Front Derailleur Standards Explained: Mounts, Clamp Sizes, Pull Direction & Compatibility

The front derailleur is the mechanism that pushes your chain between the front chainrings on bikes with two or three rings up front. Fit depends on how it mounts to the frame (clamp, braze-on tab, or direct mount), which direction the shift cable arrives from, how many gears your drivetrain has, and which brand and generation of shifter is pulling the cable. Most modern mountain bikes no longer have one at all, but they remain standard on road, gravel, commuter, and many e-bikes.

Why these standards exist

A front derailleur has to line up with three other parts at once: the frame (its mounting point), the crankset (chainring sizes), and the shifter (how far each click moves the cage). Because frames evolved from skinny steel tubes to oversized aluminum and carbon, and because mountain bikes needed different cable routing than road bikes, manufacturers created a surprising number of mounting and cable-routing standards over the decades.

On top of the physical mount, front derailleurs are matched to the drivetrain's speed count and, in mechanical systems, to a specific cable-pull ratio — the amount of cable the shifter pulls per click. Shimano changed its road front-shifting pull ratio at 11-speed, so a shifter and derailleur from different generations can bolt on fine yet shift badly. Knowing the standard on your bike lets you buy a replacement that actually works, not just one that fits.

Front derailleurs are also becoming a legacy part. After SRAM's 2012 XX1 groupset paired a clutch rear derailleur with a narrow-wide chainring, mountain bikes rapidly abandoned front shifting in favor of 1x (single chainring) drivetrains with wide-range cassettes. If your mountain bike is roughly 2015 or older, it likely has a front derailleur and needs these legacy standards; newer MTB frames often have no front derailleur mount at all.

Modern standards

What you’ll find on bikes from roughly 2018 onward. Mountain bikes abandoned front derailleurs around 2016-2018, so on modern bikes this is a road/gravel component: braze-on mount, often electronic. The MTB direct-mount variants matter only for older bikes.

Clamp-on (band clamp) mount

1950s-present

Also called: Band-on, Band clamp, Clamp mount

Band inner diameter 28.6 mm (1 1/8"), 31.8 mm (1 1/4"), or 34.9 mm (1 3/8") to match seat tube outside diameter

The oldest and most universal mount: a hinged metal band built into the derailleur wraps around the seat tube and is pinched tight with a single bolt. Because the band clamps anywhere on the tube, height and rotation are fully adjustable, which makes clamp-on derailleurs the most forgiving to set up and the easiest to swap between bikes. Many current models ship as 34.9 mm bands with 31.8 and 28.6 mm shims included.

Why it exists: Early frames were all round steel tubes of similar diameter, so a simple adjustable band was the obvious attachment. The three sizes track frame evolution: 28.6 mm for classic steel road tubes, 31.8 mm for mildly oversized tubing, and 34.9 mm for oversized aluminum frames.

Typically found on: Road, touring, hybrid, commuter, and pre-2016 mountain bikes with round seat tubes; still the default on metal-framed bikes

Braze-on mount

1980s-present (dominant on road since the 2000s)

Also called: Braze-on tab, Direct mount (road)

Single M5 bolt through a vertical slotted tab welded, riveted, or bonded to the seat tube; the slot gives roughly 1-2 cm of height adjustment

The derailleur bolts to a small tab that is part of the frame itself, eliminating the band. Nearly all modern road and gravel race frames — especially carbon frames with aero or non-round seat tubes — use this style, and all current Shimano, SRAM, and Campagnolo road front derailleurs are sold in braze-on form. A clamp-style adapter band with a braze-on tab lets you fit a braze-on derailleur to a round seat tube, but not the reverse.

Why it exists: Carbon and aero seat tubes are not round or not safe to squeeze with a clamp, so builders moved the interface onto the frame. It also saves a little weight and fixes the derailleur at the correct height for the intended chainrings.

Typically found on: Modern road and gravel bikes, especially carbon frames; most performance drop-bar bikes since ~2005

Cable pull direction (top / bottom / dual)

Bottom-pull 1950s-present; top-pull 1990s-present; dual-pull 2000s-present

Also called: Top-pull, Bottom-pull, Dual-pull, Top-route/bottom-route

Defined by where the cable approaches the anchor bolt from: below (via the bottom bracket) or above (down the seat tube or along the top tube)

Traditional road frames route the front shift cable under the bottom bracket, so the derailleur is pulled from below (bottom-pull). Mountain bikes moved the cable up and over the top tube to keep it out of mud and tire spray, requiring top-pull derailleurs. Dual-pull models have an anchor arm or pulley that accepts either routing, which makes them safe replacement choices when you're unsure.

Why it exists: Cables routed under the bottom bracket sit in the line of fire from the front tire; off-road riding gummed them up. Rerouting the cable from above solved that but reversed the direction of pull, forcing a matching derailleur design.

Typically found on: Bottom-pull: road/gravel. Top-pull: MTB and many hybrids. Dual-pull: replacement-market and trekking derailleurs

Shimano road pull-ratio generations

2012-present (11-speed era); pre-2012 groups use the older ratio

Also called: New-style long-arm FD, 11-speed road FD, Toggle-link FD

10-speed road shifters pull roughly 3.4 mm of cable per click; 11-speed road front derailleurs use a longer anchor arm and a different (lighter-action) pull ratio

When Shimano moved road groups to 11-speed (Dura-Ace 9000, 2012, then Ultegra 6800 and 105 5800), it redesigned the front derailleur with a much longer lever arm and a new cable-pull ratio to lighten shifting effort; Tiagra 4700 (10-speed) adopted the same new ratio. The R9100/R8000/R7000 generation added a compact toggle-link body with a built-in cable tension adjuster. The practical rule: pair 11-speed-era road front derailleurs (and Tiagra 4700) only with same-era shifters — a pre-2012 10-speed road shifter will not index them correctly even though everything bolts up.

Why it exists: Front shifting effort had become the weak point of mechanical road groups. Lengthening the arm gave the rider more leverage per millimeter of cable, but that required the shifter to pull a different amount of cable, splitting compatibility between generations.

Typically found on: Shimano 105 5800/R7000, Ultegra 6800/R8000, Dura-Ace 9000/R9100, Tiagra 4700 road and gravel bikes

Electronic front derailleurs

2009-present (Di2 7970 onward)

Also called: Shimano Di2, SRAM eTap / AXS, Campagnolo EPS / Wireless

No cable-pull spec; motorized cage driven by wire (Di2, EPS) or wireless signal with onboard battery (SRAM eTap/AXS, Campagnolo Super Record Wireless)

Electronic groupsets replace the shift cable with a motor: Shimano Di2 and Campagnolo EPS use wires to a central battery, while SRAM eTap/AXS derailleurs are fully wireless with their own batteries. Cable-pull ratio disappears as a compatibility concern, and the derailleur auto-trims to prevent chain rub. In exchange, components only pair within one brand's electronic ecosystem and, in some cases, within a specific speed generation (e.g. 11-speed Di2 vs 12-speed Di2).

Why it exists: Motorized shifting delivers identical, low-effort shifts regardless of cable friction or housing wear, enables shifting from multiple button locations, and self-trims — solving front shifting's classic weaknesses.

Typically found on: Mid-to-high-end road and gravel bikes from ~2012 on; nearly all top-tier drop-bar groupsets since 2021 are electronic

1x drivetrains (no front derailleur)

2012-present

Also called: One-by, Single-ring, Narrow-wide

Single chainring (narrow-wide tooth profile), clutch rear derailleur, wide-range cassette (e.g. 10-50T, 10-52T); frame may have no front derailleur mount at all

Not a front derailleur standard but the reason many bikes lack one. SRAM's XX1 (2012) proved that a narrow-wide chainring plus a clutch rear derailleur could retain the chain without a front derailleur or chain guide, and 12-speed Eagle (2016) closed the gear-range gap. Mountain bike frames designed since roughly 2016 increasingly omit the mount entirely, and SRAM stopped making MTB front derailleurs. 1x is now also common on gravel bikes and e-bikes (motor torque and mid-drive layouts rarely accommodate front shifting).

Why it exists: Removing the front derailleur eliminated the drivetrain's most temperamental component, saved weight, quieted the bike, and freed frame designers to optimize suspension pivots, tire clearance, and chainstay length.

Typically found on: Nearly all mountain bikes after ~2016, most e-MTBs and mid-drive e-bikes, many gravel bikes

Legacy standards

BikeQuiver focuses on modern bikes, but these earlier standards are worth knowing when you’re identifying parts on an older bike — or figuring out whether a used part will fit a new one.

Show 5 legacy standards

High direct mount

circa 2007-2018

Also called: Shimano D-type, SRAM S1, High DM

Single mounting bolt into a boss on the seat tube or swingarm, with a vertical locating ridge on the derailleur's back plate; Shimano models carry a -D suffix (e.g. FD-M617-D)

A mountain-bike direct-mount standard where the derailleur bolts to a single threaded boss relatively high on the seat tube, roughly where a high clamp band would sit. Shimano called it direct mount or D-type; SRAM called the equivalent position high direct mount, with S1 (and a fore-aft variant S2) describing bolt offset versions for different frame designs — SRAM's variants are not interchangeable with each other.

Why it exists: Full-suspension frames with pivots, curved tubes, or interrupted seat tubes often had nowhere to put a round clamp. A dedicated boss let frame designers place the derailleur exactly where it needed to be regardless of tube shape.

Typically found on: Full-suspension and some hardtail mountain bikes from the late 2000s to mid 2010s, 2x/3x drivetrains

Low direct mount (E2 / S3)

circa 2010-2018

Also called: E2-type, SRAM S3, Low DM, E-type without plate

Two mounting bolt holes 22.1 mm apart, offset about 5 mm front-to-back, on a boss near the bottom bracket

A two-bolt direct mount low on the seat tube, derived from the older E-type standard with the bottom-bracket plate removed — the derailleur bolts straight to bosses on the frame. Shimano low direct mount and SRAM S3 share this bolt pattern, so it is the most cross-compatible of the MTB direct mounts. Shimano versions typically allow a little height and angle adjustment within the slots.

Why it exists: Mounting near the bottom bracket keeps the derailleur in a fixed relationship to the chainrings even on frames with odd seat tube shapes or suspension members, and frees the seat tube entirely for pivots, shock placement, and bottle cages.

Typically found on: Mid-2010s full-suspension and hardtail MTBs running 2x10 and 2x11 drivetrains

E-type (bracket plate)

1990s-2000s

Also called: E-type, BB-mount, Shimano FD with mounting plate

Flat steel plate clamped under the drive-side bottom bracket cup, plus a small screw into a boss on the seat tube; no height adjustment — plate is chainring-size specific

The original plate-style mount: the derailleur hangs from a steel backplate that is sandwiched behind the bottom bracket's drive-side cup and steadied by one small screw into the frame. Because the plate fixes the height, E-type derailleurs are sold for a specific largest-chainring size and cannot be adjusted up or down.

Why it exists: 1990s full-suspension and unusual frames (and some folding/step-through designs) had no usable seat tube section at derailleur height. Hanging the derailleur off the bottom bracket sidestepped the problem entirely.

Typically found on: Older full-suspension MTBs, some hybrids, folding bikes, and step-through commuters from the 90s and 2000s

Top-swing and down-swing clamps

Down-swing 1950s-present; top-swing 1990s-2018 (MTB)

Also called: Low clamp (top-swing), High clamp (down-swing), Conventional swing

Same band diameters (28.6/31.8/34.9 mm); differ in whether the pivoting linkage sits above or below the clamp

Two layouts of the same clamp-on idea. A down-swing (traditional) derailleur clamps high on the seat tube with the mechanism hanging below. A top-swing derailleur clamps low, with the mechanism swinging above the clamp — this clears water-bottle cages, suspension pivots, and dropped top tubes. Shifting performance is equivalent; the choice is dictated by what fits your frame.

Why it exists: As MTB frames gained suspension pivots and interrupted tubes in the 1990s, the traditional high clamp position was often blocked. Moving the clamp low and flipping the mechanism above it (top-swing) restored compatibility.

Typically found on: Down-swing: road and older rigid MTBs. Top-swing: 1990s-2010s mountain bikes and hybrids

Shimano Side-Swing

2015-2020

Also called: Side swing, Front-routing FD

Cable enters horizontally from the front of the derailleur; sold in clamp, high direct mount, and E-type versions (model suffix like FD-M9025-M for mid clamp)

Shimano's final generation of mountain front derailleurs (introduced with XTR M9000, ~2015) rotated the whole mechanism so the cage pivots sideways and the cable arrives from the front rather than above or below. It shifted with less lever effort and, crucially, tucked the mechanism away from the rear tire, allowing shorter chainstays and bigger tires — but it requires a frame with front-entry cable routing.

Why it exists: Growing 29er wheels and plus-size tires were colliding with conventional front derailleur bodies. Side-Swing was Shimano's attempt to keep 2x MTB drivetrains viable by reclaiming tire clearance, arriving just as the market moved to 1x.

Typically found on: Late-model 2x Shimano MTB groupsets (XTR M9000, XT M8000, SLX M7000, Deore M6000)

What to record about yours

These are the values worth writing down when you add this part to your quiver — the critical ones drive compatibility matching.

Spec	Matters for fit	Common values
Mount Type critical	The mount must match what your frame provides — a round seat tube for a clamp, a welded/riveted tab for braze-on, or specific bolt holes for direct-mount types. A derailleur with the wrong mount simply cannot be installed without an adapter.	Clamp-on (band) · Braze-on · High direct mount (D-type) · Low direct mount (E2 / S3) · E-type (BB plate)
Clamp Diameter(mm) critical	Clamp-on derailleurs must match your seat tube's outside diameter. Many derailleurs ship with a large 34.9 mm band plus shims to fit the smaller sizes.	34.9 · 31.8 · 28.6
Rear Speeds (Drivetrain)(speeds) critical	Front derailleur cages are sized for the chain width of a specific rear-cog count (e.g. an 11-speed chain is narrower than a 9-speed chain), and mechanical models are matched to same-generation shifters. Use the number of rear cogs your drivetrain has.	11 · 10 · 12 · 9 · 8 · 7
Front Chainrings (2x / 3x) critical	Double (2x) and triple (3x) derailleurs have different cage shapes — a triple cage has a taller inner plate to lift the chain across two gaps. A double derailleur usually shifts a triple poorly, and vice versa, and the left shifter must match (2-position vs 3-position).	2x (double) · 3x (triple)
Actuation critical	Mechanical derailleurs are moved by a steel cable and must match the shifter's cable-pull ratio; electronic ones (Shimano Di2, SRAM eTap/AXS, Campagnolo EPS) use a motor and only pair with their own brand's electronic system.	Mechanical · Electronic (Di2) · Electronic wireless (eTap/AXS) · Electronic (EPS)
Cable Pull Direction critical	The shift cable can arrive from below (bottom-pull, typical road), from above (top-pull, common on older MTB), or either (dual-pull). This must match your frame's cable routing or the derailleur cannot be actuated. Not applicable to electronic models.	Bottom-pull · Top-pull · Dual-pull · Side-swing (front routing)
Swing Type helpful	Describes where the pivoting body sits relative to the clamp: down-swing (traditional, body below a high clamp), top-swing (body above a low clamp, clears water bottles and suspension pivots), or Shimano's side-swing (cage pivots sideways with the cable entering from the front). It affects frame clearance and cable routing.	Down-swing · Top-swing · Side-swing
Brand critical	Mechanical front derailleurs generally need a same-brand, same-generation shifter because each brand uses its own cable-pull ratio and indexing. Electronic derailleurs only work within their own brand's electronic ecosystem.	Shimano · SRAM · Campagnolo · microSHIFT
Series / Model helpful	The model code (e.g. FD-R8000, FD-M617) pins down speed count, mount, pull direction, and shifter generation in one string — the single most reliable identifier if you can find it.	Shimano 105 FD-R7000 · Shimano Ultegra FD-R8000 · Shimano Tiagra FD-4700 · SRAM Rival/Force eTap AXS · Shimano Deore FD-M6000 · Campagnolo Chorus/Record
Max Chainring Size helpful	The outer cage plate is curved to hug the largest chainring; manufacturers state a maximum (and sometimes minimum) tooth count. Too big and the ring hits the cage; too small and the gap causes sluggish, unreliable shifts.	50T · 52T · 53T · 46T · 48T · 44T · 40T
Capacity (Tooth Difference) optional	The maximum allowed difference between the largest and smallest chainring (e.g. 50-34 = 16T). Exceeding it can cause dropped chains or chain rub because the cage can't manage the size gap.	16T · 14T · 12T · 10T · 13T
Design Chainline(mm) optional	The distance from the frame centerline to the midpoint of the chainrings that the derailleur was designed around. Mostly matters on MTB and e-bikes with wide (Boost) rear ends, where a standard-chainline derailleur may not reach far enough outboard.	43.5 · 45 · 47.5 · 48.8 · 50 · 52

How to identify which one you have

By looks

Look at how the derailleur attaches. A metal band wrapping the seat tube = clamp-on (mechanism below the clamp = down-swing; above it = top-swing). A tab that is part of the frame = braze-on. Bolts into bosses on the frame = direct mount (one bolt high on the tube = high direct mount / D-type; two bolts low near the BB = low direct mount / E2 / S3; a steel plate behind the bottom bracket cup = E-type). Then follow the shift cable: from under the bottom bracket = bottom-pull; from above = top-pull; entering horizontally from the front = Side-Swing. No cable means electronic — a wire port is Di2/EPS, a removable battery block is SRAM AXS. A single chainring with no front derailleur = 1x; check whether the frame even has a mount before shopping.

By measuring

For clamp-on: measure the seat tube's outside diameter at the clamp with calipers — 28.6, 31.8, or 34.9 mm (if the band contains C-shaped shims, the band itself is 34.9 and the shims adapt it down). Count chainrings (2 = double, 3 = triple) and rear cogs (drivetrain speed). Count teeth on the largest chainring to check a replacement's max chainring spec, and subtract the smallest ring's teeth to get the required capacity. Two bolt holes about 22 mm apart near the bottom bracket confirm the low direct mount (E2/S3) pattern.

By markings

Find the model code — usually stamped or printed on the outer cage plate, the clamp band, or under the linkage. Shimano codes read FD-xxxx (FD-R8000 = Ultegra 11-speed road; FD-4700 = Tiagra 10-speed; a -D suffix = high direct mount, -E = E-type, letters like -H/-L/-M on MTB models = high/low/mid clamp). SRAM and Campagnolo print the series name (Rival, Force, Chorus) on the body. Clamp bands often have the diameter (34.9, 31.8, 28.6) stamped into the metal. Searching the exact model code online returns the manufacturer's spec sheet with mount, speeds, pull direction, and max chainring.

Compatibility gotchas

Match the mount to the frame first: clamp-on needs a round seat tube of the right diameter, braze-on needs a frame tab (or a clamp adapter), and direct-mount types need the exact bolt pattern. High direct mount (single bolt) and low direct mount (two bolts) are not interchangeable.
A braze-on road derailleur can be fitted to a round seat tube using an inexpensive clamp adapter in the correct diameter — this is the standard workaround. There is no adapter going the other way.
Cable pull direction must match your frame's routing: road frames are almost always bottom-pull, older MTBs and hybrids are usually top-pull. A dual-pull derailleur works with either and is the safe replacement choice.
Keep mechanical shifters and front derailleurs in the same brand and generation. Shimano changed its road front pull ratio at 11-speed (and Tiagra 4700): 11-speed-era front derailleurs need 11-speed-era shifters, and pre-2012 10-speed road shifters will not index them properly.
SRAM mechanical road shifters do not correctly actuate Shimano front derailleurs (and vice versa) — their cable-pull amounts differ. Electronic components (Di2, AXS, EPS) never mix across brands.
Double vs triple matters twice: the derailleur cage shape differs, and the left shifter must have the matching number of positions. A road double shifter cannot properly run a triple derailleur.
Check the max chainring spec: the cage's curve must closely follow your largest ring. A derailleur rated for a 34-38T MTB ring will not shift a 50T road ring, and a road cage sits too far from small MTB rings.
Front derailleurs are less speed-fussy than rear derailleurs, but cage width still tracks chain width — a 9-speed cage is noticeably wider than an 11-speed cage, so stay within one speed of your drivetrain when substituting.
On e-bikes: mid-drive motors (Bosch, Shimano STEPS, etc.) have a single chainring by design — no front derailleur is possible. Hub-motor e-bikes and older pedelecs may retain conventional 2x/3x front derailleurs that follow the same standards as regular bikes.
Shopping for an older (pre-2016) mountain bike part? New-old-stock and used markets are the main source: SRAM no longer makes MTB front derailleurs, and Shimano's remaining 2x MTB options are limited to lower-tier groups. Confirm mount, pull direction, and swing type before buying.
If your frame has no braze-on tab, no clamp room, and no direct-mount bosses, it was designed 1x-only. Converting it to a front derailleur is effectively impossible; gear range changes must come from the cassette or chainring instead.

References

Related components

Rear Derailleur Shifters Crankset Chain