Larger chainrings/cogs reduce the frictional drivetrain losses. Just like with oversized pulley wheels, the chain links don’t need to bend as much.

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AFAIK there is more mechanical loss with an 11 than with a 13. I don't see any other explanation but I'm far from being a specialist in this field.

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In this instance a few factors at play...

1) testing what felt best with the limited track time eg. 58/15 definitely not good choice neuromuscularly for Lionel

2) knowing Lionel’s cadence preference muscular endurance wise (this being the MOST important factor)

3) sourcing the best products / correct products quickly enough

4) the COVID restrictions impacting folks manufacturing capacity

61/13 was the end result of this.

We knew about the drivetrain friction marginal implications but if we had gone 14t we would have needed a 68t front and if we’d gone 15t (both rear cogs trackie’s would prefer in this scenario) we would have needed a 70t! Honestly that big my concern was the chainring clearing the chainstays.

Mark at Pyramid Cycle Design (supplier to many world records and hour record attempts) went out of his way for us to expedite a few track chainrings all coated as per HUUB Wattbike folks.

Likewise HED pulled out all the stops to hand build the Volo’s and supply the special splined White Industries cog.

Canyon literally sent the entire bike including crank and ring and cog Alex used.

4iiii expedited firting a left side only powermeter to a Vision Metron 165mm crank so we could calibrate power output in the test runs to speed and equipment choice.

It genuinely took “a village” to make this happen so fast and for that am thankful to many folks.

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David T-D
http://www.tilburydavis.com

Pretty amazing!

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https://www.strava.com/...tes/zachary_mckinney

wow ... tough crowd.

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I think it was a class act to have Victor C and Alex D chatting with all of us throughout the attempt. Wasn't Barrie Shepley that said many years ago that Lionel should just focus on track cycling? Pretty sure he is not that far from the standard for the team pursuit. Ed Veal made the Pan Am team in 2015. Our national record is actually a very solid team pursuit effort 3:49, different team without Ed though.

David, thanks for helping make this happen. Please pass my congrats to Lionel.

In the post interview he said he did a 30min "trial" at 380 watts and I understood this to be his target for the hour. Is this accurate ?

Congrats to Ed and Steve. I actually didn't watch but listened while riding. Great job.

If Steve can say, without getting into the detail of who is paying for what, how much does an effort like this end up costing with UCI commissioners, track.....?

Based on that "trial" we expected that the "price" of 50kmph was going to be in that region. Obviously he went quicker :-)

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David T-D
http://www.tilburydavis.com

Thanks. That makes a lot of sense.

It doesn't look like barometric pressure was too favorable either. Air density just under 1.16 ?

61-13 would have more active teeth engaged in terms of friction losses. If you have more force on less teeth, I would think that should be more losses, so you want the biggest big ring and biggest rear sprocket for the same gear inches. But maybe some track folks can chime in. But a bigger chainring would also have a larger aero penalty if we are looking at all marginal tradeoffs. Does anyone know what crank length Lionel was on too. That has impact on effective gearing relative some former guys using 175s

Not sure on what the exact measurement was yesterday, haven´t seen the environmental data yet. But Milton velodrome was pretty stable at 0.072 lb/ft3 in past trials.... the temperature yesterday there was a few Centigrade higher than past trials.

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David T-D
http://www.tilburydavis.com

It was a 165mm crank.

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David T-D
http://www.tilburydavis.com

This makes the pedal force even higher than guys like Obree, Voigt and Moser who went around the same speed 51+ on smaller gearing. Lionel had the largest gear selection and the shortest cranks of all these guys making his pedal force requirements even more huge. Pretty impressive. Usually with shorter cranks the RPM comes up for the same wattage, but he did it by bringing pedal force up (relative to the other hour competitors).

Also it looked like he was the first one to use an Adamo (or equivalent) so he could have the UCI setback of 5 cm and still ride in a very forward position compared to others.

Steve, you did an excellent job on the coverage. It wouldn't be easy to keep information flowing for an entire hour but you did and had me watching the entire time.

Very impressed with Lionel and the entire crew. This is going to bring more people interested in breaking the new record, including Lionel who said he would like to try again.

Well done.

you can put more force on the pedals if you start with a more open hip at top dead center. which is what the shorter cranks give you. but as you note, the biggest obvious difference over the last 2 or so years with lionel is to move from this position (kona, 2017):



to this position:



which, yes, he does mostly by moving forward on the saddle versus where he was 3 years ago. the whole positional transformation has happened since he moved to canyon. the first time i ever saw him on the velodrome - maybe the first time he was on one - was in carson (los angeles), where canyon and jim manton worked on his position (and to determine whether he was an S or a M in his speedmax bike size). even then, he was still a guy looking like he was trying, and failing to do the hoola hoop. (at least to my eyes). he looks a lot more polished now.

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Dan Empfield
aka Slowman

Corrected the link to youtube

So let's compare Obree and Lionel in terms of crank force assuming same wattage which is likely bad, probably Obree pushed way less wind on the now banned Egg position

165 vs 175 cranks = 5.7 percet more pedal force
61x13 vs 52x12 = 8 percent more pedal force

If we say they did the same average watts (likely not the case), then Lionel likely puts out at least 14% higher pedal force per stroke to get to the same average wattage but its likely higher for the triathlete position vs Egg position.

As for shorter cranks allowing more pedal force, I always thought the idea was if you go to shorter cranks, you keep pedal force roughly constant and go to higher RPM for a fixed wattage (roughly pedal tangential speed stays the same whether is is a shorter or longer crank, for force stays the same, torque goes down due to the shorter arm, but RPM goes up, but that gets you to the same pedal tangential speed). Lionel is on a low pedal speed (short crank arm, low RPM), but high force to get to high torque so he gets to high watts.

while not checking your math, i'm not disagreeing with you. what i'm saying is, it's easier to apply more pedal force if you approach the problem starting with greater leverage. the point of hte smaller crank is to punch the same hole into the wind while starting your push on the pedals with mechanical advantage. in this case biomechanical advantage. so, it's not like - wow, look at lionel's pedal force compared to others - it's that lionel gets to apply more pedal force because he begins with greater biomechanical leverage. and he needs that increased pedal force, because he's giving up the mechanical leverage of the longer crank.

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Dan Empfield
aka Slowman

 
On the position change, please correct my probably flawed logic

If a 380 watts "budget" gave 50km/h, knowing air density would be around 1.16, we can work backwards to a CDA of .225. I assume total weight to be 74kg and CRR .003. Very rough numbers. I suspect his CRR was slightly better, but I don't know.

With the same parameters, at 51km/h he probably came closer to 400watts. Based on Lionel's Zwift races I think people pegged him around there. I don't think there are too many surprises here.

In 2016 Lionel was measured as a 0.230. That was published by the Alphamantis guys here on ST.

Has his position changed that much ? That was full tri setup and bike.

So what has changed ? Is he that much more aero, is he more powerful ? What is the surprise here ?

I think people are truly impressed with how well he rode. Actually I'm not that surprised, I remember when filming "Chasing the Lion", on day 2 at the end he was quite good on the track. He adapted very quickly.

Are we really surprised at Lionel's ability to suffer through this ? I'm not. It's known to be one of his greatest assets.

Where is my logic flawed ?

there's aero, and then there's aero. if you look at a lot of pro cyclists in time trials - contador comes to mind as a very notable example during his career - they fidget constantly while aboard their aero bikes. so, aero when? at what snapshot point during the ride? what i like about lionel's position now is that it's a no-fidget posture. i think we saw that yesterday, and the hour is the prototypical race where you can't fidget. there was some upper body movement, when he was trying to get some english on the pedals, but his keister was nailed to the saddle, in one spot, the whole ride. this is (imho) the real world aerodynamics that is sometimes overlooked. if you've got 3 different positions on the bike, and you only display 1 to your aerodynamicist, you're fooling him and yourself, but you're not fooling the wind or the clock.

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Dan Empfield
aka Slowman

thank you. That is an excellent point.

You posted old and new pics. Aside the obvious arm positions, what do you see that I don't ? When I say I don't, I'm blind as a bat on these things. I'm the guy where you need to find the 7 differences between two pictures and I can't find one.

I was being complimentary. Lionel beat Jens Voigt; that is impressive. Yes, he is far, far off the WR, but account for altitude and air density and that delta effectively halves. Again, impressive, especially for a triathlete with no track background.

Literally 3 min after he was done in the interview that Fleck did Lionel says he wants to try again with proper prep and even try at altitude. He seemed to imply that he's not done with this hour after round one.

since this was mentioned in this thread, his 5k "PR" was done in what exact version of skecher shoes?