Road Cycling - What size to get?

I'm looking to buy a new road bike soon, and while shopping around the net for bikes I have noticed they have listed frame sizes, ranging from 49cm to 64cm. My question is how do I determine which size is the best for me? I'm guessing I have to measure myself in some way then plug my dimentions into some sort of formula, but i can't find any type of formula anywhere. Can someone help me?

well im personally 5'10 and ride a 56cm but that is just me. it all depends on your arm length, your height, your inseam height. its hard to say what size you should be as a road bike is more precise in size than a mountain bike. your best bet is to go to your LBS and get sized there

You'll have to help me out here, I'm quite new to this; what does LBS stand for/mean?

Local Bike Shop.

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

Some fitting guides assume you are an athletic racing cyclist who is used to the racing position, but the above guide is more general purpose.

LBS=Local Bike Shop :)

local bike shop/store

yah 3 for 3 in the same minute..
the LBS im referring too

Originally posted by MichaelW
Check out
http://www.peterwhitecycles.com/fitting.htmAll that article talks about is mainly how to adjust certain componets of the bike to fit the rider. In other words, it still doesn't tell me which frame size to get.

A few days ago I was on ebay, and I remember one auction for a 57cm bike. The seller said it would fit most riders between 5'10 to 6'. I am just a little shorter than 6', so I'm guessing my size should be around 57cm, does that sound correct? I understand it doesn't have to be perfect. Also, I don't think I'm done growing yet.

Try http://www.coloradocyclist.com/bikefit/sizing_worksheet.cfm

Originally posted by hillyman
Try http://www.coloradocyclist.com/bikefit/sizing_worksheet.cfm
Ah, so I guess the magic forumla is inseam legnth multiplied by .67

Now, to make myself look even more ********, what exactly is inseam legnth? I'm thinking its the distance from my feet to my crotch (haha crotch), but I'm not complety sure.

Frame "size" is actually the measure of the seat tube [the vertical tube] of a bicycle frame which, though important, is not the only size issue. You can get your vertical size by multiplying your inseam [in cm, measured in cycling shoes or a reasonable facsimile from the floor to right up jammed up into your family jewels] by 0.67 or 0.65 [experts differ]. My inseam is 77.5 cm, so my size is somewhere between 50cm and 52 cm [my road bike is a 50cm, my cyclocross bike is a 52cm, which breaks all the rules... but nevermind].

Getting your reach is a little more complicated. This is to find the ideal top-tube, or horizontal, length of your bike. Your "reach" is essentially your top tobe length, plus stem length. I'm kind of long-backed, and my reach is 65 cm -- my road bike's top tube is 53 cm and my stem is 12 cm long. This is best done with a frame or a fit kit in a real store.

However, if you have a tape measure handy, you can use the bike fitting calculator at Wrench Science (http://www.wrenchscience.com/) to get a reasonably accurate fit. At least it's a starting point.

There are lots of different opinions about how to determine the correct fit. I would surf around a bit (search for "bike fit" on google, or also here at bikeforums). And, they'll all come in within a certain range. I would also go to several LBSs and see what they say (and you can use the knowledge you've gained over the net to ask sensible questions).

Since you mention having looked at eBay, I would warn against buying over the internet--only because you want to have taken the bike for a test ride. Any LBS worth its spokes should take time to fit a prospective bike to your dimensions as closely as they can. The test ride will be unfortunately short ride, but you will feel the difference between two bikes of different sizes and/or different geometries.

Good luck.
Jamie