How to use a Park Tool CT-4.2 Master Chain Tool
The following information was derived from the Park Tool Company instruction Manuals
CT-4.2 MASTER CHAIN TOOL
The Park Tool CT-4.2 Master Chain Tool quickly and easily removes and installs chains
used on derailleur-equipped road and mountain bicycles as well as indoor cycling and exercise bikes. It is specifically
designed and precision machined to work with most 10 and 11-speed chains
and other high quality derailleur chains. The CT-4.2 is not compatible with
Wipperman brand chains.
The procedures for separating and assembling derailleur chains vary
significantly, depending on the type of connection system used by the chain
manufacturer. Always consult the chain manufacturer for instructions
specific to the type and model of chain. Below are general instructions for
u sing the Park Tool Company CT-4.2 on three chain types:
Chain Using a Connecting Rivet
With this type of bicycle chain, the Park Tool CT-4.2 is used to press out one of the original rivets.
A special connecting rivet is then pressed back in to reassemble the chain (Fig. 1).
a. Place link of chain into link pocket of the Park Tool Company CT-4.2.
b. Turn handle to force rivet completely out backside of chain.
a. Insert pilot end of replacement rivet into the bicycle chain link. Place chain link
into link pocket of CT-4.2.
b. Turn handle until rivet is pressed into the bicycle chain. When properly assembled the
end of the rivet should be almost flush with the side plate of the chain and
an equal amount of rivet (not including the pilot) should be showing on each
side of the bicycle chain.
c. Remove the Park Tool CT-4.2 from the chain and remove the pilot according to manufacturer’s
Note: Campagnolo® 11-speed chains require specific procedures for installing
the connecting rivet. After pressing the connecting rivet into the 11-speed
chain with a CT-4.2 Master Chain Tool, the end of the rivet must be “peened”
or “deformed” to prevent chain failure. A Park Tool CT-11 Rivet Peening Tool is
used to perform this critical procedure.
Bicycle Chain Using Reusable Rivets
This type of bicycle chain uses reusable rivets, which are partially pressed out of the chain
with the Park Tool CT-4.2 during separation and then pressed back in during assembly (Fig. 2).
a. Place link of the bicycle chain into link pocket of CT-4.2.
b. Turn handle to force rivet out just enough to allow the bicycle chain to be separated.
Do not press rivet completely out backside of chain.
a. Join link together and place into link pocket of the Park Tool CT-4.2.
b. Turn handle until rivet is pressed into bicycle chain. An equal amount of rivet
should be showing on each side of the chain.
c. Remove Park Tool CT-4.2 from the bicycle chain.
Chain Using a Master Link
This type of chain uses a special master link to separate and assemble the chain
(Fig. 3). Separation and assembly of this type does not require a chain tool. The
process is performed by hand or with a Park Tool Master Link Pliers (MLP-1). The
Park Tool CT-4.2 is only used to remove links when shortening the chain length.
Shortening Chain Length:
a. Separate chain at master link according to chain manufacturer’s instructions.
b. Determine length of chain to be removed and place appropriate link of
chain into link pocket of CT-4.2.
c. Turn handle to force rivet completely out backside of chain.
d. Assemble chain with master link according to manufacturer’s instructions.
Loosening Tight Links
A tight link can sometimes develop during the assembly of a chain. To
remove the tight link, simply use hands and thumbs to flex the link back and
forth slightly until it pivots freely.
Replacing Bicycle Chain Tool Pin:
a. Unthread plunger from body.
b. Unthread nut from plunger.
c. Pull pin from plunger, taking care the bearing inside.
the plunger does not fall out. Install new pin.
d. Thread nut onto plunger.
e. Thread plunger into body.