Compact Frame Sizing

nickl360 Posts: 59
edited February 2012 in Road beginners
Is it the norm to go down a frame size when buying a compact frame compared to a normal geometry frame because of the sloping top tube?

I'm 186cm (just under 6ft 2") and wear 34" leg trousers. I understand there is more to it than just height and leg size however I thought I'd need a 58cm but reading around it suggests a compact would require a smaller frame size?


  • flasher
    flasher Posts: 1,734
    The most important measurement is the virtual top tube, work out what reach you need and go from there.

    All makes sizes their bikes slightly differently, one makes 56 is anothers 58 or L/XL etc....
  • I was looking at the Forme Vision 2011 at CRC, particularly the 58cm frame, but just realised its a compact and thought I might need a 56cm frame which they don't have stock.

    For people who ride both standard and compact, did you go down a frame size for the compact?
  • flasher
    flasher Posts: 1,734
    No, and the Vision is semi-compact at best, look at pics of a Giant road bike to see a full on compact road frame.

    FWIW. I'm 5' 11" and ride a 56 Forme Plateau..........
  • fosst
    fosst Posts: 45
    As it has been said, top tube dimension is the one to look at.
    I have a couple of non compact frames in 56cm, my Giant is a 50.
    Top tube dimensions are identical across all three bikes but stem length varies between 110-120 to get the fit I want.
    Oddly, the seat post on the Giant is about 5mm up from the lowest possible position, but if I went for the next smallest size of frame then the reach would have been too short.