"Joerg" wrote in message
...
On 2018-02-08 16:01, Frank Krygowski wrote:
On Thursday, February 8, 2018 at 4:14:47 PM UTC-5, Joerg wrote:
On 2018-02-08 12:20, AMuzi wrote:
On 2/8/2018 2:08 PM, Joerg wrote:


Those 2.4W bulbs were a joke. My bikes (after my teenage
years) always had better lighting than that. Now it's all
LED on my bikes but the real stuff with more than 500 lumens.


For years with a Margil cover or, after a Krygowski mod with O ring,
and
without a switch (always on) I have no complaints about function or
longevity. YMMV.


How much does that O-ring reduce the drag? In the old days (with a real
power bus on the bike) I often rode the first miles with the dynamo off
because of the drag. I only put it back to the wheel when the "steam
gauge needle" (remember those?) got too close to the red range.

First, the terrors of dyno drag are mostly a myth. This article deals
with it:
http://www.myra-simon.com/bike/dynotest.html
"the slowing down has more to do with psychology than the actual power
required
to turn it."
and
"All of the generators were easier to turn than riding up a 1 in 300
slope.
Another way of putting that is a rise of 18 feet per mile; and there's
quite a
cluster of sidewall and hub-driven models around the 1/500 line, or 10 ft
per
mile."


Well, take another look at your link. I routinely ride at 30km/h at which
bottle dynamos waste 15W or more. That is nothing to sneeze at.

Bottle dynamos also tend to slip if wet or muddy.