YES! I like Carbon!

[Bram_on_Madone]

That picture of the broken carbon seat post was a bit scary - is that something that is likely to happen with normal use, as I will start having visions of a snapped post causing serious anatomical damage to my rear....

[Eldron]

2. Every material has its place' date=' pros & cons. What you get out at the end of the day depends on what is engineerd into the design. It is possible to design a composite frame that stops bullets - sweeping statements like "carbon frames are fragile" is a bit too, well, sweeping.

 

5. Of the mainstream frame materials, carbon composite is the only one that can have different stiffness properties in different directions (orthotropic). 

[/quote']

 

I love essays

 

"Carbon is fragile" IS a sweeping statement but I still will never use it for an mtb frame (unless I'm sponsored!). In the common wall thicknesses used in bicycle frame manufacturing carbon is prone to penetration/cracking whereas alu/steel will dent (and remain usable). Used in the correct manner ie: no rocks hitting it or crashing your ass off -  carbon will easily outlast it's owner.

 

Whilst carbon is orthotropic - the difference in stiffness in frames comes more from the design than the material. Alu frames are generally larger in diameter than steel because alu is not as stiff - to achieve the same stiffness the diameter has to increase. It's one of the reasons I prefer alu and carbon to steel - steel is limited to round/ovalish tubes - hydroforming has allowed a crazy amount of tube designs in alu and carbon has unlimited tube designs. Steel CAN be manipulated but due to the crazy thin wall thicknesses (to keep the weight down) forming steel is a risky business.

 

I had one of the early Alan aluminium frames and it was diabolical - anything more than gentle pedal when out of the saddle had the wheels rubbing on the brake blocks rapidly followed by motion sickness brought on by the snaking frame curving it's way down the road 

 

[swoosh1973]

8. Having a bike that is 200 or 300 grams heavier won't slow you down in races in SA. the routes over here are just too short & flat - no serious mountains around here.

 

 

Short & Flat!!! Listen boet, you come ride with me here in Somerset West and i will take you on a 80km ride of non stop hils. You will wish there was a flat somewhere. In fact i can take you on a ride that will give you a non stop 22km climb. This one climb alone takes you from sea level to about 1100meter.

 

Oh by the way i agree with you 100% on everything else. The lightest carbon bike will eventualy feel as heavy as lead when your legs turn to wobblies.

[Christie]

the difference in stiffness in frames comes more from the design than the material.

 

Which is true for isotropic metal frames.

 

 

In a composite frame, the shape mechanical properties are determined by shape and laminate properties. For example, one would think the s-shaped seatstays of a Pinarello Prince would give it a soft ride. This is simply not the case - vertical stiffness of the Prince is 436 N/mm, compared to 263 N/mm for a Scott Addict, 188 N/mm for a Look 595Ultra, and 202 N/mm for a Cervelo R3SL.

So I would say fiber direction, plus number of plies, has a big influence, and that there is a significant difference frome one CF frame to the next.

 

( For interest's sake, the lateral stiffness of the Prince BB is 66 N/mm, while the Scott is 51 N/mm the Look 53 N/mm, and the R3SL 65N/mm. From the lab tests, it looks like Cervelo's engineers are a bit more skilled than Pinarello's )  

 

Imo alu frames are way under-rated. Too bad the carbon craze prevented "Scandium" of reaching its full potential as a frame material. I would not mind having a Merckx TeamSC ! Too bad Cannondale never made a "Scandium" frame, they were one of the leaders in alu frame design, it would have been a beaut.  

[Christie]

 

Short & Flat!!! Listen boet' date=' you come ride with me here in Somerset West and i will take you on a 80km ride of non stop hils. You will wish there was a flat somewhere. In fact i can take you on a ride that will give you a non stop 22km climb. This one climb alone takes you from sea level to about 1100meter.

 

[/quote']

 

You talking about the climb up to the dam from Gordon's Bay? Thats fairly decent, I agree. But few races goes up climbs like that, or finish on top of them. Some of the Euro climbs have the same gradient, but are a20km long - hectic

 

 

[Eldron]

the difference in stiffness in frames comes more from the design than the material.

 

Which is true for isotropic metal frames.

 

 

In a composite frame' date=' the shape mechanical properties are determined by shape and laminate properties. For example, one would think the s-shaped seatstays of a Pinarello Prince would give it a soft ride. This is simply not the case - vertical stiffness of the Prince is 436 N/mm, compared to 263 N/mm for a Scott Addict, 188 N/mm for a Look 595Ultra, and 202 N/mm for a Cervelo R3SL.

So I would say fiber direction, plus number of plies, has a big influence, and that there is a significant difference frome one CF frame to the next.

 

( For interest's sake, the lateral stiffness of the Prince BB is 66 N/mm, while the Scott is 51 N/mm the Look 53 N/mm, and the R3SL 65N/mm. From the lab tests, it looks like Cervelo's engineers are a bit more skilled than Pinarello's )  

 

Imo alu frames are way under-rated. Too bad the carbon craze prevented "Scandium" of reaching its full potential as a frame material. I would not mind having a Merckx TeamSC ! Too bad Cannondale never made a "Scandium" frame, they were one of the leaders in alu frame design, it would have been a beaut.  

[/quote']

 

Either you trawl the internet a LOT or you have access to some interesting info!! Nice!

 

The "hand made" nature of carbon frames is one of the reasons I'm a bit wary of them. Alu frame builders tend to buy tube sets and just weld them together - they can't change the ride quality - the only risk is weld cracking.

 

I'm with you on Scandium bikes - I have a Easton GX2 Scandium Niner and I love it.

 

And that is part of the problem - "I love it" is such a poor description. I don't think 99% of people would know the ride quality differences between carbon/alu/steel. Like you said in the test with disguised frames - comfort and quality is the sum of seat, wheels, tyres, frame, bars, stem, fitness, weather etc....

[Eldron]

 

Short & Flat!!! Listen boet' date=' you come ride with me here in Somerset West and i will take you on a 80km ride of non stop hils. You will wish there was a flat somewhere. In fact i can take you on a ride that will give you a non stop 22km climb. This one climb alone takes you from sea level to about 1100meter.

 

[/quote']

 

You talking about the climb up to the dam from Gordon's Bay? Thats fairly decent, I agree. But few races goes up climbs like that, or finish on top of them. Some of the Euro climbs have the same gradient, but are a20km long - hectic

 

 

 

Weight is so over rated.

 

I'm a serious weekend fun racer with minimal body fat and I weigh 78kg (I'm 6'2") with a pretty good mtb which weights 11kg (it's a 29er) so even 300g is only 0.33%. Hardly a huge penalty.

 

I value stiffness, strength and (some) comfort over weight weenie stuff. A good example is a saddle - sure you can buy a 111g saddle but the 165g one I have easily outperforms the 118g in terms of all day comfort. Likewise carbon bars, stem and seat pillar - I prefer alu in those departments.

 

 

[Christie]

 

Either you trawl the internet a LOT or you have access to some interesting info!! Nice!

I have an interest in structures' date=' and spent some time collecting some real info on the good, bad & ugly.  Gives some idea about who spends money on salaries for engineers, and who stumbles along using more outdated approaches, and then market it as "the ultimate"

The "hand made" nature of carbon frames is one of the reasons I'm a bit wary of them. Alu frame builders tend to buy tube sets and just weld them together - they can't change the ride quality - the only risk is weld cracking.

This is the crux of it - it is all about quality of design & quality of manufacture. At the risk of sounding like a bike snob, I would steer clear of the cheaper carbon bikes - money would be better spent on a top alu frame.