Lisa-
First off, welcome. Glad your here. I'm too am a larger gal and now a rider and thought the same thing. It's FALSE. Just because your not a 4% body fat tour rider doesn't mean you can't have SO much fun on a bike and continue loosing weight.
OK. You may need to stay away from the zippy bikes right now and the cool "new" thing is low spoke wheels that are lighter and more aerodynamic. You don't need that in a fitness bike. What you need is a bike that fits you and feels good under you. I have Trek Pure "comfort" bike.. some call then pedal-forward, crank forward, and cruiser bikes. You're not laid out like on a road bike when your down in the drops.
A little more then two months ago I didn't know HOW to ride. At all. I can't say enough for what the bike has done for me once I conquered my fear of failure. I used to wake every morning with back and leg pain and sometimes still do, but the pain is less, plus after a ride (even the short ones) I feel so much better. I even breath much better too, even at rest here at work, so here's to you and your bike.
Oh, I'm 5'5" and the 15" bike (38.1cm) fits me pretty good.
Here's my ride:
http://www.trekbikes.com/us/en/bikes...resportlowstep
26" wheels with big tires and 32 spoke wheels
Good luck!
Shannon



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