I was cruising through Cervelo’s website, and was checking out the S2 and S3. Are they popped out of the same mold, rendering frame aerodynamics the same?
I get that the S3 might have a higher end carbon layup, etc. And that it’s built up w/ higher level componentry, wheels, seat. But what about aero differences? Here they are:
S2:
S3:
MSRPs are $2500 for a 10 sp 105 S2 and $2300 for the S3 frameset alone. So, why not pick up an S2, sell off components, and end up w/ a hell of a frameset for like $1200-1500! You could even reroute cables to clean things up w/ the proper set of handlebars and a set of nuts to drill in the top tube. 
Thoughts??
P.S. jackmott, I didn’t see anything on aeroweenie.com. I figured if it was on the interwebs, you’d have already found it.
same frame, different fork
.
only the fork differs, the S2 has a fork that is a bit cheaper to manufacture and thus a bit wider in places or with less aspect ratio.
if it is like the P2, Cervelo doesn’t even know for sure because they never tested it, but it is probably a little less aero.
The S2 is definitely the smart man on a budgets obvious buy. The S3 makes sense if you have money to burn and want to run wider tires than the S5 will accept =)
only the fork differs, the S2 has a fork that is a bit cheaper to manufacture and thus a bit wider in places or with less aspect ratio.
if it is like the P2, Cervelo doesn’t even know for sure because they never tested it, but it is probably a little less aero.
The S2 is definitely the smart man on a budgets obvious buy. The S3 makes sense if you have money to burn and want to run wider tires than the S5 will accept =)
Are we talking like less than 50 grams of drag? Less than 25 g?
Or over 100 g of drag?
Or are these totally useless guesses…
Thanks.
If you forced me to guess I would guess 25g +/- 50g
lol
I tried to get Damon Rinard to guess once and he refused.
only the fork differs, the S2 has a fork that is a bit cheaper to manufacture and thus a bit wider in places or with less aspect ratio.
if it is like the P2, Cervelo doesn’t even know for sure because they never tested it, but it is probably a little less aero.
The S2 is definitely the smart man on a budgets obvious buy. The S3 makes sense if you have money to burn and want to run wider tires than the S5 will accept =)
Are we talking like less than 50 grams of drag? Less than 25 g?
Or over 100 g of drag?
Or are these totally useless guesses…
Thanks.
If you forced me to guess I would guess 25g +/- 50g
lol
I tried to get Damon Rinard to guess once and he refused.
Sissy.
S3 MUST be more aero cuz everyone knows that red is faster than blue.
.
Quite appropriate coming from Iron Buckeye
S3 MUST be more aero cuz everyone knows that red is faster than blue.
.
Ha! I actually had sports cars on my mind. Didn’t even think of it the way you did.
If you forced me to guess I would guess 25g +/- 50g
lol
I love you Jack Mott. I’m stealing your brilliant approach to guessing! ha ha
I tried to get Damon Rinard to guess once and he refused.
Well, now we have the wind tunnel data, no guessing is needed. Good news: the S2 and S3 forks have no measurable difference in aero drag.
(Still haven’t measured the P2 fork yet.)
Cheers,
Sweet. My error bars were sufficiently large!
Damon-
Is there any incentive to buy the S3 over the S2 now other than the upgraded components? Is the S3’s fork lighter? laterally stiffer? Vertically more compliant? Or is it just deeper?
Hi pyrahna,
Performance-wise, just the component differences.
Our mission is to make Cervelo riders faster. This philosophy helps explain the engineering of the two forks.
We developed the S3 fork first, using the same advanced engineering tools we’ve honed in engineering the Rca and P5: CFD, FEA, laminate analysis, etc. The somewhat large surface area (due to the long chord) means we’ve chosen higher modulus fibres in some areas, to help reduce weight.
Afterwards, to make the S2 fork, we chopped a centimeter or so off the trailing edge of the S3 fork’s CAD model. That reduction in surface area let us save some weight, which we put back into the fork in the form of thicker walls (but not as high modulus fibres). Those two changes combine in a cancelling effect: same weight and stiffness. In the end, the main difference is the S2 fork costs less.
Only afterwards did we find there was no measurable difference in the wind tunnel!
Cervelo S2 fork: weight neutral, stiffness neutral, aero neutral.
Lucky for S2 riders, eh!
Cheers,
Sounds like some people in the CFD/optimization software dept. need to do some explaining. Can I request a version of the S2 fork with better materials and therefore less weight?
Not entirely better materials. For instance, the S2 fork is probably more crash damage resistant than the S3
Sounds like some people in the CFD/optimization software dept. need to do some explaining. Can I request a version of the S2 fork with better materials and therefore less weight?
I was sort of expecting Damon to call me out on that…shall I be more specific and say higher modulus carbon materials to keep the stiffness the same and lower the weight?
I thought so too, at first. Talking to our aerodynamicist though, fork aerodynamics aren’t simple (naturally). A particular fork can have less drag, but the characteristics of its wake affect the drag of downstream parts as well. So the total aero drag can be different from what you might expect.
This observation seems obvious in hind sight, but it crystallized for us especially well during P5 R&D, and we ended up calling it AeroZone engineering analysis. You can read more about it starting on page 9 in the P5 white paper: http://www.cervelo.com/media/docs/P5-Technical-White-Paper-cd55ee37-81a3-4d19-8b4f-39946cd71205-0.pdf
Cheers,
Hey! That’s a great idea! Stand by…
Holy moly. This is actually gonna pan out?!?!? I’ve been looking for a nice aero road frame to build up that wouldn’t break the bank. You know, that $1200ish range I was talking about. I figured I’d need to wait for a used S3 or Felt AR or Boardman AiR to come around.
That why you gotta ask the question…
Thanks for chiming in, Damon.
You’re welcome Steve. Enjoy your S2 project!