Common Tread

Learning your Harley ABCs

Apr 02, 2013


Harley-Davidson model names sometimes look like a foreign language. Or code. But there is some reason behind all that alphabet soup.

Here's a quick and dirty crash course in H-D nomenclature. This is not comprehensive or complete. Factory records are even spotty from some time periods (there was a big fire in the 1950s), and Harley built and did strange stuff over the years. Respected Harley historians aren’t even in agreement on many aspects of things, especially regarding the early bikes. Remember, the original shop in Milwaukee was akin to your modern bike shop. It was just a couple of dudes wrenching away.

Also, there are thousands of common H-D nicknames for stuff. If you don’t know what a mousetrap, ratchet lid, Pan-Shovel, or electric foot are, it’s OK. You’ll get there.

Super-glossed-over early-ish Harley-Davidson history

Harley made some weird items. Thumpers. Peashooter flat-trackers. A BMW boxer copy. They licensed Aermacchi small-displacement bikes, which were sold as H-D products. They built snowmobiles and golf carts. Harley even had the Nova project in the 1980s, looking into a liquid-cooled V-4.

Not all of this stuff was bad ideas and psychedelic drugs. A lot of these innovations paved the way in motorcycling. They began using conventional hydraulic front ends on the Hydra-Glide in 1949. Bikes got suspension at both ends in 1958 on the Duo-Glide. The Sportster was the BMW S 1000 RR of its day. It was a performance contender, a hot bike and a research test bed. The 1965 Electra Glide was the first common H-D to receive electric starting. Take a moment to think about that. In 1963, you could buy a premium, top-line touring bike, and you would be kick-starting its cantankerous ass to life.

None of this is particularly important, but you need to know that Harley was making bikes from the very beginning of motorized history, and they were crude and rough, made to last even if they were not too refined. Harleys are infinitely rebuildable right up through the Evo engine, and usually, the value they command makes it worthwhile to do so. The proliferation of Sportster parts alone speaks to the vastness of this demand. If you see an old Shovel on the road, chances are it’s on its third overbore, and probably has had six owners.

Now, a fast breakdown of the stupid letter system. It didn’t used to suck; that’s recent. The first two letters in air-cooled Harley letter codes back in the 70s told you about the engine and front tire (well, it was the fork, which governed the tire, but now the tire is really the only semi-reliable way to gauge what fork could be on the bike.) XL was the Sportster with a 19-inch or 21-inch tire (and a Narrowglide). FL was a Big Twin engine with a 16-inch (or now sometimes 17-inch) front tire (and the heavy Touring front end). FX was a Big Twin with a 19-inch or 21-inch tire (and a Narrowglide).

Narrow and Wide Glide referred to the distance between the front fork tubes, by the way. That’s the big deal. They named a whole bike after fork tubes that sit farther apart, swear to God. Original Narrowglides were about seven inches wide center-to-center, and original Wideglides were about 10 inches. Now there’s a proliferation of forks, tubes, and trees, all of which are reproduced with even different specs by aftermarket suppliers, so the terms are muddy. These days, Wide Glide is the only sure bet, which is the front end that comes on the FXDWG (Dyna Wide Glide). They even make a Mid-Glide nowadays. My head hurts.


FL (Touring bike, big engine) plus XL (Sportster, little unit engine) equals FX (Super Glide — big engine, sporty-handling front end). Get it? That used to be pretty much the three models they sold. A chimp could remember those three.

The third character to come along was the frame, as Harley started using different ones. (And sometimes the fourth character, too, depending what frame is used. I’m looking at you, Softail.)

The Harley Softail utilizes ST frames (usually — sometimes they are simply an “S,” like in the FLS Softail Slim... I hate you, Harley). Touring frames with fork-mounted fairings are H frames, and Touring frames with frame-mounted fairings are T frames. Dynas are D frames. Rockers, a crazy variation of the Softail, were C frames. Rubber-mounted FX frames are R frames, designed by a young Erik Buell, they are easily picked out by a metric-style “triangle” of frame tubes joining under the saddle. V-RODs are their own bastard child. “VRSC” anywhere is a V-ROD. Next to nothing on them interchanges with a “normal” Harley.

The rest of the letters after the first two, three or four represent options. Some common ones are:

  • SS: Springer Softail
  • SC: Springer Classic
  • WG: Wide Glide
  • FB: Fat Boy
  • SE: Screamin’ Eagle
  • D: Deuce

Current model names and letters

This section is sort of bleed-over from the previous section. It’s born from the wild proliferation of options as customers began demanding more and more crazy stuff. Blame it on the 1990s.

Harley let the letter thing get out of control. Now they try to just use model names in the showroom, but the letters are still there. Old Harley guys ignore them because they make no sense to normal, breathing humans. Hence, if you can figure out really fast that an FLHTCUTG is an Electra Glide Trike, you’ll look like a genius.

Currently, there are five model families within H-D: Touring, Sportster, Dyna, Softail and V-ROD.

Let’s start with the easy one. Sportsters always start with “XL.” There are other letters that can follow, and numbers sometimes indicating displacement, but just remember that an XL is a Sporty. Sporties have unitized motors. To this day, The Sporty has four cams, and that atypical-for-H-D setup means that the pushrod tubes run parallel to one another. You can pick a Sportster engine out a mile away because of it. Done.

Next are the Harley Touring bikes. These bikes all have heavy frames, bags, and either 16-inch or 17-inch wheels on non-CVO models.

(A brief aside: CVO is “Custom Vehicle Operations.” It is the performance division of H-D. Usually, bigger engines that will later appear in production bikes are showcased here. Crazy paint is the norm, and hot rod parts and trick wheels are to be found. They are pricey and limited numbers are produced each year.)

There are really only three types of touring bikes: those with batwing fairings (named, duh, because it looks like a bat wing), those with glass, and those with sharknose fairings. (These look like a, uh, nose. Like, on a shark.) Batwings mount to the forks, sharknoses mount to the frame, and I assume you all know what a Plexiglass windshield looks like. If you wiggle the bars and the headlight moves, it’s a batwing. If you move the bars and the headlight points down the road still, it’s a sharknose and a Road Glide, one and the same. If it has just a windshield, it’s a Road King. Road Glides with the frame-mounted fairing start with model code FLT, while every other Touring bike is an FLH.

Moving right along, we now have Softails. They’re easy to spot. They have a hidden rear suspension that looks like a hardtail at the rear triangle. Popular ones include the Heritage Softail, the Fat Boy, and the Night Train. Pssst... they’re pretty much all the same bike, even though they look crazily different! Their whole goal is to look like rigid-rear bikes. Pose much?

They come in two main varieties: FXST, Softails with a front tire 17 inches or larger (with narrow forks), and FLST, Softails with a front tire 16 inches or smaller (with wide forks).

Some oddities about Softails. Some letter codes buck the trend — the Softail Slim, for instance, is an FLS. Why? Because it’s Harley; they can do whatever they want. Honestly, FLST was already taken, and to start stacking more letters in was going to be ridiculous. The Blackline is the same way. It’s an FXS. Why? FXST was taken, and to use a different name, they’d have to make alphabet soup. To make matters more confusing, before the ST (Softail) frame existed, an FX-framed bike was a Super Glide! So, if a rookie tells you he has an FXS, it might be a Shovelhead with exposed rear shocks, or it could be a Twin Cam with hidden rear suspension.

Incidentally, if anyone tells you they have a “Springer,” the Softail is the only modern bike Harley put springer front ends on. They will fit on other stuff and guys do it... but H-D only ever put them on Softies.

There’s one caveat here in the Softail category: Heritage Softails. Man, they look a lot like a Road King. They’re patterned, really, after an old Hydra-Glide, meant to look suspended in front, and rigid in the back. Road Kings are patterned after the old Duo-Glide. They’re not trying to trick you into thinking that they don’t have rear shocks.

Well heck, this is easy, right?

Next up are V-Rods. With liquid-cooled engines, they're unlike any traditional Harleys. The letter code on all of them will go VRSCsomethingsomething.

Finally, we have the Harley Dyna. The cheapest way to get into a Big Twin, this model is easily distinguished by its exposed rear shocks. They all start with FXD, with the exception of the new Switchback, which is an FLD (because it has the little front wheel and is the only Dyna to have the wide-ish Touring forks).

Harley engine names

They’re not separate from the bikes, they’re in conjunction with them. Realistically, you could refer to your bike as a Blockhead, a Dyna, a Wide Glide, an FXDWG, a Big Twin, or a Harley, and still be pretty spot on with all of it. And I think that most people just feel cool when they talk about a “Panhead.”

Harleys from the old days did not differ much from one another, and the models were often just referred to by their powerplant, which were usually nicknamed due to the shape of their rocker box covers. The practice stuck, even when a bike name would have been more helpful, but people do what people do. Most older Harleys wind up getting cut up into Frankenbikes, so it at least gives people an idea what era the bike came from. Basically, there are two groups: Big Twins, and Everything Else. Big Twins have separate transmission assemblies and left-side final drive. Here are the notable players in the Everything Else category:

  • 45 (Flathead), 1929 to 1973. Found in motorcycles until 1952, and then its use was relegated to the Servi-Car (letter code G), a little run-around trike originally meant for automobile dealers, but later outfitted for all sorts of urban delivery chores. Not usually lumped in with big twins. Also not to be confused with Big Twin flathead. This one’s kind of a freak, don’t worry about seeing one, they’re pretty rare and slower than all bejesus (50 mph on a good day with a downhill stretch and a tailwind.) Oddly, they were pretty much unchanged up until the 1970s, so you were really riding history, even back then.
  • Ironhead, 1957-85. Found only in XL models (Sportsters). Motor is different from big twins in a variety of ways: four cams instead of one, and it is unitized (transmission and motor are all in the same casting). It’s easy to pick these out. The pushrod tubes are parallel to each other. Existed in 900 cc and 1000 cc versions.
  • Evo (Evolution) Sportster, 1986-present. Sportster only. Comes in 883 cc and 1200 cc versions.

Here are the notable Big Twins (non-unit motors):

  • Flathead, 1930-48. It was made in 74 cubic inches of displacement and, later, 80 ci.
  • Knucklehead, 1936-47. It was first 61 ci and, later, 74 ci.
  • Panhead, 1948-65. Made in 61 ci and 74 ci variants.
  • Shovelhead, 1966-84. It was 74 ci and, later, 80 ci. A word of note: Shovels from 1966-69 were made with Panhead-like lower ends. They have a flat right side like the earlier Pans and Knuckles, and are commonly called Pan-Shovels or "slabside" Shovels. The later Shovels are "cone" Shovels due to the shape of the ignition "nosecone" on the right side of the engine.
  • Blockhead, 1984-99. All Blockheads are 80 ci. A word of note: Also called Evolution or Evo, this engine is not to be confused with the Sportster Evo. Same name, different engine.
  • Twin Cam, 1999-present. There are 88 ci, 96 ci, 103 ci, and 110 ci versions. Also called the Fathead, this differed from all previous OHV Big Twins by having more than one camshaft in the engine. It looks a bit like the Evo, but can be told apart by rocker box bolts (three on the right edge, instead of the Evo’s two) and the distance between tappet blocks (Evo tappet blocks are almost touching, while the Twin Cam’s are a few inches apart, due to the extra cam in there). It has been H-D’s practice to debut a bigger engine in CVO models. That CVO engine, in a few years, becomes a new production engine. For example, the 110 ci engine is now in CVO bikes. The Street Bob and Super Glide come equipped with a 96 ci engine. All other Big Twin bikes have a 103 ci engine at the time of this writing, which was for a short time the CVO engine.