Sizing question
 

This is probably stupid, but I'm clueless. Background: I bought a bike from my LBS 8 years ago, and all I knew at the time was that I really enjoyed biking on a service mission for my church using "stock" bikes (no clue anything about them either). The salesman suggested I get a hybrid, comfort bike, since I had no idea what type of biking I'd really be getting in to. I don't even know what size it is! That bike has done great for me, but I'm thinking I want to get a "real" road bike now. I enjoy distance rides, and I'd like to participate (probably not "race") in biking events. (An insane goal I have is to complete LOTOJA, 200+ miles through 3 canyons from Logan, UT to Jackson Hole, WY.)

So how do I figure out what size frame I need to be looking for? We're pretty tight with money, so the only way I'll be able to afford a road bike is Craigslist or something like that. (It'll be enough of a struggle to convince my husband to stay with the almost-3yo and baby twins while I go out; asking to spend lots of money on top of that will not go over well.) I'm 5' 5", medium build, and have quite a bit of weight to lose (not the babies' faults). Any advice would be appreciated!

Might be some help:
http://veloweb.ca/bike-fit/

10 Wheels link is a good one.

I'd also suggest the following:

I'd use your current bike as starting reference. As a general rule, the size of the frame isn't important. What is important is the relationship between the saddle and pedals, and the distance between the saddle and handlebars. You can measure these distances with a tape measure. Just be sure to measure from the top of the seatpost to the middle of the bottom bracket. The other measurement is from the seatpost to the stem (again, middle to middle). Alternatively, you could take the bike to a friendly LBS and get them to measure it for you.

How long of rides are you currently doing? What about your current bike makes you want a "real" road bike now? Any aches, pains or other uncomfortableness? Or, is it simply a case of wanting to go a little faster?

Based on how you fit your current bike, you can make an educated guess about what size you might be looking for.

Better yet, get a picture of yourself from the side while riding your current bike and post it here. I'm sure that we could give you some pointers on what you might want to change in terms of riding position that might better suit longer rides.

Educate yourself from the above posts and many sites available regarding fit. You'll get the most practical help at a good LBS. They should measure and fit you based on your riding style and desires. Some shops and sales folks have specific points of view wrt to bike fit, with the education you will be better able to decide if you are comfortable with their approach.

I always recommend hitting a few shops to get the fit variations. It also gives you a chance to try a larger variety of bikes. Frank's Cyclery is supposed to be a good shop. It looks geared toward the high end crowd but does not seem to be snooty from the reviews. Back Alley Bikes in Chapel Hill may be a good spot now with graduation having just happened their stocks may be up.

My longest ride so far was about 55 miles, last summer. The last one I timed (at the time, I didn't have a bike speedometer) was a 50 mile ride at 6000+ feet altitude around a lake on the Utah/Idaho border, and I averaged about 15 mph. I actually haven't been able to ride for the past 9 months, due to pregnancy and birth 6 weeks ago (yay for babies and no sleep). I've been cleared to get back on again starting Memorial Day, and in prepping to do so I'm looking at what worked and didn't work before. I've already got a nice speedometer/cadence meter, so that's taken care of. Before, my hands went numb on rides over about 30 miles, or 2 hours. Sometimes my feet went numb too! I know getting real biking shoes with clip-in pedals and road bars (I have the straight bar system now) will help tremendously, but I don't know how much money I want to "sink" into the current bike, if I really am going to race in the future. It almost seems more worth saving the money to get a "real" road bike that comes with those things already. I never had my bike professionally fit to me, so that could have a lot to do with the issues too. Maybe just getting the extra "stuff" for this bike, including a fitting, would be the way to go, but I have no idea. I'm planning on going on a ride with some friends on Monday for the holiday, so I'll bring along the digital camera and see if I can get someone to snap some pictures for me. Any other advice in the meantime would be greatly appreciated!

Thanks for the links and advice!

@masiman: I'd never heard of Back Alley Bikes. I'm excited to stop by there in the next few weeks. Thanks for the tip!

Given what you are intending to use the bike for, I'd say go get professionally fitted. Tell them up front about your situation, that you intend to try to find a bike second hand. They might charge you bit to do the sizing, but it will still save you money in the long run by getting the right bike first time 'round.

One other thing to keep in mind: When shopping for a used bike, figure that you'll probably have to swap out a few bits to get the fit 'just right', so make allowances in your budget for this.