Shimano Chainset removal and replacement

Discussion in 'Cycling Equipment' started by BILLYHOLMES, Feb 4, 2007.

  1. BILLYHOLMES

    BILLYHOLMES New Member

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    I am upgrading my 06 Trek Madone 5.2 Shimano Ultegra chainset (10 speed) and bottom bracket to a Dura Ace 7800 (10 speed) mainly because I need 165mm cranks and the Ultegra's only go down to 170mm. Assuming I get the two special tools required TL-FC32 and TL-FC16 how difficult is it to do, is it a sinch, or should I get the LBS to do it?
    Regards,
    Bill.
     
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  2. hazychris

    hazychris New Member

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    Really easy.

    I don't think you need to replace the bearing, just slide the old chainset out and put the new in.

    You can get away with no tools if you use a set of narrow-nosed pliers to tighten the tightening cap on the left crank - you just need an allen key, but best to use a torque wrench for the crank bolts.

    Cheers,
    Chris
     
  3. sideshow_bob

    sideshow_bob New Member

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    it's a snap, less than 5min of work. i'd give the shimano tools a miss for this one. get one of the alternatives that has the bb ring at one end and the preload cap tool at the other. you should be able to pick up the park equivalent for less than $20.

    as the other poster said you probably don't actually need to take the bearing cups out at all, but i usually do this a couple of times a year just to clean everything out in there.

    --brett
     
  4. BILLYHOLMES

    BILLYHOLMES New Member

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    Is removing the cups easy? I think I would for sure need tool TL-FC32, however in using the tool how do you know what torque you are at.... feel? Shimano say 35-50 NM using the tool, but the tool has no way of connecting to a torque wrench so how do you know what the torque is?
    Thanks for your time.
    Bill
     
  5. sideshow_bob

    sideshow_bob New Member

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    you need the shimano bb tool (or equivalent). like i said my preference is not the shimano product.

    the torque spec is a pretty wide range and i'm comfortable doing it by feel. (different to say a stem on a carbon bar that says 6-8nm, that is a narrow range and you want to get right). 50nm is reasonably tight, i don't go too crazy putting it on, just cinch it tight then a single solid turn. i'll pretty much guarantee that 90%+ of shops you take it too do it the same way via feel.

    i usually find in servicing mine that once i've got the tool on the cup, i need to give it a couple of light taps with a rubber mallet to to loosen it.

    --brett
     
  6. BILLYHOLMES

    BILLYHOLMES New Member

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    Thanks Brett I feel quite confident about the whole thing now thanks to you guys.
    Regards,
    Bill.
     
  7. sideshow_bob

    sideshow_bob New Member

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    no problem. theres not really much that can go wrong unless you strip or cross a thread. so:

    a) if you take the cups off and clean/grease make sure they spin back on nice and easy and the thread is seated right before you crank them with the bb tool.

    b) don't overtighten the crank pinch bolts. again it's just alloy, and is easy to strip a thread out, then your off side crank becomes a paper weight.

    c) if you don't over tighten the preload then the offside crank should come off pretty easy. however as you didn't assemble it, it may be over tight and you need to slip a flat head screwdriver between the crank and the cup bearings to ease the crank off.

    d) when you are putting it all together, i can't remember what the torque required is on the pre-load cap, but it's not much, maybe 4Nm from memory. as soon as you start side loading the bearings by over tightening you'll notice the cranks won't spin freely. again i do this by feel and always make sure the cranks are rotating nice and freely before torquing the pinch bolts. sideloading the cups isn't the end of the world, just reduces the functional life of the bearings, so while you want to get it right, it's not like say stripping out the pinch bolt thread.

    --brett
     
  8. bomber

    bomber New Member

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    What about changing from the old style shimano BB i.e. Ultegra 9 to the newer Hollowtech 2 variety i.e. Ultegra 10.

    Is that easy? Is there much prep work that has to be done?
     
  9. BILLYHOLMES

    BILLYHOLMES New Member

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    Sorry Brett but what is this "pre-load cap" you talk about.
    Thanks for taking the time.
    Bill.
     
  10. capwater

    capwater New Member

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    That is fairly simple and straightforward as well. New cranks and BBs required. Old cranks off, old BB our. Put in the outboard bearing cups and in goes your crank.

    With the external bearing BBs, you need to pre-load the bearings. Essentially you are pulling the crank arms together. you don't want to monster torque the cap or your cranks won't spin. Check out www.parktool.com for some specific info.
     
  11. Tech72

    Tech72 New Member

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    Very easy to install the Shimano crankset with external BB, it's a 5min. job. See the attached instructions.
     
  12. sideshow_bob

    sideshow_bob New Member

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    no the new ones just bolt straight in. the only thing is you'll need specific tools to get the old assembly out assuming you don't already have it. crank puller and a different bb tool.

    basically remove crank bolts, insert crank puller and pull cranks off (repeat for drive and off side), then remove both cup sides of the 'internal' bottom bracket. should take about 15 minutes or so.

    once out I usually clean the bb shell out with a rag with white spirit on it (or shellite or petroleum ether, all the same just different names). lightly grease the shell threads. then put the new cups in.

    --brett
     
  13. sideshow_bob

    sideshow_bob New Member

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    on the offside crank there will be a round plastic cap. this screws into the inside of the drive shaft. when you tighten it in (using the tool, or long nose pliers) it basically torques the cranks together preloading the bearings in the external cups.

    if you over tighten it the cranks wont spin freely and you need to back it off before doing the pinch bolts

    --brett
     
  14. artemidorus

    artemidorus New Member

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    The bottom bracket shell faces need to be parallel to one another or the external bearings will be misaligned and willl wear prematurely. With an internal bearing BB, this wasn't critical so the faces can be out a bit. I would go ahead and install it, but if the axle does not slip easily through the left cup, or if it spins roughly after installation, despite fiddling with the preload, I would take the cups off again and have the LBS machine the faces.
     
  15. BILLYHOLMES

    BILLYHOLMES New Member

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    Now I understand.
    Thanks Brett.
    Bill.
     
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