Road bike vs. recumbent comparison

[Balor]

Balor.....just make a nose cone.

Yup, in the process actually. And it turns out it is 'faster' (in CFD) than a full fairing, even... which is likely a CFD glitch to be fair, but still - I had no idea that nose cones alone are THAT effective - while hemisphere open side facing you is 0.38 CD, a bullet-shaped (elliptical) cone alone is 0.05 cd!

People been thinking about rear and full fairings, but they matter much more at very high (especially transonic) speeds, and completely disregard skin friction component. Riding in a 'shell' of delaminated layer seems quite efficient for low Re.
I have no idea why nose cones not that popular in recumbent world... except on LWBs for reasons stated?

Admittedly, once you are reclined enough it is very hard to see over fairing that adequately covers your legs, but my design actually address that. Plus, most bents are equipped with handlebars that are not conducive to controlling for wind load over the fairing. MBB address that
Talking about 'turning liability into an advantage'...

 

[Balor]

P.S. And a guy I've been talking with (frame builder with some interest in recumbents) been rising that point for a long time - recumbents are great at reducing pressure drag and lowering your "A", but in return you get a LOT of skin friction due to air flowing across your componentry and, most importantly - your body, but it took CFD runs and playing with speed and pressure "shapes" to ram the point home...

 

[Osiris]

Again, so long as we are talking biomechanics, few things are simple and straightforward (and work equally for everyone!).

Individual differences don't come close to accounting for discrepancies this large. I've been using power meters since 2011, and often compare data with other cyclists, including Larry Oslund. I know what the numbers should be for someone like Jim, and the ones he posted aren't even in the ballpark: https://cruzbike.com/forum/threads/...oom-recumbent-bicycle-power-production.11644/

Anyway, I think we've made about as much headway as we can on the subject. Barring any additional data, we'll just be repeating ourselves. Maybe we can move on to something more productive, like teaching me Russian.

 

[Balor]

I've been using power meters since 2011, and often compare data with other cyclists, including Larry Oslund. I know what the numbers should be for someone like Jim, and the ones he posted aren't even in the ballpark

Dunno, his power numbers seems in a pretty normal range for amateur cyclists of his age, if my Strava data is of any estimation. I don't know his training regimen, but he seems more of a business men than an athlete to me (no offence meant). Plus, he is on keto for, likely, medical resons (so am I, btw). It does great for my mood and sleep (this stuff really works, and I actually did some unwitting experiments by 'relapsing'), but my anaerobic efforts are considerably higher when I'm carbed up.
You might simply be spoiled (like I am, to be fair ) by surrounding yourself with examples of VERY gifted and highly trained cyclists and having a skewed perception of the norm.

Maybe we can move on to something more productive, like teaching me Russian.

Preved, kakdila?
Well, I make for a terrible teacher, truth be told... and sometimes I find myself wondering 'well, how would that be in Russian?', I kid you not, ehehe. I've been living in the internet for half of my life and it kind of shows.

 

[ed72]

Yup, in the process actually. And it turns out it is 'faster' (in CFD) than a full fairing, even... which is likely a CFD glitch to be fair, but still - I had no idea that nose cones alone are THAT effective - while hemisphere open side facing you is 0.38 CD, a bullet-shaped (elliptical) cone alone is 0.05 cd!

People been thinking about rear and full fairings, but they matter much more at very high (especially transonic) speeds, and completely disregard skin friction component. Riding in a 'shell' of delaminated layer seems quite efficient for low Re.
I have no idea why nose cones not that popular in recumbent world... except on LWBs for reasons stated?

Admittedly, once you are reclined enough it is very hard to see over fairing that adequately covers your legs, but my design actually address that. Plus, most bents are equipped with handlebars that are not conducive to controlling for wind load over the fairing. MBB address that
Talking about 'turning liability into an advantage'...

A large tail box turns into a bluff body once beyond a certain yaw and most definitely hurts speed.

WRT nose cones, I doubt it needs to be huge to help. I had a small handlebar bag that help lower overall CdA on my upright. Too bad you're in Russia, I suspect there are some used Zipp fairings that could adapted, maybe along with a little sock to cover those mammoth calves of yours.

 

[ed72]

Jim's 282 watts for 5 minutes on a bent isn't bad for a middle aged rider with a real job. I would bet few here could equal it for real on the road.

I can tell you for sure that this is accurate for Jim after racing with him and would guess his FTP to be 235-245 watts and Larry's to be more like 255-265 watts on a bent. If you look 15-20 minutes into Larry's TT, his HR is 175 and power is generally in that range of 260 watts plus of minus. He seems to be in MLSS and probably this represents his hour power or close, he set the course record, so the performance was there. Damned impressive if you ask me. How do I know it is accurate for Jim? I took about a 5 minute pull pretty darned hard and thru his labored breathing, he told me how much power he was making holding my wheel. So, the numbers are real.

 

[Osiris]

Dunno, his power numbers seems in a pretty normal range for amateur cyclists of his age, if my Strava data is of any estimation. I don't know his training regimen, but he seems more of a business men than an athlete to me (no offence meant). Plus, he is on keto for, likely, medical resons (so am I, btw). It does great for my mood and sleep (this stuff really works, and I actually did some unwitting experiments by 'relapsing'), but my anaerobic efforts are considerably higher when I'm carbed up.
You might simply be spoiled (like I am, to be fair ) by surrounding yourself with examples of VERY gifted and highly trained cyclists and having a skewed perception of the norm.

Jim is very far from the average middle aged businessman who happens to ride a bent. He trains very hard and participates in many races. I don't train at all and have never participated in a single race. I'm a middle aged weekend rider who logs about 60 miles per week, and yet my power numbers dwarf Jim's. My numbers, by the way, are not exceptional for someone my size, age, and conditioning. Small differences in our respective power meter readings don't account for it. I see only one plausible explanation for Jim's numbers, and it's a reason he himself offers: "Only one subject was tested, and that subject (me, the author) is also an owner of Cruzbike, Inc., and therefore may have consciously or unconsciously biased the intensity of his efforts."

 

[Osiris]

Jim's 282 watts for 5 minutes on a bent isn't bad for a middle aged rider with a real job.

You're looking at the wrong column. The 282 watt 5 minute average is listed in the "dynamic boom" column. Jim's fixed boom 5 minute average is an anemic 217 watts. That's ridiculously low. It's just five watts higher than my FTP was when I resumed riding after a 30 year absence from the sport. His 5 second number is probably something I could manage pedaling with just one leg. I wish it were the case that my performance numbers were all that impressive compared to other riders in my age group, but they're not.

 

[bladderhead]

Too bad you're in Russia

Why? Is the air thicker there?

I read somewhere about a furry surface reducing skin friction. And it will be nice and warm in the Russian winter.

 

[ed72]

WRT to power on bents, I seem to recall reading somewhere that Larry Lem only needed 190 watts for his ultrafast TT record in San Diego on his Magic Bike, which yielded an estimated CdA of 0.122 with pieces of cardboard attached in various places. It was 29 or 30 mph......in that range. I am sure he would have pushed harder if he had it. Pictures of him and kit show that he clearly understood what was going on aerodynamically and in fact, I suspect his bent is the all time slipperiest although the M5 on the track might be better, but it is not known for sure. An upright can get below 0.200 but that is very, very rare. 0.220 is very hard to achieve. So, it just does not take anywhere as much power on a properly set up bent to better an upright TT bike. Most bent riders are not under 0.200 due to poor setup and kit. That is why they need 347 watts to go 25 mph.

The various reports of power output for the M5 world record hour attempts do not quite line up. Either the power levels are exaggerated or the CdA is higher than what one reads. I believe the actual powers put to the wheels to be more like 310-320 watts and not the 360-370 watts that is written all over the place. In effect, the bike is slippery, more than we know.

In any case, 300+ watts average to the wheel in an hour is probably pretty rare on a bent but is rather pedestrian on an upright. Put it this way, I have never seen a 300 watt hour effort data file from a bent rider and I have searched. Aure's absolutely must have been over 300w but how much over???. The gentleman who set the 24 hour record at Sebring in a velo and who did a sub 3 hour Century shared his power numbers with me, he is not making 300+ watts at FTP. I thought I might see a 300 watt file from the World TT championships in Borrego Springs, CA. First lap energy but not close.

 

[ed72]

Why? Is the air thicker there?

I read somewhere about a furry surface reducing skin friction. And it will be nice and warm in the Russian winter.

Getting used stuff there from here is not easy or cheap.

We probably take access to stuff for granted. Not to say it is impossible but Balor is at a disadvantage equipment wise.

 

[ed72]

You're looking at the wrong column. The 282 watt 5 minute average is listed in the "dynamic boom" column. Jim's fixed boom 5 minute average is an anemic 217 watts. That's ridiculously low. It's just five watts higher than my FTP was when I resumed riding after a 30 year absence from the sport. His 5 second number is probably something I could manage pedaling with just one leg. I wish it were the case that my performance numbers were all that impressive compared to other riders in my age group, but they're not.

Aren't you wonderful.

I wish we were all so fortunate.

It took me 10 months on a bent to get my FTP over 200 watts.

 

[Osiris]

Aren't you wonderful.

I wish we were all so fortunate.

It took me 10 months on a bent to get my FTP over 200 watts.

What was your physical condition at the time? Were you overweight? A smoker? When I enrolled in a Vision Quest class years ago, my power numbers were pretty average compared to the other men in the class. I think only one fellow had an FTP below 200, but he was of small stature, probably weighing in the neighborhood of 135 lbs. One woman had an FTP in the mid 250's, but she had the advantage of youth and was already an experienced club racer.

 

[ed72]

What was your physical condition at the time? Were you overweight? A smoker? When I enrolled in a Vision Quest class years ago, my power numbers were pretty average compared to the other men in the class. I think only one fellow had an FTP below 200, but he was of small stature, probably weighing in the neighborhood of 135 lbs. One woman had an FTP in the mid 250's, but she had the advantage of youth and was already an experienced club racer.

In 2015 I did Paris Brest Paris in 54 hours.

I did most of my 2015/16 Brevets in under 60% of the required time and some in under 50%. Kent Polk wasn't much faster on a 300K on his M5 than I was on my fendered rando bike.

In 2016 I did TABR in 29 days with lots of injuries en route. I did a bunch of Brevets as well. Mileage 12-15,000 per year.

In 2017 I transitioned to a bent. My fitness was decent when I started.

Never smoked, no drinking except wine at Italian family holidays. Upright FTP 280-285. 60 years old. Solidly average for someone who works really hard at it.

A 50-60 Kg female cyclist with an FTP of 255 ish is hardly a club rider. This is Pro territory for a women, certainly if off 50Kg. A women in my racing club decades ago was the USCF National 40Km TT Champion and we currently have a nationally ranked women's team in the area.

I know a guy who got to Cat 2 off 220 watts FTP but he had a lot of skill and could sprint.

I suspect your training class needs its power meters calibrated or you are somehow misinformed in another manner.

https://zwiftinsider.com/rider-categorization-based-on-ftp-how-do-you-rank/

https://www.ncbi.nlm.nih.gov/pubmed/11428684

 

[Balor]

I read somewhere about a furry surface reducing skin friction. And it will be nice and warm in the Russian winter.

While my surface is certainly furry, real wind tunnel data show that it actually puts me at a disadvantage, but I think I'll go with a nose cone before shaving my legs! Way too much bother in the long run...
Studies show that fur on bats adds to parasitic drag, but it is a balance between energy conservation and heat retention. (Not sure they've been shaving them or something... just something I've heard)

Getting used stuff there from here is not easy or cheap.

We probably take access to stuff for granted. Not to say it is impossible but Balor is at a disadvantage equipment wise.

Yea, especially high-volume stuff, like, say, bents. Not to mention my salary amounting to less than 500$ a month (and that is considered pretty good one for an engineer not working in Moscow)... it does encourage me to get creative with my resources which I find an interesting challenge in itself. I did manage to juggle some 'ebay, consolidate, test, sell, repeat' before economy was tanked by our brave president playing Ivan the Terrible and reaping the consequences, and now things are 2x trickier.

Plus, even if I could buy, say, M5 CHR I'd have nowhere to ride (unless equipped with disk brakes and 27.5 40mm tires mounted, perhaps) - on my first outing with 23mm tires for aero test I've punctured a tire pumped up to the max... and I have suspension! *sigh*

 

[Balor]

I suspect your training class needs its power meters calibrated or you are somehow misinformed in another manner.

I think he is being coy at the very least (not to mention he didn't share any data as per his performance... at least *my* data is freely available for anyone to analyse, I'm not paranoid).
We have a group of amateur cyclists in our town I'm monitoring on Strava (ride with them sometimes) and only ones that train really hard are anywhere close to 300 ftp. There is one exception - a large guy with FTP a bit over 400, but he is, while amateur, has won some national level TT races.

 

[RojoRacing]

In any case, 300+ watts average to the wheel in an hour is probably pretty rare on a bent but is rather pedestrian on an upright. Put it this way, I have never seen a 300 watt hour effort data file from a bent rider and I have searched. Aure's absolutely must have been over 300w but how much over???. The gentleman who set the 24 hour record at Sebring in a velo and who did a sub 3 hour Century shared his power numbers with me, he is not making 300+ watts at FTP. I thought I might see a 300 watt file from the World TT championships in Borrego Springs, CA. First lap energy but not close.

The only reason 300+ watts for an hour on a bent are rare and only pedestrian on a DF is simply the talent pool willing to ride them and nothing to do with the mechanics of the design. I just held like 290+ watts for an hour on my DF bike a couple weeks ago and it's been a while since I've ridden the V20 but last year I held 280 watts for over 2hours on it on a hilly 50 mile ride. Hard to compare absolute potential of two designs when one is powered by a hobbiest and the other by a pro.

The thing about the Borrego event is everyone's plan is to pace themselves and the shortest race is 6 hours so finding someone to go over 300 watts for even a single lap when their average is only going to be 270 would mean they suck at pacing. Andy Jackson has the fastest 6hour effort out there and his best 1 hour power was 294 which was the first hour of the race. You can pretty much count out the team racers because most of them can't even match the solos endurance pace for even a single lap. You put a Pro DF rider with an FTP of 400 watts on a bent and you'll see what 400 watts for an hour on a bent can do, until then you and guess and estimate away to your hearts content. I don't think for a second a Pro rider will lose even a watt on a bent compared to they're DF in a 1 hour effort. Honestly I think in a 1 hour effort a rider could actually hold a few % higher watts on the bent vs the DF because on a DF you really start to struggling to hold your form in those last 15 mins and that's not as much a problem on a form fitting bent.

After all the discussion here and my recent 1 hour effort trying to take a 25 mile KOM on the DF bike I'm curious if I could do better powerwise on the V20. If I even get settled in down here in socal and bring the V20 down I'd like to see if I can find a place to go all out for one hour on both bikes and compare.

 

[RojoRacing]

I think he is being coy at the very least (not to mention he didn't share any data as per his performance... at least *my* data is freely available for anyone to analyse, I'm not paranoid).
We have a group of amateur cyclists in our town I'm monitoring on Strava (ride with them sometimes) and only ones that train really hard are anywhere close to 300 ftp. There is one exception - a large guy with FTP a bit over 400, but he is, while amateur, has won some national level TT races.

Outside of elite racers a 300 watt FTP or FTP over 4.5wkg are very rare. I've ridden with and know personally at least 20 riders who have a 4.0wkg or higher FTP and of all of them, I'm the only one who doesn't road race at all, much less regularly. So if a person was to search for riders who have that magically over 300 watts ftp they could strait away exclude everyone who isn't at the local races every weekend. I think people toss around high ftp values to easily and it warps the general communities perception of what is average. It's like the Zwift effect when the local fast guy jumps onto his first calibrated smart trainer and start claiming it's broken because he can't race with the A riders and in the real world he's the fastest guy in town. The truth is on average the local fast guy that has all the KOMs in town is only a B level rider on a world platform like zwift.

 

[Balor]

Outside of elite racers a 300 watt FTP or FTP over 4.5wkg are very rare

Well, high FTP and high watt/kg are not necessarily correlated, an I'm not even talking about track sprinters... *sigh*

they could strait away exclude everyone who isn't at the local races every weekend

Assuming one is interested in 'social aspect' of racing. I have a bit similar personality to Osiris (if my 'personal profiling based on forum avatar' skills are up to scratch ) - and I also race VERY rarely, but I'm very interested in raw performance because it is an enjoyable challenge *in itself*.
Strava KOM-hunting is also quite different (psychologically) from racing, because it allows one to assess your relative performance without all the hassle of gong to the races.

I think people toss around high ftp values to easily and it warps the general communities perception of what is average.

That is, undoubtedly, very true.

 

[RojoRacing]

Well, high FTP and high watt/kg are not necessarily correlated, an I'm not even talking about track sprinters... *sigh*



Assuming one is interested in 'social aspect' of racing. I have a bit similar personality to Osiris (if my 'personal profiling based on forum avatar' skills are up to scratch ) - and I also race VERY rarely, but I'm very interested in raw performance because it is an enjoyable challenge *in itself*.
Strava KOM-hunting is also quite different (psychologically) from racing, because it allows one to assess your relative performance without all the hassle of gong to the races.



That is, undoubtedly, very true.

:lol do track sprinter even have FTP's I mean honestly I know those guys are insanely powerful but I wonder what they can hold for an hour even if you exclude their weight handicap. High FTP and high Wkg are definitely not always the same thing which is why I mentioned it. Many riders aren't that elite cycling average of 68kg so when guy like yourself see ftp of 300-350 it's common to think well hey that ain't so much higher then mine, forgetting that their own weight in 90kg. You mention you have a local who is a big guy and probably rolling with an ftp of close to 400 which sounds crazy strong(it is) but does his extra body weight drop his Wkg back down to the realm of 4.5wkg with guys like me.