Cervelo answers that exact question for you here:

http://www.cervelo.com/tech/articles/cervelo-calc.html

Enjoy...

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Thank you.

Damn I love this forum!

I'm curious how "Real world" these results are. First thing that strikes me is 40K TT at 30MPH. I'm certainly not that fast and I don't know too many people that are. In fact I can honestly say I've never seen that speed in any OLY distance tri.

Also wouldn't these numbers be MUCH closer at a more realistic speed like 20mph?

Also even at 30MPH there's only a 1:37 difference between a Cervelo one and a P3 worst case.

I guess my point is why would you advertise something like that? I'm guessing real world, 20 MPH or so, gain from the low end bike to the high end bike is likely less than a minute, Does that appeal to the masses?

Never mind answered my own question....anyone willing to spend tons of money on dropping a few grams will certainly spend it to gain a few seconds...

~Matt

Let me just say that it is unclear to me if the P3SL is any faster than the Soloist. This says a lot about the Soloist. the P3SL is fast, but so is the Soloist. Part of this may have more to do with how I sit on the bike and the relative airflow between me and both bikes based on my body geometry. I am not sure how much this transitions over to the Dual, but I suspect the Dual is also reasonably aero, at least aero enough for most of us that aren't doing 5 hour Ironman splits, or 2:15 Half or 55 min Olympic. Seriously, we've all been sucked into all the marketing with all these neat toys.

It is a bit of an arms race, you gotta drop $$$ for fast gear just so you don't get thumped due to having poor equipment. This is what is cool about running and swimming. You can't really lose with poor equipment. Sometimes I wish that all we had are standard bikes with drop bars, no aero wheels, 32 spoke three cross etc etc. Then it would just be about the engine and technique, things you can improve with training. Now I have a P3SL and fast wheels just to keep up with the arms race, not cause I care to own all this stuff. "I hate buying speed, but I love to work to get faster".

As far as I am concerned, owning material goods just complicates one's life. It is more stuff to service, support and maintain. Just like owning a big house. Just a pain in the ass. Only reason why I ended up with the P3SL is cause I had an insurance settlement from a crash and the cheque was made out to my LBS so basically, I had to spend the whole amount on a replacement.

GO FOR THE DUAL

Great value for the money and you can whip by with a big ass smile on your face when you pass posers like me on P3's :-)

Kinda have to agree with you, not to mention I question if there is a significant speed increase. Besides if I'm within a few minutes of someone...we tied.

~Matt

Matt, I agree. I want to see more 18, 20 and 22 Mph tests. We're not Lance and Jan motoring at 32 mph.

27 seconds. Margin of error? Two fish.

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Quid quid latine dictum sit altum videtur
(That which is said in Latin sounds profound)

Drag coefficient should be the same at 20 as at 30 mph. Airflow will still be laminar at both speeds.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

hey Dreamer

i would look at the P2 and with the $$ you save get a Disk wheel and one of the many fast front wheels.

a good fast set of wheels is what will make you go faster, well that and riding your bike alot!

Dan...

Depends on who is riding it...

Get the Dual and some race wheels.

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*Your Mama*

Ok I'm not fluid dynamics guy but doesn't the drag pressure drop precipitiously, I hesitate to use the word geometriclly as that has a definate meaning, as teh speed decreases?

Drag coeffiecinet stays teh same but not the actual effort needed to overcome the drag.

~Matt

But power is what YOU generate. That doesn't change how much faster, percentage wise, the frame will be aerodynamically (within reason, as RR becomes a bigger percentage of power requirements as speed decreases, and you obviously have to consider the whole system).

P ~= CdA*v^3

So you will need to generate significantly more power to go a little bit faster. But the drag coefficient doesn't change. It is, as you can see, a constant. That is why the drag coefficient calculated at 30mph is just as valid at 20mph. Down around 15mph or so, aerodynamics become less important, but if you are doing 15mph, you have some other issues that you need to work on first. That's why Cervelo can calculate one drag coefficient and it is valid for a 40K TT @ 20, 25, 30mph.

I believe that all these numbers become greatly skewed once you introduce a rider pedaling on a bike, but that doesn't change the fundamentals of fluid mechanics that say that if you test a rider+frame at 30mph, you will get very, very, very closer (i.e. the same) drag coefficient as when you test at 20mph if you hold position/cadence/etc. constant.

And I believe the word you were looking for was "exponentially." :)

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

As a past MOP'er and current FOP'er I would say "not enough to make you a FOP'er!" I ride a stock '04 Dual and have a top 10-15 bike split in local races. The only change between when I was MOP and FOP is the engine - the bike stayed the same. If you are within seconds of winning races - I would buy the P3 - if not get the Dual with some race wheels or Power meter and ride, ride, ride. Good luck.

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Well I believe in God, and the only thing that scares me is Keyser Soze

This is not an apples to apples comparison, but back about 11 years ago I used to ride a round tubed Slingshot tri bike (remember those?), I traded up for the Softride Power V convinced the the superior aerodynamics of the design would make a big difference in my bike splits. I cant say as I noticed any difference in my age group placings from that year to the next couple of years.

A couple of years later I started training with a guy who pounded me into the ground on rides, I pushed harder than I ever had before. I would get back from rides and collapse in a heap. The end result was that I knocked about 10 minutes off of my bike split and 2-3 minutes off my run split at Springfield Ironhorse.

The lesson, the bike doesnt make as much difference as hard training.

[reply]I'm curious how "Real world" these results are. First thing that strikes me is 40K TT at 30MPH. I'm certainly not that fast and I don't know too many people that are. In fact I can honestly say I've never seen that speed in any OLY distance tri.

Also wouldn't these numbers be MUCH closer at a more realistic speed like 20mph?

Also even at 30MPH there's only a 1:37 difference between a Cervelo one and a P3 worst case.

I guess my point is why would you advertise something like that? I'm guessing real world, 20 MPH or so, gain from the low end bike to the high end bike is likely less than a minute, Does that appeal to the masses?

Never mind answered my own question....anyone willing to spend tons of money on dropping a few grams will certainly spend it to gain a few seconds...

~Matt[/reply]

Nope. These results are not for 30mph, these results are for whatever the time indicates. If it shows 1h05 for the 40k TT time, that is obviously not 30mph, that is 22.9mph. That sounds a lot more like a speed you could attain, doesn't it? The 30mph is not used to determine the drag (which is dependent on your speed), it is used to determine your drag coefficient (which is not dependent on your speed, at least not in that speed range of say 10-100 mph).

As you can also see from the results, the slower the times, the bigger the time savings. That's because although the drag is lower and the drag difference is lower, you spend more time on the road. So as a percentage the savings are less, but as an absolute number the savings are greater.

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Gerard Vroomen
3T.bike
OPEN cycle

In addition to the information on the Cervelo website, which is rather pragmatic, I will offer this perspective:

I think a more comfortable bike is usually a faster bike. The rear of the P3SL has very good ride characteristics. I think the narrow, aero seat stays do have a fairly significant shock-absorbing capability.

If you are more comfortable, it may be less likely you'll ease off the pedals- even subconciously- when going hard on rough pavement. I think there is a natural tendency to back off when a bike rides hard on rough pavement.

I would suggest that there is a possibility the more comfortable ride characteristics of the P3Sl due to the curved seat tube and aero seat stays may give you nicer, and ultimately faster, ride.

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Tom Demerly
The Tri Shop.com

On the last point I totally agree with Tom. I have ridden tribikes from QR, Litespeed, Guru and the P3SL and by far the P3SL is the most comfortable tribike I have every ridden. I even had a plush softride, and I'd almost take the P3SL over the softride for comfort.

must have not mad emyself clear and I think Gerard answered my question. I was thinkning the time savings posted were as if someone where doing a time trial at 30 MPH. I realize the drag coefficient is the same under most circumstances, but drag becomes MUCH more of a hinderance at 30 MPH than it does at 18.

~Matt

Maybe not in a Oly distance race, but a mate of mine managed 29+ mph in a du with a 20km bike (on a round tube Cannondale to boot)...and that was after he did a 14:50 for the first 5km run. He faltered on the second run and only managed 15:20 for the second 5k. Bugger! He's done a 2:35 marathon too and in high school managed a 4:07 mile!

Luckily he swims like a stick! so he only beats me 2 outta 3 :-)

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TriDork

"Happiness is a myth. All you can hope for is to get laid once in a while, drunk once in a while and to eat chocolate every day"

AaaaHaaa....My bust.

I looked at that chart a couple of times and something didn't seem right....it does now....although 22.9MPH still doesn't seem like *MY* real world.

Definately more "feesible" and a more realistic marketing tool at those speeds though.

"s you can also see from the results, the slower the times, the bigger the time savings."

Does that trend continue into the lower speeds or is there a point of "diminishing return" The total range of speeds goes from 22.7 to 30.3, a range that probably doesn't cover the "bell curve" of triathletes.

Anyway thanks for pointing that out makes more sense now.

~Matt

Gerard & I basically said the same thing. He just said it much better and more clearly (as I imagine he answers that question much more often). I'm sure I'm was unclear in my answer, but glad you've got your answer...

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

Yes, you'd be surprised at how low a speed you can still have a measurable benefit to earodynamics. For example, on an SRM you can easily pick up the benefits of drafting, even on a very steep climb.

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Gerard Vroomen
3T.bike
OPEN cycle