Originally Posted by bigskymacadam
New to cycling, I had purchased a 57cm frame and bike a couple months ago. Now that I've done some measurements from Greg Lemond's book and the fit calculator at wrenchscience, it seems a 52cm would be a better fit. (I'm 5'10"; 153 lbs; 80cm inseam)
I feel no joint or back pain after a 90 minute ride, but could I probably get more efficient with a professional fit at the LBS, fixing some of the issues of a larger frame?
Or am I out of luck and should wait a year to get a new frame? My riding goals are to build base milage, ride a couple centuries, and train for racing next season.
I'm 5'7" and have a 78 3/4 cm inseam, so I'm guessing you have a long torso. This being the case, a 57cm may not be all that far off for you. Proper bike sizing has more to do with torso length, reach, top tube and stem sizes rather than inseam length and seat tube length. One thing you should also know is Lemond bike sizes (as well as some others) are measured from the BB to center and not the top of the seattube as is the case with most others. So a 51 Lemond frame would have a similar seattube length as a 53 on most other frames. Compact geometry of some frames throws another big monkey wrench into the mix. So you can't really derive much from just saying you think you need a 52cm frame. You need to be more specific regarding the frame model.
If you're feeling comfortable after a 90 minute ride, you most likely have a bike that fits you reasonably well. Given the same frame model, I don't think you're going to make much efficiency gains by going to a different size.