As I’m a keen hockey player I treated myself to a nice, lightweight KH20 frame. I know there have been quite a few of these fail (BROKEN kris holm longeck frame!!!; Another broken KH frame?; Broken KH frame…again, etc.) but I assumed that was all gnarly young kids jumping off buildings and doing 1080s. As a middle aged man riding riding round a sports hall I thought I’d be OK. I was just lining up to shoot when it just gave way and I ended up sprawled accross the floor. I finished the session on my 20 year old Sem. The cranks were too long, the saddle too short and its a bit rusty but it is still in one piece. Maybe they really don’t make 'em like they used to :). Now nursing a bruised knee, I’ve just rebuilt wheel from the Kris Holm into a cheap steel frame, it looks OK but not as a bling although I quite like the stealth black look. I’m pretty sure mine had no signs of cracking, in fact there was barely a mark on it as it was only used indoors, but it might be worth having a close look if you ride a similar frame.
If you only have done hockey and stuff like that, it is defenitley a design error! My KH fram has lasted really bad stuff and thers is NO problems with it. I’ve been riding it for about 2 years now. You gotta email Kris and tell him what happend!
The crown has been changed to stop that happening, like people have mentioned. Probably worth asking if KH or UDC will replace it, or at least give you a good deal on a new one - they seem pretty good about that sort of thing.
(But don’t tell them about all those 10ft drops and street tricks you’ve been doing in between matches ;))
I had a Nimbus hub fail on my muni (flanges came away from the axle) a couple of years back and just bought another one (I didn’t really consider four or five years of rocky, wet, gritty muni such a bad lifetime for a £30 part). I happened to mention it to Roger some time later in conversation and he said I should have told him - he would have replaced it. If you don’t ask you don’t get!
Mine broke the same way last weekend. It was before the upgrade on the seat post tube to address the issue. Not much to say…but it is probably time for both of us to order a new frame, which has this issue fixed.
I am considering welding it. It would really need heat treating after welding to bring it back to full strength and probably a gusset added as the metal is pretty thin. Overall it probably isn’t worth it.
Yeah, no TIG welder yet, but I’m searching for a used one I can afford. I do have a MIG welder; you can do aluminum with MIG, but it requires a different gun, and a different spool of wire (obviously, aluminum), and a different bottle (pure Argon instead of Argon and CO2). Hardly anyone uses MIG for Al – it isn’t worth the setup time, and the welds don’t look as good as TIG can.
The thread title makes it sound like its new that frame is from 2005, so maybe constant use for 6 years could do something like that to an aluminum frame.
Mine, but without reinforcement. It lasted less than a year after I dot it re-welded, but I rode it really hard, I always ride my unis really hard, but this one was the one that took the most beating in all my uni frames I think. It was an awesome frame
Its by far the newest unicycle I own and being in two parts is a new feature Its had a few hundred hours riding, always indoors, never jumped, rarely dropped. I’d expect it to last longer.
If this was a cheap frame that had been heavily used then I would say fair enough but it was a top of the range frame that has had pretty light use. Funnily enough when it broke I swithed to my old Sem which is a cheap frame that has been heavily used and it still worked fine:D
The lifespan of this aluminium frame was pretty short. Its certainly not an issue that has to plague aluminium frames, I’ve got a 15 year old mountain bike frame that’s still in one piece and there are thousands of older MTB frames out there.
I agree that lifespan is not something that should be much of an issue for aluminum frames, given the lower load on uni frames than bike frames (even in the super agressive riding styles).
On a higher-end frame the trick is getting in right in terms of the balance of strength, durability and weight - how strong is strong enough without being redundantly heavy.
Since 2005 there’s been a lot learned and several generations of KH frames.
In the crown, the bottom of the seat tube is now butted - tubing sidewall thickness is about twice as thick as the 2005 frame, and this also allows the seat tube to wrap further around the horizontal tube in the crown. The horizontal tube is about 30% thicker. Nothing is indestructable but these changes have made frame failures rare compared to the number sold.
now use a shaved try-all 
that frame is from 2005, so maybe constant use for 6 years could do something like that to an aluminum frame.