Preface: I ride about a 56cm. I may be picking up a 'too small' bike (looks around 50cm give or take) which is
obviously too small, right? However. I've been on a quest the last year or so to try to find my 'correct' size. It turns out 'correct' can mean a lot of things, and it seems like there is quite the willy-nilly approach to sizing, given the application - French fit, race fit, and what not. What initially got me thinking about this was a couple years ago when I picked up this little Novara Randonee which is probably about a 52cm. Again, obviously too small. But the bike had a tall stem, and the saddle raised up high enough for me. It was actually really comfortable. I stopped riding it because I got a weird feeling in my knee when I rode it.
However, I've been playing around with geometry and adjustments a lot recently (via the Guerciotti and Huffente in the other thread), and just for kicks, I took a look at the Randonee again. Re-adjusted the saddle, and have been riding it. No knee pain (which makes sense, if the saddle/crank relationship is identical to other bikes I ride). So it got me thinking...
just what is 'too small'?
I sort of get the feeling that seat tube length means nothing, apart from standover. You can simply adjust the seatpost higher, and it adjusts along the same angular plane of the seat tube angle, so if that was taller, it wouldn't change a thing. Where it seems like it matters a lot more is in top-tube length, and overall wheelbase length, where a shorter wheelbase would create more toe overlap, and a shorter top tube would necessitate a longer stem, which changes steering.
Case in point: I've been looking up bike pictures recently, and here are a few that I've found that are interesting:
Both of these are Miyata 1000s. Probably both around 50cm. Look at the saddle, and then look at the stem. There are plenty of people that would look at these two bikes and say 'too small!' for the rider. But these people are riding these bikes. Are they wrong? Are these bikes too small for the rider? Is there too much toe overlap? Is steering negatively affected? Is having a shorter top tube somewhat looked more favorably on a touring bike, where it may be considered a less aggressive position?
I'm going to try to make this 50cm bike work. If it doesn't, it is an easy pass to one of my kids, or potential trading material in the '
frame doesn't fit pass-around game' thread.
I'm also paging
campfire as his Bianchi Grizzly is setup the same way - small frame, higher seatpost and stem -
If anyone else rides a bike in this configuration, with a small frame/shorter top tube, and higher saddle and stem, I'd be interested in your thoughts.