Upgrade derailed

The front mech of my 2007 Trek Pilot 1.0, a Shimano FD-2203 triple, is getting a bit tired, with a lot of play in the main pivot. I can’t find a like-for-like replacement. I am using a 52-42-30 chainset with an 8-speed cassette. All the triple front mechs I have found are now suited to a maximum 50t chainring and, apparently, narrower chains.

Will the Shimano Claris FD-2403 triple front mech (max 50t) work with 52t or should I drop the size of my chainset either by complete replacement or changing the chainrings?

Neil Hodkinson

The problem with currently available road triple mechs is not so much the size of the outer chainring as the difference between it and the middle ring. The Claris front mech is designed to work with a 50-39-30 combination. The inner plate is contoured to match the 39t middle ring when the mech is correctly positioned over the 50t outer. If you use it with a 52-42 combo, the surface shaping for the 39t middle ring will be in the wrong place. The mech should still shift, but will do so with much less ease and precision than on the correct chainring combo.

Furthermore, its maximum capacity is 20t, so on a 52t outer the cage will not be best placed for your 30t inner ring either. The good news is that examples of the FD-2203 do turn up on eBay from time to time if you are prepared to wait.

Richard Hallett

​​Cycle’s Technical Editor

This Q&A was published in 'Cycle' the magazine for members of Cycling UK. To contact the experts, email your technical, health, legal or policy questions to editor@cyclinguk.org or write to Cycle Q&A, PO Box 313, Scarborough, YO12 6WZ