Automatic Shifters (e.g. Sturmey Archer): Chain Never Pops Off?

I went back to have a second look at the Giant Melbourne bike that I may
purchase soon. It has a Shimano Nexus 7 gear shifter which is one of
those integrated hub shifters that can be shifted even when the bike is
at a standstill. This represents a considerable advantage to me and to
my characteristic bike use which is in stop-start traffic most of the
time.

However, the salesman boasted of another advantage which I am anxious to
confirm. He said the chain never pops off as it does with derailleur
type shifters. Is that true? On my current bike, I get the chain popping
at least once a week. Last week it popped twice in a 500 meter stretch.
This is a serious pain in the wazzoo.

Elisa Francesca Roselli
Ile de France

In article ,
says...
I went back to have a second look at the Giant Melbourne bike that I may
purchase soon. It has a Shimano Nexus 7 gear shifter which is one of
those integrated hub shifters that can be shifted even when the bike is
at a standstill. This represents a considerable advantage to me and to
my characteristic bike use which is in stop-start traffic most of the
time.

However, the salesman boasted of another advantage which I am anxious to
confirm. He said the chain never pops off as it does with derailleur
type shifters. Is that true? On my current bike, I get the chain popping
at least once a week. Last week it popped twice in a 500 meter stretch.
This is a serious pain in the wazzoo.

Then it must be out of adjustment; a properly adjusted chain will
basically *never* pop off. I haven't had one come off in more than 20
years.

--
Dave Kerber
Fight spam: remove the ns_ from the return address before replying!

REAL programmers write self-modifying code.

On Fri, 10 Oct 2003 13:42:09 +0200, Elisa Francesca Roselli wrote:

I went back to have a second look at the Giant Melbourne bike that I may
purchase soon. It has a Shimano Nexus 7 gear shifter which is one of those
integrated hub shifters that can be shifted even when the bike is at a
standstill. This represents a considerable advantage to me and to my
characteristic bike use which is in stop-start traffic most of the time.

However, the salesman boasted of another advantage which I am anxious to
confirm. He said the chain never pops off as it does with derailleur type
shifters. Is that true?

It certainly should be. If the chain is properly adjusted and the rear
wheel is on tightly, the chain really should not come off. With a
derailleur system, the chain is _meant_ to go from cog to cog, so indeed
will occasionally come off. A well-adjusted bike should not do this, but
as the chain wears, or if an adjustment is off, or if the road is very
bumpy, it can happen.

--

David L. Johnson

__o | The lottery is a tax on those who fail to understand
_`\(,_ | mathematics.
(_)/ (_) |

"Elisa Francesca Roselli" wrote
However, the salesman boasted of another advantage which I am anxious to
confirm. He said the chain never pops off as it does with derailleur
type shifters. Is that true? On my current bike, I get the chain popping
at least once a week. Last week it popped twice in a 500 meter stretch.
This is a serious pain in the wazzoo.

Elisa Francesca Roselli
Ile de France

If your chain pops off while you are shifting, chances are that the
derailleur limit screws are not correctly adjusted, allowing the derailleur
to move the chain too far. If the chain pops off under hard pedalling,
chances are the chain and/or the chainring and/or the cassette are worn and
in need of replacement.
Either way, this is indeed a serious pain in the wazoo, and elsewhere on the
rider's body.

Chain life varies according to riding conditions (rain, mud, etc.) and how
diligently the rider lubricates the chain. Cassette/freewheel/chainring life
varies according to how badly worn the chain is.

Since the Shimano Nexus has the shifting mechanism built into the hub, the
derailleur limit screw adjustment is a non-issue. Excessive chain wear,
however, wil be an issue, so keep the chain lubricated on any bike you buy.
--
mark

I'm using the SRAM 24 speed Dualdrive and I have to agree with you that it
is nice to never worry about the chain popping off the front derailleur.
I'm so far very impressed with this system.

Ed


"Elisa Francesca Roselli"
wrote in message ...
I went back to have a second look at the Giant Melbourne bike that I may
purchase soon. It has a Shimano Nexus 7 gear shifter which is one of
those integrated hub shifters that can be shifted even when the bike is
at a standstill. This represents a considerable advantage to me and to
my characteristic bike use which is in stop-start traffic most of the
time.

However, the salesman boasted of another advantage which I am anxious to
confirm. He said the chain never pops off as it does with derailleur
type shifters. Is that true? On my current bike, I get the chain popping
at least once a week. Last week it popped twice in a 500 meter stretch.
This is a serious pain in the wazzoo.

Elisa Francesca Roselli
Ile de France