The Cooper was my "A" bike until a few months ago, when I picked up the Tarmac on ebay. Since then I've been trading off rides between the two bikes, and so far I have about 400 miles on each. I have some strong impressions of the differences between the bikes so I thought I'd post my thoughts. Whenever I am thinking about some new gear, I find posts about real-world experiences like this to be useful.
2010 Specialized Tarmac SL3
Shimano Di2
Specialized carbon crank BB30
Roval Rapide SL45 wheels
15.5 lbs
2008 Lynskey Cooper
SRAM Rival
Fulcrum 3 wheels
17.5 lbs
Both bikes have a 50/34 crank and 11-25 cassette (it's steep here). Setup/fit is identical, except that the bars are set 1cm lower on the Tarmac. Wheelset weights are similar (~1600g), though the Rovals are carbon/aero, which of course makes a big difference to the ride. About half the weight difference between the bikes is from the frame, half is from the Di2 vs Rival.
Tarmac:
This bike feels like it could not be any stiffer. Every watt gets converted directly to forward motion. I am significantly faster on this bike, both on the flats (where the aero wheels are a factor), and on the hills. This part is psychological, but because the power transfer is so efficient, it is hard not to attack hills as hard as possible. I have never once been caught on a hill while riding the Tarmac.
The Tarmac is also fatiguing to ride. It's partly because of stiffness -- it feels like every variation in the road surface gets transferred directly to your hands. (It is no fun at all to ride this bike on gravel.) It's also because the bike rewards a higher level of physical output. After 30 miles I start to feel beat up, and I've never gone more than 50 miles on it without a break. I usually get off the Tarmac feeling like I have gone as fast as I could, but glad that I didn't have to ride 10 miles further.
Cooper:
I can ride this bike forever. The geometry of the bike is more performance than comfort -- compact frame, straight seat stays -- so it's not like riding a sofa, but it is amazingly comfortable. I did a very hilly 70 mile ride last week and at the end, I was tired, but without any specific physical complaint -- no buzzing hands, no stiff back, no soreness. Despite the high comfort level, the Cooper still feels like a light, fast, high performing bike.
The Cooper is also noticeably softer, springy and flexy, especially after coming off the carbon bike. The chain will rub if I stand and mash up a hill, and it can get downright squirrelly on a fast descent. I know this is a cliche, but it also feels more alive. I get a sort of high when riding it, especially up hills and through tight curves. I usually get off the Cooper with a sense of exhilaration that I just don't get from the Tarmac.
I get good use out of both bikes. I'll take the Tarmac for any ride where performance is the goal -- either because it's competitive, or because I want the hard training -- and be confident that I will get the maximum performance out of it. I'll take the Cooper for any ride where enjoyment is the goal, and be confident that I will get the maximum fun out of it.
