Professional Cycling For the Fans - Pro riders return to metal frames?

I wish I had your enthusiasm for things that really have no affect on my life.


Thanks, OP brought it up, mustve been affecting his.

A 5 second google search brings up that Aluminum is still being used by todays riders on the tour, see for yourself:


The BMC racemaster SLX01 (http://www.bikeworldnews.com/tag/bmc-racemaster-slx01/)
Before moving to the impec, the Racemaster SLX01 was George Hincapie’s choice. The prize winning design unites carbon and aluminum in a racing frame that guarantees uncompromising rigidity and a high degree of ride comfort at the same time. The integrated streampost seatpost can be adjusted for height with a single turn and remains perfectly aligned due to its tear drop shaped profile. The result is a comfortable and incredibly fast racing machine made for curvy mountain passes and for effortless gliding over any tarmac.


Im aware it's also carbon, but they're still using aluminum in bikes as well, which was my point from the beginning.

Thanks, OP brought it up, mustve been affecting his.

You just don't know when to let something go do you?

The noise from here traveled all the way from my computer to where I was outside. Noisy noisy noisy. So noisy that after awhile, all you hear is white noise like on a TV with no station. Mr Fanforeve, please leave this thread. Thank you.

I didn't bother reading all the posts in this thread, but I do want to add this:
The UCI mandates that all pro riders must ride CARBON FIBER bikes, "or ELSE <fist shake>".

Wasnt trying to be a dick, someone claimed a fact, then i asked for said proof, and they got all pissy and then reaffirmed the fact. I asked a second(and 3rd) time for them to show me where every single rider on every team on tour olny rode 2 kinds of bikes, and they couldnt. OP was asking...I said I didnt think they were only racing on 2 frames...then it went crazy.



Please show me where i said you did say that? I was responding to those who said that there were only 2 kinds of bikes currently being ridden on the tour as we speak: TI/CF, and thats not the case, as someone cited a team from last year that rode Alu......I will stick to my assumption that not every single rider/team rides only CF/TI on the tour, and until someone can post proof otherwise, i will stick that that assumption. Not a "dickish" thing, not an any "thing", just said i didnt think that folks rode those frames specifically, no one has proven otherwise, no big deal really.

http://i.imgur.com/m86Vz.gif

nonsense

I don't know why you keep saying CF/ti. No one is using Ti.

The statement was specific to this year. Last year, it was different. There were a couple of guys on alu frames. They were exceptions, generally due to fit issues, but they were out there.

This year, there are none. It's very simple. 2011 is different from 2012.

Everyone gets this except for you.

A 5 second google search brings up that Aluminum is still being used by todays riders on the tour, see for yourself:


Before moving to the impec, the Racemaster SLX01 was George Hincapie’s choice.

Im aware it's also carbon, but they're still using aluminum in bikes as well, which was my point from the beginning.
Hincapie road the carbon BMC impec in the 2011 tour.
http://www.cyclingnews.com/features/photos/more-bikes-of-the-tour-de-france-what-the-pros-are-riding-this-year/132461
The impec was also used by BMC in the 2010 tour -- didn't bother looking hard for references to whether or not Hincapie or any other BMC riders road the Racemaster in 2010.

If you are going to post a reference to prove your point you might want to be sure it actually proves your point.

Night Ranger, seriously? heed your own advice and YOU STFU.

I see you're more of a Milli Vanilli kind of guy. Whatever floats yer boat, kook.
Good to see you stopped snorting Bath Salts and moved on to Robotripping, as evinced by you STFup.

FYI, a Tarmac SL4 frame is around 4.3 lbs.

No, it does not, nice job bending the truth there

[QUOTE=Bacciagalupe;14242705]FYI, a Tarmac SL4 frame is around 4.3 lbs. QUOTE]

3.257 lbs for frame, fork, & seatpost

3.257 lbs for frame, fork, & seatpost
Yeah, my bad. Apologies to Specialized. :D

That said:
Seven Axiom SLX (titanium) + Seven "Stock" CF fork = average 3.3 lbs
Cervelo Soloist / S1 (aluminum) + CF fork = ~3.8 lbs
Seven Resolute SLX (steel, alloy unknown) + Seven CF fork = average 4.3 lbs

Even if Seven is putting their thumb on the scales, I'm confident that you could build a 15-pound bike with a metal frame. And we already see hydroformed aluminum frames in the same shapes as CF, many of which are stiff and reasonably comfortable.

I don't think it is likely​ that pros will switch to metal any time soon. But if they did, it would be because the manufacturers see a sales advantage to pushing metal as the super-high-end, and thus a marketing advantage to putting pros on metal bikes.

Yeah, my bad. Apologies to Specialized. :D

That said:
Seven Axiom SLX (titanium) + Seven "Stock" CF fork = average 3.3 lbs
Cervelo Soloist / S1 (aluminum) + CF fork = ~3.8 lbs
Seven Resolute SLX (steel, alloy unknown) + Seven CF fork = average 4.3 lbs

Even if Seven is putting their thumb on the scales, I'm confident that you could build a 15-pound bike with a metal frame. And we already see hydroformed aluminum frames in the same shapes as CF, many of which are stiff and reasonably comfortable.

I don't think it is likely​ that pros will switch to metal any time soon. But if they did, it would be because the manufacturers see a sales advantage to pushing metal as the super-high-end, and thus a marketing advantage to putting pros on metal bikes.

There were 15lb steel triathlon bikes in the early 1990's or earlier. So, yes very possible. In the mid 90's I called Quintana Roo to ask some general questions regarding their steel triathlon frames. I was immediately transferred to their frame builder. He spoke to me at length about building a 15lb steel triathlon bike for Scott Tinley. It was noodly, but that included aero bars.

But, as you say, it is more about what the bike companies can market & make the most profit from.

That said:
Seven Axiom SLX (titanium) + Seven "Stock" CF fork = average 3.3 lbs
Even if Seven is putting their thumb on the scales, I'm confident that you could build a 15-pound bike with a metal frame.

I've got that Seven and your weights are exactly what mine weighs. Built up with pedals and cages it's at 16 lbs. By using tubulars and a couple minor changes it is easily 15 lbs. But I wouldn't want to race it because the frame has flex and won't accelerate or climb as quickly as my CF bike

This is a solution looking for a problem.

Other than custom builds where the one-off job-ability of metal (steel, Al, Ti) makes sense, I still don't know see what problem isn't better addressed by CF.

This is a solution looking for a problem.

Other than custom builds where the one-off job-ability of metal (steel, Al, Ti) makes sense, I still don't know see what problem isn't better addressed by CF.

Road shock, vibration, & comfort.

Personally I'm unconvinced that very stiff frames are any faster, in a road race, than less stiff ones. On the track, especially sprinting, sure. You need instantaneous response there. But on the road? I don't think one loses much, if any, energy on a springier frame. It seems to me it's pretty much a closed system, the energy used to flex the frame will help propel the next pedal stroke as the frame recoils.

Sorry, but this is simply not true. It's an open system because the flex is not returned into the drive train. I believe Ride or one of the British magazines did a test with 80's era steel frames vs. today's carbon. The wattage loss was in the 8-11% range on a climb and to a person the testers hated descending on the steel frames. I had a long talk with Andy Hamsted on day about the frames of the era. Given that he sells and ride Ti, you'd have to give his opinion some weight. He'd be racing on carbon.


Road shock, vibration, & comfort.

Incorrect.

Let it go.

Years ago I did a blind test on various forks run by a university commissioned by a regional manufacturer. I picked a particular carbon fork over all the others as the best all-around for comfort, stiffness and vibration transfer. A cromoly fork did well on points 1 & 3, but was well down on the list for #2. That's been my experience for frames as well.

The problem with metals is that you're beholden to the alloy you pick. Carbon provides a huge range of options is shape, layup, epoxy, Etc. We're just touching the iceberg on what can be done with this material, as Calfee pointed out in a recent issue of CSA, it's a very young technology while metallurgy has been around for a thousand years.

BTW, I own several metal bikes.

Sorry, but this is simply not true. It's an open system because the flex is not returned into the drive train. I believe Ride or one of the British magazines did a test with 80's era steel frames vs. today's carbon. The wattage loss was in the 8-11% range on a climb and to a person the testers hated descending on the steel frames. I had a long talk with Andy Hamsted on day about the frames of the era. Given that he sells and ride Ti, you'd have to give his opinion some weight. He'd be racing on carbon.





I'm racing on carbon too, so clearly I'm not a total "steel is real" merchant. And since I'm not an engineer either, I'll take your word for it on the wattage.

Having said that, my 1980s Reynolds 531 Raleigh is the most comfortable bike I own. They're all set up similarly, I'm comfortable on them all, I've ridden centuries on my race bike, but I can ride that Raleigh all day and barely know I've been out. I'm very happy descending on it too - it's different from carbon, especially when one hits a bump - I can imagine someone new to the material finding that "twang" pretty disconcerting - but if one is accustomed to it, it's fine. Not for racing, OK. But still a nice experience.

Having said that, my 1980s Reynolds 531 Raleigh is the most comfortable bike I own.

My old Trek 470 was awesome on Texas chip seal. All my carbon stuff was more biased towards the racing/stiff end of the spectrum.

Sorry, but this is simply not true. It's an open system because the flex is not returned into the drive train.
At the risk of perpetuating a perpetual flame war ;) I have not seen any objective evidence to indicate that a stiff frame increases the amount of power getting to the drive train (see below). Modern riders may prefer stiff frames, and they may handle better in certain circumstances such as descents -- and we should not discount that in a race setting. But it doesn't mean it's more efficient in terms of power transfer.



I believe Ride or one of the British magazines did a test with 80's era steel frames vs. today's carbon....
It was Procycling. The older bike used a vintage frame and vintage components, including downtube shifters (!) and a 6-speed freewheel (!). The course was 3k with a 7.2% grade, so performance on the flats and descents were not objectively tested. The vintage bike weighed 5.5 pounds more than the new one -- and in theory, that explains most (if not virtually all) of the performance differences between the two.

The field test also had a surfeit of variables -- geometry, handling, gearing, shifting, aerodynamics, saddle type, wheel weight, frame weight and rider preferences.

Thus the Procycling field tests can definitely assert that "vintage racing bikes are slower on the climbs," but I don't think it viably proves that "lateral stiffness improves drivetrain efficiency."

What you'd have to do is at least two bike builds, where the only variable is the degree of stiffness in various areas (e.g. BB, CS, head tube, wheels), and compare the power meter data and handling characteristics for performance on the flats, on various climbs, in corners, on descents, over long distances, and with different amounts of power. As far as I know, no one has done anything remotely along those lines.



We're just touching the iceberg on what can be done with this material, as Calfee pointed out in a recent issue of CSA, it's a very young technology while metallurgy has been around for a thousand years.
True, but then again, people haven't been making bicycles for a thousand years. ;) Metal has also advanced quite a bit in recent years, with newer alloys, butting methods, frame designs and hydroforming. It's unclear how much metal frames could improve if given the same R&D efforts as CF.

And let's not forget, Calfee occasionally advocates bamboo as a high-end frame material, which like metals, is beholden to its inherent properties and isn't as manipulatable as carbon fiber. :D

Again, I concur that it's unlikely that road racing pros will switch back to metal any time soon. But IMO a lot of that is strictly business, as they'd have to roll back well over a decade of marketing materials to push anything other than CF.

Sorry, but this is simply not true. It's an open system because the flex is not returned into the drive train. I believe Ride or one of the British magazines did a test with 80's era steel frames vs. today's carbon. The wattage loss was in the 8-11% range on a climb and to a person the testers hated descending on the steel frames. I had a long talk with Andy Hamsted on day about the frames of the era. Given that he sells and ride Ti, you'd have to give his opinion some weight. He'd be racing on carbon.



Incorrect.

Let it go.

Years ago I did a blind test on various forks run by a university commissioned by a regional manufacturer. I picked a particular carbon fork over all the others as the best all-around for comfort, stiffness and vibration transfer. A cromoly fork did well on points 1 & 3, but was well down on the list for #2. That's been my experience for frames as well.

The problem with metals is that you're beholden to the alloy you pick. Carbon provides a huge range of options is shape, layup, epoxy, Etc. We're just touching the iceberg on what can be done with this material, as Calfee pointed out in a recent issue of CSA, it's a very young technology while metallurgy has been around for a thousand years.

BTW, I own several metal bikes.

The bold portion of your comment is one of the reasons why I pointed out that they can be great for road shock, vibration, and comfort. My wife has an inexpensive fixed gear, steel frame & fork. When other people ride it (who own carbon or titanium with carbon forks) they are amazed at the comfort.

You can tune a steel frame to flex where you want it & how much. Not all steel frames are 80's era designs as you seem to believe. And, there has been numerous testers than prefered frames that had a bit more flex for descents, rough surfaces, etc. Traction can be lost a lot sooner on a frame that does not flex enough. Perceptions about handling are often wrong. We tend to erroneously trust a frame that is stiff. It feels solid & gives confidence through corners. A noodly frame is not confidence enspiring, but can offer much more traction.

Your experience is different than mine. Just because you prefer it and you did a bind test, doesn't mean you are the expert. If you look at some of the bikes ridden long distance, they are often not carbon for good reason. And, not just because carbon is harder to repair.

I significantly doubt the accuracy of the testing that found an 8 - 11% wattage loss. How was it measured? Were all components the same except for frame & fork? Wheels, tires, etc the same. I can tell you from my own experience sprinting on climbs, that to get an 8-11% increase in wattage required due to the bike takes a great deal of differences. A lot more than a frame and fork.

At the risk of perpetuating a perpetual flame war ;) I have not seen any objective evidence to indicate that a stiff frame increases the amount of power getting to the drive train (see below)...

I don't flame ;)

I go to simple extreme examples for physics questions like this. Take two identical bikes, and cut out one chain stay on one bike to simulate a LOT of flex. Now ride them up a hill on a timed course, and in a sprint for max speed.

The results will be a big duh.

Of course a stiffer frame will deliver more power to the rear wheel. The question isn't if, it's how much (and also if it's relevant to the owner). And I'll stop you before you start...there's nothing that happens with a cut chain stay that doesn't happen on a flexing frame. It just happens to a more extreme measure.

And as far as objective, I've seen multiple dyno runs where motorcycle frames were tested with the same engine. The less stiff frames produced less power at the rear wheel.


But IMO a lot of that is strictly business, as they'd have to roll back well over a decade of marketing materials to push anything other than CF.

They had to roll back 8+ decades of steel marketing to push non steel. And here we are.

The market for carbon developed because the consumer liked carbon more than metal. Period. The manufacturers aren't wedded to any material, all you need to look at is a 25 year timeline and you'll see all manner of of metals in dozens of alloys from ti/alu/steel/mag, carbon, carbon/metal, and now bamboo. In some cases a new material or blend introduced every year.

Do you really doubt that if there was a metal, wood, polymer, or mineral that would produce a lighter, better riding, higher performing frame than the current offerings that the manufacturers would NOT race to get it to market because they didn't want to have to roll back marketing?

And it's not financially driven. Low end steel and aluminum can be had for less than low end carbon. High end is what the market will bear.

I don't flame ;)

I go to simple extreme examples for physics questions like this. Take two identical bikes, and cut out one chain stay on one bike to simulate a LOT of flex. Now ride them up a hill on a timed course, and in a sprint for max speed.

The results will be a big duh.

Of course a stiffer frame will deliver more power to the rear wheel. The question isn't if, it's how much (and also if it's relevant to the owner). And I'll stop you before you start...there's nothing that happens with a cut chain stay that doesn't happen on a flexing frame. It just happens to a more extreme measure.

And as far as objective, I've seen multiple dyno runs where motorcycle frames were tested with the same engine. The less stiff frames produced less power at the rear wheel.



They had to roll back 8+ decades of steel marketing to push non steel. And here we are.

The market for carbon developed because the consumer liked carbon more than metal. Period. The manufacturers aren't wedded to any material, all you need to look at is a 25 year timeline and you'll see all manner of of metals in dozens of alloys from ti/alu/steel/mag, carbon, carbon/metal, and now bamboo. In some cases a new material or blend introduced every year.

Do you really doubt that if there was a metal, wood, polymer, or mineral that would produce a lighter, better riding, higher performing frame than the current offerings that the manufacturers would NOT race to get it to market because they didn't want to have to roll back marketing?

Of course a stiffer frame can deliver more power to a rear wheel. But not always in the real world. A dynomometer has an extremely smooth surfaced roller. So, of course it is more representative of an indoor velodrome. Not the same when the surface is not smooth. But, show me the results of those dyno tests. I seriusly doubt that there was even 1/2% HP loss unless the frame or suspension was so flimsy that it was completely impractical. Was it done on a rigid? You have a rear suspension to deal with that allows flex. Swing arms that are too stiff on a motorcycle can be an issue in hard cornering where you are leaned over & therefore the rear suspension has less flex. This is a good comparison however, in that a motorcycle has a suspension for good reason to keep both tires on the ground. Try riding a rigid motorcycle on rough roads at high speeds. Then try one with a very finely tuned suspension. Quite a difference. If your theory that stiffer is always better were correct, then this wouldn't apply. Bike frames can be built too stiff & traction can be lost as a result.

As far as a real world delivery of power to the rear tire test, try riding a mid 90's Canondale aluminum tri frame on a non-smooth road. Can you keep the rear wheel on the ground? Probably not. I couldn't. It resulted in a large loss of wattage as the rear wheel lifted off the ground & torqued to the right with the turning of the cranks. So, as far as your simple extreme examples for physics tests, there was one. Stiffer isn't always better.

If stiffness is so important to energy transfer, someone please explain why dragsters are built with those noodly, flexing frames.

The team mechanics take over , after the race day, and may put a new bike together
for the rider to be ready for the next day's sign in.

so there may be a few frames consumed in a grand tour, before it's over .
but the rider still has a bike that works, every morning.

recall one of Eddy's sponsored riders won both green Points and yellow for the stage win,
and next morning he started on a new bike frame ,
green from one side , yellow from another.

fresh paint from the Merckx factory in Belgium..

Bacciagalupe -- thanks for an informative, balanced post! You had me worried for a moment, I had to double-check that I was in BikeForums (at least THIS specific forum) ;).

I'm torn. The scientist in me agrees with your reasoning of a flawed study, at least for the purposes we're extrapolating it. The engineer in me accepts that the power is going somewhere from the flex and even a 1/2% loss (net after any dubious minimal gain for the "suspension" benefit) is a deal breaker at the pro level and that any such study would be akin to the '3 whoppers a day makes you fat' research.


If stiffness is so important to energy transfer, someone please explain why dragsters are built with those noodly, flexing frames.

The "noodly" bits of dragsters' frames aren't inserted into the drive train like a bike frame is between the rider (engine) and wheel. So they are not involved in power transfer, just in keeping the front wheels & spoiler way out in front for control and balance. The drive train is as stiff as it can get.

...

What you'd have to do is at least two bike builds, where the only variable is the degree of stiffness in various areas (e.g. BB, CS, head tube, wheels), and compare the power meter data and handling characteristics for performance on the flats, on various climbs, in corners, on descents, over long distances, and with different amounts of power. As far as I know, no one has done anything remotely along those lines.


...

Jan Heine has done mostly that, and published the results in his "Bicycle Quarterly". If you google his theories on 'planing' you can get some of the info.

I'm not suggesting that this research solved the issue, mind you, at all. He did the best he could with the resources he had, and I think the results are valid so far as they go, but it was hardly a super rigorous scientific test.

This guy has some ideas on it too: http://www.kirkframeworks.com/Flex.htm

Of course a stiffer frame can deliver more power to a rear wheel. But not always in the real world.

I wasn't referring to horizontal compliance, let's not shift what we both knew was a lateral stiffness discussion, lest you end up pulling out the full suspension mountain bike card. I'm sure I can find roads where one of these would be faster than a road bike. I throw in what Kirk refers to as BB/drivetrain flex into the lateral bucket because it's lateral deflection that's the power grabber in this equation.

My recollection of the power loss on the motorcycle test was around 5%...2HP on a 50HP give or take motor in a road race specific frame. I was there, we looked at the printout and went "well that ain't gonna cut it". Like all race builders, we stumbled on this when the engine suddenly lost power...we fumbled around in the dark for a bit with various things then said WTF and tossed it into the old frame. Hello ponies.

This was still in the tube frame era BTW, today's perimeter frames let guys do stuff that would have put me on my ass. Back then speed wobbles were a constant, if you could get a bike to go in the general direction of the course you were pretty happy. The bike (and me on it) ended up in a national mag later that year.

Your point on the rollers vs. road is a red herring for a motorcycle BTW, unless you plan on taking off the suspension and running bicycle width tires.

As far as the amount of loss (nice to see slcbob gets this) it is a deal breaker for a racer...stiff is always better provided the frame if it's ridden in longer events, can provide enough compliance to the contact points that the rider doesn't feel like he's had the stuffing kicked out of him after four or six hours, where you're already a crampy mess.

Interesting to note that when Cadel was riding for one team, the bike maker built a frame to these exact specifications. I owned and raced one for a season and it was great for longer races and stage races; for Gila I set the bike up with less stiff bars and stem because I was willing to sacrifice a bit of stiffness for being fresher at the end when I knew the race would be decided.

The same year another pro team was on the make and model I raced in crits...very stiff, laser guided missle handling, but really beat you up after a couple of hours. I watched the Tour riders on those that year and I felt truly sorry for them.

FWIW these aren't just theoretical mullings for me, I compete on a national level in road and track events and spend a lot of time looking for small advantages. I've won and lost nats medals by 1-4 seconds over various distances. Given that this is a racing related thread I'll chime in, and I've enjoyed the discussion. Had this been a general road thread I'd say go ride something that makes you smile.

I wasn't referring to horizontal compliance, let's not shift what we both knew was a lateral stiffness discussion, lest you end up pulling out the full suspension mountain bike card. I'm sure I can find roads where one of these would be faster than a road bike. I throw in what Kirk refers to as BB/drivetrain flex into the lateral bucket because it's lateral deflection that's the power grabber in this equation.

My recollection of the power loss on the motorcycle test was around 5%...2HP on a 50HP give or take motor in a road race specific frame. I was there, we looked at the printout and went "well that ain't gonna cut it". Like all race builders, we stumbled on this when the engine suddenly lost power...we fumbled around in the dark for a bit with various things then said WTF and tossed it into the old frame. Hello ponies.

This was still in the tube frame era BTW, today's perimeter frames let guys do stuff that would have put me on my ass. Back then speed wobbles were a constant, if you could get a bike to go in the general direction of the course you were pretty happy. The bike (and me on it) ended up in a national mag later that year.

Your point on the rollers vs. road is a red herring for a motorcycle BTW, unless you plan on taking off the suspension and running bicycle width tires.

As far as the amount of loss (nice to see slcbob gets this) it is a deal breaker for a racer...stiff is always better provided the frame if it's ridden in longer events, can provide enough compliance to the contact points that the rider doesn't feel like he's had the stuffing kicked out of him after four or six hours, where you're already a crampy mess.

Interesting to note that when Cadel was riding for one team, the bike maker built a frame to these exact specifications. I owned and raced one for a season and it was great for longer races and stage races; for Gila I set the bike up with less stiff bars and stem because I was willing to sacrifice a bit of stiffness for being fresher at the end when I knew the race would be decided.

The same year another pro team was on the make and model I raced in crits...very stiff, laser guided missle handling, but really beat you up after a couple of hours. I watched the Tour riders on those that year and I felt truly sorry for them.

FWIW these aren't just theoretical mullings for me, I compete on a national level in road and track events and spend a lot of time looking for small advantages. I've won and lost nats medals by 1-4 seconds over various distances. Given that this is a racing related thread I'll chime in, and I've enjoyed the discussion. Had this been a general road thread I'd say go ride something that makes you smile.

I've been involved with dyno tuning quite a bit, and a lot more than 50hp. It was almost always with chrome moly round tubing. That frame that lost 2ph in a 50hp engine was crap. A 4% power loss? Try 200 hp in a steel tube frame. I don't know what frame you were using, but again not a suitable one for the road let alone the track.

I've been a national class duathlete, and I still disagree with you that stiffer is always better.

If you are concerned with lateral stiffness only, any frame is going to be crap. If you are limiting your thought process to that, then you are totally missing out on proper frame design. They go hand in hand. In order for a frame to corner very well over various surfaces, not just a smooth indoor velodrome, then a designer needs to consider both vertical and horizontal compliance.

My recollection of the power loss on the motorcycle test was around 5%...2HP on a 50HP give or take motor in a road race specific frame. I was there, we looked at the printout and went "well that ain't gonna cut it".
50hp = 37,284 watts. I'd guess that a motorcycle's drive train has much higher tolerances than one on a bicycle. And, of course, it's very likely that stiffness in the head tube will have no effect whatsoever on the drive train, or we may find that any modern road bike is stiff enough to avoid a performance loss, and so forth.

For example, Specialized claims (based on its own tests of course) that the Tarmac SL3 has a torsional stiffness around 100 nm/deg, whereas the Scott Addict is around 80 nm/deg. Does this matter? We can quantify the stiffness, but can we go from there to quantify a (theoretical) performance increase? If so, then why isn't this touted in the same numerical fashion as the theoretical advantages from improvements or aerodynamics? What formula ought we use to quantify the alleged performance gains? Specialized is obviously more than capable of running the numbers and stating "the Tarmac SL4's stiffer BB makes it 5s faster over 40k than a Cannondale SuperSix" -- so why don't they run the numbers, and trumpet it in their marketing material?

I.e. bicycles would clearly require a separate test than motorcycles, if for no other reason than to quantify the alleged losses.

Or, to put it another way: If you ran a lateral stiffness efficiency test on a bicycle, and on that basis concluded that lateral flex would be problematic for a motorcycle, would that really be a sufficient guide for a motorcycle designer? ;)



As far as the amount of loss (nice to see slcbob gets this) it is a deal breaker for a racer...
That may be the case, but that doesn't change the fact that if you're going to blame a specific aspect for a performance loss, I'd want to see an objective, single-variable field test to back up and quantify the claim. It doesn't help that we've seen sprint after sprint, and race after race, where the rider on the bike that offers a theoretical 60-second-over-40k advantage gets beaten by the guy on the "slower" frame.

Not to mention that when it's a pro on the bike, with the notable exception of one rather famous TT no one says "so-and-so got beat because he was on a frame with more flex" or "he lost by 1/2 a wheel length because his bike wasn't aero enough." But when it's us who loses a sprint by a hair, it's the fault of the bike. How does that work, exactly? :innocent:


And on a non-technical note, guys concerned about and bragging about stiffness.... The jokes write themselves. :D

[QUOTE=Bacciagalupe;14406078]



It was Procycling. The older bike used a vintage frame and vintage components, including downtube shifters (!) and a 6-speed freewheel (!). The course was 3k with a 7.2% grade, so performance on the flats and descents were not objectively tested. The vintage bike weighed 5.5 pounds more than the new one -- and in theory, that explains most (if not virtually all) of the performance differences between the two.

The field test also had a surfeit of variables -- geometry, handling, gearing, shifting, aerodynamics, saddle type, wheel weight, frame weight and rider preferences.

Thus the Procycling field tests can definitely assert that "vintage racing bikes are slower on the climbs," but I don't think it viably proves that "lateral stiffness improves drivetrain efficiency."

QUOTE]

Does anybody have a link to the Procycling test? I know it was referenced in a thread here some time ago, but I can't find it now.

This is an interesting thread to me, and not just because of the discussion of the performance of different frame materials in race conditions, though in part because of that.

Ultimately, race sponsorship is a way for frame manufacturers to sell bikes to consumers. So, the sales returns must ultimately exceed the cost of sponsorship, at least if we assume the manufacturers are rational.

There is still significant consumer interest in metal frames. You would think, then, that this fact alone would incent at least one manufacturer to fit out a team with metal frames. Should a rider have a great success on a metal frame, you would think that fact would redound to the benefit of that manufacturer's bikes in the popular metals segment of the road bike market.

Pretty much all the teams are fitted out with carbon frames now, though. I wonder, why is that?

One possibility is that carbon just is a much more advantageous material in race conditions than metals, even given the present UCI weight floor. A sponsor that offered up metal frames could expect, other things equal, to be outclassed by equally strong riders on carbon frames.

I'm not sure I believe this possibility is real, though. Given the weight floor in particular, I'm not sure I see why one of the TdF winners of the past few years could not have won with, say, an aluminum frame, all other things equal. So, again, I wonder why no teams at least try to offer metal frames.

Another possibility, I suppose, is that metal simply does not offer the sheen of innovation. Carbon frames make a statement about a manufacturer's cutting edge technological expertise, so that the advertising benefits of sponsorship are magnified with carbon frames. If carbon frames are no worse than metal, even if they are not really better, this would be a reason for sponsors to offer carbon frames rather than metal frames.

We can consider NASCAR as a parallel. Sponsors there seem to think that even cars that are widely understood by the fan audience to be very different from consumer models can help the sponsors sell consumer cars. So, likewise, perhaps sponsors like Trek and Specialized think they will reap about as much benefit in the sales of their consumer-model metal frames from race-sponsored carbon fames as they would do from race-sponsored metal frames. Offering carbon frames to racers would also give their carbon lines more credibility to consumers, too. So, offering carbon frames would be a rational choice. Again, this strategy would make sense even if carbon frames did not offer any significant advantage in racing conditions.

Our friends at Specialized are apparently doing a very limited run of S-Works Allez frames. E5 alloy, thin-walled tubing, very smooth welds. No internal cable routing though. Frameset weighs less than 1200g, complete bike is 14.5 lbs. ( http://www.bikerumor.com/2012/07/10/2013-specialized-road-cyclocross-womens-commuter-bikes-roubaix-disc/ )

I for one would be curious how it racks up in Specialized's own tests, in terms of torsional stiffness, lateral compliance and so forth. Would they admit it, if this frame beat CF on any of those measures? :D