Chainset Upgrade

Hi, im thinking of upgrading from Tiagra 9 speed to 105 on my Trek 1.5 when things start needing replacment, but i have a couple questions re compatability that hopefully somebody might be able to answer for me?

1) My Trek currently has a Shimano sealed Cartridge Bottom Bracket but the 105 cranks that i looked at come with a hollowtec 11 BB. Is this BB compatible with the size & Threads on the frame? If not can the 105 crankset be fitted to my cartridge BB?

2) Obviously i will need to fit a 10 speed cassete but will this fit directly onto my Hub or will a new hub/wheel be required as well as this is another cost that needs to be dealt with?

Thanks in advance for any advice


  1. You will need to use as you say the hollowtech BB, yes it will fit your frame, no need to change cassette, if you went to 10sp you would need new shifters as well

  2. The 10 speed cassette will fit your hub but you will need to add a spacer to the hub beforehand (hopefully comes with the cassette but can otherwise be sourced from the likes of CRC or Wiggle)

  3. I upgraded a 2011 Allez Sport (Sora 9 speed) to 105 5700. The Shimano freehub is 8/9/10 cassette compatible. The 105 5700 10-speed cassette came with a thin spacer to place behind the big sprocket.
    I also upgraded a 2010 Rockhopper from Shimano Deore cranks and Octalink ES52 sealed BB to Race Face cranks and Hollowtech II BB. The BB shell is threaded to accept the cups for the sealed units and the outboard HT II BB, so you don't need to do anything about the threads. However, as the HT II BB cups screw up against the outer faces of the BB shell, you need to make sure that the left and right hand faces are parallel and perfectly smooth (with no paint). There is a procedure called 'facing' that your LBS can do to prepare the BB shell faces for HT II BB's. I didn't get it done as my Rockhopper's BB shell had already been machined and looked to be in perfect condition for fitting the HT II BB - I took the risk that the threads were parallel, as I had spare HT II BB.

  4. Thanks everyone for your advice! As mentioned above i will also need to change the shifters and i remember reading somewhere about different pull ratios on the brakes, will i therefore need to replace the calipers as well?? This upgrading from 9 to 10 speed can get expensive me thinks!!

  5. Merlin Cycles have a complete 105 groupset for about 300!! Bargain!

  6. The 105 5700 STI and callipers changed the pull ratio from the earlier 105 5600 and Tiagra and Sora. The 5700 now matches 6700 and 7900. But I have found that the 5700 brakes to be much better than the Sora 3400 that I replaced.

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