Hey guys!

I'm looking forward to buying a "proper" road bike, and both the Synapse and Roubaix 105 models are within my reach - pricewise and local availability. I'm interested in these two bikes specifically because I want a comfortable road bike, something that I can spend hours on the saddle over not exactly perfect roads with comfort. I've been cycling for that last three decades, but my last road bike was some 10 years ago. Since then I've been only on mountain bikes and lately on CX bikes, but I want something specifically for smooth roads.

In terms of price they're basically equivalent, and for my cycling level a 105 groupset delivers a perfect bang-for-the-buck - my CAADX has a 105 drive train and I love the thing. I'm fairly certain that the Synapse accepts 700×28C tires, and being quite heavy (105 kg) that would be the first thing I would change. But what is the widest tire that I could use on the Roubaix? And though I know this is hard to answer, what about frame rigidity? How does the Synapse compare to the Roubaix? I want comfort, but like everybody out there, I would not like to waste power on a too-soft frame.

I'm confident both are great bikes, and possibly very equivalent, but any general info on these two models would be greatly appreciated .