Broke the fool thing!

Duane Morin (dmorin@tiac.net) wrote:
: Ok, I’ve had this 24" Sem/XL for about a week now. And today one of my
: crank/pedals falls off! What gives? Does this happen to everybody, did I
: buy a piece of crap, or have I just fallen so many times that I should
: expect such stuff to happen? And most importantly, how do I FIX it?

No, it is not supposed to happen. The XL is a solid enough unicycle, but the
crank arms have to be put on tight at the “factory”. You should have a nut that
holds the crank down, and you’ll have to torque it a lot; at least 75 foot/lbs.
If you are lucky the nut will be flopping around behind the dust cover,
otherwise you can get a new one from a bike shop, where you might also want to
get the crank reattached.

One thing I learned the hard way, is that if your cotterless crank starts to
wiggle, stop riding it NOW. The wiggling may damage the metal enough that you
won’t be able to tighten it properly. This happened to me with an XL, and in the
end I needed a new crank. The vendor replaced it for free, and I’ve had no
trouble since.

Beirne


Beirne Konarski | Unicycling Web Page: bkonarsk@mcs.kent.edu |
http://nimitz.mcs.kent.edu/~bkonarsk/ Kent State University | “Untouched by
Scandal” |

Ok, I’ve had this 24" Sem/XL for about a week now. And today one of my
crank/pedals falls off! What gives? Does this happen to everybody, did I
buy a piece of crap, or have I just fallen so many times that I should
expect such stuff to happen? And most importantly, how do I FIX it?

Duane

============================================================
Duane Morin dmorin@tiac.net OR, come see my new house at: (denizen of
alt.romance) http://www.tiac.net/users/dmorin (See original plays and other
neat stuff!!)
====== “Now I will believe that there are unicorns…” =====

Re: Broke the fool thing!

dmorin@tiac.net (Duane Morin) wrote:
> Ok, I’ve had this 24" Sem/XL for about a week now. And today one of my
> crank/pedals falls off! What gives? Does this happen to everybody, did I
> buy a piece of crap, or have I just fallen so many times that I should
> expect such stuff to happen? And most importantly, how do I FIX it?

Having only had experience with Schwinns, I don’t know if this will be any help
to you, but at HMC, we’ve sometimes had pedal troubles when the seat isn’t the
right direction. Unicycles have a definite right and left side, even if you’ve
got a symmetric seat. Often (at least on the Schwinns) the cranks are labeled
“right” and “left.” We know this, but our local Schwinn dealer doesn’t. When
we’ve taken unis in to get them repaired, we have to check the seats to make
sure they’re “facing front”. If the seats are facing the wrong way, the pedals
can come unscrewed from the cranks. This can also happen if you do a lot of
backwards riding when the seat is facing the right way. If the seat’s facing
the wrong direction, all you need to do is face it the right way and retighten
the pedals.

Jennie

Re: Broke the fool thing!

dmorin@tiac.net (Duane Morin) wrote:
> Ok, I’ve had this 24" Sem/XL for about a week now. And today one of my
> crank/pedals falls off! What gives? Does this happen to everybody, did I
> buy a piece of crap, or have I just fallen so many times that I should
> expect such stuff to happen? And most importantly, how do I FIX it?
>
>Duane

>From what I’ve heard, this should be a very rare occurance. I hope I’m not
mistaken since I just ordered a 26" Sem/XL to replace my 8 year old 24" that has
finally seen the end of its productive days. I bent the axel and stripped out
the crand. That finally gave me enough of an excuse to replace
it.How hard is it to replace the axel? I’ve never done much beyond simple work
on my bicycle, but I’m reasonably handy and have a roomate that could
probably help if things get tricky. I thought this might be a good place to
start on learning more about the workings of the wheel I’ve been riding
forever. Shops in San Diego are terrible from the one wheeled viewpoint. I
ordered my new uni from Tom Miller and will probably order an axel through
him as well once I get over the withdrawl from being down for several weeks.

 _ _ Doug Borngasser
(i)(u)             San Diego CA db db@ucsd.edu \__/ You know you're a
                   unicyclist when walking feels strange.

Re: Broke the fool thing!

Thus did bkonarsk@condor.mcs.kent.edu (Beirne Konarski) speak:
>No, it is not supposed to happen. The XL is a solid enough unicycle, but the
>crank arms have to be put on tight at the “factory”. You should have a nut that
>holds the crank down, and you’ll have to torque it a lot; at least 75 foot/lbs.
>If you are lucky the nut will be flopping around behind the dust cover,

Yup, I lucked out. Thanks. Popped that baby off and there she was. I cranked it
back down as hard as I could by hand, but I have no idea if that’s enough - it’s
all it’s gonna get for now!

The only other signs of damage are a whole lot of mangles and scratches on the
edges of the pedals and the front and back seat protectors (? screw on black
guards that take most of the hit). I’m assuming that this is normal, and when I
get in the habit of falling less, I’ll get around to replacing them.

Duane

============================================================
Duane Morin dmorin@tiac.net OR, come see my new house at: (denizen of
alt.romance) http://www.tiac.net/users/dmorin (See original plays and other
neat stuff!!)
====== “Now I will believe that there are unicorns…” =====

Re: Broke the fool thing!

In article <3ucma2$bpe@sundog.tiac.net>, dmorin@tiac.net (Duane Morin) writes:
|
|> Yup, I lucked out. Thanks. Popped that baby off and there she was. I cranked
|> it back down as hard as I could by hand, but I have no idea if that’s enough
|> - it’s all it’s gonna get for now!

Should be fine, A normal socket wrench will give you plenty of torque. Just
don’t break the spindle or strip the nut! Generally the nut should have
serations on it or have a lock washer under it. That will keep it from loosening
up. And like Bierne said if your crank gets a little wobbley stop and tighten it
down. The same goes for cottered cranks they’re even easier to ruin.

In the future if you ever have your cranks off, put some good quality bike
grease on the spindle before putting the cranks back on. Not a lot of grease but
a nice thin coating. They are much easier to remove if you do. Any good bike
mechanic will do the same. You’ll still need a crank puller to remove them if
they are properly tightened.

Have fun,

Let us know how you progress

Eric

Re: Broke the fool thing!

In article <3uej5m$jfc@riscsm.scripps.edu> Doug Borngasser <db@ucsd.edu> writes:

>How hard is it to replace the axle? I’ve never done much beyond simple work on
>my bicycle, but I’m reasonably handy and have a roommate that could probably
>help if things get tricky. I thought this might be a good place to start on
>learning more about the workings of the wheel I’ve been riding forever. Shops
>in San Diego are terrible from the one wheeled viewpoint. I ordered my new uni
>from Tom Miller and will probably order an axle through him as well once I get
>over the withdrawal from being down for several weeks.

Lacing up and truing a unicycle wheel is not too hard. The easiest way is to
have another wheel to follow as a pattern. Use the same length spokes and same
spoke crossing pattern. Tighten the spokes up exactly the same amount so the
axle will be centered. Later, if necessary side to side truing can be done with
the wheel in the unicycle frame itself. (Truing stand not needed - bicycle wheel
truing stands don’t work very well for standard unicycle wheel - giraffe
unicycle wheel can be trued in a bicycle truing stand though.) Anchor thumb to
frame next to rim and turn the wheel. Note or count the spokes in a sequence
where the rim for a section is to one side; loosen spokes about a 1/2 turn on
that side for the section; tighten the spokes on the other side a 1/2 turn to
pull that section of rim to the center plane of the wheel.

On One Wheel,

Ken Fuchs <kfuchs@winternet.com

Re: Broke the fool thing!

Beirne Konarski <bkonarsk@condor.mcs.kent.edu> writes:

>You should have a nut that holds the crank down, and you’ll have to torque it a
>lot; at least 75 foot/lbs. If you are lucky the nut will be flopping around
>behind the dust cover, otherwise you can get a new one from a bike shop, where
>you might also want to get the crank reattached.

One thing to add to this which is critical–DO NOT use the torque of the nut to
reattach the crank arm to the axle!!! Doing this will strip the threads. The
crank arm must be firmly in place on the axle before you tighten the nut, since
it only serves to hold things in place. I learned from Tom Miller to use a
solid, nonmetal object (Rubber mallet, Ball Peen hammer, block of wood + hammer)
to firmly mount the crank arm onto the tapered end of the axle as far as it
would go. The arm should feel almost as “snug” as new. At this point it is safe
to thread on the holding nut and torque to the appropriate foot/lbs.

Happy riding!

David Winston, winstond@delphi.com Huntington Beach, CA U.S.A.

Re: Broke the fool thing!

I spent this Sunday pulling the whole thing apart, including removing the
bearings. The hub on one side where the spokes tie in was more messed up than I
thought. I was able to hammer it out, but I wouldn’t trust it for any serious
bumps anymore. My plan is to replace the spokes while I’ve got it apart and the
nipples sounds like a good idea. I haven’t worked out the details on the new hub
yet, but I think my old bearings will still work and I have now figured out how
to get them on and off through trial and error.

I just got a new SEM 26" for off road and distance riding. So now I can use the
old wheel for experimenting without loosing time on top and if I break something
it just gives me another excuse to learn. I’m enjoying the learning how this
thing works that I’ve been riding forever.

Does anyone know much about “cut down mountain bike cranks?” I’ve seen them
mentioned in a few posts and was wondering what was involved. Getting cranks in
San Diego I’ve found is very difficult and if this is a workable option it might
give me some more things to work on here.

 _ _ Doug Borngasser
(o)(o)             San Diego CA db db@ucsd.edu \__/ You know you're a
                   unicyclist when walking feels strange.

Re: Broke the fool thing!

eag@n8pph32.nt.com (Eric A. Gebhart) advised:
> In the future if you ever have your cranks off, put some good quality bike
> grease on the spindle before putting the cranks back on. Not a lot of grease
> but a nice thin coating. They are much easier to remove if you do.

I was told by a bike mechanic to not put any grease on cotterless cranks, as
this increases the risk of an alloy crank splitting. You need to retighten a
short while after fitting to prevent any possibility of the retaining bolt (or
nut) coming loose. It should not be easy to remove—if it was, you didn’t
tighten it enough!

Mark

| Mark Tillotson | Harlequin Ltd. | markt@harlequin.co.uk |
| http://www.harlequin.co.uk/ | +44 1223 873829 |

Re: Broke the fool thing!

In article <MARKT.95Jul24134956@atlas.harlqn.co.uk>, markt@harlqn.co.uk (Mark
Tillotson) writes:
|> eag@n8pph32.nt.com (Eric A. Gebhart) advised:
|> > In the future if you ever have your cranks off, put some good quality
bike
|> > grease on the spindle before putting the cranks back on. Not a lot of
grease
|> > but a nice thin coating. They are much easier to remove if you do.
|>
|> I was told by a bike mechanic to not put any grease on cotterless cranks, as
|> this increases the risk of an alloy crank splitting. You need to retighten a
|> short while after fitting to prevent any possibility of the retaining bolt
|> (or nut) coming loose. It should not be easy to remove—if it was, you
|> didn’t tighten it enough!

I was a bike mechanic for several years… I worked at a very nice shop that
did a large business in building up custom bikes. Not to mention the 500 bikes a
year I built from the crate.

Never seen a cotterless crank split. If the grease becomes a contributing factor
to spindle failure there is something else drastically wrong with the setup. As
someone else already posted the crank should be seated with a rubber mallet. The
bold or nut is just hold things in place. It should be as tight as it needs to
be the first go around!

The grease is to keep things from binding or rusting. I have seen cranks which
were all but impossible to remove. Usually cheap ones, usually rusted.

Bolts and nuts should also have a very light coating of grease before putting
them together. We’re not talking a lot here just a thin coating you can just
tell is there. Wipe any excess off after it’s altogether – it’s a dirt
collector.

Eric

Re: Broke the fool thing!

David Winston <winstond@delphi.com> writes:

> One thing to add to this which is critical–DO NOT use the torque of the nut
> to reattach the crank arm to the axle!!! Doing this will strip the threads.
> The crank arm must be firmly in place on the axle before you tighten the nut,
> since it only serves to hold things in place. I learned from Tom Miller to use
> a solid, nonmetal object (Rubber mallet, Ball Peen hammer, block of wood +
> hammer) to firmly mount the crank arm onto the tapered end of the axle as far
> as it would go. The arm should feel almost as “snug” as new. At this point it
> is safe to thread on the holding nut and torque to the appropriate foot/lbs.

I don’t think the threads are at much risk here, it’s a question of not
tightening the nut onto a misaligned crank, thus causing it to be gouged by
the end of the taper. Once the crank is in place centrally and correctly, if
only hand-tight, applying the design torque is perfectly safe to the threads.
Hammering the crank too hard, on the other hand, may well stretch it over the
taper beyond its design load, (and split it). I don’t recommend hammering any
alloy components, as they are much less ductile than many steels. You definitely
do need to recheck the tightness of the nut after a little use as it will bed
in—any looseness is bad news. (you lose the nut, notice too late, and damage
the crank)

Mark