Cracked kh frame question

Time for a new frame, or can it be re-welded or braced? I’ve had this frame for a good 4 years now and have ridden the heck out of it, so it’s probably just time to buy a new, improved version of the kh 24 frame, but I’d still like to know if this one can be adequately repaired, so I could at least keep it as a backup.

frame crack.jpg

You could have it repaired. But aluminum will fatigue and at some point have failure from use. You might have other areas/spots that have also fatigued and will eventually also fail.


As a weldor, I would suggest getting it re-welded. Do it now before it gets worse. It should be easy and not too expensive. Get them to quote a price before you leave it so you will know if it is worth it. I bet the repair will last a long time or at least you will have a “back up”.

They will drill small holes at the start and end of the crack to stop it spreading and do a bead of weld over it. Looks like you caught it just in time.

Has the kh24 finally changed as I bought one at the start of the year and it saw the same old uninterrupted horizontal crown type, I thought it was only the KH26 and above that got the better crown (I have a KH20 as well that is the old style?

As I have already had a KH24 I got an Impact Gravity 24" and it is stunning so maybe time for a change?

Yes, all the newer/current KH frames have the butted seat tube that is enlarged near the crown. Thanks for the advice on getting it re-welded.

Here’s Jacob Spera’s KH frame with a brace welded on, as his frame had a similar crack in the same area. He had that spot welded as well.


Spera MUni.jpg

ahh is that all that was done, I though you meant Kris changed to the interrupted crown tube like the larger frames as although the thicker butted tube will help the load at that point it will just move to the crown horizontal tube and rip out there (which is where the other failures have been from pics posted on here).

I do want to point out that I am not having a pop at KH frames as I have had 4 and all have been perfect and it only seems it is the hardcore boys who break stuff :wink:

I am sure you could slip a nice impact frame into your KH family just like I did :smiley:


3 unicycles small.JPG

Dont use an impact frame if you like riding with wide tires. The clearance with a 3inch duro is barely anything at all. If your rim is bent you will rub against the frame. If you are wanting an aggressive trail uni then yes use the impact with a 2.6 tire and you will be fine. Besides that impact made their frames to skinny :frowning:

Perfect for a street frame though! Muni not so much

So how would this frame compare to the KH 24 for durability? We know the KH is 7005 T6 aluminum, but the only stats I could find on the impact is that it’s “alloy”. The Impact frame weighs 690g or 1.5 pounds. The KH 24" frame is only slightly less at 670g.

The frame is stronger I think. You have less flex on it and the way that the seat tube is attached to the forks it wont break like the KH. I have only seen one rider break the impact frame and this was on a 20inch. I would be worried about denting the impact more than anything since it has large flat surfaces. But then again I would never ride that frame for muni…

I would be using it only for super steep road climbing, (25%+) so I’m building the wheel (24") as light as possible, hence the M41 (ISIS) Ergal, (286g) 30mm wide Alienation Deviant rim (375g), intense 24 x 1.75 micro knobby tire, rated at 100psi (410g). Hub tire and rim together weigh only 2.3lbs. Add the frame at 1.5lbs, cf based saddle, thomson seat post, utlra light cranks and pedals, spokes & nips, tube and rim strip, and the entire uni should weigh in at under 8lbs! It would look pretty sweet with the impact frame.

8lb ! Look at this !

bunch of gravity

Wow! What a thing of beauty! Is that a hard rubber tire or pneumatic?

Ahhh stupid website lost my post ahhh

I saw the video of the 20" Gravity snapping but he did have 1" of seat post in the frame :stuck_out_tongue:

My 24" Trials/muni/street build is only 5kg / 10.2lbs so I am sure you can trim more fat off the wheel

The large flat legs are concave on the inside faces and have a raised section on the outside giving a very rigid leg, the larger seat tube butt and wide legs gives a large welded join again making for a very strong interface.

For hill climbing don’t you want one of the 24" racing unicycle frames rather than the burly/heavy MUni orientated ones? Or maybe easier to buy a complete uni?

impact gravity 5 small.JPG

impact gravity 4 small.JPG

Nah, when complete, my new 24 climber will be around 3.65kg, or 8lbs. The problem with the racers is that the frame is too narrow and won’t fit the standard 100mm hub, which I wanted for more stability. I also want to have the option to use the frame for MUni, so I can put it on my other MUni wheelset once in a while. Plus, I want the maggie bosses so I can have rim brakes for the descents, which the racer frame lacks. The final factor in choosing my setup, is to have a light, narrow rim/tire combo without going so insanely skinny that I won’t have as much stability for climbing 33% grades, and it would be very dicey for doing corrective balance hops on a rock-hard tire!

pneumatic but “can be” tubular.


The seat tubes only go through the crown for 26" and up. The 24" and 20" don’t because minimum saddle height isn’t much of an issue and they are stronger this way.

i don’t know where the pictures are at the moment, but when mine broke (completely off) i had it re-welded on and i had the welder make some brackets like are on the bottom of the fork. it still looks good, and is much stronger. mine has been fixed for 3 or 4 years. it is the 19" trials cycle

Silly me, turning the seat post clamp 180 deg so I could mount a Garmin Rear light/Radar… Frame is cracked… could be from the impacts of the aerobars onto the ground

Photos from riding along the Arakawa River which runs thru Tokyo, Japan

I was advised on this forum to use a brace for the Aero bars, and I guess this is the result of constant fatigue on the aluminium from the aerobar…in normal use and UPDs.

I think I have a quick fix to this.
I might get a second KH seat clamp
(KH Frame would have to be ordered from UK, none in Aust UDC)
File off the “stop” on the internal diameter of the seat post and slide it down over the crack.
Also postion a bar that connects the two seat posts and is just the right width that fits in gap while seat posts are tighten up.

If you got this far, thanks for following my “ramblings”

If you have enough seatpost left, cutting below the crack, drilling and making a new slot might also be a good semi temporary fix.