Gear system and chain
44
HP
Velotechnik
Make sure that any chain links in the chain are
not stiff, as this can cause some annoying and
not obvious problems with the gear system.
Make sure that you have not twisted the chain
180 degrees before joining it back together.
Chain tubes
The chain protection tubes are made of a long
lasting plastic that features very low friction,
slow wear and good noise damping. The tubes
protect your clothes against the chain oil as
well as the chain against dirt from the
road.The upper tubes are fastened with an
interchangeable retention spring, the lower
tube runs through an adjustable clip.
The tubes are worn by the chain and have to
be cut at the ends and expanded again (or
exchanged) after 3.000–5.000 km approxi-
mately, depending on the chain type and the
overall riding condition. You can extend this
maintenance interval by turning the tubes by a
quarter turn from time to time so that they
do not keep wearing out in the same place.
The intensity of the wear depends mainly on
the chain type.
In order to perform any work at the chain
tubes, you'll have to open the chain and finally
close it again. Please see the instructions on
"Chain" on page 42.
The distance of the upper chain tube to the
chain wheel can be adjusted by sliding the
tube in the retention spring. It must be se-
cured with the rubber tube over the spring.
Attention!
Take care that the chain
tubes keep at least a 5 cm distance to the
rear and front derailleur when the chain is
stretched to the maximum, and that the
tubes are well fastened. If necessary you
will have to shorten the tubes. If the end of
a chain tube gets into the rotating parts of
the drive train the drive train can be
blocked and the chain tubes may be de-
stroyed.
Attention!
The rear ends of the up-
per chain tube have to be secured against
moving with a tight rubber tube over the
retention spring. Without the rubber tube
the chain tube may be dragged forward
into the turning chain roller or chainring
and thus be damaged by the chain.
Attention!
Check the chain tubes
frequently if they are damaged or defective.
Replace defective chain tubes immediately.
If the chain tubes are worn in the area of
the retention spring or tube mountings,
the chain will touch the retention spring,
leading to failure of the spring and mount-
ings. As a result, the chain tube can get
into the drive train and block it!
Expanding the tube ends
The ends of the tubes are expanded like a
trumpet so that the chain can enter smoothly
without friction and without making noises.
When the ends are worn out you can renew
them by expanding them again. Remove the
chain by opening the power link or open it
with a special chain riveting tool. Cut the
worn part of the tube exactly perpendicular
with a sharp knife.
Heat the last 5-10 mm at the end of the tube
with a gas burner, a hot air gun, or a candle
and turn it permanently until the colour of the
utmost edge turns from a dull black to a shiny
black. Now you expand the end with a proper
tool, e.g. the rounded grip of a screwdriver.
Quench the expanded end immediately with
cold water.
Take care that the tubes don't catch fire. At
any rate work in a place with sufficient ventila-
tion. If the tube is too short after you have
cut it so that there is not enough protection
anymore it has to be replaced. You can buy