Road bike vs. recumbent comparison

[Osiris]

Yesterday's ride provided the last bits of data which answers the question as to whether I made the right move by trading my Bacchetta CA2 for the Vendetta V20. Numerous coast down comparisons show beyond any doubt that the V20 is the more aerodynamic of the two, but I wasn't yet sure that the V20 would be faster under power. Due to differences in geometry, I could generate significantly more power on the CA2 than I could on my much more aerodynamically efficient M5 CHR. The M5 would easily win every race when top speed is the determining factor, but in certain situations when I couldn't capitalize on the M5's superior aerodynamics, the CA2 would actually be faster. Would the same thing be true when comparing the CA2 to the more aero V20? As it turns out, the answer is no. When comparing my best results on various Strava segments, my power numbers were almost exactly the same on both, but my speeds on the V20 were still higher. The M5 CHR remains in another league when it comes to top speed, but you give up a lot for that. For 90% of the riding I do, the V20 is just the better recumbent, and it does this while giving up nothing to the CA2.

 

[jond]

Yesterday's ride provided the last bits of data which answers the question as to whether I made the right move by trading my Bacchetta CA2 for the Vendetta V20. Numerous coast down comparisons show beyond any doubt that the V20 is the more aerodynamic of the two, but I wasn't yet sure that the V20 would be faster under power. Due to differences in geometry, I could generate significantly more power on the CA2 than I could on my much more aerodynamically efficient M5 CHR. The M5 would easily win every race when top speed is the determining factor, but in certain situations when I couldn't capitalize on the M5's superior aerodynamics, the CA2 would actually be faster. Would the same thing be true when comparing the CA2 to the more aero V20? As it turns out, the answer is no. When comparing my best results on various Strava segments, my power numbers were almost exactly the same on both, but my speeds on the V20 were still higher. The M5 CHR remains in another league when it comes to top speed, but you give up a lot for that. For 90% of the riding I do, the V20 is just the better recumbent, and it does this while giving up nothing to the CA2.

I think you will continue to see marginal measurable gains on the v20 .

Anecdotal evidence only but seemingly a shared experience reveals most of us acquire our complete skill set 10,000 klm in twelve months cycling the vendetta.

Many of us continue to mod and develop from simple ergonomics and on board storage to aero add ons.

Anyhow your results Osiris are in. Well done on the journey so far.

 

[Osiris]

I think you will continue to see marginal measurable gains on the v20 .

Anecdotal evidence only but seemingly a shared experience reveals most of us acquire our complete skill set 10,000 klm in twelve months cycling the vendetta.

Many of us continue to mod and develop from simple ergonomics and on board storage to aero add ons.

Anyhow your results Osiris are in. Well done on the journey so far.

I'm so comfortable riding the V20 now that I don't even have to think about what I'm doing. Starting, stopping, turning, and shifting have all become effortless. I can't say I've ever reached that level of proficiency on any of my other recumbents, despite having spent much more time on them than I have on the Vendetta. This seems counter-intuitive, because a MBB should be more difficult to ride than a fixed boom recumbent, but in practice it hasn't turned out that way.

 

[Balor]

http://lefthandedcyclist.blogspot.com/2012/03/arm-power-and-avatar.html

A very interesting article that seem to confirm Eds, my (and also Osiris'es) ideas:

In the second edition of their book, “Textbook of Work Physiology”, Astrand & Rodahl do a literature study comparing the maximum oxygen consumption (Vo2 max) of various activities. If running uphill is scaled at 100%, horizontal running is between 95-100%, upright cycling is 92-96%, supine cycling is 82-85% and arm and leg cranking (where the load on the arms is 10-20% of the total load) is 100%. The above data must be taken with a grain of salt since it is a compilation of different tests. It does serve my purpose though, and that is to indicate that more power can be obtained by adding arm power to leg power, especially for pedaling in the recumbent position.

...

In the post “Rx for a Healthy Commute” I extol the comfort I experienced in riding an Avatar 2000 recumbent over a period of 22 years. What I didn’t mention was I never obtained upright-bicycle speeds while riding it.

...

The bottom line, though, was I always felt I had cardio-pulmonary capacity I wasn’t using and the only way to remedy that would be to add more muscle mass to the job of propulsion.

The only downside I can see with this approach is the added weight, added friction and the loss of the under-seat steering which I find so comfortable. On the upside the speed is significantly improved, especially on hills and it makes the bike a lot more fun to ride. It is especially fun to race along next to someone without using the arm power and then kick it in. You should see their faces! And because of the front wheel is lightly loaded, rapid application of rowing power has resulted in wheelies on a number of occasions; quite unheard of for a recumbent bicycle!

So:
Basically, your legs are 'underperfused' when recumbent, degree of adaptation vary and some people, basically, never adapt. (Those that do can disregard my musings)
Using that 'spare' pulmonary capacity by adding arm work to leg work, ESPECIALLY uphill (when your legs get less and less perfused) does seem advantageous.

So, the concept of 'bar swinging' is solid, but based on my calculation (and Osiris empirical data) you cannot add *much* power this way - power stroke is too short, and perturbing the steering results in frictional losses that can easily eat up all your benefit (hence, no real gain in speed). You can refine the technique, of course, and this is better than nothing, but...

FWD bike with 'swinging bars' just like on that Avatar recumbent may be an interesting solution - while driving the rear with arm power. You, basically, get 'all wheel drive' this way.
An other interesting idea - leisurely cranking a hand-powered dynamo and having a light, low-powered hub motor in the rear + a moderate sized battery.

On the flats you accumulate power and store it in your battery. On hills you kick in your motor. If you will not have any means of charging the battery from the outlet, it would still be, technically, human power. According to my calculations, even large conversion losses and weight penalty (battery, motor, dynamo) would still be compensated for, provided you can charge the battery between bouts of 'hill surfing'.

 

[bladderhead]

There was a bloke who did not like chain drive. He did not like shaft-drive either. So he got a motor and put a dynamo in the BB. There is a motorbike driven by hydraulics. I wonder how fast the liquid flows, and how much friction it generates against the tubes.

 

[Balor]

There was a bloke who did not like chain drive. He did not like shaft-drive either. So he got a motor and put a dynamo in the BB. There is a motorbike driven by hydraulics. I wonder how fast the liquid flows, and how much friction it generates against the tubes.

Yea, I know. Cconversion losses are huge, literally an order of magnitude higher than on a chain drive. "However" the power you add by arms (in case your legs are 'underperfused') is, basically, 'free', and your legs transmission on FWD is as efficient as it can get.
So, you can crank out 50 watts (more than manageable), and even with 50% losses an hour of cranking will get you about 6 minutes of 250 watts of 'high power' when you need it most - climbing steep grades, when your legs get even less perfused and hence 'overdriving' your power output results in huge hydrogen ion accumulation (so-called lactic acid burn).

P.S. Free so far as your aerobic systems are concerned. Calorie-wise it is not free, yet I don't exactly lack in 'fuel storage', quite the other way around.

 

[bladderhead]

Underperfusion will be my curse until I die. I do not think arm-wrestling will help me.

 

[Balor]

I do not think arm-wrestling will help me.

It depends on kind of underperfusion. Of you have some pulmonary condition, than indeed unlikely (though it might depend on other factors).
If you have circulation problems like I do... it might very well help. I think this is worth a try - not with electric drive -I'm not sure it will be brevet legal - but with 'rowing bars' like on that avatar.

 

[bladderhead]

COPD, otherwise known as emphysema.

 

[Balor]

COPD, otherwise known as emphysema.

Yea, that sucks. Still, even if you have limited gas exchange capacity compared to more healthy people, circulation problem on top might well be cumulative. Or not. I lack nessesary knowledge even for an educated guess.

 

[Balor]

http://www.ruder-rad.de/15/Modelle/Ruder-Flow.htm
Anyone has spare 3.5k Euro lying around to test my hypothesis?

 

[Osiris]

So, the concept of 'bar swinging' is solid, but based on my calculation (and Osiris empirical data) you cannot add *much* power this way - power stroke is too short, and perturbing the steering results in frictional losses that can easily eat up all your benefit (hence, no real gain in speed). You can refine the technique, of course, and this is better than nothing, but...

It seems we're finally in agreement. While I did get one seemingly positive result from handlebar swinging, that illusion was shattered over the following weeks when I got even faster times without swinging the handlebars at all. My current record on the same uphill segment is an average speed of 21.4 mph. My best average speed up that hill when swinging the handlebars was 19.7 mph. This was after many, many runs, so I can't dismiss it as a statistical outlier.

 

[Balor]

I don't think you get severe foot numbness on a high BB either?

I think I can guess why 'hand and foot' power is not really popular even in recumbent world so far as high performance is concerned - those people are self-selected. You cannot get more power than your total aerobic + anaerobic capacity, hence people that don't get (much) 'recumbent power penalty' will dominate those that do, and even those that use legs+arms because of losses in friction (and aero, obviously) - you cannot get more aero than a 'stripped-down' lowracer and aero is king (unless this is uphill TT). Unless one builds a streamliner...

And there *very* few of those around - and they cost arm and leg, something a 'causal rider' might be disinclined to give up (he'll have nothing to pedal the bike with, ehehe)

 

[Balor]

It seems we're finally in agreement. While I did get one seemingly positive result from handlebar swinging, that illusion was shattered over the following weeks when I got even faster times without swinging the handlebars at all. My current record on the same uphill segment is an average speed of 21.4 mph. My best average speed up that hill when swinging the handlebars was 19.7 mph. This was after many, many runs, so I can't dismiss it as a statistical outlier.

Ehehe, I think you may like wha this frenchman did:

http://users.belgacom.net/bn574802/coyote.htm

 

[Balor]

Got an interesting idea, that seem to click into my 'information framework' I got by analysing anecdotal reports:

A lot of people (mostly racers) say that a lot of recline actually help them delivery more power AS COMPARED to a moderate recline (not DF position) or at least the situation is unchanged. What gives?
Well, the more open your position is, the more *glutes* work as compared to quads. Reclining a lot opens up your hip angle AND reduces pressure on gluts, allowing better blood flow.
Plus, gluts, as compared to calves and, ESPECIALLY, calves, are the most perfused muscle groups on a bent (unless you put too much pressure on them... that is one of the reasons why seat pan on Railgun seat is so wide I presume).

From biomechanical POV, you should maximise working the muscles that are more effectively perfused. Situation on a recumbent is drastically different from DF...

Also, that familiar pain 'on top of knee'. I really don't think it is some muscle - I suspect that is some tendon attachment point that is being overworked... I really need to oval rings installed and test some theories .

 

[ed72]

I have a railgun seat and box being made and will have the chance to test your theories, Balor. I have been messing around with compression thingies on my calves but I can't say one way or another if they help other than it seems my legs fatigue less on longer rides when I use them but not sure, it could be placebo. There are not a lot of reports on the railgun seat and you have to look for them but they are all positive. Kent gave me a range of percentage increases in power to expect, I can't remember off the top of my head but would be very happy with half those figures.

I have been using the Thor seat for a few months and it does provide more support at the lumbar and is wider at the glutes. Very good seat. Well worth the money. I let my subscription lapse but what I have found on all the short climbs (2-5 minutes) around here is that I consistently hit personal bests on Strava. It looks like my W' or HIE has gotten better using this seat???. My threshold power has not gone up for sure but my ability to withstand those shorter efforts is better. Is it the shape of the seat? Cooler temperatures? I don't think it is fitness because I have gained weight and volume is down. The only other change is using a Ventist pad because riding in the cold rain with a foam pad is no fun. I also tend to only use the big ring now (53) because the etap front derailleur sucks and I am too lazy to convert back to mechanical.

 

[tiltmaniac]

Yea, I know. Cconversion losses are huge, literally an order of magnitude higher than on a chain drive. "However" the power you add by arms (in case your legs are 'underperfused') is, basically, 'free', and your legs transmission on FWD is as efficient as it can get.
So, you can crank out 50 watts (more than manageable), and even with 50% losses an hour of cranking will get you about 6 minutes of 250 watts of 'high power' when you need it most - climbing steep grades, when your legs get even less perfused and hence 'overdriving' your power output results in huge hydrogen ion accumulation (so-called lactic acid burn).

P.S. Free so far as your aerobic systems are concerned. Calorie-wise it is not free, yet I don't exactly lack in 'fuel storage', quite the other way around.

I have some old papers from the 90s where I had a combined suspension and hydraulic drive.
The base idea was to put the energy from the bumps back into the drivetrain.
You could do this without hydraulics, sure, but I was a kid imagining as kids do!
You could imagine using this as a bounce' drive as is used in at least one of the hydroplane gadgets.

 

[Balor]

Erm... there is no 'energy from bumps'. There is only *your* kinetic energy. Using rebound "damping" to do some useful work instead of simply heating up universe is indeed an interesting idea, but it would still get extracted from your speed - you are not getting anything 'for free'.

But when I was playing around with using pneumatics for adjustable geometry (currently I think I've come up with much simpler solution), using suspension to pump up air reservoir might be interesting, but:
On smooth roads you are not getting anything at all.
On rough roads you might end up exploding your reservoir .

 

[Osiris]

Last weekend I was reminded once again just how much better the V20 handles than my other bents. There is one particular Strava segment which I ride often, and until several months ago, held the KOM on. At roughly 26 mph, the average speeds for riders at the top of the leader board for that segment don't look particularly impressive. On straighter segments, my average speeds on the M5 are normally in the low to mid 30 mph range, but this particular segment has some rather nasty turns in it which cost riders dearly. Trying to negotiate those turns at 30+ mph on my faster but twitchy handling M5 would have been suicidal. There is one S turn which is particularly tricky, so when I saw that I was heading into it at 32 mph, I had serious doubts that I'd make it. I felt the bike shimmy a bit, which may have been the result of a temporary loss of traction in the rear, but I emerged from the second turn still doing 28 mph. That meant that I was right on target for beating the record. A 90 degree left hander came moments later. If I blew that turn, I would only have bounced off a chain link fence, which wouldn't be fatal. Happily there was no loss of traction that time, which allowed me to pour on the gas right away. Two more turns remained, with the final 100 yards being uphill, so I'd lose quite a bit of speed there without having to brake. When I crossed the "finish line" and noticed that I was still moving at 22.4 mph, I was all but certain that I'd beaten the record. In fact, I'd beaten it by four seconds, carrying an average speed 0.5 mph higher than the old record, and 0.6 mph faster than my previous KOM obtained on the M5.

 

[Balor]

That's cool! I think that is more about you taking easily to leg steer (can you ride no-handed yet?) and 'Cruzbike cockpit' that is responsible to both your differences from M5 - aero AND control.
If you could get away with stubby bars like Larry , you'll likely be as fast as on M5. But even Jason stays away from those...

Btw, adding a steering damper/stabilizer might allow one to have those bars AND retain better control.... turning it from a 'crutch' most people here seem to scoff at to a 'performance-enhancing' device.

And, of course, low-speed behaviour is massively better on MBB than on a dropped-chain high/low racer, no question. Major PITA.