Checkout my cool full suspension MUni, hands up who wants one?
sweet lord that is an awesome muni.
Wouldn’t the rim have to flex? Looks fantastic tho! Well done
Heh, cheers mate… unfortunately this model wouldn’t quite work. I think it needs hinges between the hub & the rockshox or/and (as you say) flexible rim but it’s just an idea. Here’s a closeup.
Thats really cool Pete!
When I clicked on the thread I thought it was going to be another person asking if you can get suspension unicycle… but I was pleasently suprised with your pic!
WHOA thas friggin tight! I want one! Nice model too man, what program did u use for that?
Is it Cinema 4D? Did you do it from scratch? If so, how long did it take?
The problem is that the spoke force is tensional, not compressional. So mabey if the piston shafts were flexible and had a pulling shock absorbtion, it’d work. The biggest problem is the rim’s not strong enough to handle most muni riding. It’d taco on the first hop.
Pete that’s awesome. If it works I definitely want one (raises hand)
Any engineers out there able to comment?
Agreed, Pete that’s an awesome graphic. VERY nice work!!
From an engineering sense there would need to be hinges at the hub end of the pistons. Assuming the rim was strong enough to hold together as a semi-rigid hoop (heavy, but possible), then think of what happens when you squish the wheel down. The bottom spoke compresses, which is fine, but the upper two spokes aren’t pointed in the right direction so they can’t. If the upper two shocks can’t pivot at the hub then the pistons will jamb sideways in the cylinders.
Ok, so let’s imagine that the hub ends of the rockshocks are pivoted. Now it has beautiful suspension action. Sure, the rim has to deform a bit, but there’s a lot of room for deformation so it could be done without any catastrophic failures. What happens when you pedal?
If the hub ends of the rockshocks are hinged freely then the hub can spin a bit within the wheel. If it’s really free then the hub could rotate 30-40 degrees in either direction without sending any torque to the rim. This would be really bad. The unicycle would not be ridable. So purely free action is out too.
There might be a way to compromise. Perhaps use hard rubber bumpers on either side of the hub hinges so that the spokes don’t rotate around the hub very freely.
As Edison said, invention is 1% inspiration and 99% perspiration. Most people don’t ever get to the 1% bit. Pete, you’re well past that part. Keep at it and you’ll get to a ridable machine. Once you do can I take it for a ride?
Would more shocks help the strength issue? How about welding “spokes” that go across the diameter of the wheel without hitting the hub? I don’t know to much about the physics of this, but it looks like a real cool idea.
I like the idea, very novel. I designed a couple of unicycles to isolate the wheel from the cranks a year or two ago. They only ever made as far as the back of an envelope, not on to CAD and certainly not into prototyping. It all started to get a bit complicated.
Anyone remeber the Tioga (IIRC) disc wheel that was laced up with kevlar string (again IIRC) to give a form of suspension? This design reminds a bit of that. Might go and look it up.
Edit: Found a picture of it here:
So I didn’t dream it
Hey Pete, good idea!
It’s cool to see that I’m not the only one who want to push the limits of the MUni designs.
I’m a student in mechanical engeneering, and I had a conception project about a fully suspended unicycle.
The design I came up with (after more than 10 other models), is way more complicated than yours. But one of the rejected design was similar: instead of the RockShocks, it had curved metal plates (like a trailer suspension) disposed as spokes.
We will soon be producing a prototype out of the final design. Since nothing is machined yet, I don’t want to show the complete 3D model. But you will certainly hear of it when it’s done and after we had tested it severely.
Here’s an overview about what we started with:
suspended unicycle.txt (3.54 KB)
(Sorry for the crappy link, this is what I meant)
SUSPENDED UNICYCLE PROJECT
The project was designed to improve the mountain unicycles used in very technical and rough terrains. For the first prototype, we are going produce it from basic steel. If the feeling of the design is good and we want to continue with the idea, we are going to make another prototype correcting the possible mistakes made on the first one and make it from chromo and aluminium.
PRINCIPAL OBJECTIVES :
The proposed solution should be adapted for downhill utilisation. The suspension system should help to gain control and stability, which is necessary for that type of practice, and by the way reduce fatigue a little. The solution should be light enough and resist to the conditions met in unicycle downhill.
ESSENTIALS CONDITIONS :
The proposed solution should:
·have a suspension system, adjustable from 3 to 7 inches
·permit the use of some standard parts:
-26’’ wheel with a 3’’ wide tire
-6’’ disc brake conformed to the SI standard
-27.2mm seat post
-Profile crank arms
-Standard bicycle shock
·resist to the abuse of a 190 pounds load from a 12 feet drop
·resist to impacts inherent from the practice
·not weight more than 25 pounds for the total assembly
·reduce the effects of pedaling on the shock
·permit to the distance between the saddle and the cranks axle to not be affected by the suspension
·permit the alignment between the saddle, the axle and the wheel to be the most constant possible trough the suspension path
·permit the propulsion to work like a standard unicycle, without play between forward and backward
·permit saddle height adjustment from 21 to 27.5 inches (from the axle to the top of the saddle)
·not cost more than 2000 CAN$ in material
·have to lowest profile possible
I would be very interested to see how you guys figured out how to do this. Not only because it would be fun to ride one, but I like mechanical things. You have any idea as to when you will show your designs?
That looks like an enormous amount of work. Design, mostly. There seem to be so many problems, but I’m optomistic!
That was a great graphic. Too bad the concept doesn’t work, because if the suspension can be in the wheel, the rider has a chance of having his feet, not just his butt, isolated from the bumps of the trail. That should be the goal of a suspension system for MUni.
The obvious challenge is to make something that will allow the wheel to deflect, or deform, without weighing a ton, and while not interfering with the transmission of drive force to both turn and stop the wheel.
Sorry, I don’t have any bright ideas at the moment…
I’m thinking if some one designed a slow-rise suspension peddle and a suspension seatpost, you could just put both of those on any unicycle and turn it into a full suspension. I know it wouldn’t take any preasure of the wheel put it would take preasure off your ankles and back. I don’t know that’s just my Idea.
Re: Suspension MUni
In article <johnfoss.16f5bv@NoEmail.Message.Poster.at.Unicyclist.com>,
johnfoss <johnfoss@NoEmail.Message.Poster.at.Unicyclist.com> wrote:
)The obvious challenge is to make something that will allow the wheel to
)deflect, or deform, without weighing a ton, and while not interfering
)with the transmission of drive force to both turn and stop the wheel.
What about in the hub? You could start with a design like Blue
Shift’s hub, and instead of having gears in between the central axle
and the secondary (spoke flange) axle, you could have small
piston-type shock absorbers. If you ran them fairly tight, they
wouldn’t affect handling too much.