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-   -   Science behind the steele frame (https://www.bikeforums.net/classic-vintage/1211646-science-behind-steele-frame.html)

steve sumner 08-30-20 11:13 AM

BITD I think it was Tom Ritchey who said: a really good road bike is supposed to react like a spring
you don't make springs out of aluminum" that springy, resiliant, alive feel only comes from steel or titane
bikes alu-alloy and carbon fibre will feel dead. but the rider who only wants lightness combined with
stiffness will sadly never have the time or inclination to feel it

alcjphil 08-30-20 11:37 AM

The stiffest, least comfortable bike I own is made of steel. It is pretty much unrideable with tires less than 30 mm width. The most comfortable lively bike I own is carbon fibre, nothing dead feeling about it

xroadcharlie 08-30-20 12:43 PM

Perhaps one reason steel bikes are preffered by some people is because when aluminum frames where introduced the low end ones used larger, thick diameter tubes to compensate for the reduced strength of aluminum vs steel by volume. This design regardless of material makes for a stiffer frame.

Also, Steel is springy, Aluminum much less so, but absorbs more vibration. A well designed carbon frame might offer an almost perfect ballance of absorbing vibration, feel/springyness and low weight, and why it is the gold standard for performance road/gravel bikes.

gthomson 08-30-20 02:05 PM

Korina Interesting videos, thanks for sharing.

I will agree my OP was a loaded comment/question considering the audience but I wanted to get some facts behind my statement that steele is a good frame material (note I didn't say better) acknowledging that there are many other factors. I guess I have forgotten what a real crappy bike rides. like the ones I had as a kid. I guess I could head over to a big box store and take one of those bikes out for a spin. I did also change my wheels recently on my vintage steele bike and that's made a big difference in the ride.

Trakhak 08-30-20 02:32 PM

Curious how people are now obsessed with fitting the widest tires possible in their vintage steel bikes. Apparently not quite comfortable enough.

As I've mentioned on this site several times before, I rode pro-level steel bikes for racing and training from 1965 to 2005, when I bought my first aluminum bike. I may have ridden a couple of my steel bikes (Reynolds 531 or 853; all the Columbus SL or SP bikes are gone) a few times since then, but they're all collecting dust in the basement these days.

As Sheldon Brown wisely said, in response to a question on the topic of frame material and comfort,

"A bicycle frame is made up of triangles, and there is no compressibility in the frame members whatever they're made of. You've fallen for folklore. . . . Ride comfort is much more affected by geometry, saddle type, and, even more important, tire choice/pressure."

I still like looking at beautifully painted steel bikes, but I choose aluminum for every ride (4 hours yesterday and 4 hours today; no fillings lost).

skier 08-30-20 02:46 PM


Originally Posted by xroadcharlie (Post 21668906)
Perhaps one reason steel bikes are preffered by some people is because when aluminum frames where introduced the low end ones used larger, thick diameter tubes to compensate for the reduced strength of aluminum vs steel by volume. This design regardless of material makes for a stiffer frame.

Just to add the the great reply here, it’s also worth nothing the steels have a knee in the S-N curve where you can essentially achieve “infinite life” if you stay below a certain stress level. Composites can also be designed to not be impacted by fatigue.

Aluminum (and titanium) do not and can fatigue over time which can also play into the tubing size and design margins.

xroadcharlie 08-30-20 03:59 PM


Originally Posted by skier (Post 21669071)
Just to add the the great reply here, it’s also worth nothing the steels have a knee in the S-N curve where you can essentially achieve “infinite life” if you stay below a certain stress level. Composites can also be designed to not be impacted by fatigue.

Aluminum (and titanium) do not and can fatigue over time which can also play into the tubing size and design margins.

That might explain why we don't see many aluminum springs. But some cars do have composite springs...Fiberglass specifically.

conspiratemus1 08-30-20 05:44 PM


Originally Posted by gthomson (Post 21669012)
. . . I wanted to get some facts behind my statement that steele is a good frame material. . . I did also change my wheels recently on my vintage steele bike and that's made a big difference in the ride.

Sorry you didn’t get the joke in post #13 .

gthomson 08-30-20 06:19 PM


Originally Posted by conspiratemus1 (Post 21669340)
Sorry you didn’t get the joke in post #13 .

Remington Steele?.

conspiratemus1 08-30-20 06:46 PM


Originally Posted by Trakhak (Post 21669055)
Curious how people are now obsessed with fitting the widest tires possible in their vintage steel bikes. Apparently not quite comfortable enough.
[heh, heh, good zinger. Steel is real when it suits us, but rubber rocks when the going gets tough.]

As Sheldon Brown wisely said, in response to a question on the topic of frame material and comfort,

"A bicycle frame is made up of triangles, and there is no compressibility in the frame members whatever they're made of. You've fallen for folklore. . . . Ride comfort is much more affected by geometry, saddle type, and, even more important, tire choice/pressure.” . . .

This is not correct. An ideal triangle cannot shorten any side but this assumes the sides and joints cannot bend — if a line segment bends, the polygon is no longer a triangle as there are now four angles and sides or else one side becomes a curve. So this geometric precept involves some question-begging. Real triangles do deform under load and the degree to which they resist, spring back or even begin to vibrate in resonance depends on the factors Mr. Brown mentioned, but also the material, which he wants to debunk. Make a triangle out of solid copper wire with the joints soldered. If you push in one side ,the other two sides bend in to compensate. That would not make a vey good bicycle, or a bridge, or any other triangulated structure. The same mass of copper formed into hollow tubing would be stiffer but no stronger. Using steel, or polystyrene plastic for the triangles would give different properties again.

OK, this is reductio ad absurdum but my point is the role of material in a bike frame (or a bridge or an orthopedic implant) cannot be dismissed just by saying triangles can’t deform, because they do. As the owner (but never racer beyond sprinting for road signs) of several high quality steel bikes I am prepared to admit the only reason to prefer them over newer materials is that they are much cheaper and fit at a sweeter spot on my personal marginal utility curve. And I have actually ridden one or two CF frames short distances. Impressed but not blown away, for the price.

And the risk of asplosion.

rosefarts 08-30-20 07:18 PM

So I've mentioned this in other threads. I'll mention it here too.

In my racing days, I got relatively cheap aluminum frames, slapped Ultegra or Dura Ace on them, and away we went. They were fast, responsive, and light. Maybe they rode rough on 23's @ 120psi but I was like 24, who cares. They weren't sought after or special.

Lately, being done with racing I've been riding high end steel or custom made steel. There is no question that they ride better and are more comfortable. It's probably not frame material but frame quality. We also know more about tires now, so the standard 25-28 certainly help. It really isn't a fair comparison.

I did end my racing on a Litespeed Vortex. Around 2005-6. I hated that bike. It was squirrelly and slow.

FlemmingM 08-31-20 01:31 AM

Mike Burrows take on frame materials:

I think the classic steel bike looks the best! And especially I have a soft spot for lo pros. The biggest advantage of carbon fiber, beside the strength-weight ratio, is the form freedom it gives the designer. The UCI rules have kept designers from using this advantage, and thereby keeping the difference between the materials smaller.
Maybe my fascination of the lo pros is also the reason I find modern triathlon bikes far more interesting than modern road bikes (interesting is far from equal to beautiful...).

xroadcharlie 08-31-20 07:22 AM

Steel does seem to be an excellent choice for bike frames, Perhaps better then alluminum if we use good steel tubing (like thinwall cromoly).

Is it possible that the bicycle industry's marketing team had worked overtime, and sucessesfly convinced average consumers that alluminum bikes are better then steel to boost sales.

Then theres manufacturing cost. I'm not an engineer, But it wouldn't surprise me if it was less expensive to build good quality, inexpensive alluminum bikes then steel ones with the tighter tolerances and careful welding needed for thin tubing.

And while we could, and someone probably does build high quality, performance steel frame bikes to this day that might rival some carbon frame ones, Carbon might be the best choice for mass production.

Trakhak 08-31-20 08:02 AM


Originally Posted by xroadcharlie (Post 21670001)
Steel does seem to be an excellent choice for bike frames, Perhaps better then alluminum if we use good steel tubing (like thinwall cromoly).

Is it possible that the bicycle industry's marketing team had worked overtime, and sucessesfly convinced average consumers that alluminum bikes are better then steel to boost sales.

Then theres manufacturing cost. I'm not an engineer, But it wouldn't surprise me if it was less expensive to build good quality, inexpensive alluminum bikes then steel ones with the tighter tolerances and careful welding needed for thin tubing.

And while we could, and someone probably does build high quality, performance steel frame bikes to this day that might rival some carbon frame ones, Carbon might be the best choice for mass production.

Back in the early '90s, the Trek sales rep who regularly visited our bike shop mentioned in passing that they were spending much less on frame warranty replacement since their aluminum frames had come to dominate their sales. That would be a big motivator for any manufacturer.

Bimmer69 08-31-20 08:35 AM

I thought it would have been racing that would influence the move to aluminum and CF.
would they not want to shave every last gram of weight for that bit of competitive edge?

I do agree, as a non competitive rider steel is my daily ride.

old's'cool 08-31-20 07:28 PM

A premise has been made, that the tubes of a frame triangle provide compliance by bowing, i.e. pre-buckling, which I question. A mathematical analysis would show how much bowing would be needed to provide the equivalent of a compliant suspension, and I suspect it would also show that not only aluminum, but also steel and titanium frames would be in a fatigue regime if they were bowing to such an extent. So, I tend to agree with Sheldon about the compressibility of the frame triangle.
I will grant that a steel tubing frame will twist more than one of aluminum tubing, under the same torque loading and when designed for the same mission with the same skill and resources.

conspiratemus1 09-01-20 12:15 PM

I think I agree that a triangular bike frame cannot bow from vertical loads with anywhere near the amplitude of a compliant suspension. (Steel forks, which are not triangulated, do move enough that it has to be considered in avoiding the tire interfering with fenders or handlebar bags on rough roads.). I was thinking more about the tiny movements set up in the frame members which each impact, which can’t be seen even if they can be felt. If you strike a hard-thrown baseball with the wrong part of the bat, the vibrations transmitted to your hands are painful. A hit in the sweet spot is painless (and will more likely result in a base hit.) My thought was that different materials might be expected to handle these low-amplitude, high-frequency vibrations from road roughness differently, with the differences perceived as “lively”, “dead”, or “harsh” with “notes of assertiveness without overpowering fruitiness” :rolleyes:. And these vibrations must be propagated through the frame tubes by tiny compression-rarefaction deformations of the (triangulated) frame material.

Dick Chainey 09-01-20 12:36 PM


Originally Posted by conspiratemus1 (Post 21669434)
An ideal triangle cannot shorten any side but this assumes the sides and joints cannot bend — if a line segment bends, the polygon is no longer a triangle as there are now four angles and sides or else one side becomes a curve. So this geometric precept involves some question-begging.

Indeed, and there's a distinct difference between triangles and "triangles."

https://cimg8.ibsrv.net/gimg/bikefor...506fd3566.jpeg

Sluggo 09-01-20 12:38 PM

The article in this link shows measured data that supports Sheldon's (and Trakhak's) statements with some discussion and caveats: There is not a significant amount of vertical compliance in triangulated frame. Tires (and maybe fork) are the only suspension you have.

conspiratemus1 09-01-20 01:37 PM

N

Originally Posted by Sluggo (Post 21672486)
The article in this link shows measured data that supports Sheldon's (and Trakhak's) statements with some discussion and caveats: There is not a significant amount of vertical compliance in triangulated frame. Tires (and maybe fork) are the only suspension you have.

Thanks. Not surprised by his results and expectation/perception bias (aka placebo effect when you’ve spent money on something) is undoubtedly decisive in the macro sense. But in the micro sense, does the difference between “twanggg” and “klok” matter more than as acoustic cues to the placebo expectation?

ofajen 09-01-20 02:01 PM

I’ve only owned and ridden steel frame bikes, so I’m no authority on comparing frame materials. OTOH, I do appreciate the fact that perfectly rideable low-end steel frames from the 80s are nearly free these days.

That said, I suspect my ride comfort comes mostly from riding technique, bike fit and choice of tire width and pressure.

Otto

70sSanO 09-01-20 02:28 PM

I’m sure everyone realizes that posting this question on a C&V subforum will yield the expected results.

John

vespasianus 09-01-20 07:29 PM


Originally Posted by steve sumner (Post 21668778)
BITD I think it was Tom Ritchey who said: a really good road bike is supposed to react like a spring
you don't make springs out of aluminum" that springy, resiliant, alive feel only comes from steel or titane
bikes alu-alloy and carbon fibre will feel dead. but the rider who only wants lightness combined with
stiffness will sadly never have the time or inclination to feel it

There are a lot of "steel" builders that have forgotten this.

PhotonDon 09-01-20 10:00 PM

My 531 TREK 760 from1985 may be my favorite bike from an overall ride perspective. Just the right amount of springiness for this 210 lb frame., But my favorite attribute may be the quiet ride I can achieve on steel that I can't match on my Ti, CF, or AL bikes. Its akin to just floating, and since I'm old and will never again be fast or go for long days in the saddle, the quality ride of ferrous still makes me happy. At the end of the day, or the end of a two hour ride, Im reminded, THIS is what a bicycle should look like. Your experience may vary.

Russ Roth 09-01-20 10:58 PM

Materials matter some and shape matters some. I've got a nice carbon frame that rides about as nice as any steel bike I've ever owned, on the other hand I recently threw a leg over a rock lobster and I think it rides better then any other bike I've ever ridden and that's even after owning two DeRosas that fully convinced me the mantra that nothing rides like Derosa was a truth. I was turned off of aluminum by a trek 2300 and a schwinn fastback pro that I demo'd the first year they came out. Both had me thinking I was going to die, especially the Schwinn constantly going airborne on a rough curvy mountain descent at 50+mph. Yet I've hopped on aluminum since that was a joy to ride. Steel is real; real nice, real comfortable and real heavy but it is a legacy material that still works in this modern world to make a top notch bike for whatever purpose you need it for. But I wouldn't shun any other material on the claim its inferior, I've ridden them all; I love my steel, the carbon is sweet and I miss my Ti Litespeed classic. Just get the bike that fits your form and purpose best.


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