Cervelo states that the S2 is stiffer than the S1.  I'd really appreciate hearing from anyone that's ridden both to get their actual experience.  Thanks!

Check out the Descending thread on page one. It might provide a little insight. I've never ridden and S2 so I can't compare, but I can say the S1 is incredibly stiff.

i can't imagine needing anything stiffer than the S1 but if cervelo says it's stiffer it probably is. if your thor husovd the S1 might not be stiff enough for you!!

 The S2/SLC has the stiffest BB of anything I've ever ridden.  It's the reason I bought one.  I've never ridden an S1, but I've ridden a great amount of bikes, and none, were as stiff in the BB area, as the S2. 

SLC:

 The S2/SLC has the stiffest BB of anything I've ever ridden.  It's the reason I bought one.  I've never ridden an S1, but I've ridden a great amount of bikes, and none, were as stiff in the BB area, as the S2. 

I guess you never rode an R3 or R3SL as just two examples of stiffer bikes.

carbon generally is the stiffest ride. if cervelo says the S2 is stiffer than the S1 than it is. the S1 is definately super stiff though. i've never thought mine wasn't stiff enough.

Unless you are Thor and Cav or The Rock (LOL), I can't imagine you will be flexing any of these 'pro' bikes.

 Correct I never did.  The SLC was the only Cervelo I've ever ridden. 

I would do an intestive search if you want data on stiffness of the two frames, anything you are offered here will just be our opinions based on experience or heresay. Specifically, which area are you concerned with the stiffness in? I swapped my SLT for an S2 as I found the vertical compliance was too much with the SLT for my back condition, whereas the S2 is fine.

So in vertical compliance the S2 appears to be less stiff than the SLT. But that is a desireable trait, can you see what I mean?

 

 

 

Well, we are talking best riging race frames here anyway....S1 is VERY stiff. I'm pretty sure that 99% other-than Cervelo carbon frames are flexyer. Specially rear triange of S1 is hallmark of how alloy frames should be done.

Main differences in S1 vs. S2 is weight, price and comfort. You can quess what is where....

 If I would be low budger racer, S1 would be my pick. Just add SRAM Rival qroup and few sets of Ksyrium Elites/SLR seats, 3T Pro parts, Michelin tyres...

 Wheels and seats are first needet to change after race crashes so few extra sets for this and no carbon frame. I bet S1 can take some beating that any carbon frame can't. Low weight seat, may be S2/S3 seatpost to shave weight from top, low inertia/good price/good hub whees, solig/light bar/stem, light/sure working group...I really would like to see Cervelo going more SRAM!

 On size 51-56 you get really nice looking bike. Pictures doesn't make it enoeght.

 I've had an SLT and an SLC. I now have an SLC-SL.

 Laterally, the SLC and the SLC-SL are quite a bit stiffer than the SLT was.

Vertically, the stiffest was the SLC by a mile (perhaps atypically; see past posts from me on this). The SLC-SL has probably marginally better vertical compliance than the SLT. 

 I own both SLT and SLC.(56 size)

I satisfy the BB shell stiffness of SLT but I don't think it has super stiffness because I am a heavy rider.(about 200 lbs).

After getting SLC, I can't find any flexiblity in BB shell. SLC has really stiff BB shell.

Yes, SLC(S2) is stiffer than SLT(S1) absolutely.

R3 or R3-SL or other stiff bike can be stiffer than SLC(S2).

But I think the stiffness of SLC is enough to sprint and to do everything although I am a heavy rider.

And on SLC, I can do down-hill better than SLT. Maybe SLC has better torsional stiffness than SLT.

 

But still SLT is really good bike.

 

I love both of them.

I don't think it is. I have both a Soloist (S1) and a 2009 S2. I'm a powerful rider, the S1 is extremely responsive, put the pedal to the rivet and it goes without a flinch, then comes back at you wanting you to do more. The S2 on the other hand is a little supple, sure drill it in the saddle and it holds steady and rockets forward, the BB is sensational. Hop out of the saddle and wind up for a sprint and it flexes a bit in the stays and in the head area (forks and steerer), it is carbon after all. Overall yes both are stiff frames, the S1 in particular is, but there is a subtle difference.

.. regarding weight, yes there is a subtle difference but not much either.