JOAJOA Posts: 21
edited November 2011 in Workshop
I know this has come up before but I can't search for anything at the moment.
I am currentling running a shimano 2300 groupset and I'm upgrading it up to 105 5600 which makes it the same as my race bike.
I've got a new set of sti's, cassette and chain.
I am about to get a new chainset and front mech and cables.
Do i need a new bb or will the 2300 one fit and is there anything else I'm missing.

Also is this going to be a pain in the arse to do it myself?


  • Gary D
    Gary D Posts: 431
    Yes, you will need a new Bottom Bracket.
    The 2300 is a square taper sort (BB-UN26), whereas the 105 5600 is a Hollowtech II. They are totally different.
    Sometimes when you buy a crankset of this type, it will include the bottom bracket as part of the package. However, if you have to buy one separately they are less than £20. You will need a special tool to tighten the BB and the retaining plug for the LH crank. The Park Tools one is BB-T9 http://www.parktool.com/product/bottom- ... tool-bbt-9 although you can get other makes.
    I presume it is just an omission, but you will also need a new rear mech :wink:
    The changeover shouldn't be too difficult - just take your time and refer to instructions :oops:
    Good luck!
    Oh and I feel like I've been raped by an Orangutan :shock: And I've got legs like Girders :lol:
    JOAJOA Posts: 21
    The bb I have on my race bike is an internal press fit, I was thinking of going for the same on this bike rather than the external bearings. Which would be better?
    I was also not going to get a rear mech, I thought you could just use the old one?
  • keef66
    keef66 Posts: 13,123
    If your frame has a UN26 BB at the moment you can't switch to a press-fit BB system, you need something with threads like the HT2.

    You might be able to get away with the 2300 rear mech, but if it was mine, that'd be the one component I'd want to upgrade.
  • John.T
    John.T Posts: 3,698
    You do not need to change the front mech. It is the last thing on my list for changing. The rear one, while not the best, will work fine. You may as well wear it out a bit more over the winter. You need shifters, cassette and chain. The rest will work OK and can be upgraded later if money it tight.