dpd3672

I found a great deal on a 2007 Cervelo P2 SL frame, that came with the seat post and aerobars/forks. I had intended to take my time and build it up as a Dura Ace bike, getting parts and pieces as I find them on Ebay/Craigslist, either as a group, individually, or off of a donor bike. That said, I'm getting more confused the more I look into it.

I really, REALLY want a Dura Ace group, but am struggling to justify the extra expense over Ultegra. I doubt I'll ever be at the level where the very slight differences are apparent, is it really worth spending the extra money, other than bragging rights? Are the differences in the generations very apparent? That is, is an older DA 7700 group still better than a newer, Ultegra 6800 group (for example)? I know most of the improvements "trickle down" with each new generation, but it's not as clear what major breakthroughs have been made with each new generation.

What about gears? Most of the extra pieces/parts I have are for a 9 speed Ultegra. Would it be advisable to stay with 9 speed, so I can use my extra wheels/cassettes/etc, or will it make little difference if I go with a 10 or 11 speed group? My other bikes are 9 speed Ultegra, so is the cross-compatibility worth staying with 9 speeds and older "tech?"

Finally...the bottom bracket. Try as I might, I can't find which BB to order for the 2007 P2SL frame. 68mm English is as close as I can find, would I just look for a Shimano 68mm BB that matches the crankset I buy (7700, 6800, etc)?

Most of my riding is on very flat roads. Not a lot of hills in my neck of the woods. Is a compact crank that valuable on a tri bike that pretty much stays exclusively on flat courses?

I'm sure I'll have more questions, but this will at least get me started, thanks!

cvskates

I can't answer all your questions, but I'll bang out a couple.

If every other bike I owned was 9 speed, I would stick with nine speed. I went 11 speed on my tri bike because I only have 2 other bikes, and one is a mountain bike, the other my touring / commuter. With 11 speed I find it easier to fine tune my wattage for long course races. 5 or 10 watts off target doesn't do much for a sprint or olympic, but over 112 miles you'd notice it when you got to the run.

My road bike was a Norco with a newer 105 group on it. I sold that to buy my tri bike, which has a newer Ultegra group on it. I don't often notice subtle differences between bikes in terms of performance, but I do notice how much nicer my Ultergra is to shift compared to the 105. If Dura Ace was that much nicer again, I would strongly consider it.

I swapped my crank out for a compact, but that was because I'm mostly in the mountains when I ride. Having said that; there are lots of articles on the internet explaining how you can get the same or hiring gearing on your top end if you match the right cassette with your compact crank. I'll let you google that, there is lots of good articles on it.

Hope some of that helps.

dpd3672

Thanks, I decided to avoid regrets later and went with all Dura Ace 7700 9 speed, even down to the cables, chain, and cassette. Now I can swap cassettes and wheels with my other bike, to have some options for different gearing if the need should arise. I got full size cranks, and I figure I'll find the right combination with my cassettes through trial and error.