Quote Originally Posted by bonnypriest View Post
The Roubaix was very comfy, but the Tarmac was a freakin' RACE MACHINE! I love it. My question is how would it be for hills (& I mean TX hill country hills not CO mountains).
Well, I don't happen know the gearing or any of the other features of the Robaix or of the Tarmac off the top of my head, so I'll go by what you're telling us here.

If you tell about the gearing on the Tarmac vs the Roubaix you might get an answer to that question.

Also would a century be ok to do on the Tarmac?
Not sure what you mean by "ok". Would the organizers allow you to ride the Tarmac on the century? I suppose so.

All other things being equal, I think you might agree that comfort would be a high priority for a century ride.

But, if you love your race machine, what they heck, go for it, it might get you through that century faster. It might not be as pleasant an experience as on the comfortable bike, but that might not be a priority for you.