The importance of crank length to the cyclist.

[Hawkwood]

The circumference of the circle is relevant. The question is what happens to the other elements involved in power production when you make that change.

For instance, increasing crank length means increased pedal speed for the same cadence. It is harder to apply force to the pedal if it is moving away from you faster (and easier to put negative force on the upstroke if the pedal is coming up faster). Further, it might be harder to apply force if the knee configuration is adversly changed.

As I tried to say before, we have to look at all the elements involved in this equation to see what happens. If we want to understand how these elements play against each other it seems to me what we want to do is actually run the experiment to see what really happens then try to explain the data rather than predict what we think would happen then not run the experiment to see if we are right. Surely no one would predict that one-rep power would be max at 145mm crank length. But that is what Martin found. How does one explain that outcome?

As I mentioned in my earlier post my biomechanics reading is way out of date. I do remember reading about a 1970s test that suggested that racing cyclists were all pedalling too fast, and that lower cadences were more efficient. It was also stated that racing cyclists weren't strong enough and needed to do more weight training in order to push higher gears at a lower cadence. The problem was that when this was transferred to the real world it didn't work, as little things such as acceleration came in.

I mentioned Indurain earlier, this is a real world example of someone who was big, tall, and very fast both going up mountains and also in time-trials. Indurain was known for spinning smallish gears on the climbs. Now the shorter crank argument would be that this was not efficient, yet I assume that Indurain went through scientific testing to work out the best equipment to use.

 

[Boeing]

When cranks are shortened the saddle must be raised to keep the "bike fit" at BDC the same as before. But, shorter cranks means the knee is lower at TDC which means it is further away from the chest (because the handlebars do not change). Because there is less "cramping" now at the top the rider can consider lowering the front even more.
.

I dont have enough information to agree or disagree with you entirely but I will say that your take on bike fit here is interesting and an approach I have never considered


let me ask you this frank, do you think that every bike one rides, mountain, track, TT, Tri should have the same crank arm length? serious question

 

[FrankDay]

As I mentioned in my earlier post my biomechanics reading is way out of date. I do remember reading about a 1970s test that suggested that racing cyclists were all pedalling too fast, and that lower cadences were more efficient. It was also stated that racing cyclists weren't strong enough and needed to do more weight training in order to push higher gears at a lower cadence. The problem was that when this was transferred to the real world it didn't work, as little things such as acceleration came in.

I mentioned Indurain earlier, this is a real world example of someone who was big, tall, and very fast both going up mountains and also in time-trials. Indurain was known for spinning smallish gears on the climbs. Now the shorter crank argument would be that this was not efficient, yet I assume that Indurain went through scientific testing to work out the best equipment to use.

One would expect that a rider like Indurain would be tested completely but I would really be surprised if his testing included crank length. Even if it did our data suggests that a 10 mm change in crank length, at the same power, will only change HR 2-3 bpm. This change is too small to be easily picked up because the daily variation is likely to be that large. It appears one must test multiple times over a large range to see this relationship.

The issue isn't whether Indurain raced well on 190 mm cranks. The issue is whether there is data to show that was actually the best crank length for him and whether that data, if it exists, relates to you, me or anyone else. I, personally, don't care what is optimum for Indurain or any other pro. I don't train like them. I don't put out the same power. I think we should all be concerned with what is best for each of us.

 

[Oldman]

I am sorry, what is your testing protocol for evaluating crank length effects on the rider? You stated you were trying to "match" the length to the rider, what are you matching the crank length too?

You select the ones that make the rider go faster for the given task. Position is adjusted for each individual as a product of their certain attributes. Remember the "egg" position, banned from use by the UCI although Obree set the hour record using it? How do you think it would test out with your protocol and would it work for the average cyclist?

 

[FrankDay]

let me ask you this frank, do you think that every bike one rides, mountain, track, TT, Tri should have the same crank arm length? serious question

Not necessarily. My suspicion is that the more power one is putting out the longer the optimum crank length is (at least for power production). So, if the track bike is being used for the 3000 m pursuit and the tri bike being used in the Ironman I would expect the same rider to be putting out substantially different power for those two events. Therefore, he might do better having two different crank lengths on those two bikes.

But, the other issue is one of specificity. Can a rider see the theoretical advantage of the crank length change if he doesn't train on it all the time? Since the power differences are not large we have to wonder if the rider might be better off choosing one length and sticking with it. To become as good as he can at pedaling that length regardless of the event. So, I can argue either way. I think the rider would have to make that decision for themselves and then be content with the fact that others may think differently.

 

[Oldman]

Not necessarily. My suspicion is that the more power one is putting out the longer the optimum crank length is (at least for power production). So, if the track bike is being used for the 3000 m pursuit and the tri bike being used in the Ironman I would expect the same rider to be putting out substantially different power for those two events. Therefore, he might do better having two different crank lengths on those two bikes.

But, the other issue is one of specificity. Can a rider see the theoretical advantage of the crank length change if he doesn't train on it all the time? Since the power differences are not large we have to wonder if the rider might be better off choosing one length and sticking with it. To become as good as he can at pedaling that length regardless of the event. So, I can argue either way. I think the rider would have to make that decision for themselves and then be content with the fact that others may think differently.

that's been my point. Any rider has a limited amount of training time dedicated to position and mechanical adjustments each season. We agree on that count and that requires real world experimentation.

 

[FrankDay]

[/B]

that's been my point. Any rider has a limited amount of training time dedicated to position and mechanical adjustments each season. We agree on that count and that requires real world experimentation.

Other than rest and recovery, isn't that what the off season is for, experimenting with things that might help next season's effort? This isn't the kind of change one should try 3 weeks before the TDF. How much crank length experimenting do you do now? Not much I suspect. I am simply saying I think it is something that everyone should consider as I think it has huge potential.

 

[FrankDay]

Remember the "egg" position, banned from use by the UCI although Obree set the hour record using it? How do you think it would test out with your protocol and would it work for the average cyclist?

The egg position would work fine with this protocol, although I see little incremental advantage once the head is below the top part of the back. One of our pro triathletes has been able to lower his front end more than 10 cm going from 175 to 115 cranks. He was able to get his head below the top of his back while still in a traditional aero bar position and maintain power. However, he has since raised the front some and gone "longer" on his cranks (130) since then for comfort/endurance reasons. My guess is he didn't have enough time to fully adapt to the extreme changes before the season started so he had to back off a bit. We will see what he does this next off-season.

 

[Oldman]

Other than rest and recovery, isn't that what the off season is for, experimenting with things that might help next season's effort? This isn't the kind of change one should try 3 weeks before the TDF. How much crank length experimenting do you do now? Not much I suspect. I am simply saying I think it is something that everyone should consider as I think it has huge potential.

I've experimented enough over 20+ years to know that changes are necessary within each season. I learned that increasing to 172.5cm cranks from 170 meant I needed to get out of the saddle to gain a quick response on hills as opposed to riding seated. I ride 167.5 on the track and can say reliably that does not apply to a fixed gear going up the banking; I need to get out of the saddle to accelerate on that "hill". My pursuit position is very low but 170cm cranks suit the cadence and track I'm on; not 167.5. These are small incremental changes and knowing my own attributes and having ridden as small as 165cm cranks find your smaller crank idea as a lab ideal. You may actually get someone to perform to that protocol but generalizations are pointless in my considerable experience.

 

[on3m@n@rmy]

Well, I am 6' 2" and my testing suggests that 105 (or thereabouts) is optimum for me. What testing have you done to support your choice?

None. Well, I've used 175s but I would not call that testing. But even if I tested optimally at 100 I would not change from my 170s. I like the way my 170s feel and would have a mental block changing drastically from that.

 

[Oldman]

None. Well, I've used 175s but I would not call that testing. But even if I tested optimally at 100 I would not change from my 170s. I like the way my 170s feel and would have a mental block changing drastically from that.

You should be able to make the adjustment in the off season testing, according to Frank.

 

[FrankDay]

None. Well, I've used 175s but I would not call that testing. But even if I tested optimally at 100 I would not change from my 170s. I like the way my 170s feel and would have a mental block changing drastically from that.

We all like what we are used to. I went back and rode some 170's in testing a new prototype crank we would be offering and almost found it impossible to ride the bike. It would be like you suddenly putting 250 mm cranks on your bike. I got on some of our PowerCranks at an expo set at 150 and to demonstrate to a customer how to ride out of the saddle and had a little trouble doing so because I wasn't used to lifting so far even though a year ago I could do so without any difficulty on 175 cranks. Different always feels strange. One cannot know if different is better or worse without testing (and proper testing may require an adaption period).

Anyhow, you are welcome to stay with what you are familiar with. I simply put it out there that for the serious athlete, there might be better choices available than what they are doing now.

 

[FrankDay]

I've experimented enough over 20+ years to know that changes are necessary within each season. I learned that increasing to 172.5cm cranks from 170 meant I needed to get out of the saddle to gain a quick response on hills as opposed to riding seated. I ride 167.5 on the track and can say reliably that does not apply to a fixed gear going up the banking; I need to get out of the saddle to accelerate on that "hill". My pursuit position is very low but 170cm cranks suit the cadence and track I'm on; not 167.5. These are small incremental changes and knowing my own attributes and having ridden as small as 165cm cranks find your smaller crank idea as a lab ideal. You may actually get someone to perform to that protocol but generalizations are pointless in my considerable experience.

The difference between a 165 and 172.5 crank is about 4.3%. My expectation (Martin only saw a 1% change going from 170 to 145) is that any power differential between these two lengths would be well less than 0.5%. That is less than the accuracy of most power meters which would make it extremely difficult to actually measure what you feel as being true. My guess is that what you are feeling represents mostly placebo effect, since you know the length of the cranks you are riding.

The other issue is this is not a big deal if one is only talking power. However, my point is the bigger issue for most people is aerodynamics and what shorter cranks might allow them to do. Perhaps this is not as issue for you. It is for most.

So, stay with what you are comfortable with if that is what you want. I present my data and make my argument and you can ignore it if you want. But you present no data to counter my argument other than your anecdotal feelings. Plenty out there ignore my pedaling technique arguments based upon bias and inadequate data, I would expect much the same for this argument also? At least this one is relatively easy for the average rider to test for himself.

 

[Oldman]

The difference between a 165 and 172.5 crank is about 4.3%. My expectation (Martin only saw a 1% change going from 170 to 145) is that any power differential between these two lengths would be well less than 0.5%. That is less than the accuracy of most power meters which would make it extremely difficult to actually measure what you feel as being true. My guess is that what you are feeling represents mostly placebo effect, since you know the length of the cranks you are riding.

The other issue is this is not a big deal if one is only talking power. However, my point is the bigger issue for most people is aerodynamics and what shorter cranks might allow them to do. Perhaps this is not as issue for you. It is for most.

So, stay with what you are comfortable with if that is what you want. I present my data and make my argument and you can ignore it if you want. But you present no data to counter my argument other than your anecdotal feelings. Plenty out there ignore my pedaling technique arguments based upon bias and inadequate data, I would expect much the same for this argument also? At least this one is relatively easy for the average rider to test for himself.

Between your "guess" of a placebo and your selling of aero advantage as the overriding need for cyclists does suggest you are selling the same. I have to race and while I do depend on getting off the front and value aero advantages; the bulk of time is spent in a posture designed to move effeciently within a group of riders. That's the sport, not wind tunnel testing.

 

[FrankDay]

Between your "guess" of a placebo and your selling of aero advantage as the overriding need for cyclists does suggest you are selling the same. I have to race and while I do depend on getting off the front and value aero advantages; the bulk of time is spent in a posture designed to move effeciently within a group of riders. That's the sport, not wind tunnel testing.

We are all faced with imperfect choices all the time. Nature of life I suppose. So, yes, I am trying to sell something. I am trying to sell a concept that is at complete odds with conventional thinking. (I seem to do that more than most.) You have made your choices and don't seem interested in exploring alternatives. That is just fine. Since I haven't been bombarded with scientific studies proving I am on the wrong track I suspect I am on the right track. Time will tell.

 

[Hawkwood]

One would expect that a rider like Indurain would be tested completely but I would really be surprised if his testing included crank length. Even if it did our data suggests that a 10 mm change in crank length, at the same power, will only change HR 2-3 bpm. This change is too small to be easily picked up because the daily variation is likely to be that large. It appears one must test multiple times over a large range to see this relationship.

The issue isn't whether Indurain raced well on 190 mm cranks. The issue is whether there is data to show that was actually the best crank length for him and whether that data, if it exists, relates to you, me or anyone else. I, personally, don't care what is optimum for Indurain or any other pro. I don't train like them. I don't put out the same power. I think we should all be concerned with what is best for each of us.

Sure, but the 190 cranks were specially made for Indurain, it wasn't a case of simply getting some from the stores. I don't think this would have happened unless there was some evidence that these were going to be effective. I don't understand your point that you don't train like the pros etc, what difference does that make?

 

[M Sport]

1. Shorter cranks will improve power output for most.
2. Although this goes completely against the conventional wisdom, shorter cranks can reduce knee stress
3. Shorter cranks allow better aerodynamic positioning without sacrificing power.

And, in general, we are talking substantially shorter than what most would consider to be a short crank. Our data suggests that around 100 mm crank length would be near optimum for most. I am currently riding 105 mm cranks with good feeling.

1. Power doesn't increase or decrease with the length of the crank, there has been a study on that and I will dig it out in the morning. What does increase in longer cranks is torque. That is a pretty straight forward experiment to conduct if you want to understand why torque increases.

2. I think it is conventional wisdom that short cranks reduce knee stress. Who is saying it increases stress? I honestly have never heard that argument.

3. Longer cranks are more aerodynamic. Lower position equals lower frontal area, and a frontal area that is lower to the ground. There is obviously a limit to how long you can go to get more aero though.

When cranks are shortened the saddle must be raised to keep the "bike fit" at BDC the same as before. But, shorter cranks means the knee is lower at TDC which means it is further away from the chest (because the handlebars do not change).

You have to change the handlebar height though. This is what you didn't get in the topic you started last year trying sell your powercranks.

Let's say on average you are going from 172.5mm cranks to the 105mm you are suggesting. Straight away two issues spring to mind.

1. You have to increase the saddle height by 67.5mm to keep the same knee angle at BDC. Therefore you have to also lift the bars by 67.5mm to keep the same torso angle and saddle/bar drop.

Anyone saying you don't need to move the bars consider this. Imagine you told a rider you were going to leave his saddle in the same place, but drop his bars by 67.5mm or so. He would quite rightly tell you to take a hike.

2. The second issue with going that short in the cranks is actually getting the saddle back far enough as well. Mine for instance running 175mm is right at the limit of setback on a 30mm offset seat post, no way I could get back another 67.5mm.

So to echo what others have said, there are practical issues with going that short. Bikes and the rules just aren't designed for it. And all that aside has it ever been proven on a road bike (not TT) that anything other than your vanilla 172.5mm is faster? I doubt it. Even the best bike fitters don't have a formula. They usually quote multiple formulae to cover all the bases.

 

[lostintime]

I agree with everything M Sport said ..... Frames are just not designed with such short cranks in mind.... you'd need to lower the BB substantially to get a lower center of gravity... and how that would affect the rest of the design is unknown to me .... but I bet there'd be other issues as well.

One way to effectively shorten the pedal stroke though is to use a mid foot position over the pedal. I thought it was "out there" until I could actually try it. Anyone can try it .... hop on a bike with platform pedal pedals for fun and try it . For clipless pedals though ... you need custom mods to make it work.

 

[FrankDay]

1. Power doesn't increase or decrease with the length of the crank, there has been a study on that and I will dig it out in the morning. What does increase in longer cranks is torque. That is a pretty straight forward experiment to conduct if you want to understand why torque increases.

According to the Martin data shorter cranks means more power, at least until one gets as short as 145mm. And, according to some early and preliminary data now being accumulated by another group I have seen, it increases all the way down to substantially shorter lengths than 145 mm when in the TT position and at a lower, sustainable, power. I look forward to seeing your data but also will want to look at the protocol.

2. I think it is conventional wisdom that short cranks reduce knee stress. Who is saying it increases stress? I honestly have never heard that argument.

Lot's of people believe longer cranks "save knees" because they think, all things being equal, one would have to push harder on shorter cranks to keep the same power. Pushing harder equates to more knee stress to them.

3. Longer cranks are more aerodynamic. Lower position equals lower frontal area, and a frontal area that is lower to the ground. There is obviously a limit to how long you can go to get more aero though.

Sorry, your analysis is completely backwards. Longer cranks increase the frontal area. The reason is lowering the saddle and keeping the handlebars the same moves the hips out of the shadow of the shoulders/chest. Shorter cranks move the hips up into the shadow of the shoulders/chest. I think this is pretty well illustrated in the little video I did on this.

You have to change the handlebar height though. This is what you didn't get in the topic you started last year trying sell your powercranks.

Let's say on average you are going from 172.5mm cranks to the 105mm you are suggesting. Straight away two issues spring to mind.

1. You have to increase the saddle height by 67.5mm to keep the same knee angle at BDC. Therefore you have to also lift the bars by 67.5mm to keep the same torso angle and saddle/bar drop.

Anyone saying you don't need to move the bars consider this. Imagine you told a rider you were going to leave his saddle in the same place, but drop his bars by 67.5mm or so. He would quite rightly tell you to take a hike.

Anyone saying you do have to move the bars up when you shorten the cranks hasn't actually tried it. While you would raise the handlebars if you wanted to keep the same torso angle at BDC a different thing happens at TDC, the torso angle actually opens up even though the seat has been raised. This is because the knee is moved down but the shoulders don't change at all. It is the torso/thigh angle at TDC that actually determines how low the rider can come down. Shortening the cranks opens this angle, lengthening the cranks closes it down when the handlebars are not moved. Rather than having to raise the handlebars, shorter cranks allows the rider to actually lower the handlebars. I have a pro triathlete who was able to lower his bars 10 cm moving from 172.5 to 130. I have yet to have someone try this and not come back and say this simple change almost immediately made them more comfortable on the bike.

2. The second issue with going that short in the cranks is actually getting the saddle back far enough as well. Mine for instance running 175mm is right at the limit of setback on a 30mm offset seat post, no way I could get back another 67.5mm.

While this may seem like a theoretical problem, people who try this don't seem to have a problem.

So to echo what others have said, there are practical issues with going that short. Bikes and the rules just aren't designed for it. And all that aside has it ever been proven on a road bike (not TT) that anything other than your vanilla 172.5mm is faster? I doubt it. Even the best bike fitters don't have a formula. They usually quote multiple formulae to cover all the bases.

Who is talking formula? I am encouraging people to experiment and see what is best for them rather than relying on the current formulas and/or guesses of the bike fitters.

Your so-called "practical issues" are only theoretical issues. The only real practical issue I am aware of that keep people from trying this to the extremes I am talking about are seat post length issues (edit: and the ready availability of shorter cranks for people to try). Most people's current seat post is not long enough to allow them to go as short as I am advocating and maintain their current fit. It is not clear this is a huge drawback because I know that John Cobb is now advocating lower saddle height to maximize power. Perhaps the two changes can be combined. The only other "practical issue" I am aware of is getting used to how "funny" the cranks feel in the beginning (and getting past what your friends might say). Anyhow, once you have actually tried the change then come back and talk about the "practical issues" you encountered.

One more thing, exactly what is it about bikes or the rules that are not "designed" for this change?

 

[FrankDay]

I agree with everything M Sport said ..... Frames are just not designed with such short cranks in mind.... you'd need to lower the BB substantially to get a lower center of gravity... and how that would affect the rest of the design is unknown to me .... but I bet there'd be other issues as well.

I guess you and M Sport must be right. Perhaps you could tell me how to respond to this email we got today. Clearly this writer and I both don't understand why this can't work.

"First off, I would like to say that I am loving powercranks. They have made me stronger than ever. I cant see myself ever training without them.
I read the write up about shorter cranks and it intrigued me. I didn't believe that shorter cranks would be faster, but nevertheless I couldn't stop myself from trying them out. so, I went out and bought a set of 145mm juniors bmx racing cranks. and did some training rides all within a month of the 200mile seattle to portland classic. I found in training that speed, endurance, and climbing strength all went way up on the shorter cranks. And In the seattle to portland, I finished 4th, 6 min behind a recumbent rider and two guys who were working together the whole way even though my last 100mi were almost all solo miles. all on cranks and a saddle position adopted less than a month earlier (imagine how fast I will be when my legs fully adapt to this length). Thank you Dr.Day for raising this issue. it has impacted my athletic performance beyond my wildest dreams."

And I was thinking about talking him into trying even shorter cranks but after I read your post I guess I have to talk him into going back to "normal" cranks.

 

[CoachFergie]

"Oh, and as I watched him on the stage
My hands were clenched in fists of rage.
No angel born in hell
Could break that satan’s spell.
And as the flames climbed high into the night
To light the sacrificial rite,
I saw satan laughing with delight
The day the science died"

 

[Oldman]

I guess you and M Sport must be right. Perhaps you could tell me how to respond to this email we got today. Clearly this writer and I both don't understand why this can't work.

"First off, I would like to say that I am loving powercranks. They have made me stronger than ever. I cant see myself ever training without them.
I read the write up about shorter cranks and it intrigued me. I didn't believe that shorter cranks would be faster, but nevertheless I couldn't stop myself from trying them out. so, I went out and bought a set of 145mm juniors bmx racing cranks. and did some training rides all within a month of the 200mile seattle to portland classic. I found in training that speed, endurance, and climbing strength all went way up on the shorter cranks. And In the seattle to portland, I finished 4th, 6 min behind a recumbent rider and two guys who were working together the whole way even though my last 100mi were almost all solo miles. all on cranks and a saddle position adopted less than a month earlier (imagine how fast I will be when my legs fully adapt to this length). Thank you Dr.Day for raising this issue. it has impacted my athletic performance beyond my wildest dreams."

And I was thinking about talking him into trying even shorter cranks but after I read your post I guess I have to talk him into going back to "normal" cranks.

This is a rich endorsement, indeed! Seatte to Portland is a fun ride populated by 99% hobbyists and they discourage, not emphasize fast riding. He finished behind a recumbent rider and thought he was in a race? This will most certainly set the racing world on it's ear!

 

[FrankDay]

This is a rich endorsement, indeed! Seatte to Portland is a fun ride populated by 99% hobbyists and they discourage, not emphasize fast riding. He finished behind a recumbent rider and thought he was in a race? This will most certainly set the racing world on it's ear!

This fellow is an amateur. He is reporting that he didn't believe there would be a benefit from such a change but found his experience with short (145mm) cranks is very positive in that he found improvement in all areas of his riding in a very short period of time. He then participates in a 200+ mile ride that had over 10,000 participants (99% hobbyists means that over 100 would be serious riders) and, while not a race, actually keeps time for those wishing to test themselves (about 200 participated in the optional chip timing). He reports doing this 200+ mile ride coming in fourth overall, which impresses him.

The question had come up in this thread as to whether the Martin data, that simply looked at 1 rep maximum power, had any applicability to longer efforts. This report suggest that it does. While this report and effort may not impress you, it does go to the reason I started this thread - to encourage people to be willing to try this "outside the box" change.

edit: I originally reported he did the ride in 10:10. I somehow misread or got confused. His actual time was 13:50, about 10 minutes behind the fastest time.
Edit#2: I didn't realize I was on the wrong page of the results when I was checking this and the 4th from the top was 13:50 but that wasn't this rider. Here are the published results:
1 7360 Rudd Michael - Anacortes, WA United States 10:14:12
2 6462 Dodson Gilbert - Long Beach, CA United States 10:14:29
3 7310 Howard Martin - Long Beach, CA United States 10:14:31
4 5247 Clark Mike - Kirkland, WA United States 10:20:29
5 3891 Sifferman Justin - Kent, WA United States 10:43:00
Edit/Delete Message

 

[Oldman]

This fellow is an amateur. He is reporting that he didn't believe there would be a benefit from such a change but found his experience with short (145mm) cranks is very positive in that he found improvement in all areas of his riding in a very short period of time. He then participates in a 200+ mile ride that had over 10,000 participants (99% hobbyists means that over 100 would be serious riders) and, while not a race, actually keeps time for those wishing to test themselves (about 200 participated in the optional chip timing). He reports doing this 200+ mile ride coming in fourth overall, which impresses him.

The question had come up in this thread as to whether the Martin data, that simply looked at 1 rep maximum power, had any applicability to longer efforts. This report suggest that it does. While this report and effort may not impress you, it does go to the reason I started this thread - to encourage people to be willing to try this "outside the box" change.

edit: I originally reported he did the ride in 10:10. I somehow misread or got confused. His actual time was 13:50, about 10 minutes behind the fastest time.

This "report" is a product endorsement. If you're serious you would be paying a pro to ride them and get real feedback from someone with experience. Relying on this "feedback" is a feeble marketing strategy. You should just take out an ad and take up less bandwith. I'll stop wasting electrons, now.

 

[Damiano Machiavelli]

edit: I originally reported he did the ride in 10:10. I somehow misread or got confused. His actual time was 13:50, about 10 minutes behind the fastest time.

That is quite a correction. Three hours and forty minutes, a 36% increase. The six minutes to ten minutes change beats that at 67%. Of course, self reported numbers tend to be untrustworthy. That is why real research actually measures things.

I will wait for the next correction to bring the numbers closer to reality.