The gen 2 is a nice bike. Definitely worth the upgrade in my opinion (I had both).
The 7 series comes with aluminum seatpost unlike the 9 series which is Carbon. The 9 series seatpost also has a di2 battery bracket holder built in. The 7 series seatpost does not. You can run the 9 series seatpost in a 7 series frame.
You can get the bigger fork, base bar, and speed fin on the 7 series but it mattered which mode you bought and what year. I donâ€™t remember th details.
All the new 2018 speedconcepts are really 7 series bikes with the aero upgrades.. one thing I havenâ€™t figured out is if the Carbon seatpost comes with it or not.
Almost positive the 2018 comes with aluminum post, and although the frameset is pictured with the speedfin, I don't think it comes with it. The specs list it as speedfin compatible...
So I guess the new 2018:
- aluminum post
- lower grade carbon than previous 9 series
- UCI legal (shallower) bars
I really like the black finish though, and hard to justify spending $2000 Canadian more to get the 2017 9 series frame.
I just wish they didn't still use the same bottom bracket system. Have gen2 owners had the same frequency of issues (loosening) with the carbon BB shell, where you need the oversized bearing, or send back to trek to be re-worked?