Cyclocross - Dawes Lightning All in one?

I'm on a tight budget and thinking about combining my road bike/cyclocross needs into one bike. I do triathlons and will be training on the road for the season, but then I'll hit cx. This past season, I rode a GT entry level road bike for tris (worked great, just a little big) and raced my first cx races on an old Specialized Hardrock:
http://shorthaul.files.wordpress.com/2009/01/action.jpg?w=510&h=382
I hope to work towards averaging around 22mph for my bike legs in triathlon and as far as cx is concerned, I'd love to do better but would have fun no matter where I end up.

I'm looking specifically at the Dawes Lightning from BD (also keeping eyes peeled for a used bike), but I can't find much in the way of reviews for the bike. Has anyone ridden one? Any impressions? The components would be fine for me--I just wonder if it would work for me as a road bike or if it would be a significant sacrifice in (my version of) performance.

There are a couple of good threads here about using cx bikes on the road, but I'd also like to hear any experiences people have with road racing on cx bikes. Thanks in advance.

Hey, I recognize that race. That was a Sunday in Warwick, RI this past December, right?

As far as triathlons goes, are you mostly into the sprint variety? If so, I think you could probably do all right with a regular CX bike with some road tires on the thing. I'm no triathlete, though, my gf is into them. I use my CX bike with road tires for a rain/off season commuter bike. I think you'd be fine, especially for sprint triathlons, and I can't imagine not using a specialty bike would cause you to lose more than a minute or so off your 17 mile sprint bike ride...but, here' I'm assuming a shorter sprint-length triathlon...if you're into longer road races, I'm not as sure of an answer.

Yeah--that's the race. What a day! Man did I wipe a few times. I raced on Sunday w/ ice and snow (maybe Sat. was the same) and the course rounded out my first cx season: Dry and sunny 1st race (Plymouth), total mudfest 2nd race (Lowell), and then that race in Warwick.

I'm planning on doing some olympic distance triathlons this season (25 mile bike leg), with the rest sprint distance (12-15 miles on the bike). So I won't be going too far. I'm just interested to see whether there could be a distinct advantage to riding on road geom. vs. cross. (as in 5 minutes difference over 15-20 miles.) I know a lot comes down to engine. From what I see and hear, there's not too much of a difference at my level or distance. And with the ability to race cross and road, I'm leaning towards an all-in-one.

I'm really curious about this bike, too. I'm somewhat new to road/cross riding and I just bought a Dawes Lightning Cross bike today from BD. (I know, I know, but I'm a poor college student and I was impressed by the components in that price range.) Before buying this, I've had a number of ATBs, most recently a Marin Nail Trail and for my roadie I had a vintage Fuji. Sadly, I sold the Fuji - first road bike, I'm 5'2", sizing issues, etc.

Anyway, I'll let you know how the bike does on trails and road riding. I'll take pics, too.

Anyway, I'll let you know how the bike does on trails and road riding. I'll take pics, too.

let me know how the sizing is, since I'm 5'6" and was considering the smallest (50cm) size.