Cervelo P3C and P2C, along with the Felt DA/B2 would be my guess.

Don't ask sentania this question.

in which direction? on what part of the frame? why is the stiffest the best (I gather you're looking for the stiffest because you assume it's the best_

Laterally stiff for power transfer. Yes, I would assume that stiffer is better in terms of power transfer.

I have no emperical data and do not have that much experiance, but from my bike to others that know more than me...................Klein

Just a thought, but unless you are standing and sprinting, nearly all new tri-bikes are going to be stiff enough that there will be no difference in power transfer. If you weigh 300 pounds, I might retract that statement.

Are there any new tri-bikes that people DON'T think are stiff? Especially the carbon frames, everyone of them is reinforced to hilt in the BB for stiffness. I've never heard anyone claim a new frame was soft or flexy, except one big guy that claims his Kalibur isn't stiff and well I have Kalibur and it's plenty stiff enough for me and Normann, so go figure on that one.

---

----------------------------------
Justin in Austin, get it? :)

Cool races:
- Redman
- Desoto American Triple T

my blade is pretty stiff........

---

I shall never misuse Rex Kwon Do
I shall be a champion of freedom and justice

That's good to know. I'm probably going to be buying a new bike this weekend and just wanted some extra info. I'm concerned about the stiffness thing because my old steel road bike flexes quite a bit when I ride it on the trainer. I just want to make sure that I get a bike with solid power transfer.

I wouldn't evaluate stiffness based on flexing you observe while using a trainer.

Why not? It seems like that would be the best way to actually see your bike flexing laterally. I don't know how you would ever tell out on the open road.

When climbing steep hills, the lucero is flexy in the bb....also make sure that you have stiff wheels, low spoke counts can flex quite a bit.

BB

---

Professional Triathlete
Owner of Blake Becker Multisport Coaching LLC / Team BBMC
blakebeck@gmail.com
http://www.teambbmc.com

Exactly, you can't tell the difference out on the open road. Aerodynamics, technique and fit will have much greater influence on your speed than any gains you could ever get from a stiffer frame.

That's good to know. I'm probably going to be buying a new bike this weekend and just wanted some extra info. I'm concerned about the stiffness thing because my old steel road bike flexes quite a bit when I ride it on the trainer. I just want to make sure that I get a bike with solid power transfer.

is this in anyway a problem though when you ride it or have ridden it on the road.
is there a bike on the road this is too flexible for triathletes?
it is not as though we are Petacchi or Boonen sprinting for the line at 1500 watts +.
a certain degree of flex is required for comfort as well.

I am amazed every ride at the stiffness of my orbea ordu

Never seen a "reputable" test for tri frame stiffness. Tour magazine last summer had a pretty good test of several road bike frames though. Frames clamped it with strain gauges and all. Yes, Cervelo R3 tested stiffest ... Could one assume their tri bikes to be equally stiff? Probably.

But seriously, why are you asking? I sure can't flex any tri bike I have ever been on, especially riding at steady state for a tri! Not exactly doing a crit mashing out of corners or a pack sprint finish on the thing :)

---

____________________________________
Fatigue is biochemical, not biomechanical.
- Andrew Coggan, PhD

I'm asking because my steel bike seems to flex a lot, and I mean a lot. I can't see it when I'm riding on the open road, but it is happening and it means some power is being lost. I have never ridden a real quality bike in my life, but when I buy my new bike this weekend I just want to make sure I'm buying the best I can afford. I plan on testing everything from the Dual to the P2C. I'm really looking forward to it. I bought my road bike ten years ago off a guy who had already ridden it a lot for only $400. It doesn't fit my very well either. Cycling is my best sport so I'm looking to see what I can do with a real good bike.

Gotcha! I think you will find a quantum leap in stiffness then in "most" new carbon bikes while reducing frame weight by about 2 lbs over your old steel dinosaur. Just remember that bike fit is more important than material. Canondale was famous for super stiff aluminum frames (but at some sacrifice in ride quality).

---

____________________________________
Fatigue is biochemical, not biomechanical.
- Andrew Coggan, PhD

I personally rate stiffness highly in bike selection. I have had most of my best bike performances on bikes I would rate as stiff, over those that are light. Anecdotally I find bottom bracket sway on the trainer a good indication (I use the cateye cs1000 -forks and rear axle locked in). On the road I have noticed sway, and steep climbs have had bikes that flexed so much they changed gears! A few people I look after have certainly notices a difference going to a stiffer frame (power transfer and stability) eg Kestrel talon vs look 496. Tour magazine does do interesting test with weights (as mentioned above), and in different directions /positions.
I would stick with name brands that are not too light (you don't get anything for free). I would definitely go for a monocoque over bonded tubes if going the way of carbon fibre. Bikes I would rate as stiff: Pinarello montello, Look 486/496 , cervelo P2/P3. I think the Kuota is OK, but a little less stiff (compromise with weight perhaps).

[reply]Which tri-bikes are considered to be the stiffest, and have the best power transfer? Can you give a top 3? Has anyone done any quantifiable tests on the stiffness of bikes?[/reply]

Can you explain more specifically what you mean by "power transfer"?
Are you looking for exact numbers?

My wife's Orbea Ora has a very stiff front end--- Actually stiffer than my Colnago C-50. I haven't tested the BB but it looks very solid.

-Marc

I'm curious as well. I'd like to see some type of scientific data as it applies to frame stiffness vs efficiency. I'm guessing the correlation is somewhat weak but I can't say for certain.

Two things I think of when it comes to stiffness. How much I suffered when I owned one of the early Canondales. That bike was way to stiff and was painful to ride. I don't care how efficient a stiff bike is, any bike that stiff would make me swear off cycling.

The other thing I think of was Sean Kelly winning races on the Vitus frame. A lot of races were won on that whippy frame, so it makes me wonder how important stiffness really is.

Actually Tour tested Tri/TT bikes in the January issue, P3C/look 496 was the softest....

The old P3Alu version was tested some years ago where Tour reported it to be the stiffest TT bike ever tested by them at approx 135MM at BB stiffness.

However this year they tested as follows for Bottom Bracket / Headtube stiffness. Not impressive IMHO:

Cervelo P3Carbon 54cm : BB 96NM, HT 73NM
Cube Aerium Team 52cm :(alu frame, BB 130 HT 89NM
Kuota Kalibur sizeM: BB 105NM, HT 67NM
Look 496 TRI size S: BB 95NM, HT not measured due to fork design
Scott Plasma 54cm: BB 106NM, HT 94NM

So Cervelo and Look are actually the softest in test.

I want the stiffest possible bike as i tend to put down a lot of power. The ISAAC Joule frame was too soft for me in BB.

If stiffness is one of your primaries maybe a BT (bicycle technologies) frame? Van Moorsel won gold on one in the TT at the last olympics and they are primarily a track bike (the yellow ones ridden by the aussies). Of course its going to be a little heavier though

Interesting. I thought the whole point of carbon was so you could make a stiff bike that rode comfortably.