I recently upgraded to a new bike (Tarmac 2019) and got a size 58. I also got a bike fit by a local fitter. When we finished the fit there were a few tweaks including moving the saddle up several cm (74cm total) removing all but a 1cm spacer under the 110mm stem and moving the seat about .5cm forward.

After the fit one of the comments he made was,"You're somewhere between a 56 and 58 with this model frame."

For some reason this has haunted me. I know the reasoning for "downsizing" on a frame, you can get more aero and the frame is lighter. But should I actually worry about this? All the reading I've done says that it would be too big if was swapping out the stem for a 90mm or having to get a seatpost without an offset which I didn't need to do. Any opinions or thoughts whether I should be concerned that the bike is too big are appreciated.

  • First test -- can you comfortably stand flat-footed while straddling the bike (not on the seat)? Second test -- is the "reach" OK. If these work out then the bike should be OK. Commented Aug 25, 2019 at 0:10
  • 2
    Is it comfortable to you, as is ? If yes then just ride it. If no then tell us exactly what's uncomfortable. Right now you're worried about the fitter's idle comment - so ask him exactly what he meant.
    – Criggie
    Commented Aug 25, 2019 at 0:27
  • 3
    All of these parts are adjustable on purpose.
    – ojs
    Commented Aug 25, 2019 at 5:50
  • Thanks for the feedback, @Criggie nothing is uncomfortable its more around can I achieve an optimal position for racing or could the frame size be a hindrance? I'll talk to the fitter and see what his thoughts are. Commented Aug 25, 2019 at 16:18
  • 1
    From the description it sounds like you could set up for optimal position. The aero and weight gain from smaller frame is going to be unmeasurably small, but if you get a mental boost from it, go ahead. I'd recommend uncomfortably small frame just so that you don't forget you are seriously optimizing. Or a custom frame at 57.
    – ojs
    Commented Aug 26, 2019 at 15:40


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