Update:
I now have couple rides in on the Carbon bike, and the differences between the two are surprisingly dramatic.
Frame Design:
Cable Routing- The cable guide under the bottom bracket is a much better design on the carbon. Sounds insignificant, but the one on the Alloy was not so good, it added shift resistance and diminished shift accuracy.
Ride Characteristics:
To be honest, I didn’t think I would notice a difference. Thinking tire pressure probably has more of an affect than frame compliance. I couldn’t have been more wrong.
Compliance-The carbon frame dampens trail vibrations better than I thought a frame could. It feels like a soft tail. High frequency trail chatter just doesn’t make it through the frame to your hands, butt, and feet. It almost feels like it’s floating above the trail and only making contact at the high points. To be honest, it makes the frame “feel” soft, but it’s not. The alloy is also very compliant for an aluminum frame. They both offer a great ride, but I may prefer the more direct ride feel of the alloy.
Acceleration/Speed-As I said earlier, Alloy felt faster, I think that since more trail noise made it through to the rider, the increase in speed was more easily perceived. The Carbon feels slow compared to the alloy, it’s not. I rode my normal offroad time trial of 5.4 miles with 1,600ft climbing, and the result was slightly slower on the Carbon than what I rode on the alloy (33:20 vs. 34:03). But I had an 8 lb pack on when riding the carbon, and I’ve only been on a bike a few times over the past 2 months. I think these 2 things more than make up for the 40 second difference. Lots of variables I know, but it’s enough to make me confident I didn’t lose any speed because of the bike. I’ve ridden this route as a time trial a lot, and know pretty well what to expect for a time.
Descending/Handling-The vibration dampening and stiffness of the carbon bike give it a clear advantage, it’s not even close. It corners and holds a line better. I though the alloy was good, the Carbon is better.
Overall impression-I think the alloy is a bit more fun to ride when climbing, simply because it feels faster. The Carbon is more fun descending. I also think that the compliance of the carbon would be a benefit at the end of a long race or ride.
Component notes:
The Sram stuff shifts slightly better and more crisply than the Shimano stuff. But as usual, I prefer the ergonomics of Shimano shifters. The Elixer R Brakes have great power and modulation, hopefully they don’t have the bleeding issues that some people have experienced with some of the higher end Avids. I had a 12-34 cassette on the alloy, and a 11-34 on the Carbon. The 12-34 is better as it closes up the 20-17 tooth jump on the 11-34...it's noticable to me anyway.
I’ve got a 25 hour team race this weekend, I’m confident that Flash Carbon is the right tool for the job.
