there really are only two criteria for a good frame - weight and stiffness. the best frame is the best compromise between the two. and while the sheer materials carbon and titanium are superior in combining these two qualities than say aluminum, it doesn't translate into better bicycle frames automatically. Carbon is very tricky to process. It is much easier and much cheaper to make a good aluminum frame. In terms of their qualities usually at the same price aluminum frames are better. A lot of companies use carbon because it is chique for it*s high tech cache. The whole lunacy however begins with the fact that barely any frame actually makes use of the advantage of carbon - which is that you can mold it into many shapes. If you produce a monocoque (a frame out of one single mold) you have a frame with absolutely superior qualities. But it's too expensive for mass production. So idiotically the bike companies produce tubular shapes out of carbon fibre and glue them together - thus forfeiting all the potential of carbon fibre. The Trek Madone/5200 frames I think is made of 14 parts!!! Titanium - I dont know - I just know it's expensive and it's expensive because it's extremely difficult to weld the tubes together (cold welding). Look at weight compared to stiffness and buy the frame that combines these best at a reasonable price. If its made of bamboo and has those qualities - so what???
bike frames: titanium vs. carbon
Saw a particularly Snappy Carbon Frame this weekend and went to their website to look up the specs.
For reference, my venerable Independent Fabrications 853 frame weighed in at 3.8 lbs.
Comparably sized SCF ... 3.8 lbs.
Carl, I'm the carbon fan and have been meaning to mention that tires do matter too, as someone mentioned above. I got a Trek OCLV Carbon, after riding a used Aluminum Specialized. I adore my carbon Trek. No more road vibrations that jar the body and tire you out on long rides.
But the tires make a difference, too--width, pressure, and material.
The Trek came with silica-compound Bontrager X Lite tires, 700 by 23 -- 120 max psi. I was extremely happy with them until I got a couple wear-hole flats (spoon-sized holes in the tires that I had to patch with a Clif bar and ride to a bike shop). They're race tires and they do wear much faster than some other brands that seem popular on the road--Michelin and Continental.
I tried Michelin Pro Race, 700 by 23, pumped them up to 120 psi and rode loops in the park. The bike was shaky like my aluminum frame. Hum...I realized you can only pump Michelin Pro Race to 110 psi, not 120. Still I found the tires less buttery than my Bontrager.
So I tried Continental Grand Prix, 700 by 23, 120 max psi. These seem to be the other road favorite, especially for people looking to prevent flats. They felt nearly as buttery as my Bontragers, but I felt slower.
They have a bit of a tread, unlike Bontrager Race and Michelin Pro Race. The tread is great for traction on corners, hills, rain, ice, snow, but I didn't like the feel so I went back to Bontrager and just watch the tires and replace them as soon as I see the thread on the tire start to show.
I've also tried the Bontrager Race X Lite 700 by 25, and theoretically a fatter tire (25 vs. 23 cm width) is slower. But I couldn't tell a difference. What I did notice is that the 23's seemed to hold pressure better, which resulted in a faster tire.
So the short point here is that tires do matter--narrower and higher pressure tires will create more road vibrations. It's always a compromise between speed and comfort and traction. I think 700 by 23 is a good width for fast training on the road, and the Bontrager silica compound has a nice cushioned feel.
Basically, you don't want to get a carbon bike and then choose tires that make you feel like you are riding on stones, unless it's a race and you want speed at all cost. Then go for it.
Karol
