This need to update philosophies was apparent when I read a front page article and Wurf’s position was labeled as slack. But when you measure the angle from the bb to where his pubis bone is on the saddle, he’s at 84deg. That’s right at where most people, pros and AG’s, who are doing long distance tri naturally settle in relation to the bb. At higher watts they, like UCI folks, go to 85-86deg. innate orthodoxy.
Start with the position the person is going to gravitate towards because if you put them in a steeper or slacker position, they are going to move back towards the innate orthodox position in relation to the bottom bracket due to proprioceptively feeling where they’re applying force perpendicular to the pedal in its forward and horizontal position.
Then you set the front end for comfort, power and aerodynamics.
And last, you select crank length based on perceived glute vs quad engagement at race power.
I was thinking of how first bike fit fits (pun intended) in this whole scheme.
I need a new bike. I am like 80% of the people out there. I do the “right thing”, I go to a certified fitter. He gives me stack and reach numbers from a fit bike, and I select a bike based on them. Are we saying I will be told “there aren’t many bikes that will fit you”, we need to use an extended custom cockpit" ?
My buddy was on a M Argon 119. He is a pretty average guy. He found he didn’t have the reach he needed. So he went for a 56cm PSeries, problem solved. Was he recommended the wrong bike to start with ?
Have fitters traditionally putting people in stack/reach positions that we have learned are out of date and to get them in what we believe to be better, need more reach that the bikes don’t provide ?
If fitters are putting people in X/Y positions that match what the manufacturers provide, are we not just perpetuating the problem ?
Let’s say Cervelo has a bike with 4cm more roach across the size spectrum. Why is “Joe fitter”, not tied to any brand, always recommending Cervelo ?
If brand XY never gets recommended, won’t he adjust his geometries ?
If we call out the long bikes, will people not move to them ?
Is the problem that fit philosophy has changed and all those FIT/Retull…fitters haven’t caught up ? Is this new philosophy of fit just wrong ?
If the fitters don’t push their customers to select bikes with more reach, why would the manufacturers change ?
Last year, we had a couple of threads on this topic, and there were a lot of prominent fitters also running into the same issues. I do not think this is necessarily an issue of fitters not doing their jobs or not being as up-to-date as they could be. I do think most bike fitters nowadays have moved towards pad stack and reach and don’t pay quite as much attention to frame stack and reach, and Dan wrote about that years ago. That’s not to say that a lot of fitters couldn’t learn from looking at what the top pros are doing. The reason why so many pro athletes are on our saddles, is largely related to undoing not so great bike fits where saddle heights were too high, front ends were too low, effective seat tube angles (bb to pubis in saddle) were not in the 84-85deg range when at race power, wrong crank length, not closing off the hand to face gap, and needing a saddle to accommodate these more comfortable and more powerful positions.
But if I were to point to one thing creating this lack of reach, I would point to more athletes riding with a higher pad stack. When we had people slammed on the front end, that rotated their bodies and put their elbows further forward. As we have found a better balance between power, aerodynamics and comfort, we have brought people higher and that has brought people’s elbows more rearward.
How do you guys @Nick_wovebike and @marcag do the bike fit/aerodynamics dance? The bike fits I’ve seem have been very much set up for maximum biomechanics and not concerned much with aero. Then aero testing goes the opposite direction. I almost think that the process should be flipped. Find a reasonably comfortable position and aero test it into something slippery. Who cares if it’s out of “orthodoxy” (as the front page article mentions) but still fast?
It just seems like most of the things a bike fitter sets up are things that get changed in aero testing anyway.
I’d say they didn’t very well even 2 years ago. Maybe it’s improved a bit
I am not talking about Nick here. He asked me to come test Trevor
But I have approached several prominent fit experts, and I would say half were receptive
When I am aero testing something, I don’t say “you should do this”. I say “this is 4 watts faster, if you can work with your fitter to make it work, you’ll get 4 watts”. I strongly believe aero testers should simply be providing data to the fit process. We can provide ideas of what could be faster.
When I tested Lionel, his fitter was involved. When I tested Chelsea same. Next week I go to Girona for the team, a fitter will be there. We have a very specific protocol in a fit session : before in the studio, in the field, finalize in the studio, test over time on the road during training, rinse and repeat
We have been supplying aero sensors to fitters. The criteria for us, is open minded and competent fitters. Some get it, many don’t. Some are too stuck in their quasi religious mindsets. But I think they are slowly realizing they are becoming obsolete. If it were me, if a fitter didn’t offer aero testing as part of his services, I’d think twice.
A gigantic reason for me is that when people are put into the most aerodynamic position, such as a couple of super man positions we saw at Kona, those fall apart during the race because people’s bodies innately go back to a position relative to the bottom bracket, and so the aero position in testing is not realized in reality. That is pretty important.
I also think you might be pretty surprised with the numbers these athletes are producing in terms of CdA. I am not at liberty to share those, but I did do testing with Trevor with @marcag and if Trevor had not crashed, he would have done 3:59 on watts that set up to achieve his pre race “anything slower that 2:36 is a failure” statement.
so to clarify, we are doing aero testing and it’s a complete system and iterative process. There are just certain realities that if avoided, will lead to failure during the race. And I think the biggest of those are placing the rider too far ahead or too far behind the bottom bracket, putting the athlete on the wrong crank length and taxing their quads, or keeping the front end too low and closing off the hip angle. Those three things have to be addressed ahead of aerodynamics, and in partnership with aero testing, in my opinion and experience.
@Hanginon Pro tour cyclists are sitting in the same position relative to the bottom bracket that triathletes are. The only thing that is different is that triathletes are raising the front ends a little bit more, but some pro tour riders, including those I’m working with, are doing the same thing today, and triathletes are able to get their elbows further forward because they are not bound by UCI rules. Otherwise, the biomechanics, and a number of other factors are identical.
That’s really interesting, and confirms a little bit my thoughts about fitting, thank you both. As with anything aerodynamics, you always end up with more questions from answers.
Do you think there’s space for a rider to “get used to” or learn to hold a less comfortable position, especially if it’s significantly faster? I ask because I had this with narrow elbows. Hated it, still don’t like it, but consistently tested ~7w better than a “comfortable” elbow position. It’s annoying but holdable for an IM.
Do you guys have any way of quantifying the power loss in a different position? Losing 20 watts is massive, but if it gains 21 watts in aero it’s still a small win. I’ve tried to quantify this with lactate testing at different bar heights, but I fear that only captures short term efficiency.
This is a conversation I’ve had with Ronan of escape collective, and I think you’re spot on in terms of short term gains in some ways.
If I’m doing a fit for someone who is doing a relatively short time trial, shooting for Dan Bigham style CDA is fun. There are some things that cannot be avoided, such as realizing that getting any slacker than 82° for the effective sta, from the pubis to the bottom bracket, is not gonna be held even over most 10 mile time trials without changes in the position over the course of the short time trial. For shorter time trials, pushing down on the pedals in a forward and down motion can engage bigger muscle groups that will be by biomechanically inefficient over longer distances.
Quantifying what is given up in power & CDA takes some serious testing and I do think smo2 can help with monitoring lactate, as Ronan has played with, but Chung method and power avg’s is good. That’s more @marcag area.
For Ironman, comfort is so important and really making sure things like super uncomfortable narrow elbows truly do save as many watts as you think it does is important to test. For example, I could propose that getting the right aerobars at the right angle with the right bottom interfacing with the wind may get you to a possibly even lower CDA. Having those sorts of alternative, possibly faster positions to compare to is really important, in my opinion. It takes thinking outside of the box sometimes.
Probably the most interesting thing in terms of gravel pros using 2.1 inch tires is that the primary reason is that the tire construction is more advanced than the best gravel tires at this point. Supple casings. Really interested to learn what you find!
Also worth noting that Lachlan discussed trying the handlebar set up I will be using at gravel races this year and decided against it so he did not overtax his triceps and instead went with a low handlebar position so his arms could stay more relaxed. https://www.youtube.com/watch?v=My4d2FiZVYY
I think it was 2016 when I posted on here that I think World Cup mountain bike racers need to go to 2.4 inch tires and someone with a similar sentiment to your comment shared with me that if I need anything wider than 2.1, I need to work on my mountain bike handling skills. This smells similar
