Whether a mountain bike, road bike, or hybrid, the frame is one of the essential components since it holds the whole thing together. That said, frames come in different varieties, especially regarding the material used. You could also see different variations in frame design. So, what are the different types of bike frames, and how does that influence your buying decisions? Before we can get to that, here’s a snippet explaining how frames are manufactured.
A bike frame is typically made up of front and rear triangles. The rear triangle comprises the chain stay, seat tube, and seat stays. The chain and seat stays come in pairs and are attached to the bottom and top of the seat tube, respectively. They’re the tubes that wrap around the back wheel of the bike. It’s also worth noting that the bottom of the seat tube attaches to the bottom bracket. The front triangle consists of the seat, top, and down tubes. However, contrary to what the name implies, it may not actually be a triangle, depending on the bike design.
Often the top tube and down tube are attached to different sections of a head tube, making it a quadrilateral instead of a traditional triangle. However, looking at it from afar, it looks like a triangle. Also, some top and down tubes attach at the same point, making it more of a triangle. The steering tube goes through the head tube and is connected to the handlebar and front fork.
Also, while this is the basic design, there are variations, such as when specific tubes intersect or feature a folded design.
The manufacturing process of the frame will depend on the materials and whether the manufacturer wants seamless or welded tubing. With welded tubing, a strip or sheet of steel will be rolled into a tube and then welded longitudinally. As for seamless tubing, the material is first heated and then extruded into a hollow form. They are drawn through a mandrel rod and then elongated, making a seamless tube shape. The resulting tube can be shaped further through cold rolling, drawing, and pilgering.
As such, seamless tubes have varying shapes instead of the typical straight shapes you see with welded tubes. For instance, they can be ‘butted”, where one or more tube sections are thickened while the rest are relatively thin. In quad-butted seamless steel tubing, for instance, the center of the tube is thinned out, while the rest is relatively thick. Seamless tubes also have extra benefits, such as they’re produced to a specific chemistry to make them lighter or more robust.
Also, once the specific components of the bike frame are made, i.e., the top tube, down tube, chain stay, etc., they are put together through brazing or machine welding. Finally, the frame is painted to give it a finished look.
You can often tell the type of bike by the kind of frame, even if nothing else is attached, as shown below.
Mountain bikes are among the most common types of bikes in the market. Their frames are typically made out of carbon fiber, titanium, aluminum, or steel. Also, they’re thicker and heavier than most other frames since they’re taken through some of the harshest riding conditions.
If you’ve ever gone mountain biking, you know why a strong frame is necessary. Often you jump over obstacles with the landings requiring a solid frame so the bike doesn’t fall apart. This kind of repeated stress would likely break something like a road bike frame within a few months. As such, mountain bike frames need to be thicker and have more mass to maintain their integrity. Unfortunately, that also means they’re harder to ride up the mountain. However, that is a sacrifice you must make so you don’t injure yourself as you head downhill.
Additionally, mountain bikes have varying designs, so there may be different types of mountain bike frames. For instance, the top tube may be curved. Alternatively, you may see an extra tube attaching the top tube to the down tube for extra rigidity. It’s worth noting that mountain bike frames also typically have short headtubes. It’s also common to see a space on the seat tube or somewhere else on the frame where a shock absorber can be integrated. Ultimately, we’ve found some of the best mountain bikes in the market with different designs to suit people’s needs.
You can typically distinguish a road bike from other bikes by the frame. They’re made of light solid materials and usually have a plain design. Those made of steel have thin tubes to make them as lightweight as possible. Those with aluminum or carbon fiber frames may be thicker, but there’s an emphasis on making them as streamlined as possible. There are also titanium road bike frames.
Concerning the head tube, there may be some separation where the top and down tubes attach; hence, they can be longer than those on some mountain bikes. However, some manufacturers also choose to put them closer together. Also, the seat tube may be longer than those on other bikes since the bike is designed for an aerodynamic riding position.
Hybrid bike frames are sort of a mix between road bike frames and mountain bike frames. The frames are lightweight but with the seat tube and front tube positioned for an upright riding position. The Vilano Diverse 3.0 perfectly illustrates what a hybrid bike looks like. Even the handlebar is made for upright handling with a rigid suspension, different from what you’d get in most mountain bikes.
With a gravel bike frame, you get longer head tubes for better comfort, with the frames also strong enough to carry extra equipment and racks. Also, these frames have slacker head angles, meaning the “slack” angle is 63-66 degrees. This allows the front fork to stick out further, making the bikes more stable at faster speeds. That said, they don’t turn as quickly, leading to slower handling.
Cruiser bikes, like their hybrid counterparts, are designed for upright riding. They may also have wider frames compared to their gravel and road counterparts. Also, the fact that they typically use wider tires than most other bikes means the separation between the chain and seat stays may be wider than in other bikes. The Sixthreezero Cruiser Bike shows that even if a cruiser bike is fitted with thin tires, the frame can be broader and less streamlined than in a road or hybrid bike.
Commuter bike frames often look a lot like road bike frames. They’re thin and lightweight, and in some cases, they may even look identical from afar. That said, these bikes typically use wider tires. As such, the seat and chain stays will likely be slightly wider than those on a road bike.
Cargo bike frames are unlike any other bike frame on the market. The rear triangle is the same as you’d find in any other bike. However, often there’s a very long tube that extends from the seat tube through an elongated head tube with the front wheel placed much further forward than in other bikes. The space between the head tube and the front wheel is a cargo area. Some variants also use a smaller back wheel with a cargo area above it. In this case, the rear triangle of the bike is the one that’s extended.
As mentioned above, the manufacturing process for the bike depends on the type of materials used, with several options, including carbon fiber, steel, aluminum, and titanium. So, steel vs aluminum bike frames? Which one should you choose? Or is it better to go for carbon fiber and titanium? Well, it depends on several factors, as explained below.
Most high-end bikes in the market, whether mountain bikes, road bikes, or otherwise, are made from carbon fiber. As such, if you see one in a bike shop that costs $2,000-$4,000, it’s likely made of carbon fiber.
These frames are made when carbon sheets are bonded together with resin. They’re pretty low-density, which makes them incredibly light, and one of the extra perks is they absorb vibrations better than most other frame materials. This is why carbon-fiber road bikes are fairly comfortable despite not having shock absorbers. They also allow for a range of shapes which is why road bikes made using carbon fiber have aerodynamic frames. However, carbon fiber is one of the most expensive types of bike frame materials hence the high cost of carbon fiber bikes.
As for downsides, these bikes are hard to repair, and even light damage can mean structural issues that force you to get a new bike.
While aluminum is light, it’s not as lightweight as carbon fiber but is more affordable. Additionally, it’s firm but not as strong as steel. As such, it makes a great midpoint between steel and carbon fiber. One other perk is its stiffness, although it’s a double-edged sword since the stiffness also means it’s unable to absorb road vibrations. As such, it makes robust and light bike frames. However, aluminum bikes may not be as comfortable for long rides.
If you see a road bike that costs between $1,000 and $2,000, it’s likely made of high-end aluminum. Nevertheless, we’ve outlined some of the best road bikes under $2,000, and you’re likely to find a few carbon fiber models among them as well.
Steel bikes are becoming less and less popular by the day due to the material being heavy. You can still get a custom steel bike, although you’re unlikely to find them in most bike shops. However, the fact that they’re custom means they cost significantly more than they used to. Depending on the design, they might even be more expensive than a high-end store-bought bike.
Nevertheless, steel bike frames are pretty solid and easy to work with, so they can also be repaired quickly and easily.
Titanium is stronger than steel but also lighter. Also, compared to aluminum, it’s heavier, but you don’t need as much of it. As such, titanium frames might actually be lighter since they use less material. Other perks include being corrosion-resistant and being as comfortable as carbon fiber. After all, titanium frames absorb vibrations reasonably well. Unfortunately, the metal is rare and hard to work with, which increases the overall cost.
It’s also worth noting that bike frames come in different sizes, and here’s what you should go for depending on your height, inside leg measurements, and the type of bike you’re buying.
| Rider’s height | Inside leg measurements | Ideal frame size |
| 5’1″-5’3″ | 27″-29″ | 48 cm |
| 5’3″-5’5″ | 28″-30″ | 50 cm |
| 5’5″-5’7″ | 29″-31″ | 52 cm |
| 5’7″-5’9″ | 30″-32″ | 54 cm |
| 5’9″-5’11” | 31″-33″ | 56 cm |
| 5’11”-6’1″ | 32″-34″ | 58 cm |
| 6’1″-6’3″ | 33″-35″ | 60 cm |
| 6’3″-6’5″ | 34″-36″ | 62 cm |
| Rider’s height | Inside leg measurements | Ideal frame size |
| 4’11”-5’3″ | 25″-27″ | 13″-15″ |
| 5’3″-5’7″ | 27″-29″ | 15″-17″ |
| 5’7″-5’11” | 29″-31″ | 17″-19″ |
| 5’11”-6’2″ | 31″-33″ | 19″-21″ |
| 6’2″-6’4″ | 33″-35″ | 21″-23″ |
| 6’4″ and over | 35″ and over | 23″-25″ |
| Rider’s height | Inside leg measurements | Ideal frame size |
| 4’10”-5′ | 26″-28″ | 13″-14″ |
| 5′-5’2″ | 27″-29″ | 15″ |
| 5’2″-5’4″ | 27″-29″ | 16″ |
| 5’4″-5’6″ | 28″-30″ | 17″ |
| 5’6″-5’8″ | 28″-30″ | 18″ |
| 5’8″-5’10” | 29″-31″ | 19″ |
| 5’10”-6′ | 30″-32″ | 21″ |
| 6′ and over | 32″-34″ | 22″ |
While height is a pretty good indicator of what bike frame size you should go for, the inside leg measurement is typically more accurate. You measure from the groin area down to the ground while your legs are shoulder-width apart. You might need a friend or partner to help you get accurate results.
While you can use MIG and Stick welding to put a bike frame together if you’re skilled enough, most bike manufacturers use TIG welding or brazing because they offer greater control over the heat.
It all depends on your body proportions. For instance, if your arm span is shorter than your height, you’re safer going for a more petite bike frame. Conversely, if it’s bigger, you’d be much better off with a larger frame.
Although you may want a lighter bike depending on how you want to use it, the frame’s weight doesn’t matter much regarding durability. Even a lightweight bike can be just as strong as a heavier alternative depending on the materials used. However, depending on the riding conditions, it can affect your overall riding experience and how fast you accelerate.
Painting a bike frame is a reasonably easy six-step process.
Overall, there are different bike frames, each with benefits and downsides. Steel is sturdy and easy to work with but is becoming increasingly uncommon in the market. It’s also heavy. Titanium is relatively expensive and hard to work with but is durable and light. As for carbon fiber, it’s lightweight and a more comfortable material when riding.
Lastly, aluminum is sort of a mix between lightweight and affordable. There are also different types of bike frames to cater to different uses, whether it’s mountain biking, road racing, etc. With the write-up above, you should have a basic understanding of all of them and the reasons to choose one over the others.
