Triathlon - Bike Selection?

I am researching a new bike for next year. I bought a GMC Denali without doing in depth research last year. A reveiw from someone on this site siad it was a great bike. I eventually found a LBS to work on it and tune it as well as they could. The bike shop owner is willng to work with me on financing an entry level trek road bike. I have seen the motobecane nemisis tri bike mentioned and have been researching it and other bikes. No more $200 dollar specials.
My question is regarding carbon vs aluminum vs whatever. I am 5'10 and weigh 240 LBS (I will obviously be participating as a clydsdale). I have heard than when carbon fails, it fails catostrophicly. Not an apealing thought. I also tend to be a masher. I have already messed up the crank bearings on my denali. At the advice of my helpful LBS owner, I am working to increase my revolutions to around 80 and use the gears to maintain my rpms. Uncomfortable at first but I am getting better at it. She says my knees will thank me in years to come. I would greatly appreciate any info on bikes for someone 200 LBS plus. I am on a limited budget and want to make the most out of my nest purchase.
Thanks in advance for any advice.

I suggest aluminum or steel as carbon will likely be too expensive and also might be a little too flexy for someone at 240 lbs (I was also there not all that long ago). A lot of people bash aluminum but I've been happy with mine.

All the frames will handle your weight.
What you WILL NEED is Wheels with 36 Spokes.

I am on a Jamis Ventura Comp and was over 250 when I started. I have 28 spoke rims that work just fine and my frame is aluminum. It is not a "tri" bike, just a standard road bike, as that is what I wanted for my everyday work outs. I would say find the LBS that treats you right and use the brand that they carry. Learn to get your cadence up to around 85 - 95 on average and you will be fine.

Unless you want to do the wheel truing yourself, 10 Wheels is probably leadin you in the proper direction with more spokes because of your weight and mashing isn't going to help either.

Good luck and have fun!!!

FWIW:
I'm 5'10" 240ish# & ride a Giant OCR Limited (Carbon Frame) with Xero XSR-3 20/24 spoke wheels.
http://archive.giant-bicycles.com/us...06&model=11445 (http://archive.giant-bicycles.com/us/030.000.000/030.000.006.asp?year=2006&model=11445)
http://www.xerowheel.com/prod_detail...&id2=19&pid=20 (http://www.xerowheel.com/prod_detail.asp?btn=2&id=1&id2=19&pid=20)

I too am a masher working on improving my cadence. After 2500+ miles I have had no issues w/ the frame or wheels. I did have the wheels/spokes trued and retensioned as a preventive maintenance action @ around 1400 miles. They didn't look or feel bad, but were in dire need of retensioning. From what I understand, getting the wheels retensioned and trued after a few hundred miles is key to spoke/wheel life.

Having said that, generally I ride on good, smooth roads and no races to date. I have ridden a few centuries on rough roads. Although not a TT or TRI geometry bike, I do have clip on aerobars and plan on doing my 1st TRI (and maybe a few time trials) this coming season.

This time of year, bike sales at the LBSs are generally slow and you might be able to locate an '08 closeout at a very deep discount.

Oh, btw, USN (retired) here! Regardless of the bike you choose, enjoy!!

I have found a LBS that I really like. She is the only one who will willingly works on my denali. Can't seem to get it tuned just right due to inferior equipment. She deals mostly trek. I am debating about getting an entry level road bike and a seperate tri bike like the motobecane or just investing in a higher end road bike. For training I ride back and forth to my second job (approx 6 miles) with some serious hills.
I am still geting better at increasing my rpm's. She believes my knees will thank me and I won't destroy as many bcicyle parts. I am 47 and attempting my first sprint triathlon this year. I am 5'10 and 240. I wear a 36 waist and a 50 jacket. I tend to have a longer torso and arms and short legs. I only mention this because from what i have read and heard, bike fit is extremely important, and n0 two manufactures will fit the same. Right now I enjoy training and am trying to get to where I can afford to work less and train more. I have dreams and goals of participating in longer distances in the future. Right now I swim twice a week, lift weights twice a week, and try to run 3-4 times a week as it is my weekest area.

Try this web site: www.slowtwitch.com

I wouldn't look at 2 bikes at this point. Spend the money on a good road bike and ride the crap out of it, esp if you are commuting.

On a sprint triathlon, you will be just as well served with a good roadie. That is how I started out and after 3 years got a tri bike mainly to deal with longer distance races.

Just saw an ad in the Feb 09 Triathlete for Inside Out Sports. A 2008 P2 SL Ultegra for $1,400. If I were looking for a bike, I would jump on this.

Edit - Here's a link http://store.insideoutsports.com/browse.cfm/2,136.html