Do you happen to know what the Q Factor of the Alfine Crankset is? I've looked all over the web and can't find this piece of information. I'm interested in the single chainguard 42T version, and my frame BB shell width is 68mm.

The chainline is specified as 42.7mm which is perfect, right in the middle of my road bike's cassette. But no q-factor is specified.

If you can't provide an exact measurement, what would a likely range be? I'm confortable with a 150mm - 180mm q-factor, so if it falls within this range it's great.

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  • 1
    If you can find this same photo for a real alfine crankset, then a scale measurement might give a useful number. The photo above shows a triple crankset, and the alfine is a single chainring only.
    – Criggie
    Commented May 4, 2022 at 0:03

1 Answer 1


Alfine is Tiagra rebranded with a different BCD chainring. It's quite narrow, hardly clears the chainstays on my Trekking bike with Nexus Hub.

I measured it with calipers as described in the comment below. With both downtube and seat tube. It is 150mm (consistent Measurement). Some other interesting facts: NDS crank arm is 13.5mm thick at the end, DS is 14mm. NDS clearance to my frame is just abt 1mm. DS clearance to chainstays about 3mm. Asymmetry might be because of bent crankarm. I can't really see any bend, though. OR maybe it's normal (some experts said it is).

  • 3
    You can take off the left crank arm and mount it 180degrees to take the measurement. The Shimano cranks of this type allow the crank to be slid on at 0 degrees and 180 degrees which is useful for storage of cranksets, i find.
    – Noise
    Commented May 11, 2022 at 22:16
  • Just measure from the outer face of the crank arm to the center of the downtube or seat-tube and multiply by 2. Or do it on both sides and add them together, for a more precise result.
    – Robert
    Commented Jun 4, 2022 at 18:09
  • If you have calipers then it's simpler. You don't have to eye-ball the center of the tube, because you can include it fully in the measurement and then subtract half its diameter.
    – Robert
    Commented Jun 4, 2022 at 18:16

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