Riding a properly fitting bike can not only be the difference between comfort and discomfort (which is perhaps the most major factor in how much you want to ride). It can also mean the difference between whether or not you injure yourself, as spending huge amounts of time on a bike that is too big or too small for you can lead to a variety of maladies.

Whether you’re riding all the time or just getting into cycling, there are a few tips you can follow to make sure you’re buying the right sized bike and dialing it to your body in a way that will give you endless pain-free hours in the saddle. Because a bike that fits you well shouldn’t hurt at all.

If you’re experiencing pain, discomfort, or numbness anywhere, your bike fit is off. Of course, the pain and numbness in your butt after a 60-, 70-, or 100-mile ride is unavoidable and has nothing to do with fit. But riding a bike any distance shouldn’t result in pain or discomfort in your joints, neck, back, or anywhere else.

If you’re intending to spend a ton time in the saddle and/or dropping serious coin on a new bike, the best option is always to get a professional bike fit, which is a process where an expert fitter will analyze your body type, your riding style, even your ambitions, and dial your bike incrementally, that it perfectly fits you. My colleague Joe Ray can offer advice on getting a professional fit.

It’s also important to note that the rules for finding the best fit are different based on what style of bike you want, what your transportation needs are, and how much you intend to ride. If you want a drop-bar bike such as a road or gravel bike, a mountain bike, or a hybrid bike, the handlebar setup will affect other factors like the frame size and saddle height. Also, as men and women tend to be built differently, the design of bike frames and their components should be taken into account. Some brands such as Liv or Juliana are designed specifically for women, who tend to have narrower shoulders and shorter torsos relative to their legs than men.

Size Matters

It’s easy to wander deep into the weeds, but there are some basic things you can do to ensure you’re riding a properly fitting bike. Following these tips should help you make the most important decisions.

Start with the biggest thing! That is, your frame. There is no bigger single part of a bike than its frame. It’s also one of the only parts of a bike that is not adjustable. Your frame will always be the same shape and size, and there’s no changing that. So you want to start with the proper frame before anything else.

Most manufacturers size their frames using the small, medium, and large paradigm (with some brands offering XXS through XXL) or using measurements in centimeters. Typically, off-road bikes come in S, M, L, whereas road bikes use centimeters.

A good place to start is by researching a height chart. Considering not all bikes are built equally—not everyone’s “large” frame is the same size, for example—it’s especially helpful if you can find a chart from the brand you intend to buy.

Here’s a good example from the mega-brand Specialized. If I, at 76 inches, were interested in an Aethos model, I’d probably want to get a 61 cm frame.

If you can’t find a chart for the bike you’re interested in, you can just as easily find the bike itself at a local shop and swing your leg over a few different sizes. The general rule of thumb is that you should be able to fully stand over a bike with both feet flat on the ground with about 1 inch of clearance between your body and the bike’s top tube. Smaller bikes and bikes with compact designs have sloping top tubes; with those, you want to look for around two inches of space.

As contemporary mountain bike frames offer more extreme angles, that space between body and bike is less important. Here, it’s a bit easier to simply find a corresponding height chart from the brand of bike you’re buying. And, again, as off-road bikes are more likely to be offered in S-M-L sizes, there’s a bit more wiggle room. In other words, a large mountain bike will fit a far wider spectrum of bodies than a 58 cm road bike.

Made to Measure

Once you’ve established the proper frame height, you can focus on the more incremental adjustments, most of which pertain to saddle height and position.

When dialing saddle height, a good place to start is by standing next to your bike and leveling your saddle with the top of your hip bone.

From here, you might need a friend to hold your bike while you hop on, grab your handlebars, position one pedal at the bottom of its stroke, and place your heel on the pedal (that’s right: your heel). Adjust your saddle height so that your leg is perfectly straight and your knee locked out at the bottom of the pedal stroke. Now, using your heel, pedal backwards. If your heel stays in contact with your pedal for one entire stroke, your saddle is generally at the correct height. Once you start pedaling with the ball of your foot, you’ll notice that your leg is never fully extended and that, even at the bottom of a pedal stroke, there is still a slight bend to your knee. This what you want.

Most modern seat posts (and plenty of older ones) come with a marking that tells you the absolute maximum you can pull your seat post out of the tube. If you need to raise your saddle higher than the “minimum insertion mark,” you probably need to go up a frame size. Riding a bike with a seat post set any higher than that mark is tremendously dangerous.

Another trick is something called the “LeMond Method,” so named for American cycling great and two-time Tour de France winner Greg LeMond. Multiply your inseam measurement by .883. The resulting number will be the distance between the top of your saddle and the center of your bottom bracket.

Don’t know your inseam length? Stand against a wall while barefoot, stick a book between your legs with the spine at your crotch, mark the point on the wall where the spine is making contact, and measure that distance to the floor. Boom.

However, given that most seat tubes are angled, your saddle might be out of level if you adjust it up and down. So, bring or borrow a level (or use your phone!) to make sure the plane of your saddle stays nice and even as you adjust its height.

Speaking of saddles, they don’t just move up and down. Saddle fore and aft—or how far forward or back your saddle sits—is adjustable as well and can have a huge impact on things like pedal-stroke efficiency and knee pain, or lack thereof.

Again, grab your friend and have them hold you as you sit on your bike. This time, put your foot on the pedal in the three o’clock position, or fully forward and level with the ground. Make sure your foot is in the proper pedaling position. No heels here. The bottom of your kneecap should be directly over the knuckles of your feet. If not, adjust your saddle position forward or back to achieve this position.

For a basic bike fit, those are the biggest elements you’ll need to worry about. There are many more little things you can tweak, like stack height and reach (which pertain to the positioning of your front end), and cleat placement if you ride clipless pedals. But if you pay close attention to the basics of bike fit, you’ll wind up with the right frame size, the proper saddle position, and a bike that feels great to ride.