This is my first post I wanted to share with you as I’m engineering a titanium carbon unicycle with the legs being made from a carbon fibre wrapped titanium tube I’ve made the frame crown and the seatpost fits in so i got it titanium 3d printed I’ll try and update you guys along the way anyway here are some photos.
Plastic 3D Printed Prototype.
Titanium 3d print:
Welcome to the forum. That is super awesome! Please keep us updated.
Thank hoping to have it completed in a couple of months just prepping everything and ordering getting stuff ready for when I can do it
Thats absolutely incredible. Good luck!
Why will you combine a Ti tube and carbon fiber instead of using either one of them ? Both carbon and titanium make for strong frames on their own… 
I was going to use carbon fibre on its own but it will be combined with a titanium tube because carbon fibre has quite weak compressive strength so when using it for trials and muni riding it will be more sustainable as most the forces are compressive by using titanium tube covered by carbon fibre I get the compressive strength from titanium and the tensile and 3 point strength from carbon meaning that the frame can be as strong as possible making it to be as rigid as it possibly can.
Love the work on the unicycle, and I approve of your avatar whole heartedly.
I wonder how rigid the connection between the crown and the legs will be. I assume it’ll be a press fit, with a bolt securing the leg. Is there a (ever so slight) taper on the crown side of the interface, or is it cylindrical? Or are there minimal ridges? Or…
Its going to be bolt fit just to line it up so i can get the lengths right and to hold it in place. then the titanium tube will be either brazed or welded onto the crown
I’m curious about the print. Did you go through a titanium printing service or do you have direct access to the printer?
Also to add, I love the uni 
Looking forward to how it turns out!
yes i went through JLC-CNC it was pretty easy and cheap for what it was.
i’m really rather interested to see how this sort of process turns out. i would expect the dissimilar materials to have issues playing nice in an application like that though
Alright ive had an idea as this is going to be mainly a Muni im thinking about using nimbus nightfox legs so i can change the wheel size on the fly pretty quickly along with it also being able to be strong enough and giving the titanium good strength ive just got to try and find out the diameter of the nimbus nightfox legs
Each time I look at it I see a sloth. Two eyes and a mouth. It‘s really hard o ignore, once you‘ve seen it 
.
You wrote that you will braze or weld the legs to the crown. That begs the question what the CF is for - after all the titanium legs appear strong enough as they are. Or are they butted, i.e. thicker at the end that will connect to the crown, so that the CF is only applied to the bottom part? Or did I get something completely wrong?
it was going to be a part of the tube where the inside has a small tube of carbon fibre tube while the outer is mainly titanium I was thinking about doing something like this
But it will cost way to much to manufacture and make only spent £120 on the crown so far but this will add way more than rather being £40 for the titanium tubes this would be around £150 so probably one of the most expensive unicycle frames. I have a tendency of overengineering things and making things to last a lifetime but that usually ends with things not being cheap this. As I’m in university I had to save just for the fork crown for a while but in the end it may not be worth it although it would be lighter than the pure titanium legs it would probably give the same end result.
Looking at it now it is £97 for the legs and £20 for the carbon fibre so the total price for the whole build including shipping comes to.
£180 including shipping for the crown
£117 for the legs
£20 for bearing holders
this means this frame costs a total of £317 for a frame that will probably survive any torture that goes into it.
also not the lightest frame ever comes to a weight of around Edit (calculated the actual value and is 650g)
Although it does look cool it is overengineered and a piece of titanium tube probably will suffice.
(BIG update) ive completed the frame doing tons of tests over the past couple of days here are some photos and improvements on the design. Its been made so that forces have been accurately calculated and been put on the frame to make one of the stiffest “lightish” frames out there using topology optimisation and tons of tests and simulation results. with reinforcements in areas that need it and doing tons of hours of studying the results and changing parts even calculating the forces to extreme measures that are put upon the wheels with simulated tests that where tested to 20 tons of force to see failure and areas that need improving.
Hopefully when I get the frame assembled and tested notoriously I will try to start a website and business to start selling the frames. This is if they past the testing results as its not guaranteed to be perfect on the first iteration. Now i just have to sell one of my unused unicycles to fund this.
Ah, I see, now. Looks really cool.
Follow-up question (but by now you were already expecting this, right): Are the CF and titanium parts already „sandwiched“ when the legs are welded to the crown? If so, doesn‘t the heat damage the carbon? If not, how do you sandwich the two components? After all a tight fit appears beneficial as far as sturdiness.
Anyway, very cool procect; crossing fingers it works out as you were hoping for.
Ok so its finished didn’t go for the carbon fibre after more refining and changing a couple things and got it sent off now its here just waiting on some bolts its held on using pressure fit the fork legs where put in a freezer while the crown was heated up its not coming loose but there is a bolt just to stop and twisting that will be put on with red loctite and some epoxy round the legs.
Your uni looks very good, well done, but I do have some questions.
I suppose for a road unicycle it doesn’t matter if it is a bit heavier.
Is that a 20" wheel?
Why didn’t you create a 26" version? A bigger wheel will get you further than a small wheel (says I who rides 10km on a 19")
Is the frame crown strong enough to handle a bit of hopping, since normally the frame is made in one piece.
As you were talking about shipping cost, do you intend to create more of them for those of us who are interested?
The final price would then be £317 + wheel (and cranks, pedals) + seat post + saddle. and in your case only space for a small wheel. That sounds a bit too much like a Collector’s Item unfortunately.
The unicycle is more built for street and trials riding making it as light but with the stiffest strength to weight ratio.the production frames would be welded just to increase the strength and stiffness of the frame but just for testing purposes and for me it will do alot still has to be refined and this is only the first iteration. Cost would also be high as these are one off and would cost about 600 pounds just to make the frame. But still testing and strength need to be tested in reality
