Relaxed Fit or Geometry - What does that mean exactly
I am often perplexed by the phrase "that bike has a relaxed fit or geometry". When I hear this the first thing that comes to mind is a lower (slacker) seat tube angle which results in a less upright seat tube which results in a longer top tube length and is usually accompanied by a longer wheel base. This is supposed to result in a more confortable ride ("an all day ride").
Is this more comfortable ride due to the longer wheel base which surely results in more stability or is it also linked to where you end up sitting in relation to the entire length of the bike?
What perplexes me is this. In terms of your riding position, I have always been taught and told that your position in relation to the pedals (or bottom bracket) should be more or less the same across different bicycles because that position is directly related to your pedalling efficiency and strength. Once you find that sweet spot for strength and efficiency, you should always try to achieve that same position in relation to the bottom bracket (assuming consistent crank arm lengths). If that is the case, then with a relaxed geometry bicycle (slacker seat tube angle), it would seem to me that one would need to move the saddle forward to achieve that same relationship to the bottom bracket position. That would end up more or less putting you in the same position in relation to the handlebars (you would effectively be shortening the top tube length on the relaxed fit geometry bike) and your reach to the bars would be similar to the reach you would have if you were riding on a racing geometry bike (shorter top tube, steeper seat tube angle, saddle a bit further back). So how is the ride more "all day" comfortable when the cockpit is essentially the same? Is it the longer wheelbase that everyone is referring to when they talk about a relaxed fit or geometry? I know when I think of relaxed fit or comfortable riding, I think of a bike that pushes the upper limits of my size threshhold which allows me to ride with a somewhat lowered saddle (in terms of seatpost showing) and thus causes the handlebars to be a little higher in relation to the saddle. This does two things... It allows me to ride a little more upright (more RELAXED) and it shortens the reach to the handlebars (if I leave the stem height constant) without altering my saddle position in relation to the bottom bracket. As the saddle is lowered a little more in the seat tube it comes forward toward the handlebars but still achieves the same position in relation to the bottom bracket because the frame is just a little taller. The distance from the bottom bracket to the saddle is the same, it's just made up of more seat tube and less seat post. As the saddle is lowered further into the seat tube it is brought closer to the handlebars due to the seat tube angle, but ultimately, when the saddle is at the proper riding height with less seat post showing, it is in the same position as it is on a smaller frame in relation to the bottom bracket and pedals.
Looking for comments on this "relaxed" geometry, what it really means, and whether what I am talking about here is just all gibberish or makes any sense.
I guess another question that might pertain to the relaxed fit issue is whether bottom bracket height is a factor in relaxed geometry or relaxed fit. That would affect this whole discussion as varying bottom bracket heights would directly impact saddle height. I've never really looked into that.
Last edited by cpsqlrwn; 09-22-11 at 11:44 AM.