carbon seatstays + aluminum frame - Page 2

LOL!!! Thats funny. My dad used to race an old Campy Rossin, great bike for its day, and he put like 80,000 miles I think it was on it, i'll have to check, the thing is so fatigued, that if you romp on it, it literally shifts gears by itself, under you.

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“(Training) doesn't get easier; you just get faster”
-Greg Lemond

Well, that really doesn't make sense. I don't know what you mean by "wiggle." If you mean flex, then flex of a tube is a function of it's modulus and tube diameter, with tube diameter being dominant. If you mean transmits vibration, then you can't make such an absolute statement.

Comfort have almost nothing to do with material. It's completely dominated by bike fit, length of wheelbase, tire pressure, and how comfy your seat and bars are. That's about it. In fact, a magazine years ago did a blind test wherein riders were put on bikes that were disguissed so the material would not be known to the rider. The test showed riders sucked at differentiating between materials based on ride quality.

Interesting, but I still disagree with you. By wiggling i meant flex, I don't feel my carbon flexing under me, and it doesn't absorb vibration, even with zert inserts, unlike my alluminum frame, which took vibration very well, and I could feel it flex.

__________________
“(Training) doesn't get easier; you just get faster”
-Greg Lemond

how bout if you have let's say 2 exact setup + same geometry bikes but one is made of carbon and one made of aluminum? still no difference at all in riding comfort?

There is absolutely no comparison between the two bikes that will tell you anything about the materials. Look at the pic below. I overlaid the Tarmac Expert with the Etape (Tarmac is white and the Etape is semi-transparent and red). The pictures were sized so that the OD of the rims were as close to the same as possible. Look at the geometry differences. Look at the differences in tube profiles and sizes. It is absolutely impossible to say anything about ride quality of a given a given material based on comparison rides on these two bikes. There are so many things different between the two bikes that you cannot determine with any discretion at all what the source of the ride difference is.

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Well, first, show me two bikes that are exactly the same except for the frame material. They don't exist, because that would be engineering at it's worst. Frame's do have to be designed with proper implentation of a given material's properties in mind. The frame's ride "quality" comes from, again, the geometry, construction method, and QC.

If Richard Sachs built an aluminum frame with brazed lugs, so that the aluminum tubes were the exact same OD and ID as the respective tubes on his steel frames, that aluminum frame would likely be a whippy beast because aluminum tubes need to have larger diameters to have similar stiffness to a given set of chromoly tubes. Again, that says nothing about the ride qualities of the two materials.

I didn't say it had all to do with material, I said it has to do with both material and design, don't try to push me in a corner, and your saying that material has absolutly no affect one bit what so ever on comfort??

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“(Training) doesn't get easier; you just get faster”
-Greg Lemond

Who's trying to put you in a corner? I'm pointing out that your comparison of the Tarmac to the Etape doesn't fly in terms of materials.

Since few things are indistinguishable outside the quantum world, yes, it can be said that material makes some difference in comfort. That difference, though, is not what you think it is. That difference is found in what an engineer/designer has to do with the material to get the system properties/behavior he or she wants. The things I've mentioned a few times--design, construction, QC, fit--are all so much more important factors than material that material, for the rider, is not really a factor in comfort.

If it were, then all steel frames would be compliant, lively, and have magical rides. That obviously is not the case. All aluminum bikes would be bone jarring, uncomfortable torture racks. That's obviously not the case. Want proof? Ride a Vitus like Sean Kelly rode to so many wins: those bikes were anything but bone jarring or stiff. A ride of just a few different CF frames will show you that they do not have the same ride quality, that CF frames do not necessarily damp those nefarious vibrations in the same way, that they do not all feel dead, or that they do not {insert common CF myth here}.

I posted the composite picture to show that those frames aren't anywhere near the same, and as such, any comparison between ride quality based on material would be an error: there are just too many differences that play much larger roles in ride quality to even begin to consider material.

Also, much more important is the amount of air in your tires, how comfy your seat is, and so on. I'll bet that if you put some tubular wheels with Vredestein Fortezza Pro tubular tires on your Etape, with the tires pumped up to their max pressure, i.e. 203 psi, the ride on that bike would be anything but comfortable. That would essentially remove the tires from the comfort equation, leaving you better able to characterize the comfort of the frame. Go further. Remove your seat and replace it with a 2x4 to remove saddle comfort from the equation. Now you will have further increased the influence of frame on comfort. If you do this, you'll find there's really very little comfort left. In fact, comfort would probably not exist, whether the frame was steel, magnesium, aluminum, or the most deftly marketed CF contrivance.

I think the most important word you use in your argument is "hypothetically".

Why?

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"All that we see and seem is but a dream, within a dream..."

I didn't say anything about design, psi, or anything else you brought up wasn't a facter, all i said is that material has a role in comfort.

__________________
“(Training) doesn't get easier; you just get faster”
-Greg Lemond

I didn't say that geometry, psi, or any of the other factors you posted had more or less to do with comfort, all I said was that material had a role in comfort.

__________________
“(Training) doesn't get easier; you just get faster”
-Greg Lemond

sry for double post, comp is actin up

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“(Training) doesn't get easier; you just get faster”
-Greg Lemond

Yeah, you didn't, but saying you can feel the difference in materials is incorrect because of the reasons I stated: way too many variables.

well the best if not all MTB downhill bikes are made of Aluminium

Alu fan
P.S. Carbon Fiber cannot take sharp-end objects in a crash, like sharp stones