Jens' FIST and Low Diver positions comparison: UPDATED

May 24, 07 13:03

Post #1 of 44 (10470 views)

I got to do my first real test of the FIST position today.

The course: Canada road in Woodside CA - 1/4mile north of Jefferson to Hwy 92 & back. 10.13 miles with ~1000 feet of climbing.

Best recent "Low Diver" trial (5/8/07): 22:31 (26.99 mph) with 287 watts; pseudo-CdA:* .236

FIST trial (5/24/07): 22:29 (27.03mph) with 295 watts; pseudo-CdA* .245

*Pseudo-CdA takes air-density into account, but is calculated as if the course were flat. The true CdA for the Low Diver position in flat, windless conditions is ~.03 to .04 lower.

NOTES & QUALIFICATIONS: I suspect my power was significantly off today as I just got over a rather nasty case of bronchitis. I also blew my AWC on an earlier trial that I aborted when I dropped the chain. I would expect to gain another 5-10 watts in better circumstances.

There was a slight wind in both trials, which could easily bias the comparison. However, my experience with this course has been that the wind balances out unless it's real heavy.

What remains to be determined is how much of the power gain is due to raising the seat and how much to the slightly higher and much less extended aero-bar setup. I will hopefully find that out this weekend in side-by-side trials in real race conditions. I will also be doing more formal (0 wind) field testing trials to determine the actual cdA of each position.

This initial result is a little suprising. I was expecting both power and drag to increase more than they did.

-- jens

Last edited by: jens: May 26, 07 11:01

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 24, 07 13:22

Post #2 of 44 (10398 views)

This is very interesting and I for one will be checking back regularly for your updates. Thanks!

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 24, 07 14:10

Post #3 of 44 (10257 views)

Jens, I was just racing a Trade Team rider in an 18km TT who was decked with P3, disk wheel, 404 front, and an SRM. It was a rolly course, but by no means hilly. He weighed about 15lbs more than me, so maybe 160. He showed me his SRM after and it said he averaged 369watts with an average of around 44km/hr..or 27.3mph.

Based on your watts and your speed, does this mean the dude's CDA totally sucks? Or is his SRM wonky?

Trev

Trev Williams
http://www.thedoctrine.ca

Re: Jens' FIST and Low Diver positions: first comparison [tri-poser] [ In reply to ]

May 24, 07 14:19

Post #4 of 44 (10224 views)

Hey Trev:

Likely his position is the culprit. Sounds like he's catching lots of wind.

Ric

Re: Jens' FIST and Low Diver positions: first comparison [tri-poser] [ In reply to ]

May 24, 07 14:21

Post #5 of 44 (10215 views)

In Reply To:

Jens, I was just racing a Trade Team rider in an 18km TT who was decked with P3, disk wheel, 404 front, and an SRM. It was a rolly course, but by no means hilly. He weighed about 15lbs more than me, so maybe 160. He showed me his SRM after and it said he averaged 369watts with an average of around 44km/hr..or 27.3mph.

Based on your watts and your speed, does this mean the dude's CDA totally sucks? Or is his SRM wonky?

Trev

There are a lot of people running around with poorly calibrated SRMs. Even a correctly calibrated SRM will give 10 watts or so higher numbers than mine, because I use a powertap or an SRM-calibrated to match it. Moreover, plenty of average sized-people (e.g. Gordo) have CdAs around ~.30. That means they have to generate and extra 90 watts to go the same speed as me.

OR..... it could be that the guy has Tufos.

-- jens

Re: Jens' FIST and Low Diver positions: first comparison [tri-poser] [ In reply to ]

May 24, 07 14:25

Post #6 of 44 (10186 views)

Sounds wonky to me. If it was geneuine you'd expect him to be doing 31mph on the flat with that kind of power output. It's a national class output (depending on his size).

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 24, 07 14:26

Post #7 of 44 (10179 views)

This sounds very very promising. So without adaption you're already marginally better off ?

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 24, 07 14:33

Post #8 of 44 (10154 views)

Jens,
Was this "FIST" position the one you ended up with at Dan's (as shown in the photos), or was it with your saddle height corrected and your arms a bit more extended (as you had mentioned trying)? How does this compare (if you know) "Psuedo-CdA"-wise to the position you came out of LSWT awhile back?

Huh?...You dropped your chain? What was that you were saying on Saturday about not running a front derailluer?? I think you may have jinxed yourself. ;-)

http://bikeblather.blogspot.com/

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 24, 07 15:19

Post #9 of 44 (10075 views)

Moreover, plenty of average sized-people (e.g. Gordo) have CdAs around ~.30. That means they have to generate and extra 90 watts to go the same speed as me.

Holy cow!!! Is this accurate? I mean, to the average person I think they would look at Gordo's position and say "Hey, that guy looks good on the bike." And then look at you and guy "Hey, that guy looks good on the bike too, probably even better than the first guy." So the difference between those two is 90 watts?

Can you quantify that into time over a 40k for me?

Portside Athletics Blog

Last edited by: SwBkRn44: May 24, 07 15:19

Re: Jens' FIST and Low Diver positions: first comparison [Tom A.] [ In reply to ]

May 24, 07 19:19

Post #10 of 44 (9922 views)

In Reply To:

Jens,
Was this "FIST" position the one you ended up with at Dan's (as shown in the photos), or was it with your saddle height corrected and your arms a bit more extended (as you had mentioned trying)? How does this compare (if you know) "Psuedo-CdA"-wise to the position you came out of LSWT awhile back?

Huh?...You dropped your chain? What was that you were saying on Saturday about not running a front derailluer?? I think you may have jinxed yourself. ;-)

The FIST position was exactly as set up by Dan. On Saturday, I'll do the Diver position with the raised seat and then the FIST position. The FIST position is slightly faster than the tunnel position - no surprise because it has more drop. My guess is the Diver position with the higher seat will actually be faster than the old diver position (I have a theory about this).

Looks like I need to get a chainwatcher....

--jens

Re: Jens' FIST and Low Diver positions: first comparison [SwBkRn44] [ In reply to ]

May 24, 07 19:43

Post #11 of 44 (9879 views)

In Reply To:

Holy cow!!! Is this accurate? I mean, to the average person I think they would look at Gordo's position and say "Hey, that guy looks good on the bike." And then look at you and guy "Hey, that guy looks good on the bike too, probably even better than the first guy." So the difference between those two is 90 watts?

It was something like .29 or .30. gregclimbs remembers the actual numbers.

Quote:

Can you quantify that into time over a 40k for me?

Just this time. Next time, you do the math. With a .30 CdA and 280 watts you can do 40K in 60min. With my diver position and 280 watts you can do it in 53min.

Re: Jens' FIST and Low Diver positions: first comparison [UK Gear Muncher] [ In reply to ]

May 24, 07 21:34

Post #12 of 44 (9735 views)

In Reply To:

This sounds very very promising. So without adaption you're already marginally better off ?

Maybe. I don't know how much of the power gain is just from raising the seat yet. I have a suspicion that the diver position with the raised seat will have both higher power and lower drag than it did with before, with the lower seat. We'll see. I also don't expect to see any incremental power gains from adaptation.

-jens

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 24, 07 23:11

Post #13 of 44 (9673 views)

In Reply To:

It was something like .29 or .30. gregclimbs remembers the actual numbers.

gordo's best run in the tunnel that he published was .296

based on today's piss poor TT effort I did - I have lowered mine from .3445 @ the start of the season down to mid two's today.

g

greg
www.wattagetraining.com

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 25, 07 1:01

Post #14 of 44 (9623 views)

Keep us posted. This is one of the best threads I have read for a while.

Bryce.

Re: Jens' FIST and Low Diver positions: first comparison [gregclimbs] [ In reply to ]

May 25, 07 5:44

Post #15 of 44 (9485 views)

Do you have any pictures of before and after pictures on how you were able to decrease your CDA by .1 or so. If not could you explain how you went about changing your position. Finally how did this affect your watts and or tt time.

Thanks in advance,

Mike

http://www.MikeCaiazzo.com
http://www.USProTri.com

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

FindinFreestyle

May 25, 07 7:21

Post #16 of 44 (9381 views)

Now enough of this useful info, get on over to the peanut butter and jelly thread...oh wait it's now regressed into a lamb sauce thread. I think Julian is trying to rival the Sergio thread with her entire family recipe book. *sarcasm off*

Seriously, thanks for the post , this is why I continue to visit this site, sometimes too much swampland must be waded through to find the clear rivers of useful information. Or I got up on the wrong side of the bed.

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 25, 07 7:28

Post #17 of 44 (9353 views)

COOOL!! There is a Canada Rd in the US!! :)

Re: Jens' FIST and Low Diver positions: first comparison [Markus Mucus] [ In reply to ]

May 25, 07 8:07

Post #18 of 44 (9295 views)

Technically is Ca�ada Rd, pronounced CanYahda.

Re: Jens' FIST and Low Diver positions: first comparison [JohnA] [ In reply to ]

May 25, 07 8:11

Post #19 of 44 (9285 views)

That's not nearly as cool

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 25, 07 11:43

Post #20 of 44 (9166 views)

reactions:

i don't think you should assume that raising the saddle 2.5cm is going to give you the same benefit on the low-diver as it did, or may, on the compatto. my reasoning is as follows:

at the higher saddle height on the compatto, that saddle height was part of an overall position that got you to a hip angle producing (what i think is) your best efficiency over a threshold-ish distance. if you simply raise your saddle on the low-diver position, you'll take an already acute 97� and make it -- what? -- 95�? in so doing i think the extra leverage you get by raising the saddle may be overcome or canceled by squeezing your hip.

let's say you raise your saddle on low-diver and you combine that with raising the armrests the same amount. in this case, you arguably open your hip angle a slightly bit, maybe from 97� to 98� or so. this will give you a bit of power, but you're also hoisting your body 2.5cm higher in the air overall, and i don't know what that does to your drag.

the point is, i'm not sure whether you're going to get all the benefits out of raising low-diver's seat height that you enjoy by having the proper seat height integrated into the jens-compatto position from the start.

i'm very interested in seeing the results. is there a sub-22min position out there? ;-)

Dan Empfield
aka Slowman

Re: Jens' FIST and Low Diver positions: first comparison [Slowman] [ In reply to ]

May 25, 07 12:42

Post #21 of 44 (9088 views)

Hi Dan,

You may well be right about the power side of the equation. I was also thinking about the drag side. As you astutely noticed, in the old low-seat position I was pedalling in a crabbed fashion with the left knee flaring out. This is really bad for drag.

I think the knee flaring has gone away with the higher seat, which might explain why the 'compatto' position is more aero than I expected. I'm pretty sure this improvement will also obtain for the low-diver position. Indeed, I saw a hint of this on my easy ride today, where my power/speed numbers were better than ever.

It all underscores the benefit of having a qualified fitter really look at your position as you pedal, rather than relying on static poses.

-jens

Last edited by: jens: May 25, 07 12:42

Re: Jens' FIST and Low Diver positions: first comparison [gregclimbs] [ In reply to ]

May 25, 07 13:07

Post #22 of 44 (9042 views)

Would you happen to have pics of your .3445 and you mid 2's position? Trying to get an idea of where mine may lie and what I may be able to do to improve it (ritchey adjustable and narrow the pads is about all that's left).

36 kona qualifiers 2006-'23 - 3 Kona Podiums - 4 OA IM AG wins - 5 IM AG wins - 18 70.3 AG wins
I ka nana no a 'ike -- by observing, one learns | Kulia i ka nu'u -- strive for excellence
Garmin Glycogen Use App | Garmin Fat Use App

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 25, 07 14:34

Post #23 of 44 (8956 views)

I will get a good view of your position as you blow by me tomorrow morning. I start 1 min ahead of you but am not in the same league. Be sure to say howdy. Good luck with your experiment.
Forrest

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 25, 07 17:03

Post #24 of 44 (8845 views)

hey some of us non-qualified folks suggested raising your saddle didn't we? ;)

Sounding good though ...

Re: Jens' FIST and Low Diver positions: first comparison [jens] [ In reply to ]

May 25, 07 18:24

Post #25 of 44 (8754 views)

Are you sure about the ~1000 feet of climbing? The event website said about ~400 feet of climbing - http://www.scaledup.com/...ock/locationCan.html, but who knows how it was measured.

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