Almost always when one rotates the hips properly, the saddle height has to drop a bit. The rotation effectively lengthens the range of movement for your hamstrings and hips. However, you have a couple complications. First, in one direction, by lowering the saddle slightly you're able to use the more powerful range of movement of your quads. This means that you can put more power into higher cadence efforts (for lower cadence higher power efforts such as climbing or starting a sprint, typically out of the saddle, you're using your glutes more than your quads). However, the caveat is that you probably have to rework your complete position a bit to reorient your joints, especially your knees. I've found that most knee problems are due to bad positioning and while temporarily a saddle height adjustment may be needed to avoid knee pain, it can exacerbate other problems over time and certainly doesn't allow you to fix the real causative issues (which are typically not saddle height).

Back to the original issue of going down in frame size, I hope the OP can see that unless you've already evolved this position as described here, you have an opportunity to go down quite significantly in frame size and also potentially increase your reach (longer top tube or longer stem, or both). It's worth measuring VO2max and power output before making changes and then have an actual baseline to see whether you really improve on the newer frame geometry or whether it just feels that way (or whether you bought some aero efficiency but at the expense of power output -- it can feel better but not actually perform better). All frame changes are experiments and I don't know any fitter or builder who can tell you unequivocally that you will be a better rider in a new position (assuming you're already reasonably evolved to begin with). One of my long-standing frustrations with many builders is that they build to a current body and end up offering you a wacky geometry that doesn't really serve your long-term evolutionary process in positioning and performance. Just look at some of the bizarre frames on custom builder galleries or on eBay.

Great discussion

I'd really advise going down 2 sizes at a time as much as changing two lanes at a time on the road. We are talking about quite a big change here. A neg rise stem is a much cheaper way of finding out if you are going in the right direction.

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I haven't noticed any change to my breathing, restriction or easier expansion. Here's an interesting article.

http://inrng.com/2013/01/whats-new-with ... more-12702

Hansen is not a small dude, but he's rolling 38cm bars to decrease the CdA.

An additional note to my position change - expect new saddle sores to develop. Sitting in one position for years and then rolling everything forward - you end up sitting on new areas of skin. Not a big issue - but just expect it. Maybe it's just me... or the dry weather here...

I've found the opposite to be the case. There is however a wide range of saddle heights that can be adapted effectively.

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^agreed, when I think of rolling the hips forward I think of a saddle height increase

Correct. My typo. Thanks for catching it.

I usually end up scooting back on the saddle while I'm rolling my hips forward. Does the same thing.

YMMV and all that

M

In the context of my response/situation, I've also dropped the front end [headtube] by 1.5cm - so I think my slight saddle decrease is a partial sum of rotating forward [++] and a headtube drop [---], including, but not identified, other sorts of changes [seat angle change & top tube change come to mind].

This thread is a clear demonstration of how complicated fittings are. Don't be fooled by lasers and how far you can touch your toes. Considering how everyone requires a distinct training plan to maximize their own performance, it should only follow that everyone approaches a distinct riding position to maximize performance through iteration and progression [ex. Levi Leipheimer].

"Rotating the hips forward" has me confused. Does anyone have a drawing (stick figure, skeleton view, etc) to help me visualize what it looks like? I'm not sure if we're looking an anterior tilt to the pelvis itelf?

It's a bit of a fine line I think. You don't want to be over-doing it and have your spine in extension, but conciously thinking about it helps me to learn it as a habit (although I think some people probably do this more naturally than others). It's a subtle move, but you can certainly "feel" the difference in terms of reach and balance as well as based on what's sore during/at the end of a ride.



http://www.youtube.com/watch?v=aKR2fTJ21fc

@AGW -- extremely helpful! Appreciate both the illustrations and the video.

Today's ride certainly felt like 'bad.' Got tired mid-back muscles.

IDK quite why 'cause the last time I rode this bike I didn't have any issues. I WAS wearing many more clothes today than the last time. Maybe that has something to do with it too.

Oh, and saddle rotation: nose level = good. Nose up = bad for rotating the hips forward

M

I have PAINFULLY found out that what you say seems to be very true regarding saddle angle and hip rotation. With the saddle even slightly nose up I found it to put a ton of pressure on the soft bits when properly rotating my pelvis forward. It seems that nose up promotes the more upright spine/doesn't allow for comfortable forward rotation. Obviously this is highly dependent upon the individual but it seems to hold true for me as well.

Note that this ignores saddles like the Spec Toupe and Romin especially that have large channels allowing for your soft stuff to be comfortable even when nose up.

Nose flat or even a tiny bit ~1degree down *if having lots of trouble but not a common case* seems to be best at least from my personal observations with lots of different saddles/experimentation

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I ride on a Fizik Antares saddle and I have the same issue. When rotating my pelvis forward, it feels like I'm putting way too much weight/pressure on my soft tissue and it's just uncomfortable. I'm guessing I need to make some fine adjustments to the saddle height/position.