Originally Posted by AnthonyG

Bike manufacturers have gone beyond the concept of making bikes that fit people. The game these days is make the minimum number of different size bikes that the maximum number of people find "acceptable" fit wise. In truth a particular bike fits no one perfectly, but its close enough for many. Its not even about the average person anymore. They've gone beyond averages.

When you shorten the cranks, you need to move the saddle backwards to maintain your KOPS position, otherwise your knee will move in front of KOPS. Now strict KOPS isn't the only way to do things but its a great way to find the ball park. Moving your weight rearwards, which takes the weight off your hands and shoulders is also greatly beneficial for most people.

The seat tube angles on modern small frames is WAY too steep for human beings. It doesn't fit anyone properly but it makes the bike acceptable enough for long enough for you to buy the bike in the first place. The thing is, when you are riding a bike with cranks that are TOO long for you it does help to be in front of KOPS as it opens your leg angles up.

I'm old enough to remember child/adolescent bikes from the early 70's and even late 60's. They had VERY short cranks, 110mm, VERY relaxed seat tube angles, 69 degrees, small wheels and very short front centre distances.

That's what it took to fit a child/short person on a bike. I had one of these child bikes at the same time thatI had a custom 27" wheeled racing bike, and while the racing bike was after I was MUCH more comfortable on the child's bike and could ride MUCH further on it. The custom racing bike had an INSANE 78 degree seat tube angle to make it work.

If only I knew then what I know now.

Anthony