I really can’t figure the biomechanics behind this, but when I ride in the aero position and I ride hard, I move right up to the nose of the saddle. This happens regardless of seat tube angle. I do it when the saddle is placed at 81 degrees or at 73 degrees. You would think that when I ride steep (>78), I’d sit in the middle. Not the case.
When I ride my road bike in the roadie position, I ride in the middle/back of the saddle even when going hard.
For the life of me, I can’t figure out why I do this, but I have observed the same for a number of training partners. What are the biomechanics behind me subconsciously moving forward like this ? It seems to make no sense.
Me too. Only have the road bike as my reference, but I always end up perched on the nose, and even if I at some point consciously move back, I end up there again.
I’m sure it has something to do w/ more weight being forward and on yer arms vs. non-aero position.
In my case, my saddle is tilted ever so slightly down in front (for comfort), so I’m sure that also contributes to the effect.
I.ve noticed the same thing for myself and others. For me, at least partially, it comes from choking up on the aerobars. When I’m riding hard, I tend to tense up and pull myself forward at the bars, which pulls me out on the tip of the saddle.
Happens to me too. I believe it has something to do with my tendency to pull/ lever on my s-bends the harder I pedal. So my upper body contracts a bit.
One fitter also told me that some people ride on the saddle nose to decrease the friction between the inner legs and the saddle.
me too. As others said, it must have something to do with the aero position. When you are leaning forward like that you tend to slide forward. As opposed to on the road bike when you spend a lot of time on the hoods with your arms locked straight in front of you. I just feel more powerful (not that thats sayin’ much) when I move forward
Same here. I just assumed it was from a natural inclination to want to be upright for comfort, thus increasing the torso/femur angle. Or maybe a reflexive reaction to sitting on the boys for too long.
I’m guilty of this as well. I would try to “choke up” on the aerobars and felt the more forward I was, the more power I got out of my pedal stroke, at least in aero position. Felt like I needed to almost be in front of my pedals. So, I was sick of the pain of sitting on the nose of the saddle and got a Thomson Setback seatpost and turned it around and moved my saddle all the way forward, and STILL felt like I wanted to be further up, so I then traded that in for a Profile Fast Forward seat post and think I’ve finally got it. I can sit in the middle of the saddle for max power, and sit on the back for comfort even in aero. Works for me.
same here. What we need is someone with a power meter and hrt monitor who can tell us the difference in watts/hrt in different positions. I suspect its to do with keeping the angle of the hip open = more power.
Dev & Co. … it’s leverage! By moving forward you create longer lever over / in front of the pedal spindle. Alot of guys @ SF Grand Prix this weekend were standing & leaning way forward to create this leverage going over Filmore & Taylor St. hills! (some stayed seated and nosed forward) … when in the TT position, forward often coincides with higher cadence needs/choices.
I guess what I am asking is if there is a point of diminishing returns. The “rivet” position at 81 degrees is 8 cm forward of the rivet on 73 for my saddle height. That is 8 cm on a crank that is 17.25 cm, so almost half the crank length. It seems that at some point, it would be senseless to slide any further forward. Its at the point now that after each of my races, I have bruises and cuts on my right knee when it hits the bolt on my stem on the downstroke from time to time (my right leg is bowed and my knee comes in on the downstroke)
All this seems pretty silly to me, but my bike splits have been strong. I can still shove my saddle forward another 5 cm and sit in the middle (I’d end up at 84 degree angle on a p3) if I wanted to but that seems insane. Plus, I do like to sit up on the back of the saddle for seated climbing (so with a 79 degree angle, I can slide back to 74 degrees or so).
In any case, I do agree with others that riding the rivet also seems to conincide with choking up on the bars.
There are a few reasons one slides forward on the saddle when going hard. First, the entire body tenses include shoulders, chest, back, and abdominals. This tensing shortens the body thus resulting in an anterior movement of the hips - sliding forward in the saddle. Second, flexibility is at issue. As you get more aero, the required stretch of the low back, gluteal, and hamstring muscles becomes greater. Each muscle group has a power zone in terms of its stretch/shortening position. With lack of flexibility or full range of motion strength training (or both) the muscles will again shorten to accomodate the power zone of each muscle. Third, as you get more aero your hips rotate forward causing a change in directional application of force to the pedals. By sliding forward your body realigns itself toward its most powerful hip/knee/ankle angles for power transfer to the pedals.
Additionally there are a multitude of other factors that can play on an individual and why they may slide forward.
"riding the rivet also seems to conincide with choking up on the bars. "
I also do this on the tri bike which is set up fairly steep.
Also notice that most of the TDF TT riders tend to do the same thing despite being more slack due to the ICU rules.
In contrast when I’ve used my road bike on a tri it’s set up slammed as described by John Cobb with the seat back and dropped a bit. When I ride the road bike on the shortie Profile Jammer GT bars in this position I tend to stay back on the seat.
I do the same thing. I have a custom Guru with a 78 degree seat tube. I use an Easton EC90 Zero offset post with an Aspide Triathgel saddle slammed all the way forward. I have to be riding 81 degrees when I go hard. Only need the last 2 inches of the nose of the saddle.
I guess what I am asking is if there is a point of diminishing returns. The “rivet” position at 81 degrees is 8 cm forward of the rivet on 73 for my saddle height. That is 8 cm on a crank that is 17.25 cm, so almost half the crank length. It seems that at some point, it would be senseless to slide any further forward. Its at the point now that after each of my races, I have bruises and cuts on my right knee when it hits the bolt on my stem on the downstroke from time to time (my right leg is bowed and my knee comes in on the downstroke)
All this seems pretty silly to me, but my bike splits have been strong. I can still shove my saddle forward another 5 cm and sit in the middle (I’d end up at 84 degree angle on a p3) if I wanted to but that seems insane. Plus, I do like to sit up on the back of the saddle for seated climbing (so with a 79 degree angle, I can slide back to 74 degrees or so).
In any case, I do agree with others that riding the rivet also seems to conincide with choking up on the bars.
Isn’t this heresy? Shouldn’t the seat be in the position designated by a FIST certified fitter?
I do the same, too. But, I’ve been consciously pushing myself to the back of the seat and sliding my arms back on the aerobars for climbing. I concentrate on smooth circular pedalling while climbing (well, all the time, but more so on climbs). It feels like more power to me. I try to always stay seated for climbs up to around 10%. After that, my butt’s gonna come out of the saddle every now and then.
Hey Dev! Nice photos! You looked great in that last one. I’ve been on the P3C for the past two weeks and I am finding a similar pattern of sliding forward no matter what the angle of the seat. After many adjustments, I found a happy compromise where I’m sitting near the center of the seat- but still a bit forward. If you check out shots of Zabriskie, Jullich or Basso, the same appears to happen to them. I thought it was because I was lower in the cockpit- which definitely contributes to it, but a more neutral seat position seems to work best for me. Keep it rolling and nice job helping that dude out at the race this past weekend. Doesn’t surprise me. You’re always the gentleman.
I don’t know if you have ever been fit on your bike but have you cosidered that your position doesn’t fit you and you are sliding forward becuase ou are not properly supported on your bars?