16 Vs 20 Inch: The Best Folding Bike Wheel Size

by wheretheroadforks

The most important decision to make when choosing a folding bike is which wheel size to go with. This guide outlines the pros and cons of 16 inch Vs 20 inch wheels to help you decide which is the best folding bike wheel size for your use and style of riding. I’ll also outline other existing folding bike wheel sizes including 18 inch, 24 inch, 26 inch, 650b, and 700c.

20 inch folding bike

A 20 inch Bike Friday folding bike loaded for touring

20 Inch Folding Bicycle Wheels

I’ll start off with the most common size. One important thing to know about 20 inch bike wheels is the fact that they aren’t all the same. 20 inch actually refers to two slightly different wheel sizes. This is important to remember because tires are not cross-compatible. The sizes are:

  1. 406 mm wheels- These are the most common 20 inch bike wheels. They are used on kids bikes, BMX bikes, and most 20” folding bikes. 
  2. 451 mm wheels- These are pretty uncommon. They are used on racing BMX bikes and some folding bikes. 451 wheels are slightly larger in diameter than 406 wheels. They are generally used with more narrow tires for more road-oriented bikes.

20 Inch Folding Bike Pros

  • Easier to find replacement parts- Because 20 inch bike wheels are so common on kids bikes and BMX bikes, parts are pretty easy to find almost anywhere in the world. This is particularly important if you plan to tour with your folding bike. You’ll have more luck finding a new rim, tire, or tubes wherever you’re touring. Having said this, they aren’t the most common size. In some regions, parts will be difficult to source. 26 inch wheels are much more common.
  • More efficient to ride- Larger wheels maintain momentum better due to inertia. Once you get up to speed, it takes less energy to maintain it. This means you can cover more ground on a 20 inch folding bike using the same amount of energy as on a 16 inch folding bike. This makes 20 inch folding bike better for longer commutes or tours.
  • More stable- Folding bikes are known for being twitchy due to the small wheel diameter. The steering is more sensitive than larger wheeled bikes. When compared to the smaller 16 inch wheels, 20 inch wheels feel much more stable. The ride quality is generally better as well.
  • Smoother ride- The larger the bike wheel, the easier it rolls over bumps and obstacles in the road. This makes the ride more comfortable as well.
  • More bike options- Because 20 inch wheels are the standard for folding bikes, you have a lot of bikes to choose from. You can find folding bikes with disc brakes, drop bars, internal gear hubs, or basically any specifications you want. You can pick up a basic 20 inch folding bike for just a couple hundred bucks or you can spend thousands on a higher-end option. There are dozens of bikes to choose from in this category.
  • Less maintenance and repair- Generally, larger wheels last longer. 20 inch wheels just don’t have to rotate as many times as 16 inch wheels to cover the same amount of ground. They also don’t heat up as fast while breaking. This means you won’t have to replace rims, tires, or brake pads as often.
  • More tire options- Because 20 inch bikes are so common, plenty of manufacturers make 20 inch tires. You can find everything from slick road tires to knobby mountain bike tires in 20 inch versions. Touring tires are also available.
  • Uses standard bicycle parts- For the most part, 20 inch folding bikes use off the shelf parts. Nothing is proprietary except for the frame and hinges. Sometimes the rear derailleur is shorter but it’s still pretty standard. This makes parts easier and cheaper to replace when they break. Most 16 inch folding bikes use some proprietary parts.
  • Cheaper- If you’re on a tight budget, 20 inch folding bikes are the cheapest option. You can buy a new base model for just a few hundred bucks. You can find older used models for even less.
  • Allowed on some public transport- Many cities allow folding bikes on their metro and bus system. Generally, 20 inch folding bikes are the largest size allowed on.
    Greater luggage storing capacity- Most 20 inch folding bikes are compatible with standard racks and panniers. This means you don’t need to buy new bags to tour or carry your gear.
  • Looks better- A big guy riding a folding bike looks a bit like a clown. 20 inch wheels look slightly more reasonable than 16 inch. Of course, not everyone cares about looks but it is something to consider.
Folded folding bike with 20 inch wheels

A 20 inch folding bike in its folded form

20 Inch Folding Bike Cons

  • Less compact- Regardless of the design, 20 inch folding bikes are always significantly larger than 16 inch models. The wheels are 4 inches larger in diameter, after all. For example, a 16 inch Brompton folding bike measures 23″ x 22.2″ x 10.6″ when folded. That’s 5412 cubic inches or about 89 liters. On the other hand, a 20 inch Tern folding bike measures 15.6″ x 31.5″ x 28.7″ when folded. That’s 14,103 cubic inches or about 321 liters. This is significant. It means you may not be able to fit the bike into certain luggage compartments, car trunks, or under some desks. Make sure you measure first.
  • Heavier- Because 20 inch bikes are larger, they weigh slightly more than 16 inch models. Most 20 inch folding bikes weigh in at around 30 pounds (around13.6 kilos). 16 inch folding bikes generally weigh around 25 (around 11.3 kilos).
  • Less portable- Due to the fact that 20 inch folding bikes are larger and heavier than 16 inch models, they are more awkward to carry. If you expect to carry your bike often, the smaller the better.
  • You may end up paying extra fees to travel with it- Many travelers like to bring their folding bikes with them on vacation to explore their destination. Most 20 inch folders can pack down to fit within the airline’s checked bag limit. Some cannot. If you’re looking for a 20 inch folder that is designed for travel, check out the offerings from Bike Friday. For more info on flying with a bike, check out my guide: How to Box a Bike for a Flight.
  • Not allowed in as many places- The great thing about folding bikes is that you can bring them inside with you rather than leaving them chained up at the bike rack. Some businesses are a bit difficult with this. They don’t want bikes inside, even if they fold. The solution is to store your bike in a bag. Because 20 inch folding bikes are so large, they may look suspicious in this case. If you’re trying to be stealthy with your bike, 16 inch is the better option. They fold down small enough that they just look like a piece of luggage when they are bagged up.

16 Inch Folding Bike Wheels

Similar to the case with 20 inch wheels, there are actually two slightly different wheel sizes that are referred to as 16 inch.

  1. 305 mm wheels- These are the smaller and less common of the two. They generally use a slightly wider tire. Rims and tires are generally harder to find for this size.
  2. 349 mm wheels- This is the more common 16 inch wheel size. It’s the size that Bromptons and most other folding bikes use. The tires that fit this rim are a bit more narrow. Rims and tires for this size are generally more common. 
Folded Brompton folding bike with 16 inch wheels

A Brompton folding bike in its folded form. This bike uses 16 inch wheels

16 Inch Folding Bike Pros

  • More compact- Because the wheels measure 4 inches less in diameter, 16 inch folding bikes can fold down significantly smaller than 20 inch models. This makes carrying and storing the bike much easier. You can fit it under most desks, in pretty much all vehicles, and in various storage lockers.
  • You can take the bike with you more places- The smaller wheels allow the bike to pack down small enough that you can take it almost anywhere. Even where bikes are not really permitted. For example, you can pack a Brompton in an Ikea Dimpa bag or a specialty Brompton bag. The resulting package is small enough that no one will even suspect that it’s a bike. 20 inch folding bikes are large enough to draw attention, even if they are in a bag.
  • Lighter- If you plan to use your folding bike in a way that requires that you fold it and carry it often, 16 inch folding bikes usually weigh around 5 pounds less than 20 inch folding bikes.
  • Better maneuverability- The smaller wheels allow you to practically turn on a dime. This allows you to easily navigate busy city streets and quickly avoid potholes and other obstacles in your path.
  • Can pack small enough to fly with- Most airlines require checked bags to be less than 62 linear inches. 16 inch folding bikes easily meet this requirement with room to spare. For information, check out this great article about packing your 16 inch folding bike from Bromptontraveler.com Some travelers even take their Brompton folding bike into the airplane cabin as a carry-on. Check out Brompton Mafia for more info and some cool photos.
  • Faster acceleration- Smaller wheels have less mass. This allows you to spin them up more easily and quickly. This comes in handy for stop and go riding. For this reason, 16 inch folding bikes are ideal for city use.

A Brompton Folding Bike with 16 inch wheels

16 Inch Folding Bike Cons

  • Fewer tire options- Only a handful of companies manufacture 16 inch bike tires. There just isn’t much of a demand. You’re pretty much limited to a road tire. The most popular is probably the schwalbe marathon.
  • More expensive- For whatever reason, 16 inch folding bikes tend to cost more. Most are higher end. Expect to spend over $1000. You don’t have many entry-level options like you find with 20 inch folding bikes.
  • Less stable ride- Smaller wheels react more quickly to turns. This creates a twitchy ride. Of course, you get used to it after a couple of hours of riding.
  • Rougher ride- Smaller diameter wheels don’t roll over obstacles or potholes as easily as larger wheels. This makes for a less comfortable ride. You’ll also need to pay more attention to the road to avoid any large rocks, sticks, or bumps in your path. You can come off the bike more easily if you hit a large enough obstacle.
  • Finding replacement parts is more difficult- Because 16 inch bikes are so uncommon, spare parts can be challenging to source. Many bikes shops don’t stock 16 inch rims, tires, or tubes, for example. This is particularly problematic if you plan to travel with your 16 inch folding bike in the developing world. In some countries, you can’t just have parts shipped due to high importation costs and difficulties with clearing customs. This means that you’ll have to pack all of your own spares.
  • More proprietary parts- 16 inch folding bikes often use smaller parts that are non-standard. For example, Bromptons are particularly bad for this. Lots of parts are unique to that particular bike. Of course, this increases repair costs.
  • More maintenance is required- Smaller wheels and tires tend to wear out more quickly because they need to make more revolutions to cover the same distance as larger wheeled bikes. You’ll burn through more rims and tires than you’re used to. You’ll also have to service your hubs more a bit more often. Disc brakes solve the rim wear problem.
  • Fewer bike options- If you decide on a 16 inch folding bike, you really only have a few to choose from. The most popular is the Brompton. Dahon also makes a few 16 inch folders.
  • Not ideal for long commutes- The smaller tires lose their momentum faster when you stop pedaling. They don’t coast as far or fast when descending a hill. It just takes more energy to ride a 16 inch folding bike. This means you won’t be able to ride as far as you would on a bike with larger diameter wheels. The bike is just less efficient.
  • Less luggage storing capacity- 16 inch wheel make the frame sit a bit too low to use standard racks and panniers. They would touch when you turn. Luckily, there are a few ingenious methods people use to carry luggage on their 16 inch folders. Check out this guide to carrying luggage from The Brompton Traveler for more info.
  • Looks kind of goofy- The tiny tires make the rider look kind of silly, even if you’re a smaller person. Of course, this only matters if you care about looks.

Other Folding Bike Wheel Sizes

Although 16 and 20 inch are the most common wheel sizes for folding bikes, several other sizes are also available. There are actually dozens of different bike wheel sizes available. If you’re confused as I was, check out this excellent article about bike wheel sizes from Sheldon Brown to help clear things up. 

24 Inch Wheeled Folding Bike

This is kind of a middle ground between a compact folding bike and a full-sized bike. 24 inch folding bikes offer improved ride quality over 16 and 20 inch options. They are slightly more efficient, smooth, and comfortable. This is nice for longer commutes and tours.

This improved performance does come at a cost. These bikes are substantially bulkier and heavier than smaller wheeled models. The biggest drawback is the fact that they are too large for most public transport systems. Many cities limit the bikes allowed on their transit system to models with wheels 20 inches or smaller. You’ll also have more trouble fitting the bike in a standard checked bag size case for flights.

To me, this isn’t the ideal wheel size for a folding bike. It’s slightly too large to take advantage of portability, which is the biggest advantage a folding bike offers. It’s also just a bit too small to offer the comfort and ride quality of a full-sized bike.

26 Inch, 27.5 Inch, and 700c Wheeled Folding Bikes

These full-sized bikes are designed with a hinge in the middle of the frame so that they can fold in half. The result is a package about 60% of the size of a standard non-folding bike. While they aren’t compact like 16 and 20 inch folding bikes, they do offer some utility. They can fit in places where a full-sized bike cannot. For example:

  • Car trunks- Most standard sized cars can’t fit a bike in the trunk. If the frame folds, the bike can fit. This way, you can transport your bike in your car without using a bike rack.
  • Long-distance trains or buses- Oftentimes full-sized bikes are not permitted. Usually, a full-sized folding bike can be accommodated
  • Small apartments- If you live in a city, you probably don’t want to leave your bike locked up outside due to the fear of theft. Storing a full-sized bike in a tiny apartment is a waste of space. Full-sized folding bikes offer a nice compromise.
  • Vans, RVs, and boats- You can easily store your full-sized folding bike in a recreational without taking up too much living space.

Full-sized folding bikes offer the same ride quality that you’re used to with a larger bike. They are just as smooth, efficient, and comfortable as any standard bicycle. They look pretty normal as well. As an added benefit, you won’t attract the same stares and unwanted attention that you do while riding a small-wheeled folding bike.

Of course, there are drawbacks. These bikes just aren’t anywhere near as portable as 16 and 20 inch folding bikes. You can’t take them on most public transport systems and you’ll pay extra fees to fly with them. They are also substantially heavier than smaller wheeled models.

18 Inch (355 mm) Wheeled Folding Bikes

This is a pretty rare size. The only folding bike that I’m aware of that uses this size is the Birdy folding bike. Kids bikes occasionally use this wheel size as well. 18 inch wheels offer a mid-size between 16 and 20 inch. They offer slightly better performance than 16 inch wheels. These smaller wheels allow the bike to fold slightly more compact than 20 inch models.

This wheel size has one major drawback in my opinion. That is parts availability. To buy quality replacements, you’ll pretty much have to order parts online and have them shipped. This is fine for commuters and casual riders. Anyone looking to tour will have to pack enough spares for the tour.

Another Option: Install S&S Couplers on your Standard Bike

You may be able to convert your regular bike into a packable bike. This process involves cutting your bike’s frame in 2 places and welding on the couplers. The end result is a frame that splits into two parts, allowing you to pack your bike in a compact box for transport.

This comes in handy for flying with your bike. You can fit a coupled bike into a box that is the size of a standard checked at. This allows you to avoid additional airline fees.

This process isn’t for someone who plans to fold their bike regularly for multimodal transport. Disassembling and reassembling the bike takes too much time.

You can install S&S couplers installed on most any steel or titanium framed bike. Only a handful of bike shops have the proper equipment so you may have to ship your frame. Prices start around $800 for the service. Check out sandsmachine.com for more info.

Which is the Best Folding Bike Wheel Size?

This choice really comes down to your use for the bike and personal preference. If you are a commuter and you need to take the bike on public transportation, you’re limited to 16 and 20 inch. If you are a bicycle tourist and plan to fly with your bike, anything larger than 20 inch will likely be oversized when packed and will cost you extra to transport.

For those who plan to fold the bike to put it in the trunk of a car for transportation to a nearby trail or bike path, larger wheel sized folding bikes may be preferable. If you’re just buying a folding bike to save space in your small apartment, you may want to consider a full-sized option.

To complicate your decision even more, check out some more of my cycling analyses here:

Folding Bike Recommendations for Each Wheel Size

After you’ve decided on wheel size and any other features you need, it’s time to pick a bike. Below, I’ll outline my favorite folding bikes in each of the more common sizes.

16 Inch Folding Bike

The Brompton is the gold standard of folding bikes. These steel-framed bikes are made in England and come in 1,3, and 6 speed versions. The build quality is excellent. The fold is the most compact of any folding bike. Loads of aftermarket parts are available. The bike has a devoted fan base. The biggest drawback is the high cost. For more info, check out their website here.

20 Inch Folding Bike

Tern and Dahon are 2 folding bike manufacturers with an interesting past. They also make some of the most popular 20 inch folding bikes on the market. They offer quality folding bikes in the mid range in terms of budget and components. One of the most popular options is the Dahon Mariner folding bike. It features 8 speeds, folds down to 25.6″ x 31.1″ x 12.6″ and weighs 26 pounds.

Full-Sized Folding Bikes

Montague makes a nice range of 26 inch and 700c folding mountain bikes, road bikes, and touring bikes. They use a strong design that was developed for the US military. One of their more popular options, the Montague Paratrooper Pro features 27 speeds, disc breaks, and front suspension. It also includes a rear rack.

Final Thoughts: 16 Inch Vs. 20 Inch Folding Bike Wheel Size Comparison

Folding bikes offer incredibly versatile and portable transportation for both commuters, bicycle tourists, and recreational riders. There’s just something freeing about being able to fold your bike up and bring it with you wherever you go. Not having to worry about locking your bike up outside gives peace of mind.

When it comes to choosing a folding bike, the wheel size is the most important decision that you have to make. If the bike is too large for your purposes, you probably won’t get much use out of it. At the same time, if the performance is lacking, you won’t want to ride it very far. Folding bikes are a compromise.

For more reasons to choose a folding bike over a full-sized bike as well as bike recommendations, check out my pros and cons of folding bikes article.

Which folding bike wheel size do you prefer? Share your experience in the comments below!

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