all edges, saves the paint and the skin 
I wish crank designs were similar, always wacking my ankles 
Qu-Axâs reply (David Beckerâs)
I (and others) contacted Qu-Ax following my accident. Below is the reply I got without any modifications. I wonder what people in this forum think about his reply.
Udi
"Hi Udi,
about the functional benefit - well, itâs a rotor that has been used and made on bicycles for years. This kind of shape allows a low material use (less weight) with a biggest possible braking surface at the same time. As soon as it comes to weight - most rotors have such kind of shape:
http://www.justridingalong.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/h/o/hope_rotor_quick.jpg
http://fcdn.mtbr.com/attachments/brake-time/319822d1198076123-hope-floating-rotors-bling-gsrr1.jpg
http://www.bmtbonline.com/WebRoot/Store10/Shops/61513316/475E/0130/6D80/7D69/063D/C0A8/2936/E6C0/ARO-03_web.jpg
http://images.evanscycles.com/product_image/image/8f7/3d6/167/57316/hope-2-4-saw-floating-rotor.jpg
http://fcdn.mtbr.com/attachments/weight-weenies/449685d1240171791-alligator-serration-rotors-what-advantage-ti-nitrite-coated-version-blingle-010-large-.jpg
http://www.woollyhatshop.com/images/uploads/Disc%20Brake%20Rotors/a2z_rotor_version_2_nobolts.jpg
From this ^^perspective itâs also not so much looking like a saw - itâs not pointed - comparing these to a saw-blade is like comparing a ruler to a knife. A saw blade is sharp, thin and pointy. None of this is the case for this rotor - a bicycle-chainring - which is mounted unprotected on every mountainbike at the same place is more sharp and dangerous - I have a 5 cm scar of such a part on my calf, too. When you pedal standing on a bicycle and the chain breaks - you have a simmilar situation - with a chainring in your calf.
People are discussing about saw, shark-teeth and ninja-weapons never had this rotor in hands - they just judge from the appearance.
For sure nobody likes this kind of accident, but it would be an endless discussion what kind of cut would be deeper or worse, depending on the profile of the rotor. We can discuss if mounting the rotor inside or outside the frame is more or less safe, but when you see a bicycle: it has the chain wheels outside, and here we talk about real teeth, so what to do there? Change to belt drive, or use a chain guard for a DH Bike?
As Lutz said already - itâs a dangerous sport, riding a unicycle with a disc-brake - and especially if you are not so experienced with it and you ride the rotor on the outside-mount at a place where normally thereâs a chainring - wearing protective gear is compulsory.
I hope you still like this sport and wish you to recover soon.
Regards,
David"
Qu-Axâs reply (David Beckerâs)
That sucks about your leg being cut open. Hope it heals fast. Glad it wasnât worse than it is.
My opinion on the Qu-Ax rotor may not make you happy.
I think anybody looking at that rotor would say âman, I would hate to fall on that thingâ You probably got told that more than once by people. Not wearing the correct protective gear and then trying to put the blame on the manufacturer after an injury like this is wrong.
Totally sucks you got hurt, but protective gear would have prevented this completely.
Just for perspective, I have the alligator serration (or windcutter) rotor on 2 of my unis - both for road use. That is the âtoothedâ rotor in the 3rd link in Udironâs post.
There are a couple of KEY differences between it and the Qu-ax rotor in question. First, the ends of the teeth are quite rounded - not sharp at all. Second, the edges are slightly radiused - not sharp at all. Finally, and this the the big one, the teeth point the opposite way as the Qu-ax rotor. The direction of rotation is along the curved surface, NOT âpoint firstâ. (This is true of the Hope rotor too!)
I take no position on whether or not the Qu-ax rotor is safe, whether there should be recalls, or any of that. But, it is somewhat disingenuous of them to show the other âtoothedâ rotors and say that theirs is just like those. There are several pretty big differences that would seem to impact safety quite a bit.
That said, Iâm not sure a rounded rotor would be a lot better if it had a sharp edge. Most of my kitchen knives are âsmoothâ, but do a pretty good job of lopping off the ends of my fingers on occasion.
Im quite surprised at the response. The fact of the matter is that there is blood on the rotor. If the damage was just burn (as is likely from a non saw rotor), there wouldnât be any. Yes there has to be a degree of buyer beware with the way we use components, but to sell a brake set with such a silly rotor to start with is pushing it a bit for me even when hub mounting it (same injury just as possible).
Most disc rotor designs for bikes are just that, designs. To me the rotor looks like it would feel horrible under heavy braking and be prone to sticking. I personally would hope to see a different rotor in subsequent batches of unicycles produced.
The sad thing is that i just went looking for the rotor online. It seems to retail in around the ÂŁ20 range! The is no possible justification for the price point when in competition with things like this with more direct alternatives less than half the price.
First Off - healing vibes to udiron.
That said I donât think the Qu-ax response is that far off base. If the rotor is mounted inside the frame like on a Qu-ax or on a bicycle (for which it was intended), not only does the frame or fork protect your leg but the rotor is also tighter against the spokes which would not have allowed your ankle to fall dead middle over it.
IMO if anything should be recalled it is the Moment cranks. While I agree the rotor looks somewhat angry it is likely most any profile of rotor would have inflicted similar damage.
If it was a little kid, my opinion would be different. The hairy leg in the picture is not a little kid. I also believe the design is more for a visual wow factor than for weight savings.
I am not saying that QuAx should go recall and change everything. Only that I would hope that in the future they move towards a more conservative rotor design.
What really surprised me was the âits not our problem, heres some other rotorsâ tone, this may be partially caused by language barriers and the format of the response but still is a bit off. It would have been more productive to be less defensive and explain what steps will/have been taken (i understand udc stopped selling them loose) and send something like chocolates by post.
Remember TRP recalled the Spyre over a single cyclocross incident where someone partially lost braking due to overly worn pads before a harsh race. Just because it is a minor incident this time doesnât mean that it wont happen again possibly with more serious concequences.
That is an appalling response from Qu-Ax. The author represents absolutely no responsibility being taken by his company.
The author makes reference to the use of what he contends to be similar rotors on bicycles. This is irrelevant as, of course, those rotors are sited well way from the lower leg.
He further makes a specious analogy between Udiâs injury and a reference to chain breakage on a bicycle exposing a riderâs lower leg to the then exposed teeth of chain ring. The fact remains that the matter at hand is not about unpredictable incidents of any given bicycle but a âsawtoothâ shaped rotor supplied both as a component and on complete unicycles sold by Qu-Ax (eg, 24â QX disc muni), a manufacturer he represents. The rotor is not covered by a chain that on a bicycle may or may not break.
The letter seeks to essentially avoid the real and obvious issue: Udiâs injury was explicitly caused by a rotor supplied by Qu-Ax and used on one of their own products.
I suggest Qu-Axâs supply or installation of the rotor on a unicycle where point of difference over competitors overrode ultimate consideration of customer/rider safety was ill-judged at the outset. Udiâs significant injury bears this out.
To contend broadly that any riding of a unicycle is inherently dangerous in an attempt to avoid responsibility on Qu-Axâs part for a significant injury caused by one of their components is a most unsatisfactory response.
Rather, in the modern age it is a manufacturerâs responsibility where injuries occur that are explicitly caused by design elements of their products to react with significant regard for that consequence. In this case it was the rotor: not a crank, a seat, a frame, a tyre, but the rotor. Moreover, it was an injury attributable only to the rotor over any other components on the unicycle. That fundamental fact should be reflected in any response to someone who was thus injured and form a platform for revision of their product in order to avoid future incidents.
Take a look at vehicle products of the past, be they cars, trains, planes, etc in comparison with those of today. Manufacturers continue to go to great lengths to utilize components that are designed to avoid injury superimposed upon the risks inherent in using the product. One factor in this approach is that millions of dollars are at risk by way of compensation paid to those who have sought legal recourse for injuries resultant from manufacturing oversights or neglect. Equally, many industrial products are recalled every year due to concerns raised by unsatisfactory design/performance and consequential harm, both potential and actually, caused to end users.
My suggestion is that Qu-Ax fails in this respect with Udi suffering the consequences. Quite apart from whether or not someone chooses to ride the unicycle, clearly the rotor offered to a competitive marketplace places a rider at exponentially increased risk of the sort of injury Udi sustained. This should be of significant concern to Qu-Ax.
Any suggestion of finding fault with the victim is well wide of the mark. The fundamental question remains: is the component as supplied to consumers definably dangerous? Clearly, it can be argued this rotor is, and unnecessarily so. Jona, it is not a matter of blaming the manufacturer. It is about a manufacturer being notified of; a manufacturer making recognition of; and a manufacturer taking due responsibility for an injury caused by their product.
It would be most interesting to know if Qu-Ax supplies an advisory notice along with the rotor or a unicycle that includes the rotor in question stating that the wearing of leg protection is âcompulsoryâ as the letterâs author asserts. If not, from Qu-Axâs position to rely on such a statement would potentially see them on shaky ground. If they were to include such an advisory, to what degree would they state the protection needed to be?
In point of fact, Udi was wearing some protection, no doubt to prevent unicycling injuries. But, Udiâs injury was well beyond obvious riding injuries, pedal pin strike for example, and, to reiterate, a result of the rotor design. A ground can be argued that his physical safety was compromised by Qu-Ax.
We donât know if they are, but Qu-Ax should be all over a review of the rotor as a component on their products in recognition of what for them should be a sobering occurrence.
The authorâs comparison of his own injury, essentially minimising Udiâs injury, in a, âShucks, we all get injured, donât weâ, fashion is utterly unprofessional from any manufacturer. To additionally minimise Udiâs injury by mentioning âbetter or worse cutsâ potentially made by any given rotor is plain offensive.
I submit that Qu-Ax would do well to consider remedial removal of the rotor from their products. Taking that financial hit now could well avoid a much, much greater hit in the future.
I donât know in which country Udi lives or where the unicycle was purchased. But I suggest that, depending on provisions within any country or stateâs legislation and particularly with the Qu-Ax position as represented by the letter sent to Udi, anyone (including you Udi) would have reasonable grounds on which to investigate taking action based on any serious injury resultant from the rotor in question.
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Ammendment to above
Hi everyone
On review of Ubironâs original post on his injury, I realise some of what I have said in my above reply.
I failed to recognise that Ubi had positioned the rotor on the outside of the frame. My mistake.
I tried to edit my post in reflection of that mistake but was timed out. I have asked Admin to remove it. Some of the essence of what I stated remains my position but without the ability to successfully edit it, over all the reply is worded wrongly. I request you disregard it entirely without replying as some specific points I raise need amending or removal.
Pretty red faced here, so ask for your indulgence.
Cheers, KE
Tyre Burn!!
Not my worst unicycle injury, but definitely the one that happens most oftenâŚ
Tyre (tire) burn is damned painful, and seems to happen when Iâm tired/daydreaming 
No, I wasnât told that by people, including other unicyclists. I purchased the unicycle together with the rotor via our Israeli dealer. He didnât think of it either. This is the first disk brake I have ever had on a unicycle.
Obviously, after going through what I just did, I am looking at that rotor and thinking - âhow could I not think about thatâ. Well, I havenât. In fact, I wonder how many of those that own a QuAx unicycle with this rotor think about it. The main reason for my post is to let them know about my accident and having them thinking about replacing it as well as wearing full leg armor.
I canât say for sure what would have happened with a smooth rotor, but:
- The doctors at the hospital said that the cut looked bad due to the shape of the rotor (after looking at the rotor). Also, they told me that had I damaged my tendons and / or nerves, it would have been hard to impossible to fix them because of the way the jagged teeth cut an uneven cut.
- Even if a smooth rotor would cut me that deep (and I doubt it would), I donât think it would make such a long and deep cut. I think the shape of the rotor made the nature of the cut a lot worse.
- This is a very âdumbâ test, but nevertheless, If you hit that rotor hard with your hand you feel the âteethâ dig into your flesh. It hurts. I did the same âtestâ with smooth rotors and it didnât feel the same at all. This is obviously a very non-scientific way to draw any conclusions, but seems suspicious to me.
All this is my own personal opinion. I removed my rotor. If I ever use another I will surely get a smooth one (and probably wear full leg protection just in case).
The rotor was called at the time of the accident. It was a flat ride so I didnât use the brake at all.