Bike Fit... sweet spot or ever evolving? (Page 3)

aerolab is easier for the lazy (that is...me)

 

A good friend on BT who fits bikes has told me over and over that flexibility is not key to riding in a lower position. It is rotating around the bottom bracket. He has worked with many triathletes that have bad backs and have bad flexibility like can't reach anywhere close to the floor.

I've never been fit by him but as someone with a bad back (herniated discs with microdiscectomy) we have chatted a bit about ideal fit for bad back triathletes.

The best fitter you'll ever find is: YOU! Only you know what is comfortable, only you can feel the output (if you don't have a power meter). My humble opinion, and no disrespect to any of the qualified professional fitters out there, is that getting fit for a bike has been blown way out of proportion. I have educated myself to the point that making changes is no longer a just hit n miss scenario. I would be the first to admit I know alot less then many hear on the technical aspects of bike fit, but I know what works for me. I make changes at times. Some work, some don't. Those that work stay. Those that don't, I go back. I make 1 change at a time, beta test for 1-200 miles (or less), and I either am better, the same or worse off then I was before. I recently got more aggressive and took out a head set spacer for a lower profile. This necessitated a slight adjustment to the bars and pads. After 500 miles, it feels great, I am more aero and have picked up some speed while still comfortable. And it was FREE!

AWESOME topic!

I'll jump in and also have a question. I think fit can and even should change as time goes by. I bought my first bike as an "impulse" buy. Yes, I know it was a dumb move but moving on....I got fit about 1 month later by a well know FIST certified fitter in WI and it was a big help. Distance prohibited me from going back to make adjust ments so I tried them on my own. I am one of those people always searching for the next best thing in comfort and speed. I went through last year doing sprints but after 18 miles or so my underside would be hurting. I can't get too low due to a whiplash injury so cranking my neck up while low can get to me after a while. Last off season I bought a prologue saddle and made some more adjustments lowering my bars. Then I went over to another site to get feedback on how my "fit" looked and was told my seat was too high. I lowered it and did a "Du" a few days later (big mistake) and the entire time I felt like the seat was too low and I had no power. Moved the seat back up after that. Then as the summer went on I actually raised my bars about 1 cm and was playing with the seat fore and aft. I now have it "close" but still seem to slide forward on the seat and my right side where my hamstring meets my butt got sore in a oly I did but it's much better. I plan on going back next spring and getting refit again.

Now, which system can measure power output, Retule, Guru or some other tool? I want to do a HIM next summer and will be looking for a combination of comfort without giving up power. Probably looking at a couple different fitters in the Madison WI area.

My current fit.....





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Is this a current pic?

It's a good picture from the side angle, although it might be decieving.

I drew 2 sets of angles, your angle as you're riding the bike in the picture... and an angle representing a more normal at 90 degrees (in terms of FIST recommendations) triathlon position. You are riding way beyond 90 degrees... I can see that you're fit and flexible, but this may not be the best position for generating power as your hip position is closed off.

The second pic is my current hero and idol, uberbiker Sebastian Keinle, look as his position, he's at max 90 degrees, sitting on the seat better and looks powerful and relaxed and ready for putting the hurt on the competition at the Vegas Worlds. Mr. 2:07... not too bad.







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Here is the takeaway: modern bicycle fitting, it doesn't matter what protocol, is NOT evidence-based, it's not science based. It is based essentially on anecdotal experience (yes, some of it is decent anecdotal experience), so it is basically arbitrary. Today you can go out and get fits done by 10 bike fits done by 10 different experienced and 'certified' fitters (trained by the same protocol or different ones, it doesn't matter) and you will get 10 different fits.

That said, in my experience and from my 3 decades in this sport, good bike fit does not appear to be static, it definitely can change and evolve, even for the same person. Often for the same person. But even what I am offering here is just my opinion.

That is not to say fitting is useless, usually it is not. You just have to keep the info you get into perspective. It is just a person's opinion about how you should sit on your bike. Not much more.


Edited by DarkSpeedWorks 2013-10-06 3:58 PM

I agree, each person has to feel comfortable, and finding that takes time, but isn't it well established the position of the pelvis/torso and the approximate optimal range of 90 to 100 degrees?

I'm not proposing to be a fit expert, but it seems to me, that it doesn't matter what method is used, but I think this is where all physiologists agree, it's human anatomy and range of motion of muscles. There will be folks that can fall outside of that range and be a fully capable cyclist, but below 90 is pretty rare, unless you have the flexibilty and core strength of a gymnast or contortionist. I'd more belive that those kind of cyclists are the rarest, who can cycle with efficiency with that extreme of a hip flexor angle, unless they have short crank lengths.

I'd say that trying to get as low as possible is robbing peter to pay paul... the law of diminishing returns as anyone tries to find the perfect aero number and ignore the loss of power and comfort. I tried that route before, it didn't work for me. It could work for others, but kind of doubt it. I've been cycling for 28 years off and on and seen changes in fit phylosophy too.

Edited by tomspharmacy 2013-10-06 4:30 PM

I think that picture in particular is a bit misleading as the angle of the photo makes it look like I'm going downhill, but I'm 99% certain the opposite was true.

The power argument is a good one (and important for TT'ing especially)... but it isn't taking into account that in that ride (Olympic) I'm not trying to produce maximum power for 40k... I'm trying to finish the ride at an intensity factor close to 1.00 and then not suck for the 10k. (which I fail miserably at regardless)

Lets say I raised my front end, produced 30 more watts for that hour (close to my "real" hour power) and then what?
(Consider that my FTP #'s come from a road bike in a very "average" road position as far as aggression goes.)

here's a little better rep of my last position. None of them are current unfortunately. (my saddle was too high in both the one you posted and the one I posted)



Edited by Leegoocrap 2013-10-06 4:59 PM






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Well, that's a good question, so I ran those scenarios for you.

I'm using this link for the analysis: http://www.gribble.org/cycling/power_v_speed.html- I use this link a lot to run various scenarios and to make sure my PM is calibrated correctly.

I used my body dimensions as the example: 69" / 147lbs / m2 of .403

Example 1 screenshot: 300w

Example 2 screenshot: 270w (30 less as you said)

In example 1, I used my known est. cda of .265... I use this for my power meter settings... avg. speed of 25.44.

In example 2, I improved the .cda by 5% (assuming a tighter hip angle and loss of subsequent power)... as you can see the avg. speed went down by about 1/4 to 1/3 mph, from 25.44 to 25.15.

What if you were to worsen your .cda by 5% but were able to improve your FTP wattage by 10%, your net gain would be almost 1/2 mph.

In both examples, the assumption is a crr of .007 and no wind, and 80F at sea level with about 25% humidity.



Edited by tomspharmacy 2013-10-06 6:32 PM








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So I ask you, if we went back to that tri and I was on my road bike, riding 10% harder (assuming for arguments sake that that's my optimal power position and that it ended up being 5% less cda than my aero position - again, to simplify things) do you think my RUN split would have been faster, slower or the same?

I could never answer a question like that... I'm not you're body... for comparison sakes I have a recent experience...

Sept 15th - AZ State TT championships - avg. watts 315, NP 320 - avg. speed 25.4 with some sidewinds, w/o wind, my theoretical speed was 27 mph... 2nd place in AG of 45-49

then 1 week later

Sept. 22nd - Lifetime Tempe Olympic Triathlon - avg. watts 301, NP 312 - bike split of 1:00:40 - avg. speed 24.44 - avg. watts - avg. moving speed - 25.3, theoretically I broke the hour mark, fastest bike split in AG and 10th fastest overall - 3rd place, injury laden run, 3 to 4 minutes slower than the my avg. at this course.

Did I bike hard, yes, but I was trying to break an hour and whether I was rested from the previous week is debatable.

but my question to you is do you have a known FTP wattage from a 40k TT? or from a 30 minute threshold test? then I could answer that question.

Unfortunately around here most TT's are 8-10mi, and the last 40k (and only recent) I've done was in that Olympic. It's an ok result to look at, but not perfect since I stood on the side of the road trying to fix a dropped/jammed chain for some amount of time.

* I am envious of your watts. There's a reason some of us have to be aero weenies

Edited by Leegoocrap 2013-10-06 7:50 PM

Thanks, but it took me a while to realize that low may not be as beneficial as it seems. We're all on a personal journey of improvement. I'm just giving food for thought. Also, I'm trying to get any user of BT to understand the dynamics of fit and power. Sometimes, the cda and power can move independently in the opposite directions. It is about finding the balance between the 2. I don't know if I've found the right "perfect" either, but I feel closer than I ever have.

I'm also not trying to use me or you as a poster boy of fit and power.

I can make some educated approximation based on your previous posts and size and position, that you may be around a cda of .230, and if you did a 40k TT in one hour exactly, then your 60 minute FTP threshold wattage would be around 255 +-10 watts. But what if you raised your bars 5mm higher, let's say and got a torso angle of 92 degrees and you were able to increase by 10% in watts production to 280 watts yet you only lost 5% in cd to .245?

Your new avg. speed all things being equal would be 25.5 mph, you've gained 1/2 mph... you've got to trust the outcome, at that speed you're now doing a TT 40 seconds faster, that's significant...

BUT, let's say that you raised your bars another 5mm and power only went up 5 watts and your cda dropped another 5% to .260, then your avg. speed drops to the same as before your change to 25 mph. Then you know you've found that point in your personal aero/power profile. Then just work your training on the cycle to improve power... and doing that stuff is readily available as: 2 x 20 at 95 to 100% FTP, long rides at 70 to 75% FTP... hill work in big gears at 85 to 90%.... etc.

Yes, I believe in weight lifting...

Good luck with your journey.

Ha!!!

Actually, in triathlon, once a person can do a 40K in under an hour I believe in fast swimming and running.  You can try to gain another minute or two on the bike....or even 5...but if you're running 7-7:30 miles you're going to wish you could get more run aero against the guy running 5:30 - 6 minute miles and swimming 18:00.

In other words.....you're at 1:00:00 for 40K.....time to work on the other two where your work will pay off much better than the few minutes you will now gain on the bike with ALOT more work.

Edited by Left Brain 2013-10-06 10:55 PM

Huh? you can never be too fast on a bicycle... LOL

Touche

This is the boat I'm in... can swim pretty good (for a triathlete ), bike well, but end up losing 15+ places overall on the run.

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I could be too low (although a lot of fast guys don't think so... a lot of fast guys DO think so as well so it kind of depends on who you want to believe)

Realistically I think more than being "too low" I'm actually riding TOO LONG cranks. Unfortunately, getting 160 or lower arms is expensive. (or extremely ghetto)

I don't think there's anything wrong with riding higher up or that riding lower is the end all solution for everyone. (or even most people) On the same note, I can't produce a large amount of watts on ANY bike for an hour+, I'm just not powerful enough... so where can I gain speed?

It's like comparing Obree to Ermenault in 93. Ermenault almost certainly was the more powerful rider of the two (as was Boardman likely) but Obree still won the championship.

Fred, I don't think there is anything wrong with your position especially considering back problems. Now wearing socks...

like said by quite a few above, I don't think there's one answer to any of these questions... If there was, you wouldn't see guys like Castroviejo trying to get lower/tighter. (His hip angle is so closed it's hard to believe he makes power at all...right )

Again... I don't want anyone to think I'm saying you are wrong... I'm just trying to get everyone talking/thinking of new/different things for themselves. As my sig says... advice on the internet is worth what you pay for it.

Just curious as to why? Do you think you (not YOU, just in general) can ride 10% above a 1.00 Intensity Factor and have an optimal run in an Olympic?

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Good luck on the 1 hour I was not pleasantly surprised at the difference between my real 1 hour power and my 20min FTP test #'s haha.