Bike 101: How To Find the Right Size Bike
A very basic thing required when shopping for bikes is the understanding of size and measurements. Ironically, this is one of the last things I figured out, because it just seemed to boring… all those charts and numbers. A bike either seemed to fit me or it didn’t. While this worked out just fine when I was getting fitted by others at bike shops or bike rental places, this system failed me when trying to shop for bikes online. Perusing Craigslist for my dream bike required a bit more bike knowledge than I had, including an understanding of proper sizing.
Being the academic that I am, I thought compiling a ‘research post’ of sorts might help someone else trying to find the right size bike. Unfortunately, I found that most google results for said term only pulled up sizing charts for mountain bikes (we seem to be a very mountain bike dominated society here in the US). It took a bit more digging to compile sizing information on ‘comfort’ bikes or non-sporty bikes. And, as a gender scholar, I really couldn’t help but notice that all size chart caricatures were male…hmm…but that’s another post entirely.
For now, here is my compilation of information on how to find the right size bike for you, be it a Dutch bike, a cruiser, a mountain bike, or a road bike…
1) Find Your Measurements
To figure out the right size for you, a few basic measurements are necessary:
- Your leg inseam (from your crotch, where the saddle would be, to your foot)
- Your torso length (from your crotch to your sternum – the V-shaped curve below your neck)
- Your arm length (from the end of your collarbone to the middle of your closed fist)
2) Know Some Basic Formulas
Your inseam is the most often consulted one. Most bike size charts note the stand-over height. This is your inseam plus another 1-2 inches for comfortable clearance of that top tube. Some sources claim that road bikes require 1-2 inches clearance while mountain or commuter bikes need 2-4 inches. (If you’re using a bike with a step-through frame, then that measurement of reference doesn’t really work since the top tube is lowered.)
Another formula is that of the top tube length. I used to scoff at these details but I’ve come to appreciate that finding a road bike that is on the compacter side with a shorter top tube makes a big difference for me. I have a short torso so that distance between the saddle and the handlebars can really affect my ride. To figure out your ideal top tube length, do the following math:
(torso length + arm length) / 2 = x
x – 6 = top tube length
(Add your torso length to your arm length, divide that by two, and subtract six). This will tell you in inches what the ideal distance would be between your seat and handlebars.
3) Consult a Few Size Charts
Dutch Bike Sizing:
When it comes to cruiser bikes like my own, there seems to be the least amount of available information in terms of sizing. Cruisers are commonly sized in terms of small, medium, large, etc. rather than in inches, so there seems to be less of a direct numerical correspondence between the rider’s size and the bike size. I’ve found this video most helpful in demonstrating how a well sized cruiser should fit relative to body size. This confirmed that my Electra cruiser is a good fit for me, since it mirrored the fit demonstrated on the second and more suitable bike shown here…
4) Trial and Error
Ultimately, finding a well fitting bike is like finding any well fitting garment – only trying it on will really tell you how it fits. As Alan of EcoVelo so eloquently put it, ‘Bike sizing is an art not a science‘. Figuring out some basic math and having a few numbers for reference will certainly help get you in the right direction and it will even allow you to rule out easily identifiable ‘too big’ or ‘too small’ bikes when shopping online, but nothing will truly confirm that a bike is the right one for you until you take it for a spin. And bike fit can also be adjusted by moving the height of your seat or your handlebars. It’s all about experimenting with what feels right and comfortable to you, which is also something that might change over time as you get more confident on a bike and maybe even alter your riding style. The above are just some basic outlines for the next time you’re procrastinating by looking up bikes on Craigslist and wondering whether they’d be a right fit for you…