sarals 

I hesitated to start a new topic about this. I thought, though, after reading the scattered posts through out this site (and on Weight Weenies, Road Bike Review, etc) that starting ANOTHER topic about it, but one here in our little world, would be beneficial.

I'm looking for a race bike. We all know that! Here is what I've discovered so far about specific characteristics and what makes those characteristics attractive for different applications.

Crits - I've been reading ad nauseum about "what makes a good crit bike". Some say there is "no such thing as a crit bike". Perhaps. However, some bikes can work better in that kind of racing than others do. I've learned that a low head tube, standard (classic) geometry, and a firm "cradle" (down tube, bottom bracket, chain stays) are the important parts of such a bike. Material? Aluminum is just fine, as is carbon. Aluminum is more durable on the surface, but carbon can be too - and carbon is actually affordably repairable (if the damage CAN be repaired), where aluminum is not. Weight is not that important, as long as the total is 17 pounds or less. Gearing - for beginners (like me), compact chain rings, 12-25 cassette seem to be perfectly fine (from what I read, it's not likely one will spin out with a 50/12 on most courses). Standard chain rings can be added later. Groups? Shimano 105 is fine, and the SRAM and Campy equivalents work very well, too. If the frame is good, get better components later. Wheels? Light is good, tires are more important, though. Wheels themselves seem to be a very personal preference. Tires seem to inspire less heated debates!

So far the bikes I've found that seem to have universal acceptance as great for crit racing are the Cannondale CAAD 10, the Felt F series (carbon and aluminum), the Fuji SST, and Specialized Allez series. That's what I've found SO FAR. These are "affordable" bikes (they can be had new for less than $1800), and they have frames that are worth keeping and adding better components to down the road. IMHO!

Road racing - because of the time spent in the saddle on road races, a more forgiving ride and a higher head tube seemingly get the nod. Material? Lighter is better, because often there is climbing involved. Still, I gather the kind of bike that is favored is one that offers efficient power transfer, a reasonably compliant ride, and a comfortable seating position. What is most important here? FIT. Get a bike that FITS. Specific bikes? Heavens, there are dozens that are affordable!

TT - I don't know about it, but I do know this. Aero and Power Transfer.

I put this together in my head as a primer/bell weather as I search for a bike. This is "beginning level" stuff. When I get to the point where I am at the front and missing out because of equipment, well I'll have learned enough by then about me and what I'm riding to take care of that issue.

Now please, this is my take on my research. What people ride and why is very personal thing, and passion can ensue when a discussion starts. I get that. That said, I'm always ready and willing to be shot full of holes - I'm a big girl!

Please add to this, folks.

revchuck 

Sara - I've been doing much the same figuring in my head, and have come to pretty much the same conclusions as you have.

I've already got two bikes I can use - a Specialized Allez and a Look 585 Optimum. Since in my case I'll have to travel to almost all my races, I'll be using one most of the time. It'll be the Allez, because it hurts me to think of dropping the Look, with its miles-deep clearcoat over carbon fiber, in a crit, and I can't really afford to replace it. Besides, the Allez is set up with mostly DA 7800, so it's not much of a sacrifice.

One thing we're doing differently is the cassette - I've ordered a 12-23 and will be using it in most (if not all) of my races. That might be worthwhile for you, though you probably have to do more climbing than I do. A disadvantage of the 12-23 is that the cheapest one you can get is Ultegra, while you can get a 12-25 in 105, which is about $25 or so cheaper.

I think that current aluminum frames ride well enough that you can delete the superior ride quality of carbon from consideration. My Allez is fine for 100 mile days, as is my CAAD9. IMO, tires, seat and wheels contribute more.

Unless you really want/need an entire bike, I'd seriously consider getting just a frameset and transferring everything from whichever bike you want to replace. You can save major bucks that way, especially if you find you need stuff other than what comes stock on the new bike.

Good luck on your quest!

ericm979

There's no difference in rider fit between "classic" and "compact" style frames. Only the slope of the top tube is different. You could make two frames that put the rider in the exact same place, one with a level top tube and one with a sloping top tube. There are of course differences in fit between different makes and models of frames but the slope of the top tube does not cause that.

There are arguments for each style- the sloping top tube means a longer seat post which has slightly more give (depending on its diameter). Sloping top tube frames should, all things being equal, be slightly stiffer. But with modern carbon construction the designer can do a lot more tuning than they could with standard tubes, so that's pretty much moot. The last difference is standover height, which could be important for shorter people. But other than that, with carbon, the only real factor is looks. Some people are stuck in the past and like the level top tube, some people have more modern ideas of what a bike should look like and like the sloping top tube.

I'm in the no special bike for crits camp. But I wasn't much of a crit rider when I did them and don't race them at all now. Back in the day guys would have special crit bikes with higher BBs for cornering clearance, and shorter stays for stiffness and quicker handling. But even then I think that was just an affectation as the Europeans seem to race crits just fine on regular road bikes.

Power Transfer is a myth, dreampt up by marketing. In almost all cases it's BS. (If someone wants to argue this, please find me a study that shows a significant power loss due to flex. I haven't found one yet. Also, Sean Kelley Vitus 979 etc). A flexy frame (or any other part) doesn't make you slower, because it's a spring. When it flexes it flexes back, returning whatever energy it took to flex it. However a rider may prefer the feel of one vs the other. You'd think that a perfectly flexless frame would be best but it's not. Besides the jarring ride, you need some flex in the frame for traction. For example, when accellerating over rough pavement. If the frame flexes a little the rear tire won't skip as much. But basically it comes to rider preference.

AzTallRider

I think the key factors for a crit bike are stiffness and slipperiness. To win a crit, whether via the sprint or a breakaway, you need to go fast without a draft, and so aero frames have an advantage. Weight isn't quite as important.

For road races, weight becomes the dominant issue for most of us, but you still need handling, stiffness, and being aero sure helps.

If I was putting together a crit only bike, with price not a factor, I'd probably go Venge, and Di2 with sprinter shifters. But for now, I'm going with a bike that does pretty well for both crits and RRs. I'm not going to protect a bike by not racing it in certain races. It's a tool, no matter how pretty it might be, and I'm not going to leave it hanging on the rack if it can help me win.

sarals 

Good stuff!

Eric, that FM098 sure is sexy - just sayin'!

As for your point about stiffness, I think you're correct. I've always wondered about "stiffness". I guess for a while I was interpreting it wrong. Example - my Bianchi seems to accelerate with less effort than my Look does - it just glides along. For the longest time I attributed that effect to the Bianchi having a stiffer BB. Now, I don't think so - I think it's fit, and fit only. Me, as the engine, has a better "coupling" to the pedals on the Bianchi and therefore can use my available power more efficiently.

For the aero argument, that's totally valid, IMHO. I can certainly feel the difference at, say, 20 MPH on the Bianchi as opposed to the Look. I have a flatter profile on the Bianchi than I do on the more upright Look. When a puff of wind comes along, I feel it harder on the Look than I do on Bianchi, as well.

Chuck, I hear you on the "glossy carbon". That's why I don't want to race that Bianchi. Oh, my Look is very pretty, too, but the L'una is just special!

sarals 

Chuck, there are arguments for buying a frame and stripping a current bike of it's running gear, and arguments for buying a complete bike. I'm beginning to believe that it's more cost effective to buy a complete bike, with low line running gear, and use it as is, because the cost of a frame only is just NOT that much less than the whole bike. Then, if I decide to remove the Ultegra group from the Look (for example), I have a group to replace it with. I don't like the idea of having a frame sitting around, anyway - it's just "more stuff", and that's what I don't need!

AzTallRider

It's quite possible it's a myth, but then it's likely that "you get the power back" is also a myth. IMO, for that argument to hold water, the return would have to be at the same instant as the flex, which isn't physically possibly. And especially given that most of us apply power later than we ideally should, anything that delays power transfer is a negative. One myth begets another in this case. I certainly know that a stiffer frame seems faster and more responsive. Whether that is born out over the course of a race in improved results is impossible to tell, given how many factors there are.

chasm54

Even if you buy the notion that flex costs you something, and I think I do, the question is how stiff does a frame need to be? I recall some Giant propaganda recently that said their TCR frame was not as stiff as some of the competition, but that you'd need to be putting out some mammoth, Chris Hoy-like number of watts before it was possible to measure any difference.

ericm979

It's not like the frame stores power like winding up a spring and only gives it back on the cool down lap.

I think that we can all agree that no one has a perfectly smooth pedal stroke- you produce more force on the downstroke than the upstroke, and you produce the most force (torque) at around 90 degrees. That is the torque peak on the downstroke of each leg. The BB flex will be at its greatest at the torque peak. But as soon as you reduce the force on the frame it will spring back. That is when the power is returned. In effect it smooths out the pedal stroke slightly.

But I'll agree that a stiffer frame feels faster. I don't know why. I've ridden both super flexy frames and relatively stiff ones. I can find things to like about the feel of each. However with modern carbon you can have a frame that in the steel tubing days would be considered hugely stiff, yet will ride as smooth as the whippiest frame from back in the day. If someone was transported here from 1985 and saw the absolutely gigantic frame tubes we have now, they'd think that genetic doping has given everyone 3000 watt sprints.

Cleave

I have owned and raced quite possibly one of the most flexible race bikes ever (and I think ericm979 has as well, given his screen name); the Vitus 979. It's the only bike on which I could make the bottom bracket flex enough to make the chain rub on the front derailleur after trimming the derailleur to center the chain. I also owned an aluminum frame that was very stiff and was also the worst riding bike I've ever owned. Psychologically, flex is probably not a good thing. The physics of it as related to actual power loss are probably minimal. I'm sure that someone has studied this as part of their Engineering Masters Thesis.

I am not trying to belittle anyone's power output because mine is a pitiful as anyone's, but the difference in frame stiffness at the bottom bracket is not going to make any real difference in your performance on the bike unless you are generating pro sprinter regularly. How much better you'll perform because the bike feels good is a different, and another real, story.

As ericm979 points out, the real beauty of carbon frames is that they are stiff where it's important and flexible where it is also important. Carbon breaks the old paradigm of do you want a stiff frame or a comfortable frame? You can have pretty much both now.

As I've mentioned earlier, how you sit on the bike and how a bike handles based on how you sit on it are what will be the biggest discriminator between bikes. You can place yourself in the right position relative to the bottom bracket on almost any appropriately sized frame. Differences in geometry will dictate stem length, available saddle-to-bar drop, and weight distribution. That's what you have to figure out based on your experience with different bikes.

Regarding crit bike geometry, I think the only significant trait is bottom bracket height (all other things being equal). Pedaling through corners can be a significant advantage. As born out in today's races, I am still a bit gun shy about pedaling through corners after last year's crash and I found myself having to make up a bike length or two on today's course as I stopped pedaling at the apex of corners.

shovelhd

As a crit racer that has owned both, I disagree. The compact frames tend to have a taller head tube versus "standard" geometry. The lines get blurred when the "compact" is really a "semi compact". I think it's tough these days to delineate between the two.

sarals 

Like these?

nacler22

I don't have a dog in this fight, but can anyone tell me were the "stored energy" goes to? My anecdotal experience is that it does not contribute to forward momentum.

FWIW, I cotton to the Goldilocks type frames.

Racer Ex 

I'll be happy to debate this unless you have a pretty specious definition of "significant" by bike standards, where we have national magazines publishing studies on how to gain 3-5w.

In simple terms can you ride as fast up a hill if I cut out one of your chain stays? Sure the frame will flex, but you'll get all that power back, correct? How about I cut out a chain stay and a seat stay?

In somewhat less complex terms flex = power loss. Regardless of plane. Read the laws of thermodynamics: it is impossible to create a process which is perfectly efficient. What goes in does not come out whole.

In more complex terms the energy lost in frame flex (or wheel flex or whatever) does not equate to power returned to forward motion for a variety of reasons. Moving a bottom bracket 2" sideways takes X pounds of force (watts lost). What's returned is x-y pounds of force in that same plane, NOT to the drive train creating forward motion. So while some of that energy, but not all, is returned, it's not returned to the rear wheel. It's returned moving the frame back to "center".

As far as a practical paper I believe it was RIDE magazine that did a study a few years back where they equipped a bunch of bike of various vintages with power meters, and had folks do a climb and descent on them. Corrected for weight the flexy old bikes greatly underperformed (by around 7-11% if I recall) the newer bikes at the same wattages on the climbs. On the descents the flexy bikes also produced slower times, which no doubt had to do with the white knuckle factor.

(BTW, RIDE magazine is simply the best thing out there).

On a personal note I did a fair bit of dyno work when developing some motorcycle frames (one of which got a full page story in a national mag). Flexy frames showed a repeatable decrease in rear wheel horsepower using the same motor. If you do some research into F1 cars you'll find that's their findings as well.

The reason you don't see a ton of PhD papers out there on the subject is anyone with a tiny smattering of practical mechanical engineering and physics knows the laws of thermodynamics and proposing a paper or trying to fund a study to prove flex=power loss would be like asking for grant money to show the ocean contains salt.

If you're confident in your assertion I'll be by with my SRM and a hacksaw. If you can get up Old La Honda as fast without that chain stay on the same wattage I'll cover the new frame. If you can't you can take us all out for dinner at Morimoto's in Napa.

So nah, it's not marketing. It's physics.

That being written stiffer does not automatically equate to faster, both from a physics standpoint and from a physiological standpoint. Some compliance is some planes is good; a car with suspension will move faster over a rough surface than a car without. And too stiff a frame causes greater fatigue which decreases rider performance. All those different shapes for the various tubes aren't just marketing (in a lot of cases but not all), they are an effort to develop something that provides directional stiffness in the planes that matter while providing compliance for the rider.

As it relates to crit bikes...I'd get something that made you feel fast and confident. For an hour or so screw comfort. Shovel can speak to the Felt, the SST won me a bunch of crits including a state championship and might be one of the best values out there for this application. At the current price of carbon I'd probably pass on the CAAD. The Allez makes me yawn.

BTW I finally got my SL4. And the new Venge is bad ass.

nacler22

Thanx Ex.

That's pretty much what my cowboy engineering cyphered, and your response decoded it.



Hey look at me. I'm over 400 posts now.

Hermes

Flexy smexy...

I agree with Racer Ex's analysis. IMO, most of the BF analysis and discussion uses mechanical systems as a proxy. A spring and lever arm come to mind. In a purely mechanical system, a compressed spring returns its energy to the system and the losses are molecular heat which is too low to measure easily or matter.

However, a bicycle is a combination of mechanical and human where the human has to produce energy to compress and spring and energy to control its release. If one wanted to draw the force vector diagram of a human putting in power to a frame set via a crank, it is possible. Assuming none of us are motivated or capable of doing this, we can argue the point from a more qualitative analysis than quantitative. IMO, all the force when the frame / wheels spring back is NOT going to be additive UNLESS the human rider applies a counter force and puts in more energy. It is a bit like walking down stairs. We have to absorb some of the potential energy or we free fall.

The most important pedal stroke... Is there one? I would argue yes. It is the first one when you need a slug of power NOW. The standing start at the track is the best way to see this. The first pedal stroke is the most important with every succeeding one becoming less valuable. In crits and road races, racers attack and it is the jump that creates separation. When there is an attack, it is the response that determines position. We all know that just a little gap at 30 mph turns into a bigger one quickly. So the ability to stomp on the pedal and match that acceleration is critical, IMHO.

Once again this can be seen at the track doing jumps as a group. Frequently, I do jumps with a guy who is a 4 time world sprint champion. We roll up to the flying 200 meter start line at 10 mph in single file. The first racer across the line jumps. If I am on his wheel, I watch for the twitch in his leg and go with him. That first pedal stroke is critical and I am immediately gapped if I miss it. I do NOT want to wait for the frame to give me back the power lost in compression.

Do you think your frame is difficult to flex? Stand facing holding the seat and handlebar. With the pedal facing you down, step on the pedal and pull on the handlebar and seat. How much does the bike flex? Was it easy to make it flex? Stiff frames do not flex very much doing this test.

1000 watts versus 300 watts... When I started track cycling, my friend, the sprint champion, helped me with bike selection and components. He said any bike frame will work at 300 watts in a straight line but out of the saddle, in the turns at over 1000 watts is a completely different matter. And he was right.

If you do not believe the arguments then fine but here is the trump card. I have outgrown my Planet X frame. It is too flexible. It is good for pursuit but not for standing starts. Sometimes it just does not feel right out of the saddle in the the first turn or on the back stretch going really hard. What happens is when it feels wrong, I let up slightly.

I can do over 1000 watts but it does not take much loss of focus to drop a hundred watts which is significant in 500 meter. I do not want this as a distraction.

Sprinters, strong crit racers and track racers gravitate to stiff frames and wheels. It just feels better and feeling better means more power production.

My hope is that all of my 500 meter competitors think this is BS and marketing and buy flexible frames.

sarals 

Hermes, it's not BS at all!

Ex gave a great analysis. From my perspective, if you think of a rider and bike crankset as an engine, you then have a two cylinder engine with a 360 degree crankshaft. I know that something over 700 watts is one horsepower, and even though that is usually a short term output, it is a considerable amount of power. It has to put a considerable torsional load on each side of the bottom bracket, as well as the chainstays. Then you have the torque transfer from the chainrings to the cassette, where when under power, the cassette is trying to "wind up" - be pulled forward and upwards by the the chain. On top of that you have loads being presented by the rear wheel, which is trying to move forward in the dropouts and at the same time is applying more torque to the drive side chainstay than the non drive side. All of this is being held in alignment, in check, by thin wall aluminum, steel or carbon. If the design is improper, of course it will bend - flex! It has to. It seems to me that mitigating that frame distortion would be paramount in a machine intended for high duty cycle high power transients - make the silly thing stiff! It does amaze me when I see video of a huge guy on a spindly little carbon stick machine just mashing the crap out of the pedals and the poor thing doesn't just explode. That it doesn't is quite a testament to the state of the art, for sure.

shovelhd

******

AzTallRider

And the state of the art is clearly carbon fiber. The only valid reason to consider anything else is cost: cost of initial investment, and potential cost of replacement if you crash, since it is more likely to actually break than is aluminum or steel or titanium. And while CF may be reparable, even relatively minor repairs cost hundreds of dollars. But the metals don't have the same ability to dial in desired flexibility at key design points. So for a given stiffness, you are going to have a much heavier frame, and heavy frames suck.

I'm sticking with my criteria:

Crit bike: Stiffness, handling and aerodynamics

RR bike: Stiffness, weight, handling and aerodynamics.

sarals 

I think I'll stir things up a little. I know how contentious the discussion can get when "Chinese Frames" are mentioned (Chinarello?). I really believe there are some truly good bikes out there using those frames in the DIY arena, but there is the stigma, and then there is the idea of sending money to some far off land and wondering what will show up, or if anything will.

Now, this frame has been around for a while. It gets some decent reviews. There is even a YouTube video of it. It's the FM-098. It's pretty sexy!

shovelhd

Titanium is also a player. It's not just for doctors and lawyers.

sarals 

revchuck 

Oh, Sara - Nashbar has their house-brand carbon frameset on sale for $600 right now...just sayin'...

https://www.nashbar.com/bikes/Product...82_-1___203991

AzTallRider

That frame looks pretty "Vengesque"... certainly looks nice!

sarals 

Chuck, that DOES look nice!

AzT, it does look Vengesque, doesn't it? I might inquire about it. With a headset, seat post, clamp and one color (it would have to be black, it's the law) it goes for around $600 shipped - like the Nashbar frame.