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Compatibility [05] Front derailleurs

This post explains bicycle front derailleur compatibility of various makes and models. For a detailed explanation of front derailleur (FD in the rest of this post) mounting systems, cable routing and capacity, read this article: Front derailleur.

Before you start, to avoid any misunderstanding:
please take the 5 minutes needed to read the compatibility articles use instructions.

If you have any questions (or additions and corrections), please use the BikeGremlin forum’s compatibility section:

FDs differ in several categories (they are all explained with pictures in the above linked Front derailleur article):


  1. Mounting: braze on, clamp mounted, or direct mounted
  2. Cable routing: top pull, bottom pull, or bidirectional pull (double pull)
  3. Big front chainring teeth number that FD is designed for and mounting angle
  4. Number of front chainrings: double vs triple
  5. FD cage rotation relative to the clamp position: high clamp, low clamp, or the new Shimano side-swing
  6. MTB vs Road FD
  7. Number of speeds (number of rear sprockets and chain width) FD is designed for
  8. Exceptions


Briefly put:
With front derailleurs, it is important to have their cage match the curve of your largest chainring, and to have their movement match the amount of cable your shifter pulls/releases.

Yes, it is always safe to buy a matching set of FD, cranks and shifters, but that’s not always practical (depending on what you already have or can source) or it may not always give you the gearing range that you need.

That’s why this article lists and explains the things that you should pay attention to when mix-matching.

– T.O.C. –

1. Mounting

FDs are made for mounting on frame fixed braze on, or come with clamps for mounting on the seat tube. If FD comes with a clamp, seat tube diameter must match the clamp diameter. A newer standard, used on mountain bikes is the direct mount, it is explained at the end of this chapter.

If a frame comes with a brazed on FD mount, in order to mount a clamp on FD, the frame mount must be removed (cut off). In some (rare) cases the clamp can be put above/below the frame mount, so it can stay, as long as it doesn’t interfere with FD movement and proper mounting relative to the front chainrings.

Frame with a front derailleur braze on holder.
Frame with a front derailleur braze on holder.

Standard clamp (and seat tube) sizes are:
1 1/8″ (28.6 mm)
1 1/4″ (31.8 mm) and
1 3/8″ (34.9 mm)

If a FD is a braze on type and the frame doesn’t have a FD hanger (or the frame hanger is too low/high for the size of front chainrings used), a separate clamp can be bought so that FD can be fixed to it. This is a much more universal type of FD.

Front derailleur clamp. It is used when a braze on front derailleur needs to be mounted on a frame without derailleur holders.
Front derailleur clamp.
It is used when a braze on front derailleur needs to be mounted on a frame without derailleur holders.

Direct mount FDs can often be fitted to a frame without direct mount attachment holes using an adapter, enabling the FD to be secured by a (threaded) BB shell. There are also adapters for frames with a round seat tube cross section of a standard width, so that a direct mount FD can be attached to them.

Older system, fixed with the bottom bracket.
Older system, fixed with the bottom bracket.
Direct mount (H0, DM)
Direct mount (H0, DM)
Adapter for mounting direct mount FDs on a frame that hasn't got the required mounts.
Adapter for mounting direct mount FDs on a frame that hasn’t got the required mounts.

Frames with exotic seat tubes (either by cross section that isn’t round, or by diameter that varies from the three standar sizes), often have FD mounts made on the frame. If, for any reason, those mounts can’t be used (damaged, or not fitting the FD at hand), an adapter can be used – held in place by the BB shell – for frames with a threaded BB at least.

– T.O.C. –

2. Cable routing

There are FDs that have a cable attached from below, from above, or from any of the two. Frames usually have only one type of cable routing.

Double pull FD. Enables routing from either side. Here, two cables are routed, from the top and from the bottom. Of course, only one cable is mounted in real life - either from the top, or from the bottom. Never two! :)
Double pull FD.
Enables routing from either side. Here, two cables are routed, from the top and from the bottom. Of course, only one cable is mounted in real life – either from the top, or from the bottom. Never two! 🙂

With double routed FDs this isn’t important, but for the other models, if the FD’s cable routing doesn’t match the frame design, there is a special adapter that can reverse the cable direction.

FD cable routing adapter. Enables reversal of cable routing to the front derailleur.
FD cable routing adapter.
Enables reversal of cable routing to the front derailleur.

In the picture above, the frame has cable routing so that FD cable comes from above. FD is designed for bottom cable routing. The adapter with a wheel onto which the cable is placed is mounted on the seat tube below the FD, so that the cable can go over it and up to the FD. Everyone is happy. 🙂

Almost all the road FDs have bottom pull cable routing, while most MTB FDs have either top, or dual cable pull. 

– T.O.C. –

3. Teeth number (the size) of the largest front chainring a)
and mounting angle b)

a) teeth number

FD is curved in order to align with the curve of the largest front chainring. A typical MTB chainring has 42 teeth, while road bike chainrings often come with 53 teeth. A smaller chainring requires the FD to have a much more curve in order to align (and vice versa).

Well placed FD that perfectly aligns with the chainring shape.
Well placed FD that perfectly aligns with the chainring curve.

Imagine in the picture above that the FD cage is shaped to match the middle chainring. It would have to be mounted either too high, or it’s rear part would bump into the big chainring, since it has too sharp a curve.

FDs are usually made to match chainrings with 42, 48, 50, or 53 teeth. If FD and large chainring are mismatched for a couple of teeth, there’s no problems, it’s close enough. If, however, a difference is large, the following problems occur:

  • Chainring has a lot more teeth than the FD is designed for: like explained above. FD will have to be mounted too high, which will make shifting slow, poor and might cause chain rub on the rear lowest part of the FD after shifting onto the smallest chainring.
  • Chainring has a lot less teeth than the FD is designed for: front part of FD will be correctly positioned, while the rear part of the cage will remain high up, and the chainring curves sharply down. It will not align. This will not hurt shifting, but will cause a lot of chain rub on the FD cage – as soon as some shifting gears in the rear sprockets causes minimal amount of cross chaining.

b) mounting angle

Seat tube angle (onto which FD is mounted) is usually about 70 to 73 degrees for road bikes, while MTBs usually have a bit steeper seat tubes (closer to vertical vertical compared to road bike ones), of around 75 or more degrees. If a FD designed for a more vertical tube is mounted on a tube that has a less vertical angle, the effect will be similar to that of combining a FD designed for a lot smaller chainring, with a chainring that is bigger. And vice versa.

Though this is a bit misleading. For a full disclosure: modern road and MTB frames don’t really differ all that much by seat tube angles. What differs is the angle between the chainstay and the seat tube. MTB bikes have that angle a lot smaller, compared to road bikes (by roughly 5, or more degrees), and that is the angle that matters as far as front derailleurs are concerned (see the next paragraph, below the picture).

A FD designed for a lot steeper tube is put on a more vertical one. The rear part of the cage is too high, even though FD is mounted at the correct height.
A FD designed for a less vertically angled tube is put on a more vertical one.
The rear part of the cage is too high, even though FD is mounted at the correct height.

It is worth noting (thanks to Drew for pointing it out) that frame manufacturers provide seat tube angle as measured from horizontal (which matters for riding position fitting), while Shimano (for one) notes their front derailleur angle as the one between the seat tube and the chainstay (which actually is what matters for the front derailleurs). So those (“Shimano”) angles are often 61 to 66° degrees for road FDs, and 66 to 69° for MTB front derailleurs.

Similar problems can occur if the mounting position isn’t correct – happens on some special, or custom built frames.

A frame on which, because of the low rear axle, FD must be placed a bit behind the seat tube. A specific case.
A frame on which, because of the low rear axle, FD must be placed a bit behind the seat tube.
A specific case.

If a FD is a braze on mounted type, this can be corrected with made adapters:

Adapter for changing FD angle to a steeper one and for moving it to the rear.
Adapter for changing FD angle to a steeper one and for moving it to the rear.

– T.O.C. –

4. Double vs triple

FDs are made in two variants: for double and for triple front chainrings.

Double vs triple FD
Double vs triple FD

Double FD will work with a triple chainring if the difference in teeth number between the smallest and the largest chainring is rather small (which defeats the purpose of a triple chainring though). For example a 34-42-48 chainring. Also, if the operation (movement) of the FD is limited to the two largest chainrings, it can work OK.

Triple FD will work on a double chainring if the difference in teeth number between the chainrings isn’t bigger than 12. One can “get away” with 14 as well, but the lower difference, the better.

Compact cranksets, with two chainrings that vastly differ in size (usually 34-50 combination) will work well only with double FDs with the curve appropriate for the big ring size (50 to 52). Even when using a double FD, it is best to keep the tooth cound difference up to 16 (like with 34-50, or 36-52 chainring combinations).

– T.O.C. –

5. High clamp, low clamp, or side-swing

With older standard for FDs, the cage is below the mount, so that FD cage swings below the FD body. These are the high clamp FDs. Low clamp is a newer Shimano system meant for MTBs with rear suspension. FD cage is practically in line with the mount. This leaves more room for mounting the rear suspension to the seat tube. Previously used terms for this were bottom swing (for high clamp) and top swing (for low clamp), but with the introduction of Shimano side-swing system (explained at the end of this chapter), these terms are no longer precise enough.

Bottom swing FD - standard one - cage is below the FD body
High clamp FD – standard one- cage is below the FD body
Top swing FD - the cage is above the FD body
Low clamp FD- the cage is above the FD body

If the bike has no rear suspension, or there is enough room for a standard FD below the suspension, it is irrelevant which type of FD is mounted (as long as it’s suitable in terms of other explained criteria – angle, size etc.).

The newest Shimano system is the side-swing, where the cage rotates sideways. These FDs can be clamped with a high clamp, low clamp, or using a direct mount system.

Shimano Side-Swing front derailleur
Shimano Side-Swing front derailleur

– T.O.C. –

6. MTB vs road FD

Shimano road and MTB FDs have different cable pull ratios – that is the amount of FD movement for each mm of cable movement. This means that MTB FDs might not work well with indexed road shifters and vice versa.

With double chainrings, this issue can be fixed by adjusting limit screws and it could be made to work (if not perfectly). With triple chainrings, it is harder to get it to work properly. However, the FD cage is a lot wider than the chain and triple FDs have just 3 positions you need to “match” (unlike reaer derailleurs with 6 to 13 different positions), so depending on the particular shifter – FD combination, even that can sometimes be made to work OK.

Note that MTB shifters usually have 2 clicks (for a total of 3 FD positions), while road bike STI shifters have 2 “full clicks” and 3 “trim” clicks (for minor FD position adjustments), so a total of 5 clicks/positions. Friction shifters, of course, give you an unlimited freedom in terms of fine-tuning the FD’s position. 🙂

Having said all this and in spite of officially different cable pull, some FDs work OK with all the shifters, regardless of whether it is road, or MTB. Exception are the Shimano 11 speed road FDs and Shimano Tiagra 4700 10 speed FDs – they have a (vastly) different cable pull (and cable anchor arm), so they are not compatible. So, while this will not shift perfectly, especially with triples, it is worth giving a try and seeing if it’s good enough for one’s criteria – if what one has on hand are mismatched road and mtb shifters and FDs. If it doesn’t work satisfactory, the cheaper option is to find a FD that matches the shifter.

– T.O.C. –

7. Number of speeds

The last AND the least important.  🙂

FDs are made for a certain number of speeds, i.e. number of rear sprockets. The more speeds, the narrower the chain. There are FDs for 6 to 8 speeds, then for 9, 10 and 11 speeds. Cage width is made to match the planned chain width.

FDs for 9 (left) and 10 speeds (right)
FDs for 9 (left)
and 10 speeds (right)

However, since the chain moves left-right on the rear sprockets, FD cage is a lot wider than the chain. That is why it is possible to mount a 10 speed FD and use it with a 6 to 8 speed chain.

FDs are very forgiving in terms of speed number (even in terms of manufacturers), so they can be mixed and matched. One of the few pieces of equipment where it is possible to change a Campagnolo 10 speed with a Shimano 8 speed and it all works.

When a FD for more speeds is put on a chain for fewer speeds, the only bad effect is more chain rub. Since the FD cage is narrower, smaller angling of the chain (when changing gears at the back) will cause it to rub the FD cage. With indexed shifters, a trimming option can help, while with friction shifters this is not an issue.

– T.O.C. –

8. Exceptions

Exception to this rule are Shimano 11 speed road FDs. They will not work very well with anything but Shimano 11 speed road shifters and Shimano Tiagra 4700 10 speed road shifters. Same goes for Tiagra 4700 FDs. Newest Campagnolo 11 speed system: Revolution 11+ (older one is Revolution 11) also requires matching (Revolution 11+) shifters and derailleurs. The reason for incompatibility lies in different cable attachment and amount of needed cable pull per gear change. Why was something that had already worked “fixed” has probably more to do with the marketing, than with the engineering department of the company.

Another exception is the new “gravel” group (with hydraulic brakes): Shimano GRX. Caple pull wise it’s the same as Tiagra 4700.

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Related post – Front derailleur:

Bicycle front derailleur (FD). Types of front derailleurs, frame mount standards, FD compatibility...
Bicycle front derailleur (FD). Types of front derailleurs, frame mount standards, FD compatibility…

Compatibility posts are also available in eBook (printable and Kindle) and paperback editions on Amazon:

Bicycle drivetrain compatibility book
Bicycle drivetrain compatibility book

If you have any questions (or additions and corrections), please use the BikeGremlin forum’s compatibility section:

The existing comments (questions and answers) posted under this article were moved to this BikeGremlin forum thread:

– T.O.C. –

148 thoughts on “Compatibility [05] Front derailleurs”

  1. Hi, Hope you can help. I have bought a Calibre Stitch hybrid bike which i like, apart from the chain rubbing the front derailleur Claris) in a few gears when the chain is over angled. I have a spare front Altus, which has a wider gate. Do you think this would be compatible, and solve the rubbing problem?

    • If all is properly adjusted, having the chain rub when “severely cross chained” (as in – using the largest 2-3 rear sprockets from the largest front chainring and/or using the smallest 2-3 rear sprockets from the smallest front chainring) is a nice, harmless warning that your choice of gearing is not very good for the chain.

      I suppose that going with a wider cage FD can help eliminate that, or at least make it audible only for the very extreme combos (like the last 1 rear sprocket at the opposite side from the used front chainring, not 2-3 sprockets).

      Altus is not a perfect match for the Claris shifters, but it could be made to work satisfactory (depending on one’s criteria), especially with double front chainrings (with 3x it’s a bit more of a hassle). But it would be solving a problem that doesn’t really exist. Like using poor brakes, because a bicycle goes hardly when brakes are applied (sorry, can’t think of a better example).

  2. Thanks for that. I think i will just live with it, and take note when its rubbing, and change to a more appropriate gear.

  3. Hi, Maybe you can help me out.
    It seems there is too little information around yet about 12 speed stuff. However, I’m trying to hack together a 2X12 system for a 29+ Drop bar frame for extended off-road touring (probably using 2.5”- 3.0”). I’m a Campagnolo user and have worked out everything except for the front derailleur / chainring combinations. I’m thinking I’d like somewhere from 19-120 gear inches. Jtek make a shift mate for Campy 12 – Shimano MTN 12. So with the Shimano 12s 10-45 rear cassette I’d need a 42-28 or 40-30 chainring or thereabouts (boost spaced 104-64 spider on Race Face cranks). This leaves me with a quandary. How do I get a derailleur to work with a 12 speed Campagnolo shifter over teeth that are that size? The smallest chainrings that Campagnolo suggests for the Chorus front derailleur are 48-32. Could this derailleur be modified to work? (Angled shims, Band on adapter for boost spacing). Would the Shimano 2X12 derailleur work better even though it’s specced for 36-26 chainrings. Is the pull of the Campagnolo 12 shifter going to be able to move the derailleur into the right position? I’m so lost.

    Thanks for the write up btw. I learnt more about the front derailleur from this post than all the previous things I’ve ever read.

    • Hello,

      I’m afraid that I can hardly say anything you don’t already know – sorry. But won’t waste too much of your time (the reply is still under 10 pages long 🙂 ).

      Firstly I have to make a disclaimer: I live and work in Serbia, a rather poor, devastated country, so don’t see much of the new stuff – until it becomes the old stuff. 🙂
      My estimates from charts, specifications and manufacturer inquiries are usually correct, but think it’s fair to point out for stuff that I haven’t personally tested.
      To make things even worse, Campagnolo is like a unicorn here: everyone knows it’s nice and cool, but no one’s actually seen it! 🙂
      OK, being a mechanic, I get to see a few – more than the “normal” cyslists (if there is such a thing 🙂 ), but still not very much.

      Secondly, I’d give myself the liberty to add, even if not asked, that for touring I’d go with simpler, more robust stuff – like friction shifters and fewer cogs at the back.
      Using triple front chainrings.
      This easily provides wide enough gearing ratio, with gears still being “tight” enough so that the desired gear ratio is always available.
      Another advantage of such systems is they work flawlessly with practically any chain (or cassette for that matter) that you throw at them (this can matter in case of a malfunction while away from any well equipped store).

      OK, with all that out of the way:
      I would expect 42-30 to work OK with a derailleur for 48-32. If fast shifting under load is not needed (like when racing), and if one’s criteria of fast/smooth front shifting is not too strict, it would probably work OK. I’ve mix-matched road 50/53 large chainring double FDs with MTB cranks and had them do just fine – especially with the doubles.

      For mixing Shimano FD with Campagnolo shifter – I haven’t tried that, so will have to look up the manufacturer specs (if there are any cable pull specs) and see. I would bet a beer that it can be made to work, with a double, but can’t say for certain, unfortunately.

  4. Hi,
    Thanks for great content on the site! I have a bit of conundrum with my front mech setup, hoping you would be able to help maybe?
    I’m looking to build a CX bike around an old frame which is equipped for a top pull cable routing. I find it extremely hard to find a fitting FD
    – CX70 (top pull) seems to be good candidate, but it proves extremely hard to get (at least based on my attempts so far – either out of stock, or even when sellers claim they have this, in the end they delay and decline the order…) and then also I’m worried about compatibility – would it work with Tiagra 4700 shifter? (Shimano claims compatibility with 10 speed groupsets, but apparently 4700 has different pull ratio than previous ones…)
    – secondly, Ultegra FD-8000 claims to be “Dual Pull” which would mean both bottom and top; 105 and GRX seem to share the construction and also claim “more cable routing options” but any setup instructions only show the bottom pull setup – so how is that in real life?
    – finally another option would be to engage some MTB derailleur which more commonly come in top pull, but then again would that work OK with road shifters (Tiagra 4700 or 105 7000 series)?

    Thanks in advance for any insights on this!


    • Shimano’s compatibility charts are given on their website and are usually quite conservative – meaning that whatever they say will work, works.

      4700 front shifter (as well as their 11 speed road shifters) pulls more cable than the other Shimano’s front shifters. For doubles, FD limit screws can help so one can make it work OK (depending on one’s criteria of how good it has to be for it to be considered “OK”).

      Stated “more cable options” means that the FD accepts both the “naked” cable, and the cable that comes with housing, all the way to the FD (the FD has a housing stop built in). However, for all I know, in order for that FD-8000 to accept top routed cables, one would need to use an adapter.

      Hope this helps, let me know if you have more questions.


  5. Good day,

    Just wanted to know if the old 105 fd(5800) is compatible with the new 105 crankset (r7000)?

    Thank you in advance!!

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