elcruxio

Yeah forgot to comment on this one.

You were an engineer right? How is that you don't account for geometry when discussing stiffness/rigidity? Steel is three times stronger and three times stiffer than aluminum, but an aluminum piece three times thicker than a steel piece is far stiffer than the steel because of the effect geometry has on stiffness. I-beams are a great example of this.
So if you get an aluminum fork with three times the wall thickness of the steel fork you get the same strength (or actually likely more) but the aluminum fork is much stiffer. So to get the same amount of flex you'd need to sacrifice strength. So it actually does make sense to at least use a steel fork, preferrably with bent blades to further increase the flexing effect.

Sy Reene

They can still be found.. Eg. Ribble offers reynolds 725 versions of their road and gravel bikes.
Much I'm sure has to do with margins for the manufacturers. To make a budget cro-mo frame (eg. like the ribble), probably costs more than making a budget CF frame, while the cache of CF means exacting a higher selling price (plus the buyer has benefit of a likely lower weight bike).

Leinster

I would think if a CF bike cost less to build than a CrMo bike, the RRP for the carbon bike would also be less. Otherwise a manufacturer somewhere is missing a trick, and losing out on sales, if everyone automatically adds a markup to their carbon frames.

cyccommute 

But if you ask bicycle tourist why they pick steel, high on the list is the (supposed) repairability of steel over aluminum.

So why pick heavy steel over light aluminum? I agree that people probably won’t have a frame fixed on tour so picking steel because it is “repairable” is more of a romantic notion than a reality.

You do know that the same schools that teach welding teach people how to weld aluminum as well, don’t you? MIG and TIG welding were invented for aluminum. Aluminum can be brazed as well. There are a multitude of techniques that can be used for both materials.

The need to heat treat depends on several factors. Tube joining requires heat treatment because of the heat applied. Crack repair is quick and affects a smaller area. Repairs on broken both steel and aluminum frames should be considered temporary.

I’m not sure what your point is but I agree that none of it really matters. Both materials can work well for touring bikes but one is looked down upon mostly because of ignorance.

The reason for the few aluminum touring bikes being offered is because of that romantic village smithy repair scenario. Bicycle tourists don’t want to buy aluminum because they think the material is inferior so aluminum touring bikes don’t get made. Because they don’t get made, people don’t buy them and steel bikes keep getting made. Gravel biking and adventure bikes are changing that but touring bicyclists are a curmudgeonly bunch.

Oh, please! Just because someone rides one of the few aluminum touring bikes that do get made doesn’t mean that they aren’t “real” bicycle tourist. Cannondale made touring bikes for nearly 30 years that have been ridden all over the world in the same places as steel touring bikes have. I have 10,000 miles of tradition loaded touring on two Cannondale touring bikes (one about 8000 miles). I have another aluminum road bike that has 25,000 miles on it. They are tough bikes.

Don’t make out steel to be more than it is. Aluminum may not be impervious but neither is steel. Riding a bike into a mountain (or a wall or a car) is usually going to result in damage to the bike. I have a pretzeled frame in my garage (and a very ugly scar on my knee) from an encounter with a car nearly 40 years ago. The frame material wouldn’t have made any difference in terms of how the bike did,,,or didn’t...survive the crash.

I‘ve also crashed aluminum bikes more times than I can number without damaging the frames. Frame damage is more dependent on the speed and angle of impact than the material.

I’ve ridden and heard many creaky steel bikes. Creaks aren’t do to the material, they are due to the parts in the frame. Creaky bottom brackets are due to loose bottom bracket not the frame material.

Millions of mountain bike riders have a thing or two to say about the “weakness” of aluminum. Steel isn’t as hard to break as you seem to think. I’ve broken both...multiple and equal times. I’ve had a steel mountain bike that broke at the steer tube at fork crown, cracked at the chainstay bridge, broke at the dropout, and finally cracked a second time outside of the weld repair at the chainstay bridge (so much for steel welds holding up over time). I had another steel mountain bike that broke at the rear dropout. I didn’t even attempt to get that one welded since Specialized replaced it no questions asked.

I have also had an aluminum frame...an aluminum/boron Specialized M2 frame...that cracked in the same place as the steel bike. Again, it was replaced without question by Specialized. I also broke an aluminum frame because I put a HellBent seatpost with massive set back on the frame. That’s the one that was welded and I never had another issue with it.

Finally, if aluminum is as weak as you seem to think it is, do you tour on steel rimmed wheels with steel hubs? Do you tour with steel handlebars, steel cranks, all steel pedals, and steel brakes? If you fear the weakness of aluminum, why not? I’ve broken aluminum versions of almost all of them but I don’t fear that they will break on me to the point where I would trade them for steel versions.

Sy Reene

I think it's definite that a CF bike costs less to make. However, the manufacturers are selling on the features/benefits.. a CF bike will weigh less and has perception of being the modern and more exotic of materials, and it weighs less. So these bikes can sell for more and the manufacturers have much better margins. Maybe it's like helmets.. I can't imagine that eg. a MIPS helmet with more venting (holes) and thinner foam lining really cost much more to make than the heavier weight MIPs models, but you see some of these at 3-4x the cost from the same manufacturer.

The CroMo bikes exist because they can fill a pricepoint tier in their product lineup for buyers with low budgets. Selling a CF for less would mean they have to diminish pricing across their higher end lineup, or offer CF bikes with garbage groupsets.

dedhed

Dropouts are replaceable.
How many threads do we also see here where people can't find, or wait weeks for a replacement hanger?

dvaid

Can't really see how a bike frane is like a wrist watch. Not really passionate about it either. I guess really high end exotic materials bikes will ride and perform much better than a steel bike, notwithstanding any consideration of durability. On the other hand if I had to choose between an allie or steel bike in same (medium) price range it would be steel every time accepting all the frames were well made in the first place.

Leinster

I don't follow the economic logic of that. If I, as a manufacturer, can assemble 1,000 carbon frames for less than the price of assembling 1,000 steel frames, and could then equip both models with the same spec components, (by buying 2,000 wheelsets, groupsets, finishing kits etc) surely I should sell the CF bike for less, or risk being undercut by another manufacturer, who has access to the same OEM pricing on all accessories (let's say for argument's sake that we're not talking about Giant or Specialized who can make basically the whole bike in-house).

unterhausen

I don't think it's correct to make a blanket statement that CF is cheaper to manufacture than steel. The cheapest bikes are steel. There are some really inexpensive carbon forks, but they are quite heavy. Lightweight steel bikes might cost more to make than inexpensive carbon, and required testing is biased against steel. But all materials cost less to make than most of us think.

Sy Reene

Because each brand is maximizing profit.. and they want a lineup where they can offer options that range from eg. $1k to $10k. They sell what the market will bear. Pinarello is undercut by BikesDirect, but their bikes with similar groupsets don't have frames that really cost eg. $5k more to make. Bike jerseys are all made of of some version of polyester... but you can find some $30 models and some $200+ models.

Use these 2 examples linked below.. trying to find something in the same brand and similar component spec.
I'd strongly wager that the frame and component cost for either is almost identical, and I do think it's highly possible the CF frame is sourced at an actually lower price than the 725 version. Sure, they may well be able to lower the CF version cost, but they simply probably have found they don't need to in order to sell the most units at highest margin they feel their brand can get away with.. comparing themselves with the rest of the market offerings and the considering their own brand value.

Ribble CroMo
Ribble CF

cyccommute 

In what world are dropouts replaceable? Not the derailer hanger but the forged dropout.

cyccommute 

Not with current manufacturing methods. Carbon fiber doesn’t lend itself well to automated manufacturing. There is still a lot of hand work needed for carbon fiber bicycle frames. The reason that a small steel (or titanium) manufacturer charges a lot for a frame is because of the hand work, not the materials.

Carbon fiber is also an expensive material. It costs around $15 per pound compared to steel and aluminum which are less than a dollar per pound. The price of CF has come down a lot but it is still fairly expensive as a material.

Leinster

I think that's purely an assumption on your part.

I can believe that the difference in Ribble's cost between the 2 framesets is less than the difference between the 2 MSRPs, but I find it hard to believe that they would be making CF frames for less than steel, AND being the only ones who would have worked out how to do that. Because if they have $200+ clear that they can charge for their carbon frames, then other bike makers would settle for $150 there to ship more units of their bikes.

If high-end carbon retails at higher prices than off-the-shelf high-end steel, (and it does) then it's likely that a reason for that is that it costs more to build a carbon frame. Probably for most of the reasons Cyccommute outlines above.

Sy Reene

I think you need to distinguish material cost.. are you comparing the cost of CF and Resin to eg. triple butted CroMo tubing. If just raw material, it's kinda meaningless, as you're talking about 2-3 lbs of raw material.. it's not going to explain 100s or 1000s of dollar of price difference.

Hard to get at the data, but maybe shop around on Aliexpress and see where Reynolds 725 frames are priced out vs. CF frames

And for assembly are you considering welding costs in the steel assembly scenario (or assuming everything is machine welded)?

dedhed

On steel bikes, in the real world. Straightened, welded, replaced all happen. A search in C&V shows numerous threads of repaired or replaced. I've personally sent an old dropout off a trashed frame to a BF member who had it brazed in to repair his old Trek.
Simple, easy, unbraze, braze in new one, align.
Any frame builder and many shops will do it.

More Varieties of Frame End Repair at Yellow Jersey

drlogik 

+1 Steel is real.

son_of_clyde

I don't know much about material science, but are there frequency response plots (Bode plots) available for various materials. Seems like it would be a good way to quantify vibration damping characteristics of different frame materials/shapes.

Trakhak

Tubing diameter far outweighs material choice as a factor in vibration damping in bike frames. Steel is denser than aluminum and thus damps vibration comparatively poorly, which is why steel rather than aluminum is used to manufacture bells.

In the early days of aluminum bike frame manufacturing, when Vitus and Alan were building frames with thick aluminum tubes of the same outer diameter as conventional steel frames, their aluminum frames were known to be much more flexible and shock-absorptive than the steel frames of the day.

That said, discussions of this and other differences between steel and aluminum bike frames miss the point. The OP asked for explanations of why aluminum bike frames have effectively supplanted steel frames in the market. The answer, tautological though it seems, is that the market moved on, as markets will. Clearly, the supposed shortcomings of aluminum and supposed superiority of steel were not significant enough factors for steel to maintain a significant share of bike sales, arguments from steel proponents on BikeForums notwithstanding.

Koyote

As others have pointed out, the premise of the original post is faulty: there are plenty of chro-moly frames being produced out there.

Sy Reene

You're right that it's a guess.. but I think it helps explain why you can often find extreme pricing swings/sales on CF frames such as linked.
You won't typically ever be able to find a steel/cromo frame that can suffer a $2k price discount

R5 DISC FRAMESET

dmark 

Steel had little competition until roughly the 90's.
Carbon, titanium and more aluminum were available in the 80's but with the end of the cold war production technology for consumer goods improved faster in the 90's making steel alternatives competitive on cost.
New, different and lighter are always good marketing points.

cyccommute 

This is the main sticking point to the “dropouts can be replaced” comment. If the frame is of brazed construction it might be replaceable. Replacement on a brazed frame would depend on how much the owner is willing to spend. Not all brazed frames are worth the cost.

If the frame is welded ...which is how the vast number of frames of either steel or aluminum are made...replacing the dropout isn’t usually an option. You can’t really just heat it to remove the dropout like you can with brazing. You would need to cut the dropout out, drill out or cut out the dropout tab in the frame tubes, clean up the ends, and then weld in a new piece. It would also be something that is going to require significant frame alignment. Most welded frames of any material just aren’t worth the expense if it can even be done.

branko_76 

I have almost zero knowledge of modern bikes, frames, components, etc.

What are the alternatives and what makes them so much better?

phughes

Yes, but if people accepted indisputable fact that the premise of the OP is faulty, there would be noting for people to argue about.

Trakhak

If by "plenty" you mean between 1% and 4% of annual U.S. bike sales, the overwhelming majority being aluminum, then, yes, there are plenty of chro-moly bikes being produced out there.