Originally Posted by
digibud
One look at a World Tour race will put an end to talk about frames being too small. Many pros ride frames that would be considered way too small for a "proper" fit. A very large drop from saddle to handlebar and the need for a super long stem are ingredients that put a rider in a very low, aero position. Admittedly you have to be young, strong and flexible to ride such a tiny frame and few non-pros are capable of riding such small frames. The point here is that you (not me) may be able to ride a much smaller frame than might be considered a proper.
Pros are riding undersized frames because the head tubes have gotten taller so $10,000 bikes fit the 50+ riders that can afford them. The pros are just trying to make lemonade when even a slammed stem isn't low enough to get their preferred position.
Originally Posted by
cyccommute
Not to mention the stress that large setback seat posts put on the top tube/seat tube/seat stay junction. One of the 4 frames I've broken was broken because I had a Titec Hellbent seatpost on it in an attempt to make a too small frame fit.
A frame that is too large and has too tall a standover is a hazard to the rider. I have fought the fight of finding the proper size bike for my petite wife (5') for 40 years. She started out on a 27" Sears bike which means that she started out on a bike that was probably a 23" frame. That's my size (just short of 6'). To get off she had to hang from her right knee so that her foot could just hit the ground. She had to plan each stop so as not to fall off the bike when simply coming to a stop.
A frame that breaks with the correct amount of seatpost inserted inside the seat tube is a bad frame, not a sizing issue. Extra leverage from a longer post adds stress, but so do bumps and heavy riders.
Obviously any bike can be way too big, like putting someone on a frame that they aren't even able to stand over on their toes (how did that even happen to your wife? Was someone involved blind?). You don't need a standover gap to have a safe bike. Jumping off the saddle to land flat footed over the top tube is a maneuver that will get anyone hurt, regardless of standover clearance.
Originally Posted by
McBTC
If it's too small it's hard to get your knee over the pedal spindle with the foot at 3 O'clock (the power stroke). With a setback seatpost and the seat pushed back you might make do but riding on top of the rear wheel is not ideal. The bigger the rider the longer the desired wheelbase... just feels more natural; otherwise, you feel like you're on a clown bike. As far as being too big standover really isn't the big deal some seem to think it is (except, perhaps, on an offroad bike where you likely will come off it trying to avoid disaster)...
Small frames and large frames don't dictate your knee position, and that's because the seat tube is angled - it adds set back as you raise it.