Back in 2015 I was working as an analyst at Apple and was increasingly frustrated that most of my time was being spent wrangling messy data instead of doing the analysis and data visualization work I enjoyed. I remember thinking “You know, I have this spreadsheet of bike geometry I collected. That data is so simple and tidy! I should play around with that as a fun exercise.”

Meanwhile, across the country, Zach was playing with bike geometry data from a software engineer’s perspective- a project that would eventually grow into Bike Insights.  Amazingly enough, we both came away from the exercise resolved to purchase the same niche bike from a small frame building operation. This is basically the plot of Sleepless in Seattle but adapted for bike nerds.

Five years later, we are sitting atop the most robust and meticulously-designed bike geometry database around and we have come to the following conclusion:

Whelp… this is a lot more complicated than we thought

The complexity begins before we even get the data into Bike Insights. The way we communicate bike geometry has developed organically over the years and is really nothing more than a loose assemblage of fragmented conventions.

On the surface, measuring bicycle geometry should be a simple affair. We basically have two triangles and a fork. Maybe a couple of circles if you’re feeling fancy. Easy!

But when we get in to the details… I mean really get into the details, things get weird.

The humble beginnings of a bicycle frame. Image used with permission of The Bicycle Academy

Consider the humble bicycle tube. If I were to pluck a piece of steel tubing from the photo above and hand it to six strangers off the street to have them measure its length (in millimeters, of course), I’d get more or less the same measurement.

But if welded this bit of tubing up as part of a bike frame (let’s say as the seat tube) and asked six different bike companies to measure the length of said seat tube, I might end up with six different measurements. That’s because no one has agreed on a single way to measure the seat tube. In fact, yes, there are no fewer than six ways the bike industry measures seat tubes.

To make matters worse, these various seat tube measurements are often used to label a bike’s size. In other words, those six bike companies could sell a bike with the same exact geometry and each might label it with a different size depending on how they measured it (53cm, 54cm, 55cm, etc…).

Of course, this issue isn’t limited to seat tubes, there are multiple ways of measuring top tubes, seat tube angles, chain stays, and forks. In some cases, there are no generally-accepted terms for some types of measurements so we’ve had to create our own. We are on the bleeding edge of bike nerd stuff here, people!

Here’s what Bike Insights is doing to help improve the situation

Surveying bike industry trends

In the past year, we have undertaken a massive data quality initiative, auditing hundreds of bike brands to determine what conventions they use for measuring their bikes. We analyze the data coming into our database, double check a lot of geometry charts, and reach out to bike companies to pin them down on how they measure bike geometry. We’re already using this to QA the data in our database and in the future we’ll be using this to make it simpler for our users to add their own geometries to our database.

Interested to see what the bike industry is doing today? Here are a few interactive charts showing the adoption rates of different measurement conventions across the industry.

We expect adoption rates of measurement conventions to shift as frame design and manufacturing changes. As technology like carbon fiber, hydroformed aluminum, integrated seatmasts, flush seatpost clamps, and integrated stems become more commonplace, it becomes more difficult to use traditional measurements for bike-on-bike comparisons. If we capture this data accurately, Bike Insights can help normalize differing measurement conventions to allow for a more apples-to-apples comparison.

Expanding on existing bike geometry attributes

Curved and offset seat tubes are booming in popularity, and not just for mountain bikes. This allows for some great bike designs put poses a problem for communicating geometry. The bike industry has had to settle for vague “effective” geometry measurements, but we are working on a solution that is better for cyclists and bike companies alike. We’ll be talking about this in more detail in the future, so stay tuned.

Capturing data accurately and more simply

The old saying “garbage-in-garbage-out” rings true when it comes to bike design analysis, so we’ve taken steps to try to educate our users about the many conventions out there and to provide an illustrated guide when adding bikes to our bike geometry database. We think that a picture is worth a thousand words, so you’re now able to scan through our attribute picker and select the measurement that matches a brand’s bike geometry diagram.

We’ve also updated our Cyclopedia with improved, interactive visuals for many entries including:

Seat Tube Length

Top Tube Length

Fork Length

Seat Tube Angle

Chainstay Length


Even if you aren’t adding bikes to the database, these are good resources for educating yourself about how bike geometry works.

And much more is in the works!

In our world, every millimeter counts. There is so much more in the works to help provide quality bike geometry data and insights to our users.

If you want to help with our mission, sign up for the site and leave feedback on bikes you’ve ridden using the “I’ve Ridden” button on each bike profile. We’re working to take your feedback and use it to provide more insights that will take the site to the next level. We can’t wait to show you more!

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Also, if you’d like to help get the word out about Bike Insights, give us a follow on Instagram and Twitter to help increase our visibility with other cyclists. Thanks!

If you liked this blog post, be sure to sign up to our mailing list below to stay in the loop. We promise not to send you spam!

Also, if you’d like to help get the word out about Bike Insights, give us a follow on Instagram and Twitter to help increase our visibility with other cyclists. Thanks!