Fixed/free hub opts to be free/free

In article , Collin O'Neill
wrote:

Locktite and an english-threaded bottom-bracket ring are your friends
IMHO. Caveat: I suppose this method may apply enough torque to your
lockring that it strips your Suzue hub again.

Good luck!

Yes the BB lockring as a pseudo cog lockring is a an old trick I've
employed on several occasions - I've presently a spare wheel in my
closet employing this setup. Of more concern are the drive side
outbound spokes - I really did a number on those. Oh well, that's a
project for a rainy day; the spare wheel's already on and I'm good to
go! ;-)

Luke

In article , Kinky Cowboy
wrote:

I have a feeling chain tension is more important than chainline; even
a perfectly inline chainring and sprocket can lose the chain if it's a
bit loose. Strong argument for chain tugs, as I discovered yesterday
when I went out with none and had the chain off for the first time
since...I last went down a bumpy hill with no tugs.

Always seems to happen going down hill, when the top run is loose,
which suggests that it's easier to derail the chain from the chainring
than from the sprocket; not a surprising result.

Kinky Cowboy*

KC, my experiences in this regard finds me agreeing with your
observations.

Luke

"Luke" wrote:

James Thomson wrote:

Correct me if I'm wrong: doesn't a Phil lockring have a Campag thread?

Yes, it does. 1.32" x 24 TPI to be exact, as opposed to standard
1.29" x 24 TPI for ISO threading employed by the Suzue. I've been
using this combination for years and thought little of the discrepancy
in the components' specifications. Indeed, I noticed nothing amiss
whenever I removed and re-installed the lockring while replacing
cogs.

I'm doubtful that the non-spec lockring factored into the outcome
of the misadventu the thought of the Suzue's lockring threads
holding up against the thinner stock lockring doesn't seem likely.

Let me get this straight. You put a mismatched lockring on your hub,
stripped the lockring thread, and you don't think the thread mismatch was a
factor?

You're on drugs.

I just tried an experiment: I threaded a Campag Record lockring onto a Dura
Ace track hub. There's almost no thread engagement. I could probably strip
it with hand pressure.

James Thomson

Kinky Cowboy wrote:
On Sun, 02 Oct 2005 17:04:51 -0400, Paul Hobson
wrote:


Luke wrote:

Yesterday, a first. Sure, the chain had derailed in past but not to
such effect. On the road to work - on the same hill where my chain last
liberated itself! - my trusty fixie spontaneously converted to a
freewheeler.

I don't know what the hills are like in your neck of the woods, but I'm
pretty sure my heart would stop if that happened. Just curious: what's
your chainline like?



I have a feeling chain tension is more important than chainline; even
a perfectly inline chainring and sprocket can lose the chain if it's a
bit loose. Strong argument for chain tugs, as I discovered yesterday
when I went out with none and had the chain off for the first time
since...I last went down a bumpy hill with no tugs.

Always seems to happen going down hill, when the top run is loose,
which suggests that it's easier to derail the chain from the chainring
than from the sprocket; not a surprising result.

I have never dropped a chain in many 1,000's of fixed gear riding. If I
did drop a chain, I would never trust that bike again until I figured
out why. I have seen people drop chains on bumpy downhills, it always
has been on bikes without horizontal dropouts -- and the resulting
sloppy chains -- a really dangerous way to ride.

My son bugged me to build him a fixer. I had my doubts. I have seen too
many get into trouble with sketchy attitudes around fixers. One local
guy cut off his fingertip cleaning his chain. I built my son's fixer and
he rode it all summer, commuting to work without serious incident, but
he endured a few safety lectures. On a fixer, you don't want to: catch
anything in the chain, ground a pedal, or drop a chain.

In article ,
James Thomson wrote:

"Luke" wrote:

James Thomson wrote:

Correct me if I'm wrong: doesn't a Phil lockring have a Campag thread?

Yes, it does. 1.32" x 24 TPI to be exact, as opposed to standard
1.29" x 24 TPI for ISO threading employed by the Suzue. I've been
using this combination for years and thought little of the discrepancy
in the components' specifications. Indeed, I noticed nothing amiss
whenever I removed and re-installed the lockring while replacing
cogs.

I'm doubtful that the non-spec lockring factored into the outcome
of the misadventu the thought of the Suzue's lockring threads
holding up against the thinner stock lockring doesn't seem likely.

Let me get this straight. You put a mismatched lockring on your hub,
stripped the lockring thread, and you don't think the thread mismatch was a
factor?

More exactly, that the outcome wouldn't have been different; but I
concede your point. I was reasoning (Disclaimer: I'm not an engineer) -
along these lines: once the chain jammed and began leveraging the cog
off with the force of the bike's momentum behind it, the dynamic at
play was essentially a battle of strength between the hub's cog and
lockring threaded portions? And wouldn't the cog's greater surface area
of thread engagement over the lockring's (one installed to spec), favor
the hub's cog threads at the expense of its lockring grooves?

Ironically, the other scenario, that (the lockring having held)
would've resulted in the rear wheel remaining locked and me fishtailing
to a stop is not one I'd would've preferred given the traffic
conditions at the time.


You're on drugs.

Unfortunately, not at the moment.


I just tried an experiment: I threaded a Campag Record lockring onto a Dura
Ace track hub. There's almost no thread engagement. I could probably strip
it with hand pressure.

James Thomson


The wheel/lockring was given to me well used; the parts were not in
their prime. Since then I've added another 3 years of use - admittedly,
an interval characterized by general neglect on my part (this is my
beater). Now, I did discover a year after the fact that the lockring
was of different spec, but thought little of the matter because it
seemed neither unduly tight or loose during the 2 or 3 times I swapped
out cogs. In retrospect, I definitely should've been more attentive.
JT, lesson learned.

Luke

Luke

"Luke" wrote in message
...

More exactly, that the outcome wouldn't have been different; but I
concede your point. I was reasoning (Disclaimer: I'm not an engineer) -
along these lines: once the chain jammed and began leveraging the cog
off with the force of the bike's momentum behind it, the dynamic at
play was essentially a battle of strength between the hub's cog and
lockring threaded portions? And wouldn't the cog's greater surface area
of thread engagement over the lockring's (one installed to spec), favor
the hub's cog threads at the expense of its lockring grooves?
Luke

How did your chain get jammed?
I once bet my friend that a fixedgear couldn't freewheel. He also rides
without a lockring and he actually unthreaded the cog by standing on the
pedals, then quickly forward pedaled retheading the cog before it came off.
Guess I lost the bet because I didn't state how long of a freewheel.
btw; I ride with a lockring, but only secure it just past finger tight.
-tom

"Luke" wrote:

More exactly, that the outcome wouldn't have been different;
but I concede your point.

I thank you.

I was reasoning (Disclaimer: I'm not an engineer) - along these
lines: once the chain jammed and began leveraging the cog
off with the force of the bike's momentum behind it, the dynamic at
play was essentially a battle of strength between the hub's cog and
lockring threaded portions? And wouldn't the cog's greater surface area
of thread engagement over the lockring's (one installed to spec), favor
the hub's cog threads at the expense of its lockring grooves?

You're right that the sprocket's thread will generally be stronger than the
lockring's, *even when both have correct engagement*, but given that the
sprocket thread is going to win that battle, the interesting fight is
between the lockring thread and tyre traction. Any lockring needs to hold
out only until the rear tyre skids.

Ironically, the other scenario, that (the lockring having held)
would've resulted in the rear wheel remaining locked and me
fishtailing to a stop is not one I'd would've preferred given the
traffic conditions at the time.

Right - those are the two options. Some people prefer to ride without a
lockring for that reason.

The wheel/lockring was given to me well used; the parts were not in
their prime. Since then I've added another 3 years of use - admittedly,
an interval characterized by general neglect on my part (this is my
beater). Now, I did discover a year after the fact that the lockring
was of different spec, but thought little of the matter because it
seemed neither unduly tight or loose during the 2 or 3 times I swapped
out cogs. In retrospect, I definitely should've been more attentive.
JT, lesson learned.

Better luck next time.

Did you know about the fixed-gear mailing list? Subscription details are
at:

http://lists.davintech.ca/mailman/listinfo/fixed-gear

James Thomson

James Thomson wrote:


Did you know about the fixed-gear mailing list? Subscription details are
at:

http://lists.davintech.ca/mailman/listinfo/fixed-gear

James Thomson

Thanks for that link, I'll check it out

\\paul

Tom Nakashima wrote:

I once bet my friend that a fixedgear couldn't freewheel. He also rides
without a lockring and he actually unthreaded the cog by standing on the
pedals, then quickly forward pedaled retheading the cog before it came off.
Guess I lost the bet because I didn't state how long of a freewheel.
btw; I ride with a lockring, but only secure it just past finger tight.
-tom


That's how I started with my lockring/sprocket, but noticed that strong
back pedaling unthreaded the cog just slightly, which really threw off
my mojo. So as per some advice of Mr. Sheldon, I road up a really stiff
hill with some tools in my pocket to really thread the sprocket on
tight. At the top of the hill I took off the wheel and then really
torqued down the lockring ring hard. I've only felt the sprocket slip a
little bit a couple time while skidding (something I *hate* doing).

Can you friend who rides sans lockring do track stands when the hill
slopes downward?

\\paul
www.fastermustache.org

In article , Tom Nakashima
wrote:

"Luke" wrote in message
...

More exactly, that the outcome wouldn't have been different; but I
concede your point. I was reasoning (Disclaimer: I'm not an engineer) -
along these lines: once the chain jammed and began leveraging the cog
off with the force of the bike's momentum behind it, the dynamic at
play was essentially a battle of strength between the hub's cog and
lockring threaded portions? And wouldn't the cog's greater surface area
of thread engagement over the lockring's (one installed to spec), favor
the hub's cog threads at the expense of its lockring grooves?
Luke

How did your chain get jammed?

snip

Well I was preoccupied with other matters during the duration of the
snafu ;-) and so could only surmise the specifics post facto, with the
bike roadside, its cog unscrewed and chain swinging freely from the BB
shell and wheel's axle.

But based on observations from previous - and more innocuous! -
derailments and details particular to the event, I've a fair idea. Bear
in mind the time span from the chain's derailment and cog unscrewing
was little more than an instance; estimated speed was 45 KM/H.

Here are the sequence of events:
a) loose chain + bumpy asphalt derails chain to the inboard of the
chainring.
b) chain then derails inboard at the cog
c) the chain's top run, now positioned between the cog and flange,
is hooked by the wheels outbound spokes; it's pulled down and around
the hub, further wedging itself between the cog and flange/spokes.
d) Running out of length, the chain jams. At the time this was
evidenced by a brief but intense shuddering, grinding protest from the
rotating wheel, as the chain and spokes milled themselves.
e) Now the chain, with the force of the bike's momentum behind it,
was exerting an outbound, counterclockwise force on the cog as the
spokes tried to wrap it more tightly around the hub.
d) The wheel locks up for an instant; but the path of least
resistance is my ersatz lockring/hub combo rather than the friction of
rubber on dry asphalt.
f) Cog liberated...


Luke