Is there a science to building metal bike frames?

[oldpotatoe]

Originally Posted by qnz

That was a good read about the Mondonico frame test.

So the writer couldn't tell the difference between some of the frames, and if he did the test over again, he would probably pick different frames as winners.

What about different geometries? Same material frame, but a 73* seat tube here, extra 10mm top tube there, and this bottom bracket instead of that bottom bracket. Would the differences be just as subtle?

Test 3 pair of shoes, made with the same materials but different sizes...
Yes, bike fit is a range and not necessarily hard numbers but riding a bike that doesn't fit well, compared to one that does..pretty obvious result.

[paredown]

There are some technical issues to master, say going from steel to titaniium for example, where with titanium you need to work with inert gas to prevent oxidation--nothing I have tried myself, but I read a very interesting set of posts by someone who was switching over, and who made their own setup.

Different types of construction with steel as well--silver brazed, brazed, tigged, fillet brazed, lugs--and most builders will settle on a style they like. And having grown up with a superb wellder (and tried a little myself)--there is not science in the right temperature and the right motion with the torch, the right flux--that is techne--"techne is concrete, variable, and context-dependent" as the Wiki page says.

I got to watch my dad but weld plates (arc welder) or other projects were he had such control of the puddle, with the heat perfect, the right heat and right rod that he would get the perfect 'stack of dimes'--and one hit with the hammer, the excess flux would fall away... You only get that through a lot doing.

What you pay for with an experienced builder is that embodied craft and techne--knowing how to tack a frame, knowing the right motion, and the right sequence to minimize movement etc. For the time that the really good builders have put in to master their craft, their prices ought to higher.

[joevers]

Originally Posted by martl

Let me correct: the big brands have the marketing budget to rent a wind tunnel and shoot a few nice pictures for the ads, and pay some. Dude to write some cattle manure "study" why their design will save you any amount of watts, and they can sponsor a pro team.

I understand why you're skeptical, and believe me I love everything about steel bikes. I race road, cross, and track on steel bikes, and have a stack of tubes and lugs in my basement I'm hoping to braze this winter but:

Modern carbon bikes are so ridiculously fast there isn't any comparison at all, and that's 100% due to engineers and wind tunnels. Riding something like a System Six, which consistently tests as the fastest road bike, is absolutely and instantly noticeable as faster. Even around a parking lot. It isn't even close, and you don't need to be going 40-50km/h to notice. There's so much to love about steel bikes but pretending that carbon bikes do not have a LOT of science and design to them is naive and incorrect.

[Tandem Rider]

Originally Posted by BdaGhisallo

I also remember reading about some 7-11 pros being unable to differentiate between tube sets in otherwise identical frames and that Davis Phinney, said to enjoy stiffer frames as a sprinter, actually preferred a frame that measured as being less stiff than one that he rejected.

Being right behind Davis when he hit the gas is an experience to remember. There is a reason he went through so many bikes. The wheel would hit the frame the instant he jumped. I was always too crosseyed to tell if it was only the wheel flexing or only the frame flexing or (probably) both. Mid 80's wheels and frames are not renowned for stiffness despite that being a stated goal, especially by current standards.

[makoti]

Originally Posted by GregL

http://www.thetallcyclist.com/wp-con...Seven-Test.pdf

Well, of course that would have been in Bicycle Guide. What a smart, well written publication that was.

[martl]

Originally Posted by joevers

I understand why you're skeptical, and believe me I love everything about steel bikes. I race road, cross, and track on steel bikes, and have a stack of tubes and lugs in my basement I'm hoping to braze this winter but:

Modern carbon bikes are so ridiculously fast there isn't any comparison at all, and that's 100% due to engineers and wind tunnels. Riding something like a System Six, which consistently tests as the fastest road bike, is absolutely and instantly noticeable as faster. Even around a parking lot. It isn't even close, and you don't need to be going 40-50km/h to notice. There's so much to love about steel bikes but pretending that carbon bikes do not have a LOT of science and design to them is naive and incorrect.

I did not make a case for steel over cfk. CF offers way more possibilities to design a frame matched to the stress, thus it allows to build lighter (important) frames as well as more freedom in the shape of the frame (mostly optics).

I do not share your belief in modern bikes being faster on the road*) and i have a bit of a background in product test/engineering, enough to call bullsh* when i see 99% of the aero bike marketing, which is just as bogus as the "comfort" wave that preceeded it.

[Black Dog]

Originally Posted by martl

I did not make a case for steel over cfk. CF offers way more possibilities to design a frame matched to the stress, thus it allows to build lighter (important) frames as well as more freedom in the shape of the frame (mostly optics).

I do not share your belief in modern bikes being faster on the road and i have a bit of a background in product test/engineering, enough to call bullsh* when i see 99% of the aero bike marketing, which is just as bogus as the "comfort" wave that preceeded it.

Exactly. Claiming faster based on anecdotal observational bias and being faster based on real data are not one and the same. The difference in speed when, all else is the same, except for the frame (steel vs CF) are small.

[rallizes]

Always preferred Dario's "I am just a blacksmith" to some other builders' self-promotion

[coffeecherrypie]

Originally Posted by joevers

I understand why you're skeptical, and believe me I love everything about steel bikes. I race road, cross, and track on steel bikes, and have a stack of tubes and lugs in my basement I'm hoping to braze this winter but:

Modern carbon bikes are so ridiculously fast there isn't any comparison at all, and that's 100% due to engineers and wind tunnels. Riding something like a System Six, which consistently tests as the fastest road bike, is absolutely and instantly noticeable as faster. Even around a parking lot. It isn't even close, and you don't need to be going 40-50km/h to notice. There's so much to love about steel bikes but pretending that carbon bikes do not have a LOT of science and design to them is naive and incorrect.

How is a carbon bike going to be faster than a steel bike around a parking lot? I certainly believe it *feels* faster, but I doubt it *is* faster.

[.RJ]

Originally Posted by joevers

Modern carbon bikes are so ridiculously fast there isn't any comparison at all, and that's 100% due to engineers and wind tunnels. Riding something like a System Six, which consistently tests as the fastest road bike, is absolutely and instantly noticeable as faster. Even around a parking lot. It isn't even close, and you don't need to be going 40-50km/h to notice. There's so much to love about steel bikes but pretending that carbon bikes do not have a LOT of science and design to them is naive and incorrect.

Too bad with all that science they cant make a bike with tolerances that are worth a ****.

[joevers]

Originally Posted by martl

I do not share your belief in modern bikes being faster on the road and i have a bit of a background in product test/engineering, enough to call bullsh* when i see 99% of the aero bike marketing, which is just as bogus as the "comfort" wave that preceeded it.

If you don't believe riders who have ridden both, the engineers that designed the bike, and independently tested data, well I'm just not sure what to tell you.

Originally Posted by Black Dog

The difference in speed when all else is the same except for the frame (still vs CF) are small.

But all else is not the same. Carbon aero frames use different forks, different stems, handlebars, seatposts, cable routing etc. There are exceptionally few road bikes that even mention aerodynamics that currently use round tubes, round seatpost, normal stem and handlebars, and "normal" cable/hose/wire routing. Look at the S5, look at the new Tarmac, the Supersix, the System Six.

https://www.bikeradar.com/features/p...-france-bikes/

Look, I enjoy steel bikes a lot, but pretending that carbon bikes use fake science is just not factual. There's really an incredible amount of design that goes into those bikes by engineers. It's not marketing and design interns at Specialized drawing fun shapes on scrap paper and voting on which ones look fastest and will make the most money. It's been determined that aerodynamics play a huge, huge role in bike speed, and it's been determined that round tubes are objectively slower.

Admittedly a parking lot may not have been a good example, but test ride any modern carbon aero bike coming from a steel bike and it will get up to speed quicker and be much less energy to hold that speed. I'm not saying you have to like it more or buy one. I didn't realize aerodynamics were still controversial. I currently have 4 steel bikes, and I'll tell you that I could absolutely go faster or go the same speed for less effort if I switched them to aero-focused carbon bikes. I work at a higher end road oriented shop and test ride high end bikes all the time. I've gone to brands' events to ride for an extended amount of time their high end carbon road bikes. I'm telling you they are all easier to accelerate, and easier to reach and maintain a higher speed than my Gunnar road bike with Enve 3.4's.

[.RJ]

Originally Posted by joevers

Look, I enjoy steel bikes a lot, but pretending that carbon bikes use fake science is just not factual. There's really an incredible amount of design that goes into those bikes by engineers. It's not marketing and design interns at Specialized drawing fun shapes on scrap paper and voting on which ones look fastest and will make the most money.

Other than Specialized, Trek and maybe a few others, it sort of is that way though, its following trends and marketing, and the aero profiles have been around for over 50 years. Most of the companies dont design their own carbon layup schedules, and have to defer to the factory's engineers to figure out how to make it. But hey, if they can charge $10k for these bikes, then good for them.

You're right that they're faster, though.

[flying]

Originally Posted by qnz

With carbon frames from big name companies, they test the frame in wind tunnels and have teams riding the frames to provide feedback.

I think the reality is they have teams riding their frames to provide advertising nothing more

Feedback is free anywhere. Ask any magazine to ride they are happy for the review

Or hire one GT winner is much cheaper than a team or two.

Companies sponsor for the advertising & banking on the fact rec riders will dream/imagine they are just like X-Team or rider if they have this brand

[jpw]

Won't additive manufacture eventually allow big builders to offer personalised geometry to each customer? Might it even end the stock geo business model?

[prototoast]

Originally Posted by jpw

Won't additive manufacture eventually allow big builders to offer personalised geometry to each customer? Might it even end the stock geo business model?

Yes and no. I would expect in my lifetime, the big brands will have a personalized geometry option via additive manufacturing, but there are still going to be a lot of people who want to walk into a shop, test a few bikes, and walk out of the shop with a bike in their hands. Stock geometry won't die, but custom geometry could become a larger part of the market. Right now, I'd guess custom geometry is < 0.1 % of all bikes sold--if that expanded to 5%, that would be a huge jump in custom, but still a small part of the overall.