So im considering a "new" road bike...specifically a sworks tarmac. (don't try to convince me otherwise). Anyway, i currently have a 07 tarmac pro (54cm) that was an impuse buy but has suited me well. In my quest to find an sworks tarmac, i noticed that i fall on the cusp of the recommended frame size for my height (5.9) I know there are other factors that come into play, but was wondering what the pro/cons would be of going one way or the other. my "barefoot" inseam is ~32" if that helps at all. thanks!
Personally I like larger frames with shorter stems......not a fan of stretching out a shorter bike to make it feel bigger.
Rule of thumb is to go with the smaller bike but I think it's preference. If you felt good on the 54 stay with it. Demo a few even in the parking lot you should get the feel of it.
well, finally got around to sitting on a 56cm tarmac and it felt too big. Even side by side it looked huge compared to a 54.
I'd look into the headtube length too. If you run your stem low on the 54 (145mm) the 56 (170mm) HT length will feel like your riding your mountain bike.
I would go with the bigger bike because you have 32 inch inseam being 5' ft 9. The top tube difference is .66 inches difference for the bigger frame and the seat tube is .78 inches longer. So you could run your post shorter on the 56 and run a 10mm shorter stem that makes up the difference in the TT. I would measure the stem to the back of the seat (if you swap the parts over) and see if you can get the same measurement with the 56 frame. I would do the same with the saddle height measure from the center of the BB to the top of the saddle and see if you can line up the same way. There may be some trial and error but I would go with the bigger frame since you can adjust for the differences. It is actually harder to fit a smaller frame, believe I have tried and the longer frame works better if it is not too big.
Oh, yeah the headtube is about 1 inch taller so you take out a 20mm headset spacer and you have your difference. The 07 tarmac came with a 100mm stem and you would go to a 90mm
I had a similar decision with Specialized a couple of years ago. I went with the smaller frame. At that time, Specialized top tubes were pretty long. Obviously, there are many factors in fit, but Top-tube length is probably the most critical imo. I agree with earlier posts regarding the head-tube length. They can get pretty tall on the larger bikes.
