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My current front setup is a 28-38-48 crank with Deore XT shifter & derailer. In addition to a FD-443 and top/bottom-pull converter, what else will need to be purchased for proper shifting?

Also, yes, I do notice chainline issues on the 28 and 38, since it doesn't like 2-3 (on 8-speed), by which I mean chain-on-derailer action.

Note: the reason for the FD-443 is because "Shimano does make one model of front derailer designed to work with "road" (52-42) chainrings and RapidFire upright-handlebar shifters, the FD-R440 model." (http://sheldonbrown.com/front-derailers.html). The triple in the FD-440 series is the FD-443. As it's bottom-pull instead of top-pull, a top/bottom pulley converter is also needed.

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  • 3
    Sounds like you need to trade with Reid.
    – Daniel R Hicks
    Jun 4, 2012 at 20:35
  • 2
    I don't understand your comment.
    – moshbear
    Jun 4, 2012 at 20:37
  • Reid is looking to accomplish the roughly opposite transformation. You might actually be able to work out a part swap.
    – Daniel R Hicks
    Jun 4, 2012 at 20:42
  • 2
    @wdypdx22 -- Some of the comments could be turned to answers.
    – Daniel R Hicks
    Jun 5, 2012 at 2:42
  • 1
    Please avoid extended discussions in comments. Would you like to automatically move this discussion to chat?
    – user313
    Jun 8, 2012 at 1:37

2 Answers 2

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+50

You will need to purchase only 4 items to accomplish this swap:

  1. Crankset - Standard road triple
  2. Flat bar road shifter set ST-443
  3. FD-443 front derailleur
  4. Possibly new cables, if they don't come with the shifters.
  5. A new chain designed for the number of gears in your cassette.

You will also need to ensure that you've enough adjustment range on the frame to move your front derailleur up by up to 2cm, and that the derailleur you purchase is dual pull, so that you don't need a pull converter.

But it seems to me you've already worked that out.

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  • With regards to crankset, LBS says that there's 2-3 mm of insufficient chainstay clearance. With regards to the shifter, I'm staying away from STs because remote master cylinders don't exist yet for hydraulic disc brakes, and I enjoy the RapidFire mechanism too much. Also, high-clamp derailleurs and the frame do not go together well. I'm using a FC-M591 26-36-48, and should I need the larger gears, I can just open AutoCad and machine custom chainrings fitting HollowTech II mountain/touring cranks. It should be cheaper than machining a custom crankset.
    – moshbear
    Nov 8, 2012 at 10:22
  • More power to you.
    – zenbike
    Nov 8, 2012 at 10:55
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The chainrings you want to use are only 7% to 10% bigger [1] than the ones you currently have. You may be able to simply swap your current chainrings with the ones you want, leaving everything else the same [2]. You would need to raise the front derailler clamp (the part which holds the front derailler to the seat tube) by about 2 cm [3]. You would also need to readjust the front derailler cable after you raise the derailler, since it would be 2 cm closer to or farther from the shifter depending on whether you currently have bottom or top pull.

[1] 30/28 ~= 1.07 and 53/48 ~= 1.1

[2] This assumes that the old and new rings both use the same bolt-circle diameter, sometimes abbreviated BCD. If they don't, you'd need new cranks as well, and possibly a new bottom bracket if you can't find similar cranks.

[3] Bicycle chains use a 1 inch pitch (distance between the centers of two adjacent link pins), so a chainring with x teeth is x inches in diameter. (53 inches / (2pi) - 48 inches / (2pi)) = 2cm, so the new ring will have a radius 2 cm greater than the old one.

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  • Due to BCD mismatch, the fact that square taper starts creaking after half a year, and the fact that road triple crankarms don't clear the chain stay, I'm modifying a 4-bolt Hollowtech II mountain crank to use 5-bolt 135mm in AutoCAD and then getting quotes from various machinists / mills.
    – moshbear
    Jul 16, 2012 at 19:36
  • Also, pitch has been 1/2" for practically all bikes since WWII.
    – moshbear
    Jul 16, 2012 at 19:40
  • Your math is off. The circumference of a 53t chainring is definitely not 53 inches.
    – zenbike
    Oct 13, 2012 at 2:24
  • Yeah, @zenbike is right. A full chain link is 1". A single link covers two teeth, a half link sits on each tooth, so the pitch is 1/2".
    – jimchristie ♦
    Nov 3, 2012 at 2:07

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