slvoid

I ripped this off of someone else who ripped it off of someone else who translated this month's issue of Tour magazine.

They put Uwe Peschel on a normal bike:

Needed Watts for Speed = 45 km/h :
Stevens San Remo bike with normal handlebar 465 Watts needed to go 45 km/h
Same bike Hands down the drops: 406 watts needed
Same bikeEaston Aeroforce bar: 369 Watts
Same bike Triathlon position (5.5 cm lower bar, saddle forwards): 360 Watts
Same bike Triathlon position (5.5 cm lower bar, saddle forwards) and
carbon Tri spoke wheels front and rear: 345 Watt

Cervelo + Tri spoke front 328 Watts
Cervelo + Tri spoke front + disk rear wheel : 320
Cervelo + Tri spoke front + disk rear wheel +Giro helmet: 317
Cervelo + Tri spoke front + disk rear wheel +Giro helmet + speed suit: 307
Cervelo + Tri spoke front + disk rear wheel +Giro helmet + speed suit +
saddle 3 cm further back: 293 Watts

From 465 to 293 watts... That's a lotta savings.

Snicklefritz

holy you-know-what! That's huge!

the beef

Interesting..

brianallan

lol @ 3 watts from the aero helmet. The speed suit is interesting with a 10 watt savings.

EdZ

Just goes to show that the guys who look fast(more agressive position) usually are fast(er).

Snicklefritz

1/2 HP at 90 rpm is a lot btw

BikeWNC

I'm most interested in why moving the saddle back 3cm in the last setup saved an additional 14 watts. It's like going from a 78 degree STA back to a more standard 75 STA. I wonder if they were able to do that without raising the bars. That would close his hip angle but flatten his back some more. I guess that position is more aero but can he stay there for a while and does it cost him power to be in that position. It's all a compromise and only testing will determine which setup is faster on the road.

Snicklefritz

Just steal Dr.WJO's ride and the engine and you'll do well in the TT's

classic1

If Uwe Peschel had normal human sized thighs he could probably get down to 250W

Wurm

The problem with this is, not many people are going to ride in a tri/TT position as their main ride, or with a tri-spoke or disc wheel, or aero TT helmet, etc.

531Aussie

just in case anyone hasn't seenthe Kreuzotter calculator:
https://www.kreuzotter.de/english/espeed.htm

Check out the difference that riding on the drops makes compared to riding on the hoods

And see how little effect bike weight has on speed, even on hills


I've plugged in some Hour Record numbers (Indurian's stats, for eg), and the output & speed come out similar to other sources.

zimbo

The biggest key to reducing the wattage is putting one's body in an aerodynamic position. A TT bike makes that easier to do than modifying a road bike but even the latter can be improved upon by switching out the stem, using aero bars, etc.

All of the big improvements in that list are due to lowering/flattening the back and stretching/thinning out the torso. The wheels, skin suit, and helmet only account for 20 watts or so (still significant, of course).

--Steve

Smoothie104

no doubt... that why we're always telling people to flip the stem over so theyre not sitting so upright on their $5000 road bikes..

GuitarWizard

+1

And not only that, people have to actually stretch (off the bike) and ride in the drops to get used to it....not just drop down to 'em on a big downhill and "go for it".

Having the handlebars adjusted correctly helps too....many people, and I used to be one of them, will rotate their handlebars up to flatten out the tops of the bars/hoods to make it more comfortable riding in the hoods. While this was great, the reach was a bit too far forward to comfortably ride in the drops for any length of time (in the past, I would do most of a ride in the drops, save for climbing). Have to make sure that the position is efficient and comfortable. To do it properly, move the levers up and re-wrap the handlebars.

Serpico

I think climbing has more to do with exertion than speed (ie how many watts used to go up a hill on a light bike vs a heavier one).

BikeWise1

What good is an aero position if you can't stay in it for the duration of your ride? I have done numerous fits on guys that have "image issues" regarding the orientation of their stems because of crap like that! Arm length and ride length are what determine stem height and angle, not some arbitrary fashion. The proof is having customers riding farther and more pain-free than they ever thought possible. Racers (and those who wish to appear as though they are racers) need every bit of power they can scrounge. That's fine. But bikes are already the most efficient transportation device yet invented. Even if you are sitting upright and going slow. On whatever bike you choose to ride.*

Guys, it really is OK just to ride for fun. Try leaving all your performance measuring devices at home once in a while and just ride!

*Except of course guys who wouldn't listen to me when I said they needed a triple and are caught pushing their $5000 bike up hills.

biker7

Good comments by everybody. I read someplace that 80% of power expenditure riding a road bike at 20mph is due to wind resistance. I am a tallish guy that is going to be a bit more aero for '07. Yes it will take strengthening and a bit more flexiblity. I am used to riding with my bars only 1-2 inches below my saddle. Now building a new bike, the bars will be about 3 inches below and a bit closer in. I have ridden quite a bit with TT riders and guys who ride with big bar drop and flattish back. They have a big advantage and therefore my goal is to ride a bit more aero. As to pain in lower back and neck due to lower bars....my view is it is based upon conditioning and flexibility. Both can be increased. An older rider like myself will not likely be as comfortable with a 6" drop to the bars as a young racer but I would like to strike a happy medium at least to ride a bit faster.
George

Wurm

That's right, and if you can get yourself flexible enough on a standard road bike, it's great. I'm only saying that although the benefit for riding aerodynamically is fairly well known, most roadies I know don't wear skin suits or aero TT lids or ride disc wheels, etc. So the most practical thing would be to get your body into the best aero position, but many riders have trouble even with that.

biker7

Depends what your objective is. I am no racer but a decently fast old guy. I like to compete with my younger riding friends...no big deal. It is horses for courses. One will not be able to ride an aggressive bike as far comfortably as more of a cruiser set up. All what you want and both are good.
George

SesameCrunch

Nice post. Very informative and useful data.

Great to have some facts on BF once in a while.

DocRay

From that list, you save 59 watts just going to the drops, but only 14 watts for aero wheels.
Riding in the drops costs less.
At pro crits you will see standard and aero bikes, standard and aero wheels, but universally the guys pulling at the front never come out of the drops.

GuitarWizard

+1

superslomo

Bear in mind that this is at 45 kph, and that wind drag increases geometrically with speed. The slower I am, the less significant those additional expenses are...

If you can haul along at 45 kilometers in a TT, then the wheels/helmet/etc. make a huge difference. I wonder how much of a difference it would be for a slower pace.

Not denying the validity of the numbers, but it seems like it goes to show the difference between priorities and value for money for the pros versus a schmoe like me.

redfooj

28mph, -8 watts to go from 'standard' wheels (assumed) to full disc

so, 20mph, from 'standard' wheelset to rims with 10mm taller profile and "aero" spokes means savings of...... half a joule?

FIVE ONE SIX

that's true, but flipping the stem down is not always the answer. some people, like myself, can stay in the drops longer with my stem flipped up, so i ride with it flipped up.

if i flip it down, i can get more aero on the hoods, but i can't stay in the drop as long. if i flip it up, i'm not as aero on the hoods, but i can stay in the drops longer for a better overall ride...

i've been meaning to flip it down and take 2 tylenol before i go out, and see the results, but it's been too cold lately to try it out...