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Front Derailers from Harris Cyclery

Double
Full Sized
Double
Compact
Triple
Full Sized
Triple
Mid Sized
Triple
Compact

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There are more complications involved in choosing a front derailer than with a rear:

Mounting

There are 5 different mounting types for front derailers, depending on the seat tube diameter of your frame, among other things:

Cable Pull

Large Chain Ring Size

Front derailers shift best when they are mounted as low down as is possible without having the cage foul the teeth of the chainrings. In particular, the bottom edge of the outer cage plate should be closely matched to the curvature of the largest chainring.

If you use a front derailer with a larger ring than it is meant for, the rear of the cage will get too close to the chainring before the front of the cage is close enough to provide crisp shifting.

If you use a front derailer with a smaller ring than it is meant for, the front of the cage will get close to the chainring while the rear of the cage is still far away from it. This won't hurt shifting, but will require excessive "trimming" of the front derailer as you change gears at the back.

Mis-matched derailers/chainrings may be satisfactory with friction shifting, but will likely cause problems when used with indexed shifters, such as Shimano STI units.

If you have unusual gearing requirements, and are handy, you can re-shape the outer cage plate with a grinding wheel to match a non-standard large chainring.

Double/Triple

Modern derailers are optimized for either double or triple chainwheels. The shape of the shifting cage is tailored for the application intended.

"Double" front derailers will work with triples, but if the middle ring is much smaller than the big ring, they will be balky shifting up from the small to the middle chainring. They do, however, work well with "half-step-plus-granny" setups, where the middle ring is only 3-5 teeth smaller than the outer ring.

"Triple" front derailers may have interference problems between the extended inner plate and the inner chainring.

Indexing Road/MTB

The ratio of cable movement to derailer movement differs with Shimano's "road" vs. "MTB" front derailers. This can cause indexing problems if you use a "road" front derailer with upright handlebars or a "MTB" front derailer with drop handlebars.
For more on front derailers, adjustment and troubleshooting, see my Derailer Adjustment Article.
 

Front Derailers To Solve Special Problems:

Indexed front shifting is OK when it works, and usually works OK if you use exactly the parts and sizes that Shimano intended to work together--but if you want something a bit different, you may be in for some difficulties.

While rear indexing is the same for all recent shifters/derailers, Shimano fronts use a different amount of cable pull for drop bar vs straight bar controls. This makes it difficult if you want to use a "road" crankset, with full-sized chainrings (52, 53 top) with straight handlebars, or if you want to use a "mountain" crankset (44-48 tooth top) with drop bar STI shifters.

Shimano R453 for "road" chainwheels with straight (mtb) handlebars FD4428 $49.95 buy button

This is the only model Shimano makes that is designed to work with full-sized chainrings, up to 53 teeth, and with shifters made for upright (mountain) handlebars.

This is a great choice for converting a drop-bar road bike to upright handlebars. Available for standard 1 1/8" (28.6 mm), 1 1/4 (31.8 mm) and braze-on mount.

DESCRIPTION

Front Derailers:

For Full-Sized Triple Chainrings (Big Ring 52 Teeth or Larger)

BrandModelClampPullPriceNote
See Quality Special Order Catalogue
 

For Mid-Sized Triple Chainrings (Big Ring 46-48 Teeth)

BrandModelRingsBig RingClampPullPriceNote
I.R.D.Alpina-dTriple481 1/8"
(28.6 mm)

1 1/4"
(31.8 mm)

1 3/8"
(34.9 mm)

Braze-on

Bottom
$45.95 buy button
IRD Alpina-d Front Derailleur
The only currently available front derailer that is designed for mid-range ("compact road") triple chainwheels
and compatible with Shimano "road" (drop handlebar) STI shifter indexing.
 

For Compact Triple Chainrings (Big Ring 42-44 Teeth)

(Typical contemporary mountain bikes.)
BrandModelClampPullPriceNote
See Quality Special Order Catalogue
 

For Full-Sized Double Chainrings (Big Ring 52 Teeth or Larger)

(Typical "road" bikes with double chainrings)
BrandModelClampPullPriceNote
ShimanoSora FD340028.6mm(1-1/8")
31.8mm (1-1/4")
Bottom$27.95 buy buttonDecent quality traditional front road double.
See Quality Special Order Catalogue for more choices
 

For Compact Double Chainrings (Big Ring 50 Teeth or Smaller)

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