Chain tubes
36
HP
Velotechnik
37
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 inter-
changeable 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 ex-
changed) after 3.000-5.000 km approximately,
depending on the chain type and the overall
riding condition.You can extend this mainte-
nance interval by turning the tubes by a quar-
ter 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. Please see also the instructions
on "Chain" on page 34.
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 34.
The distance of the upper chain tube to the
chainwheel can be adjusted by sliding the tube
in the retention spring. It must be secured
with the rubber tube over the spring.
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.
Caution!
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 short-
en the tubes. If the end of a chain tube gets
into the rotating parts of the drivetrain the
drivetrain can be blocked and the chain
tubes may be destroyed.
Caution!
The rear ends of the upper 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 turn-
ing chain roller or chainring and thus be
damaged by the chain.
Caution!
Check the chain tubes frequently
if they are damaged or defective. Replace de-
fective 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 mountings.As a result, the
chain tube can get into the drive train and
block it!
