Hi,
I am researching frame materials for a muni frame.
Can anyone point out tubing that they wouldn’t
recommend for a Muni frame?
Along with that, I might ask also, what type of
frame design should one not use for muni?
While I am at it, anyone have any preferred heighth for top
tire clearance over a 24" x 3.0? I don’t see much mud.
Thanks,
Work the maze.
>I am researching frame materials for a muni frame.
>Can anyone point out tubing that they wouldn’t
recommend for a Muni frame?
-Rubber: too wobbly
-Polystyrene: light but too brittle
-Wood: Flammable
-Glass: Might shatter
Seriously though, I would really like to see a titanium Muni because of:
-strength
-light weight
-cool factor
-drool factor
-don’t need to paint it (no paint to scratch)
Re: Frame Materials
Check out http://www.extreme.unicyclist.com/
Look for Dan Heaton’s titanium?!?!?! Monty
glass would be bad but a uni made out of bullet proof glass like those new pedals atwww.atomiclabs.com sure would be nice
Anything that is a liquid or a gas at room temperature should be avoided. Metals that melt at about body temperature (cesium, rubidium) would be interesting but are highly caustic. Materials which burst into flames when exposed to air or water (calcium, sodium, potassium) would be challenging to ride but expensive to maintain.
Substances that are imaginary are always the best. They are cheaper, stronger, lighter, more attractive, and in general are self-machining, self-welding, and self-assembling. Finding them in stock is usually a problem.
RE: ?'s on frame material not for Muni
> Can anyone point out tubing that they wouldn’t
> recommend for a Muni frame?
Seriously, a unicycle frame gets less abuse than a bicycle frame. As long as
the stress areas are adequately covered, you don’t need to go outside of
bicycle science to find the right frame materials.
> Along with that, I might ask also, what type of
> frame design should one not use for muni?
You want something with a sensible bearing attachment, preferrably with an
easy way to remove the bearings/wheel. You don’t want it to be too wide on
the outside as it may bang your knees. You do need it to be wide enough on
the inside to accommodate the fattest tire you would ever use, with extra
room for mud on it. Also be aware that some frames flex, making tires touch
the sides if they don’t have much clearance. Make your frame rigid enough to
not let this be a problem.
Good luck,
John Foss, the Uni-Cyclone
jfoss@unicycling.com
“We were discussing Big Mac Meals. I think that has little if anything to do
with cow parts. There are probably more UNICYCLE parts in a Big Mac than cow
parts.” - Greg Harper on cuisine
Seems like we should be able to tie this back in with the Twinkie thread, but… nope, I just can’t do it. Sorry.
Christopher
Re: ?'s on frame material not for Muni
in article jagur.2uqma@timelimit.unicyclist.com, jagur at
jagur.2uqma@timelimit.unicyclist.com wrote on 4/9/02 11:49 AM:
>
> glass would be bad but a uni made out of bullet proof glass like those
> new pedals atwww.atomiclabs.com sure would be nice
>
I think you mean Atomic Laboratories at http://atomlab.com/
Looks like some nice products, I’d like to try out some of the pedals on my
'bent as well. I have to say, the web site is rather annoying - very busy
and heavily infested with Shockwave.
-Carl
Oh, the wit and humor that pervades the unicycling world.
You guys are just too funny. Ya’all should be on a stage…
Oh, and did I say, there is one leaving in 20 minutes. Duhh,
no that was really funny.
oh, I am so funnie. Uni- dak look
out and Jagur, my humor is the bestest.
All right, so much for my jokes.
Seriously,
I should have asked which tubing to use. I know there are different types of tubing and shapes of tubing out there, i.e. 4130 cro mo or other, or oval tubing verses cylindrical. What about diameters. I was looking for recommendations on those types of materials.
Someone mentioned frame flex. What is causing that? I want to
avoid that.
Thanks
RE: ?'s on frame material not for Muni
> Someone mentioned frame flex. What is causing that? I want to
> avoid that.
I can’t resist. You again asked a too-open question:
Frame flex is caused by applying force to it. Normal forces are what we call
pedaling.
End of joke part.
Other forces are gravity (you sitting on the seat) and drops/packing in the
car/falling on it. The gravity force you can pretty much ignore, as it will
be covered by nearly any design. You can try to build it to be proof against
drops, falling on top of it, being packed in the car, etc. but to do this
thoroughly would probably mean adding more weight than you want to. I would
just design to cope with the main forces of riding.
The harder you pedal the more force there is trying to bring your tire in
contact with one side of the fork or the other. Which way your frame flexes
depends on the type of frame. A Schwinn frame is obvious enough; as a piece
of flat steel it’s extremely strong in one direction, but extremely weak in
the other. So you can grab a Schwinn’s seat, with the wheel held in place,
twist it from side to side, and watch the frame flex.
My first “MUni” was a 26" wheel crammed into a 24" Schwinn frame. Bad idea.
Sure the wheel fit, but as soon as you tried to pedal hard it would rub the
sides. So whenever I was going up (or down) anything steep, I would get a
“brrrrip-brrrrip-brrrrip” with each crank of the pedals.
Even more rigid tubular frames have some flex in them. Greg Harper’s Uni.5
is built in a Torker or SemXL frame, but the tire is pretty wide, with
minimal clearance. When I pedaled hard it also rubbed.
Another example is my carbon frame. Carbon is super-strong and super-light,
but flexes more than steel. My frame (Roger Davies Mk 5) is built of carbon
tubing with aluminum lugs. The force of pedaling, especially when you hold
or pull up on the front of the seat, causes a lot of twisting force through
the frame. This puts a lot of stress on the joints where the tubing is glued
into the lugs, because the twisting force is in the same direction you would
twist them to take them apart. Mine has been reinforced with aluminum pins
to keep the parts from coming apart, but it’s easy to see the amount of
force going through that frame, as you generate work with the strongest
muscles in your body.
Any frame will flex. Your goal is to build it in such a way that the flex is
minimized, or allow more tire clearance for a more flexi frame.
Stay on top,
John Foss, the Uni-Cyclone
jfoss@unicycling.com
“We were discussing Big Mac Meals. I think that has little if anything to do
with cow parts. There are probably more UNICYCLE parts in a Big Mac than cow
parts.” - Greg Harper on cuisine
Stay away from PVC tubing too
-David Kaplan
Re: ?'s on frame material not for Muni
From: “rhysling” <rhysling.2uw6e@timelimit.unicyclist.com>
Sent: Tuesday, April 09, 2002 1:52 PM
Subject: Re: ?'s on frame material not for Muni
> Seems like we should be able to tie this back in with the Twinkie
> thread, but… nope, I just can’t do it. Sorry.
>
> Christopher
That’s ok.
As great as they are, it wouldn’t work. Even petrified, hollowed-out, and
glued end to end, Twinkies probably would not make for a good Muni frame.
Actually, I have no idea what a Muni frame should or should not be made of.
I don’t even know what my own Muni frame is made of.
At this point, I am not an accomplished Muni rider, although I did ride over
a twig on a trail once.
Does that count?
No?
I didn’t think so.
I wonder what it would take to become a Level One Muni rider.
Carol
Minnesota
wooden uni
Just gleaned this from rec.aviation.soaring (
news:<168253c8.0204102007.6cb60894@posting.google.com>
)
[replace “sailplane” by “uni”, and there you go.]
“The next time someone sneers at a wooden sailplane, remind them that it is made of a unidirectional reinforced laminated composite material consisting of micro-tubular fibres embedded in a long chain polymer matrix and having a near infinite fatigue life. – Tim Mara”
Have fun,
Fred