Manual
|
AC38 BOTTOM BRACKET
www.tune.de
As
of
March
2016
Page
2
of
3
Before Assembly
Before assembly check if the build in with fits to the width of your frames bottom bracket
housing. Also check if the bottom bracket housing has the right tread (BSA or ITA).
The bottom bracket thread of new frames should be rethread and the front surfaces
sanded (powder coating). Clean the bottom bracket thread of your frame.
Installation of the bottom bracket
BSA-thread: right side has a left-hand thread & left side has a right-hand thread!
ITA-thread: right-hand thread on both sides!
We recommend the Tune W2 tool for assembly.
With other tools you don’t reach the needed 40 Nm torque.
1.
Grease the thread and the right front surface of the bottom bracket housing
(we recommend copper paste).
2.
Also grease the bottom bracket seating from the inside of the bearing cups.
3.
Fill the flute of the nilos sealing rings with grease and place them in the bearing
cups (the sharp edge with grease filling should face direction bearings).
Bend nilos seals should not be used.
4.
Screw in the left bearing cup, until only 5 mm of the bearing cup protrudes.
5.
Press in the bearing cartridge and then screw in the right bearing cup as much as
possible.
6.
Screw in the left bearing cup as far as possible.
Due to the nilos seals the shaft turns hard. These have to settle, afterwards the bottom
bracket runs smooth.
Installation of the crankset
All mentioned torques refer to Tune cranksets. Please always consider the manual of the
crankset manufacturer.
Never grease or oil the shaft!
Steel bolts: for mounting only
Titanium bolts: holding function (for permanent use)
1.
The crankset gets mounted with the included black steel bolts (40 Nm). When mounting
the crankset the thread, washers and the bolt head should be greased.
2.
Go out for a short but hard test ride.
3.
Loosen the steel bolts (so that grease spreads) and re-tighten them.
4.
Replace the steel bolts for the included titanium bolts (30-35 Nm).
5.
Titanium can not be tightened with a defined torque, should the bolt twist do not
tighten further!
6.
By time the crankset moves further onto the shaft. The torque for further assembly
should sink to 30-35 Nm for steel and 20-25 Nm for titanium bolts.