How big of a difference will 2cm make?
 

Hey there, there are two used bikes I have found nearby me. One is 150$ and the top tube is 4cm too short for me, another is 300$ and the top tube is 2cm too short for me (by my rough calculations). Will the bike be a lot more comfortable with the extra 2cm? Or will it not really be noticeable?

I know this is a very open question but I have no clue how much of a difference it will make... im a newb :(

I have a bike that's about 4 cm too short for me. It makes a big difference. I'll probably sell it, which is too bad, cause I really like it otherwise.

You can't ride them both and judge for yourself? 2cm isn't a lot, but when I bought my Atlantis and followed Rivendell's sizing recommendations, I wound up on a bike 2cm bigger than my previous ones, and it made a lot of difference (to be fair, there were other factors involved, including higher handlebars and a Brooks saddle). You can compensate for a short top tube with a longer stem (it's not ideal, but it's commonly done and it works).
How did you determine that the tubes were too short, and by such precise amounts? Rigid rules about fit don't always apply to all riders--they're often based on what the pros ride, and many of us aren't comfortable with that setup. I'd really try to ride them both for at least 15 minutes or so apiece, and don't restrict your test to the top tube length. Evaluate the components, the condition of the driveline etc.

It the tube is 2cm short you can make some of that up by moving the saddle rearward and putting on a longer extension stem...but that is no guarantee that it will be comfortable. I worry less about measured dimensions and more about how it feels. My standard road bike is typically a 25"/63-65cm. I ride different frames on different styles of bikes from 19" on up to my ideal size. (Not too many above my ideal size)

Aaron:)