MTB for duathlon
 

As a commitment to my own health and well-being, I have decided to participate in a local duathlon that takes place next May. Since I am strapped for cash and only just a newbie to the sport, I will be using my mtb (2005 Gary Fisher Tassajara) for the cycling leg. I have outfitted it with 1.5 slicks, swapped the pedals for some clipless pedals, and swapped the riser bar out for a sturdy aluminum flat bar and added bar ends and some short aero bars (Cinelli Spinaci). My question(s) are, what else can I do to make this bicycle at least a little bit more road specific? I have considered swapping the fork out for a rigid fork and will probably do that anyway. Would it be possible to fit a cyclocross crankset to this bike? If so, would this require a new derailleur and/or bottom bracket? Also, would it be beneficial to swap the current 11-34 cassette to something like an 11-25? Would any of this even be worthwhile? I'm not currently to concerned about weight of the machine. Thanks!

Swapping the cassette from 11-34 to 11-25 doesn't give you a higher top gear in the cassette. I've put Tom Slicks on my mountain bike before. They are 26" tires x 1" wide. Faster than the 1.5's I used before. They do require a smaller tube than what you are probably using now.

You could look for a taller chainring. I haven't done this before so I'm not sure, but perhaps a 48-tooth ring could fit?

FWIW-after I put on the Tom Slicks I realized I needed to just make the leap and buy a road bike. Now I'm on my third and put way more miles on it than on my mountain bike now.

I wouldn't throw too much more money at that machine, as you would've been better off shopping for a used road bike at some point.

I wouldn't mess with new cranks, perhaps a new big chainring if you find yourself spinning out in high gear too much. If you can find a cassette for $25 or so, I might consider that. 11-34 is pretty wide range.

Depends, see if you can pick up a bigger large chainring, this would be the cheapest option. I'm assuming your biggest is a 44t, so try moving to maybe a 48t or 50t. It will cost you about 25 bucks for the larger chainring. Your range is currently 22t in front, so maybe change your 22t granny for a 28t or a 26t.

I would, but that's just me. Closer gearing will allow you to choose gears more appropriate to your desired cadence, you wont need the giant cogs on the trip anyway . . . 11-25 or maybe even 11-23 That would equate to 11, 12, 13, 14, 15, 17, 19, 21, 23. Pretty good jumps for road use.