Changing Inner Chainring - Shimano Compact

DubaiNeil
DubaiNeil Posts: 246
edited September 2011 in Workshop
As I generally ride in a very flat part of the world, I was considering changing from the currently fitted Shimano compact (Ultegra 6700) to a "Standard" double, as I would prefer the smaller gearing difference between the 39/52 compare with 34/50.

The price however to replace the compact chain set does not make this particularly worthwhile though.

I would also like to be able to revert back fairly easily to a compact when I have trips abroad, and therefore have to climb.

I have seen a 36 tooth 110 BCD inner chain ring available, and would like to understand how difficult this would be to fit, ideally without disturbing the cranks & bottom bracket area.

Is it possible to "slide" the chain rings off the drive side crank arm/spider etc to remove them, or does the whole crank assembly need to be removed to change the chain rings?

Before anyone says "just change the cassette" - I already have a whole set to choose from, however the one most likely to be "ideal" for me (on 34/50) is the 11-21, which is only available as a Dura-Ace version (no Ultegra or 105) so costing GBP 122!

Neil

Comments

  • Sometimes you can sometimes you cant, however with the ultegra setup removing the cranks is really easy. If you look on park tools you'll see you don't really need any specific tools as the preload nut tool can be done up and undone with a pair of needle nosed pliers fairly easily.
  • prawny
    prawny Posts: 5,440
    I've got a 50/36 set up on my boardman, it was a standard option when compacts first came out and you can still get Sram Red chainsets like this. All you need to do is take off the non-drive side crank oarm off, pop the axle through with a soft mallet or similar pop the old chainring off and stick the new one on. Shouldn't need to adjust mechs at all, maybe just the inner stop.

    I think I'm going to do the reverse of this over the winter, I often find myself wishing for a slightly lower bottom gear, especially when the weather is bad.
    Saracen Tenet 3 - 2015 - Dead - Replaced with a Hack Frame
    Voodoo Bizango - 2014 - Dead - Hit by a car
    Vitus Sentier VRS - 2017
  • markos1963
    markos1963 Posts: 3,724
    No need to remove the cranks on a Shimano compact if it's a Hollowtec one. I do this regulary, just undo the chainring bolts, rotate the chainring a bit then slide over the rh crank, then do the same with the inner ring. You'll want a tool to hold the back of the chainring bolt to stop it spinning when undoing and tightening( I use a handily size piece of steel)
  • DubaiNeil wrote:
    As I generally ride in a very flat part of the world, I was considering changing from the currently fitted Shimano compact (Ultegra 6700) to a "Standard" double, as I would prefer the smaller gearing difference between the 39/52 compare with 34/50.

    The price however to replace the compact chain set does not make this particularly worthwhile though.

    I would also like to be able to revert back fairly easily to a compact when I have trips abroad, and therefore have to climb.

    I have seen a 36 tooth 110 BCD inner chain ring available, and would like to understand how difficult this would be to fit, ideally without disturbing the cranks & bottom bracket area.

    Is it possible to "slide" the chain rings off the drive side crank arm/spider etc to remove them, or does the whole crank assembly need to be removed to change the chain rings?

    Before anyone says "just change the cassette" - I already have a whole set to choose from, however the one most likely to be "ideal" for me (on 34/50) is the 11-21, which is only available as a Dura-Ace version (no Ultegra or 105) so costing GBP 122!

    Neil

    Hi Neil,

    I have a Shimano Hollowtech II 52/39 crankset if you are after one. Cost would be £30 posted. It came off a Tiagra set-up, so not sure if it is of the standard you are looking for, but the option is there. It is in good condition and has had minimal use as I swapped to a compact a short time after purchasing the bike.

    FYI, it is a really straightforward job to swap between this and a Hollowtech II compact crankset. When I did it I was able to continue using the same chain, and didn't need to alter the front mech either.

    Cheers,

    Ben