I recently read one of Dan’s Tech articles on Steep seat tube angles that referred to scientific studies on the subject. Aside from his understandable lament that all the studies were performed in a lab “on the flat” he mentioned that one author had used a “Seat Shifter” popular in triathlon in the early 90’s. It seems to me that this was a device well ahead of it’s time and I’m sorry to have missed the opportunity to own one. Perhaps it was just to good to be true? Have moved from road racing in the 80’s, relaxing in the 90’s and doing half and a full IMs in the last 4 years, I have often wondered - mostly on long steep acsents - and descents - on my tri-bike (with 79.5 seat angle) - why such a device is not readily available today. Just getting the saddle out of my way when I stand would be a huge relief. Having the option to shift the bike geometry on-the-fly to a 73 seat angle so I could sit up, get the weight off my arms and neck, open the chest and pedal a road bike up the hill seems like something every triathlete would welcome.
Last summer I decided to run a very informal climbing comparison test on a local mountain about 5 km long. I alternated bikes between my old 80’s Pinarello (73deg) and Cervelo P2K(79.5). I installed wiring harnesses for my SRM on both bikes so all I had to do was swap the crank. I rode 5 repeats on each bike over a ten day period swapping bikes each day. My hand position on the road bike was always on the hoods. My hand position on the tri bike was always on the ends of the horns. I found I that could consistently generate 20 to 30 watts more power on the road bike. I suspect this is due mostly to a more acute hip angle. All this has got me thinking of building my own seat shifter. In the meantime, I find myself wondering if my road bike with a clip on would get me home quicker on a hilly course and where the break-even point between optimal climbing and areodynamcis lies.
I’d be very interested in hearing from anyone with knowledge/pictures or other info on the “seat shifter” or other information, links, ideas on tri-bike climbing.
BTW When I googled the 90s Seat shifter I found some predictions from a RAAM rider below.
Steep angled seat tubed bikes will be non-existent, as will LeMondesque shallow angled seat tubed bikes. In fact, seat tube angle will become largely unimportant as riders adopt systems for altering their seat positions and effective seat angles while riding. Virtually everyone will utilize a system such as the brand new Seat Shifter (an American product from San Carlos, California), which allows the rider to choose four different positions of the saddle in relation to the bottom bracket via a small handlebar mounted lever. Riders can set the Seat Shifter to provide their standard/ hill-climbing/ behind the bottom bracket position as the rearward most setting on the seat shifter, thus allowing three forward positions with a total of 4" of travel. When hill climbing, riders can move the saddle back, sit up, and climb in their most effective and efficient position. On a long climb, they can alternate between this position and the next forward position to change muscle group usage and reduce fatigue. On downhills and flats, riders can slide all the way forward and stretch out onto their aero handlebars, gaining a two to three MPH speed increase by dramatically increasing their biomechanical positioning, efficiency, and comfort. Once again, riders can alternate between this forwardmost position and its next closest position to reduce fatigue and enhance recovery. Not only will this type of system make cycling faster, more efficient, and more comfortable, but it will also eliminate almost all cases of lower back fatigue and Shermer/Solon neck.
a very interesting post. a seat shifter is an interesting, if problematic, solution to this problem. i think it would be difficult to use one optimally unless the bike was really designed around its use.
and if the power loss is only due to an acute hip angle (but no one is really sure of this because, as dan says in his article, the studies done on this topic to date are *extraordinarily *limited, and that is putting it very mildly), why not a set up that lets you open up your hip angle while climbing on your tri bike? for example, try some trials on your tri bike with your hip angle more open (raise your stem, change your stem, or add spacers temporarily?) and let me know your results. i would be interested.
also, when you “measured” seat angles on your pinarello and cervelo, how did you measure these angles exactly? from what point to what point?
M2 Racer made a seat shifter just a few years ago. I tried one on a Giant TCR. The problem was that it was hard to shift on the fly and felt a bit wobbly. Seems like a good idea that nobody has yet been able to engineer properly.
My experiments with my P2K and road bike indicated that the road bike was always faster up steep hills. The P2K was OK in the aero position but once the hills became too steep and I had to sit up, the tri bike was a dog. I used the P2K on most tris since only one had hills steep enough to warrant the road bike with clip-ons.
This is an easy one to address if it is just hip angle… Just get a set of deep drop base bars, flip them upside down so that they rise up, shorten your stem, and lengthen your aerobars, and bamo, go to your base bars when climbing. Of course this goes against the idea of the steep angle, that you are supposed to stay in the aero position for climbing, it is just that most folks dont do it (including myself in many instances).
I may still have a picture in one of my old Triathlete magazines (french version). It was quite heavy, and I don’t remember that it was that easy to change on the fly either.
Never purchased it. I had the “bike stream” though (some sort of hydration system)
I remember the ‘seat shifter’ device well. Mike Pigg- endorsed the product and used it on his bike. As I recall- it was approximately 400 grams or so- including- seat post with integrate seat shifter device, and a cable that mounted onto the handlebars- so you could ‘shift’ on the fly. Pigg always rode will before and after the device. I think this type of device would be harder to pull off today- everyone had round seat posts in the late 80s/90s- so the post with several different diameters just replaced your current post. Most aero bikes have model or brand specific posts/shapes/sizes- so the device would somehow have to go inbetween existing seatpost and seat… interesting- b/c on steep hills- my P3C does not climb like my Merlin Extralight…
Seat angles were measured by transferring geometry from each bike to my shops sizing machine using the machines transfer square. The point on the saddle rails is taken to be 20mm ahead of the clamps mid point to accomodate for seat post set back.
With respect to the question of hip angle I merely hypothesize that this is the magic variable because it is the most obvious element of my body position that changed during the test but you are quite correct when you comment that it is inconclusive and shoould be further tested. As a side note during my road racing days back in the 80’s I was also a member of the IHPVA (Int’l Human-Powered Vehicle Association). I built and raced many interesting configurations and followed the expert research that was done for the Gossamer Condor (The first human powered aircraft) and Dadelus projects. The engineering teams involved in these projects and many other great land vehicles including the Canadian built current world record holder “Varna” - 128.6 kph) performed alot biomechanical testing to optimize hip angle and the scores of other variables that required careful analysis. Sadly I doubt any of the collective testing involved large trials because this is not necessary unless one is trying to prove a point or create a paradymn shift.
I think the seat shifter concept is worthly of redevelopment and testing not only for the potential benefit of changing position while climbing but also for descending. In another of Dan’s tech articles he points out that the forward aero position compromises weight distribution and he expects to see longer wheelbases in the future as the rules are relaxed. This was one of the original reasons why I bought the very long P2K. I wanted to use a short(60mm) stem to keep the weight back. If I could slide the seat back and descend with more weight over the rear wheel I’m certain the bike would handle alot better not to mention the potential to adopt the fully extended ‘superman’ position.
I had a Seat Shifter many years back. I remember liking it, and I don’t recall why I stopped using it. Probably because I moved out of Boulder and it was just toooooo tri-geeky for anywhere else in the world. I recall that it did not come with its own seat post. Rather, is was attach-able to the top of a standard seat post. I had to get a very long stem (a long, MTB type stem), to compensate for the far forward seat position (I had a standard, Guerciotti road bike), and that was far from perfect for climbing, b/c you couldn’t move the handle bars back. So you were quite stretched out when the seat was back.
It was heavy, though. No question. And it was spring loaded to shoot forward when you pulled the lever, so you could really snap yourself in the nuts if you weren’t paying attention.
I don’t even remember what I did with it. Hmmm. I must be getting old.
is your p2k set up like this one? becuase i have no problems at all descending on this one.
i think on a well-designed frame most descending problems are not due to a ‘forward’ CG, i think they are due to a high CG because a rider with a full aerobar set-up has no super-low drops to get in to, and must stay high (as if i were riding on the hoods on this bike). and being that high on super fast turns and descents is dicey.
with respect to the admirable work you’ve done quantifying the differences in position while climbing, i am one who’d contend that you’re missing an important variable, that being the way you’d climb on a tri bike if you had the opportunity to perform that task (in what would say is) correctly, versus how the masses tend to climb on their tri bikes. for one person’s recent “conversion” to the more appropriate way to accomplish this, read here.
the seat shifter makes sense if you don’t employ proper ascending technique while on a tri bike. but if you do, you’ll save yourself 2 or 3 pounds, which is what the seat shifter weighed.
I climb as much as possible in the aero position (to keep my hip angle closed) but it is not fun! I find there are both balancing and biomechanical problems with aero climbing. First, your head - and inner ear - are oriented in the wrong axis thereby reducing your ability to balance. Second, your centre of gravity is lower again reducing your ability to balance. Third there is too much weight over the steered front wheel which results in oversteer - a real issue at low speed). Fourth, your elbows are locked in which constrains your bodies imbalance response impulses. (I have found that a wider elbow pad setup really helps for aero climbing - but compromises aerodynamics - alot!) On the biomechanical side the forward seat position interferes with climbing out of the saddle.
You raise the interesting idea of using a deep base bar which would maintain a closed hip angle similar to the road bike. I have in fact adopted this setup using an Easton carbon base bar that angles down; it does help restore the power loss but the position is still “off-balance”. I think the ‘magic’ of the upright “road climbing” position is all about getting your centre of gravity directly over the loaded pedal. (It is similar to climbing stairs or walking up a steep hill- an activity that through evolution humans are biomechanically adapted to). There is no load bearing by the arms which effectively off-loads some of your body weight from the pedal thereby reducing the applied force. After years on the road bike I have found that with the correct cadence (must be slow enough) I can climb out of the saddle for sustained periods with less effort that seated. With the option to switch between seated and balanced (no weight bearing with arms) ‘out-of-the-saddle’ climbing I can get up a steep climb alot faster than being locked in a forward position.
My P2K is setup alot more forward. I’m using a 79.5 seat angle. The post is flipped around and saddle is as far forward as possible. The pads are further forward and the aero bar is longer. I am bearing alot more weight on the handlebars.
I agree from my experience with motorcycles that a lower CG is better but proper weight distribution is also very important. Perhaps even more important is the mass that is carried ahead of the steering axis (arms, hands, etc)
this mass tends to cause over-steer with standard ‘trail’ geometry. To compenate more trail is called for. A straighter fork is helpful (40mm offset).
Interesting. I suspected that there must have been something wrong with the seat shifter. Apparently, the problem was one of execution more than concept. A 2 to 3 lb weight penalty is certainly unacceptable. Perhaps with greater engineering resources this could be brought within acceptable limits - something in the range of 200 grams I should think.
With respect to the suggestion of spinning up hills in the aero position I have found that this is very workable for me personally on softer grades such as those in Kona. I received this suggestion from a pro several years ago and have done what I can to implement it. As a former sprinter on both the road and track I am very used to pedaling at a 140+ cadence albeit for short distances and on flat surfaces. When I get onto a long steep mountain grade however (I’m on the West Coast of Canada) I go nuts being locked down in the aero-spin position. Even the lightest and best climbers in our club naturally tend to alternate between sitting up and aero. Alot of our club riders simply won’t buy tri bikes because of the climbing characteristics. Perhaps a well-designed seat shifter would change their mind?
I remember when Lemond blew away the field with Scott’s triathlon aerobar but I just can’t imagine him going faster up (or down) the Alps in the aero-spin position. It certainly begs the question of whether the triathlon pros climb using the aero-spin position because it is preferred or required?
I guess I’m still intrigued if you think a properly designed seat shifter and the 'polymorphic" bicycle that it would offer makes good practical sense?
"With respect to the suggestion of spinning up hills in the aero position I have found that this is very workable for me personally on softer grades "
Bingo. On rollers it works great, but not on the steep stuff. There’s a reason why the Tour is on road bikes riding up the Alp d’Huez and not on their TT bikes. Could you imagine Zabriskie trying to keep up to the pack on a mountain stage on his P3C? Gauranteed he’d be dropped.
Thanks Bernie, unfortunately I’m about 12 pounds over the weight limit. I’m looking for alot more than 20mm of travel too - closer to 3 inches is required to go from an 80 deg seat tube angle to 73 deg. at my leg length.
Yes, indeed. My sense is that aero-spinning is a great example of inside-the-box thinking; it’s about looking at the problem from the back end; its about making the best of a less than ideal situation; its about finding a way to climb on a bike that isn’t designed for the job; it’s a about finding a way to change the rider instead of the bike. Even the dinosaus in the UCI don’t do this in the Tour de France. When they get to the mountains they through away their road bikes in favour of their purpose built climbing bikes; when they get to a TT they ride a TT bike. Knowing the French if they had to do it all in one day they would probably create transition zones!
The pros are very good at making difficult techniques look effortless; let’s not kid ourselves, they practice alot. Watching a top pro on an ascent using the aero-spin technique can easily leave the impression that there is nothing to be gained by changing the bike. They make the problem appears to be with the incorrect technique preferred by the ‘masses’ - as Dan surprisingly calls us.
I find myself wondering what Mr. Reid or Mr. Stadler would say if you offered them the choice; if you told them they could change bicycles whenever they wanted with no time penalty, what would they do? At the base of Richter Pass at IMC Canada would Reid switch to his purpose built climbing bike or aero-spin on this TT bike? Which would actually get him to the top in the shortest possible time?
I have a great deal of respect for Dan’s creative talent and sense of techical right and wrong so I’d like to put this question to Dan again. He gave me a bit of a left-handed answer this morning when he said that a seat slider made sense if one wished to use the wrong climbing technique and pay a heavy weight penalty. But is the essential problem really the upright riding form or the bike? In other words if you weren’t forced to ride a TT bike up a hill and you could use a climbing bike surely one would prefer the upright climbing technique, wouldn’t one?
(some sort of hydration system)