Park Tool Co. CT4.2 Master Chain Tools


Park Tool CT-4.2 Master Mech Chain Tool The CT-4.2 will work with 8, 9, 10 and 11 speed chains. Also fits the asymmetrical Shimano chain designs such as Dura-Ace 7900. Specially designed to work with the tight tolerances and narrow pro...


Showing 1-1 of 1  
[Nov 17, 2012]


Works fine for opening a chain that will subsequently be closed with a master link.


Substantially deforms the back link plate when opening a chain or pressing in a new link pin to close a chain.

For the purpose of opening chains that will subsequently be closed with a master link, this tool is fine. However, for driving new chain pins in a 10- or 11-speed chain, or for removing chain pins that will be subsequently be replaced with a new chain pin, it is unacceptable. Here's why:

When driving in a new chain pin or driving out an old one, the back of the chain is supported by a flat surface with a hole in it. The hole allows for a new pin to protrude beyond the surface of the back link plate, or for an old link pin to be ejected. This is true for any chain tool. On a Shimano chain tool, this hole is 4.15mm. On a Campy tool this hole is 4.25mm. The Park tool has a 6.25mm hole. This excessively large hole provides inadequate support for the back link plate, so the link plate is substantially deformed by the force of link pin installation/removal. Campy 11 link plates are very obviously deformed, and Shimano/Campy 10 are also deformed, though less severely. The Shimano or Campy tools do not deform the link plates at all because their smaller holes provide adequate support for the back link plate.

The resulting chain closure with deformed link plates does seem to work - I have not personally seen a chain failure due to this issue. But if you look at two Campy 11 chain closures side-by-side, one done with the Campy tool and the other with the Park tool, the difference is shocking. The link plate deformation is certainly not what the chain manufacturer intended, and it's probably not what anyone wants to be riding.

Roadbikereview Newsletter

Get the latest roadbike reviews, news, race results, and much more by signing up for the Roadbikereview Newsletter




© Copyright 2020 VerticalScope Inc. All rights reserved.