Sentinel — Dual-Side Chain Catcher

For most Road and CX, 2 chainring applications.
Works with Braze-On Style Front Derailleur and with clamp on style braze-on mounts with a flat surface mount.

Order for Road, Cyclocross and Gravel bikes.
– See Notes Below for Compatibility.

$ 39.99$ 43.99


Dual Sided Chain Catcher:

A dual-sided chain catcher for road, gravel and cyclocross bikes with braze-on mounted front derailleurs as well as clamp on style with a flat mount surface.  The solution for precision chain control with adjustability both inside and outside to fit any road and cyclocross ring spacing, and can be adjusted without affecting front derailleur position.  Our patent has issued in the US and will issue soon in Europe on the dual sided chain catcher.


Dual-Sided Chain Catcher:

For braze-on style front derailleur mounting.
– Abrasion Resistant Black Delrin Composite inner and outer guides, black anodized aluminum cap.
– Stainless steel bolts.
– Weight: 23 g (including FD mounting bolt)


– Fits most bikes with a braze-on style front derailleur or clamp on style (road, gravel, cyclo-cross).
– Mounts on existing FD braze-on tab with most makes of Front Derailleurs.
– Chain size independent (works with 8, 9, 10, 11, 12 speed).
– Intended for use with 2x setups that include a Front Derailleur. (Not recommended for 1X).

–  Available now- an adapter for the clamp on style flat mount braze-on where the outside of the braze-on is not curved.


The Sentinel:

Imagine riding along, and when you come to that change in pitch you shift the chainrings (up or down) and the chain drops.  Sucks, Right?!?  You have two options:  awkwardly slow pedal and shift the front derailleur to try and push it back onto the rings, or, stop, get off your bike, and get your fingers dirty.  Neither option sounds very appealing, especially in a group or race situation.  We’ve been there too.  Maybe it was a weird bump at the time of the shift, or maybe the derailleur adjustment wasn’t just right . . . whatever the reason, it’s not a happy moment — and that’s why we created the Sentinel.

Of course, we still recommend thorough and careful front derailleur adjustment, but the Sentinel offers that extra protection and insurance against those awkward moments and those FD’s that just can’t be dialed in perfectly.  A dropped chain can cost you a race and at the very least frustrate you, eliminate that problem with the Sentinel in racing and everyday riding.

Dual Sided Chain Catcher:

Sentinel provides all the function of a standard chain catcher, but the Sentinel differs in that it’s dual-sided, eliminating both dropped chains and over-shifting.  It allows adjustability for both the inside and the outside chain watcher arms so that it fits any road ring spacing.  — Best of all, it can be adjusted without affecting front derailleur position.

       Mounting instructions:

  1. Remove your stock FD bolt and the stock spacer then mount the Sentinel cap by running the bolt through the braze-on mount and into your FD.  Adjust the FD cage clearance and hand tighten the bolt inside the cap with a 4mm Allen wrench.
  2. Once you’re sure the FD is properly adjusted and hand tightened, torque the bolt to 4.0Nm first, double check the FD alignment, then torque to 5.0Nm (approximately 44.3 (pound force inch).
  3. Place your chain on the small ring and the large cog.   Mount the Sentinel inside catcher with the two small Allen bolts to the cap and adjust the inner catcher so it barely misses touching the chain.  There is adjustment wiggle room on the inside catcher around the two Allen head bolts, move the inner guide over so it’s as parallel and as close to the chain as you can get it, then tighten the two bolts with a 2.5mm Allen wrench.  You need to make sure the chain cannot fit between the inner chain catcher and the teeth of the small chainring.
  4. Move the chain to the big ring and the small cog.  Mount the outside catcher to the Sentinel with the two Allen head bolts, then adjust for minimal clearance to clear the chain and tighten the bolts with a 2.5mm Allen wrench.


Note: On Shimano road chainrings the over-shift pin is mounted closer to the base of the teeth due to the rings being hollow, the Sentinel is designed to have some tilt adjustment so you can tilt the outer catcher so it just misses the over-shift pin on the Shimano road rings, on all other rings the over-shift pin is further away from the teeth so you can move the outside catcher down a bit until the proper clearance is obtained between the chain and the outside catcher. The closer the fit between the inside and outside chain catchers and the chain the better.

For a Quick Video on mounting the Dual Sided Chain Catcher, use this link Quick Fix Videos.

Shown here mounted with a Shimano Ultegra FD and 53/34 Road Ultra rings on a Gravel bike.