I’ve been thinking about the differences between
unicycle pedals and bike pedals, and I think that
I’ve convinced myself that they should be completely
different.
A bike (except for a track bike) can’t be ridden backwards,
whereas a unicycle not only can, but it is a common thing
to go backwards. So this business of threading the pedals
in one direction or another for a uni is completely bogus.
In addition, I would love it if the pedals had some sort
of quick release mechanism so that they could either
be folded or removed for storing/shipping the uni.
Why not have the pedals installed on the cranks
the same way that the cranks are installed on the
axle – with a square shank and a nut ? It might
still be necessary to use a crank-puller, but perhaps
some other arrangement would work better.
Perhaps someone else in this group has some
ideas?
Is that not complicating things rather than simplifying them? The you’ll need a spanner and a crank puller rather than just a spanner.
As things are pedals are fairly simple to remove, they just requier a bit of brute force occassionally. Maybe just a longer spanner (or welding an extension onto an existing one) may be all that you need.
The quick release idea sounds okay, though strength/moveability of interface might be an issue (moveability issue similar to creaky Profile crankset).
Maybe something like this (hope it attaches okay). The pedal spindle end would be square section or maybe splined. Harper, apologies for incorrect depiction of threaded sections, it’s all I could do in MS Paint and 10 minutes…
I’d thought about a different way of attaching pedals, too, then came to the conclusion there would be no obvious advantage.
Using a system similar to the way cranks are attached to the axle would be no good: I’ve had cranks work loose at least as often as I’ve had pedals work loose, and using a crank puller is more complex than using a pedal spanner.
On the whole, if it ain’t broke, don’t fix it.
But what about the argument on right and left hand threads? Yes, unicycles go backwards quite often, whereas bicycles don’t. However:
I'm sure that most unicycles go forwards more than they go backwards, by a very wide margin indeed, so the left hand/right hand effect is still there.
As things stand, you can go out and buy any of dozens of designs of pedals from any bicycle shop. If your uni had two right hand threads, you'd either have a limited selection, or you'd have to buy two pairs and throw the two lefts away (or vice versa). Few obvious advantages here.
And as for the folding pedals… imagine the hilarity that could ensue when freemounting.
why not keep the cranks the same and think about how the pedals could be made to stay on better.
what about a set of pedals with extra long tapered sections that can have an lock nut on the end.
or you could drill holes in the axles in your pedals, thread them internaly and secure them on with a bolt like splined cranks do. this wouldn’t be too hard to do, you’d just need a bench drill and a tap and die set.
this would sacrifice some axle strength strength but then i’ve lost more pedals to stripped threads than snaped axles.(bent axles are annother story though)
profile racing would probably make you a set if you paid them enough monney.
then agian if i was going to get profile to build me a set i’d have them splined with a matching set of custom cranks.
I’m not sure what the actual problem is. I go backwards a lot these days and have no problems with the pedals staying on. If I want to remove them it’s easy with a simple 15mm wrench. Putting them back on needs the same wrench and a little blue loctite. No problem and takes a minute or two max to do the on or off part.
there apear to be two problems that require two different solutions or one very clever one:
problem 1: some uni riders want pedals that come off easily in a way that doesnt requre tools.
problem 2: trials riders (like me) don’t want their pedals to loosen up when doing pedal grabs.
i recon my solution to problem 2 is workable, i’ve got a spare pair of pedals. i’m going to drill holes into thir axles and then thread the holes so i can bolt them on to the cranks and see if it works.
Have you tried some Red LocTite before you drill holes into your pedals. That stuff is ment to be perminate, I just use the blue stuff because it holds good enough for me, but with a bit (alot sometimes) of force you can still remove them and swap out parts. Just a thought
The current design of pedal thread direction is backwards anyway. I have often wondered why everybody follows this convention. If a pedal bearing is sticking enough to turn the pedal axle, your pedal will only tighten itself if you are pedaling backwards. When you thread a pedal onto a bicycle by starting the thread and then spinning the crankarm, which way do you spin the crank to tighten the pedal? That’s right. (Try it.) So ride backwards all you want. Forward pedaling is the problem. Red Locktite is the fix for most people. And maybe a little oil on the bearings every now and then.
>The current design of pedal thread direction is backwards anyway. I have
>often wondered why everybody follows this convention. If a pedal bearing
>is sticking enough to turn the pedal axle, your pedal will only tighten
>itself if you are pedaling backwards. When you thread a pedal onto a
>bicycle by starting the thread and then spinning the crankarm, which way
>do you spin the crank to tighten the pedal? That’s right. (Try it.) So
>ride backwards all you want. Forward pedaling is the problem. Red
>Locktite is the fix for most people. And maybe a little oil on the
>bearings every now and then.
This question comes up periodically (I asked it myself once, some time ago).
Actually it’s not the friction of the pedal bearings that causes the pedal to
unscrew, but rather an entirely different force the official name of which I do
not know offhand (precession?). It’s a bit counterintuitive but it can be
demonstrated. Form a small circle with your thumb and forefinger, tight enough
to loosely grasp a pencil or other similarly-shaped object. Your hand is the
end of the crank-arm, and the pencil is the pedal axle. Very lightly hold the
free end of the pencil -just pushing it with one finger is best - and move it
so that it traces a circle in the air. You will see the body of the pencil
rotate in the direction opposite to the direction in which you are moving the
end. This is what happens to the pedal axle as you ride. As you ride forward,
the force applied to the axle of the right pedal pushes its end in a
counter-clockwise circle relative to the crank-arm, so it tends to tighten
clockwise. It didn’t make sense to me either until I did the pencil thing,
thanks to someone on this group a year or two ago.
Joe
=============================
If Teddy Grahams crackers
were shaped like goats instead of bears,
would they be Billy Grahams?
If your unicycle is having problems with a pedal coming loose it is probably due to cheap pedals in cheap cranks.
The threads on cheap pedals are rolled on (they are not cut or machined) and the tolerances are not held very close. The threads can end up undersized. The threads in cheap cranks also can suffer from poor workmanship. A combination of poor threads on the pedal and poor threads on the crank mean you will never be able to keep that pedal tight.
Higher quality pedals have machined threads that are held to higher tolerances.
Put quality pedals on quality cranks and you will not have problems with cranks coming loose.
>> *The current design of pedal thread direction is backwards anyway. *
>
>There is nothing backwards about it. See the following thread “Why is
>the left pedal left-hand threaded?”
><http://tinyurl.com/ys0>
>… … …
>john_childs
> not know offhand (precession?). It’s a bit counterintuitive
> but it can be demonstrated.
It can be demonstrated even easier using the “scientific” method. Turn your
unicycle’s seat around and do some hard riding. Just remember to bring your
wrench with you because you’ll need it.
>> not know offhand (precession?). It’s a bit counterintuitive
>> but it can be demonstrated.
>
>It can be demonstrated even easier using the “scientific” method. Turn your
>unicycle’s seat around and do some hard riding. Just remember to bring your
>wrench with you because you’ll need it.
>
>JF
All of this has got me to thinking (that was the grinding noise you heard a
moment ago)… When we pedal a unicycle downhill, unlike riding a bicycle,
we’re actually putting back-pressure on the pedals, as we would if we were
riding backwards. So even though we are moving forwards, if we are going down a
long steep hill, our pedals are trying to unscrew themselves. So do pedals come
loose more often for people who ride in hilly areas?
Joe
=============================
If Teddy Grahams crackers
were shaped like goats instead of bears,
would they be Billy Grahams?
When riding forward, whether uphill, downhill, or on level ground, the pedals are still rotating about their axles in the same direction. The fact that one is applying backpressure makes no difference.
The motion that causes pedals to LOOSEN or unscrew when rotating in the correct sense is called precession. The frictional force that causes the pedals to TIGHTEN when rotating in the correct sense is caused by the counter-rotation of the ball bearings (the actual balls) against the inner race of the pedal bearing.
A pedal with healthy, properly adjusted bearings and an axle tightened securely to a straight crank exhibits a minimum of precession. Loose, worn, cheap, bent, or otherwise degraded pedal bearings allow the pedal to exhibit excessive precession in some cases. Once loose, the wobbling of the pedal axle exacerabates the problem.
Complex and frustrating discussions like this are why wheel walking, gliding, and coasting were invented.
Yeah, I know. I replied to the wrong thread. Maybe it will make more sense here.
Thanks guys. I love to stand corrected when I learn something. My apologies to the industry. Why didn’t my Physics professor mention this ‘precession’. I’m sure I would have taken note. I assume this process is aggravated by cheap threads (mentioned earlier in this thread) and I can envision the forces being reversed at the other end of the axle. I haven’t actually had pedal problems in years. But, my original comment came from experience many years ago when jumping bicycles into lakes was a common pastime. The dried out bearings overcame the precession, and unscrewed the pedals every time I forgot to oil them (while re-greasing every other #@?$ bearing on the bike). It was a high maintenance pastime. So, as I mentioned earlier (especially for MUni riders playing in the mud) if you are having problems, red Lock-tite and oil should help. And I know it’s basic (or I thought so yesterday), but if all of this confusion has you totally confused, just make sure you have a clockwise thread on the right, counterclockwise on the left. I’m sure there are a few unicycles out there that have the seat accidentally reversed.
