Skip to main content.
Bikes. Parts. Chaos.

Here at Surly HQ, all sorts of questions land in our inbox. From time to time, we review them and catch a whiff of something worth exploring.

“How much can I haul with my Big Dummy?”

“What’s better: Riding Loaded or Riding ‘Loaded’?”

“What year is my Surly and how do I read my bike’s serial number?”

All fine questions to be sure, but we’re gonna focus on that last one. So, why does the serial number matter? Well, some Surly riders want to know how old their bike is and which parts are compatible with their frame generation. Others just really like their bike and want to be ready in case someone else rides off with it. (With that said, if you haven't registered your bike yet, set your beer down and register your Surly bike right here.)

Now, the very first Surly bikes don’t have model codes or serial numbers. We’re sorry about that, and we recommend hanging onto those legacy models extra tight so nothing bad ever happens. About 10 years ago, though, we started putting serial numbers on all of our bike frames and forks. Let’s check out how they work.


As long as you are not currently sitting on your Surly bike, flip it upside-down and put your eyeballs on the bottom side of the bottom bracket shell.

You should see a model name or code stamped into the steel. This’ll look something like “Troll XL” if you’re riding an extra-large Troll, or “1xFun S” if you’re riding a small Lowside.

If you can’t read the serial number, there are a couple of tricks that may help you read the serial number better:

Trick A: Try using the old crayon / pencil rub technique. Take a piece of paper, lay it on the BB shell, then rub gently with the side of the crayon to see the letters/numbers magically appear on the paper. Straight out of James Bond’s playbook.

bike serial number - pencil rub

Trick B: This is probably the easiest and most effective, so we recommend starting here. Use a flashlight and shine the serial number at a low angle to help create shadows.

bike serial number - flashlight

Fun Fact: Instead of always using the model name, we’ll sometimes use a code name like 1xFun to amuse ourselves. At the bottom of the Spew, we’ve added a list of all the model codes you might see on a Surly frame.

After locating the model code on your bike, look for a series of letters and numbers nearby. The letter comes first and indicates the factory where the frame was produced. If you see a big “M,” that stands for Maxway. Located in Taiwan, Maxway is currently Surly’s only frame supplier.

Following the factory letter, the first two digits mark the year. Next, two more digits mark the month, and the four final digits tell you the unique production number assigned to your specific bike.

The final result might look something like M19051234, with M once again standing for Maxway; 19 standing for 2019; 05 standing for May; and 1,234 indicating that 1,233 other bikes rolled off the factory floor that month before yours did.

But what if you look for that series of letters and numbers and it starts with a “W” instead of an “M”? We can explain that, too. Axman in Taiwan assembles almost all Surly frames and follows the serial-number format explained above, but starting with the launch of Big Easy in model year 2019, we partnered with a new frame assembler ­— Willing in Taiwan ­— because of their familiarity with Bosch electric bike motors and batteries. Willing has also assembled a few model year 2019 Cross-Check and Steamroller frames for us, and they do serial numbers a little differently. Here’s how they look.

Starting with a W for Willing, the second letter is E, which is how Willing identifies Maxway as the frame supplier. Next is the number 9 for model year 2019. Future model years will be coded by a letter instead of a number, such as A for ’20, B for ’21, or C for ’22.

After WE9 comes the production month, marked by A for January, B for February, C for March, and so on. So if, for example, you get your hands on a Big Easy, Cross-Check, or Steamroller assembled in August 2019, its serial number will begin with WE9H. Finally, the serial number will end with five digits indicating how many unique frames rolled off the line before yours that month. A serial number that looks like WE9H00168 means your bike was the 168th Surly frame Willing assembled in August of 2019. It might look a little different from the rest of the Surly serial numbers out there, but that just means your bike is special, which you already knew.


Because Surly frames and forks are often sold separately, Surly forks need a serial number that’s unique from the one on the frame. And because we currently use three different fork suppliers, our fork codes vary a bit depending on where they come from. The good news? One day all the fork codes might look the same. We’re working on it, anyway. In the meantime, if you have any questions about how to read the code on your fork, contact or call 1-877-743-3191 and we’ll help you sort that out.

Till next time,



Here’s that list of model codes we promised.

Big Easy: BE
Big Dummy: BD
Big Fat Dummy: BFD
Bridge Club: BC
Cross-Check: CROSS
Long Haul Trucker: LHT
Disc Trucker: LHTD700
Ice Cream Truck: ICT
Karate Monkey: KM
Krampus: KRA
Lowside: 1xFUN
Midnight Special: MS
Ogre: OGRE
Pack Rat: PR
Pugsley: PUGSLEY
Steamroller: STEAM
Straggler: STR
Troll: TROLL
Wednesday: WED