General Cycling Discussion - General frame size question (road bike)

I'm looking for a used road bike (cyclocross or touring) for primarily commuting duties but I'd also like to be able to do longer tours (MS150, etc.) with it as well. I'm 6'4" with pretty long legs. In general, what size frame should I be looking for? I'm thinking somewhere around 60cm. Does that sound about right?

http://www.peterwhitecycles.com/fitting.htm

http://www.rivendellbicycles.com/html/bikes_framesize.html

Read 'em both & you'll know.

if i had to guess: 62... i'd even go larger for longer headtube and consequent comfort

FOR THE LOVE OF GOD, DON'T BUY A 60!!!
There--now that I have your attention, I'm your height, also with fairly long legs (34-inch pants inseam; don't remember my cycling inseam), and I've never been so happy as since I quit riding teeny bikes.
I've been riding for 30 years, and for most of that time, I've been on 62cm bikes. It's the largest size most shops carry, the largest many companies make, and salesman after salesman has told me it was just right for me, stiffer than a larger frame, we'll just put on a long seatpost and you'll be fine.
When I bought my Atlantis, I followed Rivendell's size recommendations. They put me on a 65, which Riv didn't have in stock, so I bought a 64. It's a HUGE improvement over anything I've had since my old, 25-inch college bike in the '70s (25 inches = 63.5cm). Instantly, I could ride 50 percent farther in comfort, which meant I spent more time on the bike and got stronger and faster.
There's a lot to bike fit, and the Rivendell sizing system (which somebody else recommended here) works pretty well. One quick rule of thumb, though, is to set the saddle height so it works for you, then close your hand around the exposed part of the post. If your fist doesn't cover or nearly cover the exposed portion, the bike's too small. DON'T BUY A 60!

Istanbul, I like those links, and I think Rivendell is right- many many people ride bikes that are too small. WHen I go on club rides, people look at me like I'm crazy for being 6 ft. tall and riding a 60. I've seen guys my size riding 54's with about 9 inches or more of exposed seat post. And these guys want to tell me that the bike shop I went to took me for a fool and sold their last 60 to me. I'm not saying that they can't be comfortable riding their smaller frames, but I really like my fit, and I think that far too many riders are riding frames that are too small for them.

soem people like small frames becaus the reach to the bars is shorter. i like this because i constanly slide forward with long frame. i think my 17" mtb is even a little too long. i have like 10 inches or so of seat tube sticking out.

I'm looking for a used road bike (cyclocross or touring) for primarily commuting duties but I'd also like to be able to do longer tours (MS150, etc.) with it as well. I'm 6'4" with pretty long legs. In general, what size frame should I be looking for? I'm thinking somewhere around 60cm. Does that sound about right?

There are two key dimensions to consider. Seat tube length and top tube length.

You said that you are 6.4" with pretty long legs. That means that your torso must be shorter than average for someone who is 6'4". In other words, a bicycle that fits your leg length well and has the handlebar height to go with it might feel too long in the top tube.

My advice is to find a local guy who is good at bike sizing and pay him $50.00 or so to give you an intelligent opinion as to what size seat tube and top tube length you need. This is especially important since you said that you are looking for a used bike.

When you go into a shop to buy a new bike, you can pick out the bike that you want and leave it to them to get you the correct size. When you go looking for a used bike, there's usually only one. You have to already know what size you need and you have to have the discipline to hold out for the right size regardless of what the price and components are.

soem people like small frames becaus the reach to the bars is shorter. Right (wow, did I actually use that word following something Merton said? :) ), and, more generally, fit is not just about overall height. The original poster mentioned a "rather long" 34" inseam, but at 6'4", I'm guessing that's pretty average, or perhaps a smidge on the short side, for his height. I'm only 5'8" (if that), and have a 33" inseam. I had to buy a women's specific design frame, and still had to get a zero-offset seat post, and it's out of the tube just about to the max marks.

Even Peter White's text about crank length is not the complete story. His measurement takes into account most of the leg length, when in fact, it's the length of the femur that mostly determines crank length. When I went in for my fitting, one of my first ideas was to go from my existing, pretty-much standard 170mm arms to a set of 172.5 or 175's. He measured my legs and said no. Even though I have unusually long legs for my height, most of that anomaly, in my case, is in the tibia. My femurs are not that unusually long, so the 170's are appropriate.

This is why, esp. for someone of a height or proportion that is significantly out of the mainstream (which is the demographic for which most production bikes are designed, after all), such as the OP, I'd recommend some kind of fitting service. Even if you can't get a bike, or equip yours in a way, that exactly matches the specified dimensions, at least you've got a goal, and can figure out how best to approximate it.

Thanks for all the suggestions. I will definitely go over to the LBS for a proper fit and then wait until I can find something that'll fit me. My two MTBs are a little on the small side for me (both 20-inchers) and they make distance riding a bit uncomfortable. I'm looking forward to getting a bike that actually fits me. :)