Why It's Impossible For Steel Frames To Be More Comfortable Than Aluminium

[ichitan]

You may hear that steel or titanium bike frames are more comfortable than aluminum, because they absorb the bumps or vibrations better. This may sometimes be used for marketing. It is not true. Following are two videos from different sources explaining this.

https://www.youtube.com/watch?v=Lb4ktAbmr_4

https://www.youtube.com/watch?v=1CTjg1TFHDc

[ReapThaWhirlwind]

Being more rigid would mean they don't absorb the vibrations, but they're transferred more proficiently to the end points; or points of flexation.

That's the experience I have with steel frames.

Where they tend to excel is where you don't get lots of bumps, and thus the rigidity makes more greater power transfer; such as with the depth of bike rims. Nothing makes as big a difference in the performance of bike wheels as this.

[Frankly]

(11-20-2023, 02:58 AM)ichitan Wrote:  You may hear that steel or titanium bike frames are more comfortable than aluminum, because they absorb the bumps or vibrations better. This may sometimes be used for marketing. It is not true. Following are two videos from different sources explaining this.

https://www.youtube.com/watch?v=Lb4ktAbmr_4

https://www.youtube.com/watch?v=1CTjg1TFHDc

Well yes and no.
1. Almost all vertical compliance is in the tires. So the frame has no effect on this and tire pressure does.
2. Measuring vertical compliance of a frame using a steady state force is not a real world condition. Out here on planet Earth, we do not have a constant force but shock loads. Steel has a lot higher shock compliance than aluminum or titanium. Steel frames should have an aluminum seatpost because the sharp rear edge is known to cut and break carbon fiber seat posts though I admit that I have never had that happen. But a very experienced team mechanic told me so.
3. You and I do not ride racing bikes that are significantly smaller than a proper fitting production bike. Those custom fit bikes are designed to keep the racer out of the wind and the production bikes are designed to be somewhat comfortable to ride. So the exposed seatpost is much shorter and flex is less.

With these facts in mind steel bikes are very slightly better than aluminum or titanium but in actual riding I can't tell the difference except when hitting pretty dramatic potholes. The tires with the proper pressure in them (see Silca's pressure calculator) absorb nearly all of the shocks except for those potholes though riding Paris--Roubaix cobbles might be a different story. My steel bikes especially my last version of the steel Basso Loto seem to handle shocks better. But that could be the addition of the curved fork. Another bad pro racing note for the sports rider is the straight fork and super solid construction which is hard on the carbon fiber construction. But they are using carbon fiber under the most trying conditions now without suspicious behavior problems. Though I have been told that they do not focus the camera on major frame failures.

New custom steel frames can weigh less than a kilogram from the lightest carbon fiber so I wouldn't consider weight a problem. I was riding a heavy John Slawta Road Shark for a long time and it was not a problem except for the longest steepest climbs when I would become exhausted before the others in the group.

One of the problems I have had with all very light bikes is that under extreme pressure (descending a high speeds around bends) the bike could start steering itself. I went into a ditch because of that and cracked a carbon fiber fork on a C40.

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(11-20-2023, 02:29 PM)ReapThaWhirlwind Wrote:  Being more rigid would mean they don't absorb the vibrations, but they're transferred more proficiently to the end points; or points of flexation.

That's the experience I have with steel frames.

Where they tend to excel is where you don't get lots of bumps, and thus the rigidity makes more greater power transfer; such as with the depth of bike rims. Nothing makes as big a difference in the performance of bike wheels as this.

Back when we all used 120 psi 23 mm tires that was a problem but even 25's at 90 psi don't allow road vibrations through and now we're all riding 28's or even fatter.

[froze]

All I can say is what my personal experiences have been. I have 7 steel road bikes, not including a touring bike since that is technically not a road bike, and I have a titanium road bike, and I used to have a scandium road bike.

The harshest riding bike I had was the Scandium, while it was a racing bike the geometry was not as tight as one of my older steel racing bikes. The steel one was so tight that I had to deflate the rear 23c tire to get it to clear the seat tube, and then it took a little squashing of the tire to do so, whereas with the scandium wasn't necessary. That bike felt as if I was riding on Fred Flintstone's stone wheels, that's how bad it rode.

The most comfortable riding bike I've ever had is the titanium bike. That TI bike has deeper dish wheels than any of my other bikes, so those wheels should feel harsher riding, but I guess the TI mutes it?

Before I bought the TI bike I test-rode a lot of bikes, including riding two friends' TI bikes, and that constant factor was the TI bikes were more comfortable, so after a year of trying bikes while waiting for the right sale, I opted for a TI bike.

While none of the bikes have the same wheels, they have on occasion a couple used the same tires, because when a really good sale is found I'll buy 2 pairs, and one ends up on one bike and the other on another. I always use the same PSI in the same size tire. Since my steel road bikes are older I have swapped wheelsets between some of them and never noticed anything doing that.

I don't know about those videos, all I know is what I've experienced, not what they've experienced. I also know that my 2 friends with their TI bikes all said the same thing, the TI bikes were more comfortable to ride than any of their other bikes. I'm not trying to argue against what anyone else has said, just telling you what my experiences were.

[meamoantonio]

recently shifted from an Aluminum frame to a Steel Frame bike. Vibrations really do feel dampened, I only noticed it after the first ride and every time I switch back to the aluminum frame, both bikes have carbon forks too. Maybe its one of those you have to experience it for yourself even if scientific literature says otherwise