want to ride a century

aa9t8

my dilema
i want to ride a century. my choices for a ride are an aluminum mtb bike with good seat and suspension seat post. i have also put an 11-34 rear cog on it as well as skinny high pressure tires. oh yeah and bar ends.
my other choice is a flat bar road bike with a tri bar on it.
the mtn bike is by far the most comfortable. but the flat bar will go faster.
looking for some input. thanks

strings&gears

First, I would primarily train with the bike you intend to ride. Second, the lighter the bike the easier it will be to complete a century. However, you mentioned the mtb is more comfortable. It really boils down to personal choice, imo, as a century can be done on either style of bike. I've done the local MS150 and saw several heavy mtb's along the route. That takes me back to my first point. Train with the bike you intend to ride. All other points of training (intervals, hill work, etc) apply to either bike. Hope this helps a little.