Carbon frame

[boydj]

Cannondale have proven that aluminium bikes can be comfortable. Carbon can be tuned to give the bike whatever characteristics the manufacturer wants. Quality double-butted steel or titanium frames can be racing stiff or touring comfortable. Whatever the material, quality counts. The modern trend for wider rims and tyres ridden at lower pressures will improve the ride for most bikes.

 

[Randomnerd]

So the 'steel is real' thing is, to the best of my understanding, blx.

Well, it isn’t. A lugged steel frame of high quality flexes and rides quite differently from a high quality carbon frame.

 

[SheilaH]

Carbon can be tuned to give the bike whatever characteristics the manufacturer wants.

That is what the marketing says. The reality is very different. It is enormously difficult to do in reality, and very easy to get wrong, especially is one of the characteristics the manufacter wants is cheapness.

Quality double-butted steel or titanium frames can be racing stiff or touring comfortable

But they can't be stiff and light

 

[SheilaH]

Well, it isn’t. A lugged steel frame of high quality flexes and rides quite differently from a high quality carbon frame.

No different to Ti or aluminium. You can build a flexy frame in any material, but with steel it will also be heavy regardless of the compliance.

 

[boydj]

That is what the marketing says. The reality is very different. It is enormously difficult to do in reality, and very easy to get wrong, especially is one of the characteristics the manufacter wants is cheapness.

But they can't be stiff and light

Why not? We're not talking about cheap bikes here. We're talking about relatively light for steel, and titanium is lighter than steel anyway. I'm sure the steel bikes that TdF riders were using until other materials became available were both light and stiff compared to bikes more readily available to the man in the street.

 

[SkipdiverJohn]

I'm sure the steel bikes that TdF riders were using until other materials became available were both light and stiff compared to bikes more readily available to the man in the street.

All things being equal, size-for-size, a lightweight racing steel frame will be more flexible than a gas pipe frame, despite it being possibly over twice as strong per unit weight of material in terms of how much you can load it before structural failure occurs.
If you take material out of a steel frame by double butting, or just using thinner wall plain gauge tubes, if the outer tube diameters remain constant then you make the frame both lighter and more flexible.
I have two steel frames that are absolutely identical in both design , geometry, and size, except one is plain hi-tensile and one is butted Reynolds tubing. The butted frame is slightly lighter and rides slightly differently - subjectively more comfortable.
There are three ways you get a stiffer frame, you use more material, you use larger section tubes, or you use tube shapes that resist bending forces better. In a traditional steel road frame you can't/don't do either of the last two, which only leaves using more steel if you want more stiffness.
The thing is though, so long as the frame doesn't flex so much that the front and rear wheels run significantly out of line with each other, why would you even want the frame to be that stiff? When a frame flexes, almost all the energy it takes to flex it is merely stored, and is subsequently returned as motion when the cyclically applied force is removed. Hardly any energy is actually dissipated as heat, so there is no real efficiency benefit to making a frame stiff.

 

[monkers]

All things being equal, size-for-size, a lightweight racing steel frame will be more flexible than a gas pipe frame, despite it being possibly over twice as strong per unit weight of material in terms of how much you can load it before structural failure occurs.
If you take material out of a steel frame by double butting, or just using thinner wall plain gauge tubes, if the outer tube diameters remain constant then you make the frame both lighter and more flexible.
I have two steel frames that are absolutely identical in both design , geometry, and size, except one is plain hi-tensile and one is butted Reynolds tubing. The butted frame is slightly lighter and rides slightly differently - subjectively more comfortable.
There are three ways you get a stiffer frame, you use more material, you use larger section tubes, or you use tube shapes that resist bending forces better. In a traditional steel road frame you can't/don't do either of the last two, which only leaves using more steel if you want more stiffness.
The thing is though, so long as the frame doesn't flex so much that the front and rear wheels run significantly out of line with each other, why would you even want the frame to be that stiff? When a frame flexes, almost all the energy it takes to flex it is merely stored, and is subsequently returned as motion when the cyclically applied force is removed. Hardly any energy is actually dissipated as heat, so there is no real efficiency benefit to making a frame stiff.

Ah well, there is some difference in the analysis of stored energy in a system such as frame under torsion, than there is the stored energy in a deformed material such as compression in a chainstay. As many profiles on a dating site will say - 'it's complicated'.

 

[Eribiste]

I thought a road buzz was one of those public service vehicles that pull away from the kerb just as I'm riding past them. Or is that a rude buzz.

 

[Chislenko]

Just my tuppence, nowhere near as clued up to the relative building process of various materials but my bikes

Carbon: Love it, light, comfortable, handles well, can easily do 100 miles with no adverse body pain.

Aluminium X 2: Both nice to ride but heavier than the carbon, one I use periodically, one is a winter kitted out bike.

531 Steel: The frame is now a wall decoration, just too heavy for me, just seems like a lot of extra energy expended to get to the same destination a lot slower. Just my personal opinion but I would never ride another.

 

[Soltydog]

Am I too heavy for carbon I'm about 95-100 kg though 6.0 so never gonna b 60 kg ,would u get aluminium

I'm a similar weight & had issues with 'budget' carbon frames, I switched to Ti a few years ago & not had any problems, the ride feels smoother & more comfortable. Being a heavier than 'normal' rider I'd recommend getting a frame with a good warranty from a reputable company I did give in & bought another carbon bike (Giant) about a year ago & have since fit some carbon rims & got to admit it is now the most fun to ride out of all my bikes, but it's still not my favorite bike 👍