Gravel Bike Sizing Made Simple

We get it, choosing the right size bike – any bike - can be a bit daunting. So, whether you’re looking for a new gravel bike, or you’re just starting out and looking for your first bike, this guide is designed to help you saddle up in comfort from the very first turn of your pedals.

The kinds of adventures you’re planning with your new gravel bike – from bike packing to high-speed racing – can have an effect on the size that’s going to be best for you. But the key ingredients are generally your height and leg length, combined with your flexibility to get the recipe right first time.

Size Matters

Bike size shouldn’t be mixed up with bike fit. And the two are totally different things.

Getting your bike size right first is important, with bike fit being the thing you can do afterwards to tweak, adjust and customize the parts of the bike specifically around you.

Generally, following our sizing guide will match you with a Cannondale bike that fits you really well to get the most out of your gravel riding.

Of course, this can always be refined and improved upon. So, once you’ve discovered the perfect size for you, you can chat to your local Cannondale dealer to about getting a pro fit with your new gravel ride.

Gravel Bike Sizing 101

First things first, gravel bike sizing refers to the frame size of a bike and its dimensions. Not the wheel size and not tire size. In fact, while the whole topic can be kind of confusing, nearly every adult gravel bike – whatever their purpose – actually uses one of just two wheel sizes; 700c or 650b. So that’s one part of the puzzle that’s pretty straight forward at least!

Most modern bikes are sized in centimeters. Originally this size referred specifically to the length of the seat tube. But, as bike designs and silhouettes have evolved, the sizing is more of a general index now and reflects an approximate size. So, a 54cm gravel bike frame probably doesn’t have any measurement on it that equals 54cm, but it’s still somewhere roughly the size of a 54cm bike in the original approach to sizing.

Whichever gravel bike you’re considering, Cannondale offers something for everyone. You’ll see between five and eight different sizes in each gravel bike model, designed to fit riders anywhere between 5ft (155cm) to more than 6ft6 (198cm) tall.

Finding the right size for you

You guessed it; your height is an important factor when finding the right size gravel bike. But so is your leg length, AKA your inseam.

You want to be able to work out the stand over height of the bike you need by accurately measuring your inseam. This will mean you can comfortably straddle your new bike while standing over. And comfort is king when it comes to bike sizing.

So, how do you measure your inseam? Well, start by standing with your legs 8-10 inches (20-25cm) apart. Now, measure the distance from the floor to your crotch. Since you need to have a bit of space between your crotch and the top tube, subtract 1-2 inches (2.5-5cm). To convert inches into centimeters (if you're not using metric measurements), multiply this number by 2.54. Then make a careful note of it to remember it.

When you find a gravel bike model you like the look of on the Cannondale website, you can find the “Geometry” section and look for the “Standover” line in the geo chart. The best size for you should be the one that falls closest to the measurement you noted earlier.

Keep in mind that safety dictates you have enough standover clearance to comfortably stand over the top tube with your feet in shoes and standing flat on the floor. So, it’s best to always have 1-2 inches (2.5-5cm) of clearance between your body and the top tube.

Now, you might find that your standover height measurement actually falls between two frame sizes. Several factors can come into play to select the right one for you in this case. If you have a long torso, you might want to choose the larger of the two, as the longer top tube will suit you better. Shorter torso, meanwhile, and the smaller of the two frame sizes you’re might be a better bet. Since the smaller frame will come with a shorter top tube, you won’t find yourself too stretched out to reach the bars.

Arm length can also be considered. And also your relative flexibility. This is ultimately where a professional bike fitter would help choose what’s best. If possible, take a test ride on the two sizes you’re considering, as you'll get a better idea of the differences when riding them.

Racing vs Bikepacking vs Endurance

It's also worth keeping in mind the kind of riding you're mostly planning to do with your new bike. The kind of riding isn’t going to wildly change the frame size you need per se. But, if you’re between two frame sizes, you might want to give it some thought.

Racing for example usually leans towards a more aggressive, racy fit. So, a lower front end and a longer, more stretched out riding position. So, on a bike such as the SuperX, if a rider is between sizes, they might want to opt for the smaller, more compact option for weight savings and aero gains.

Meanwhile, bikepacking and more endurance riding are better suited to a more upright, comfortable position on the frame, to allow for longer hours in the saddle and increased comfort.

If you’re interested to learn more about the differences between Cannondale’s different gravel bikes with a view to learning which one might be best for you, check out this article about choosing the right kind of gravel bike.

Dialing in your fit

So, you've found the kind of gravel bike you want. And you’ve worked out the ideal size frame you need. But what then? Well, there are a few different adjustments that you can look at making that could have a huge impact on your comfort on the bike.

Naturally, saddle adjustment is possibly the single most important thing you can adjust and tweak when it comes to fitting yourself to the bike. And while everyone knows saddle height is adjustable, some riders forget all about that the fore/aft positioning of the saddle. This is adjustable by sliding the saddle forwards and backwards on its rails where it meets the top of the seat post.

Then there’s the saddle itself. This is often one of the first items riders switch out and upgrade. Since we're all different, finding a seat that’s ideal for your anatomy and the riding that you’re doing can make a huge difference in how much you enjoy your time on the bike.

A proper bike fitting can be a fairly involved process. So we strongly recommend you visit a shop you trust and talk to a pro about getting a bike fit if you want your Cannondale to feel even better.

Wherever your gravel bike adventures take you out there – be they racing, roaming or bike-packing – we're sure you’re going to have an epic time once you find the right bike for you, combined with the best possible fit!