Front Mechs

When selecting a front mech for your bicycle you need to know the following information:

Road Mechs:

Is the front mech a braze-on or band on?

Braze on front mechs mount to your cycle frame via a plate attached to the frame or an adapter. Band-on front mechs have a band that closes around your cycle frame seat tube:

If your front mech is a band-on what diameter is it?

Most road front mechs are 28.6mm diameter. However, some modern frame designs with oversize tubing may use a larger size. The size is generally stamped inside the clamp for easy identification.

How many front rings does your cycle have?

Your road bike will have either a double or triple ring front chainset. Select the correct mech for your bike. Triple ring front mechs have a longer cage to cope with the range of gears so you do need to use the correct mech to match the number of chainrings on your bike

Mountain Bike Mechs:

Is the front mech a band-on or does it mount on a plate?

Band-on front mechs are very common on mountain bikes, but there is also the plate mounted front mech (or "e-type") which is found on some frames where there is insufficient space for a band, or due to the suspension design.

What is the diameter of the front mech?

Choose the correct diameter for your front mech. if you have the old one then often the diameter is stamped to the inside of the band. (Tip: The new Deore and Deore XT front mechs are 'multi-fit' style so has adapters to fit any diameter of tube)

What type of 'swing' does the mech have?

You need to select the correct style to match your existing mech. Generally, top- swing mechs are becoming more common as they are more compact. Conventional mechs are used on some frame designs due to pivots etc being in the way.