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

In article <[email hidden]>,
[email hidden] says...

Quoted message said:

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.

Elisa Francesca Roselli said:

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

Quoted message said:

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" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

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