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This post compares 20-inch and 24-inch BMX bikes.

What Are The Advantages of 20″ BMX Bikes?

1. Greater Demand

20-inch BMX bikes are the standard and thus dominate the market.

The diversity increases the customer’s choice and stimulates competitive pricing.

2. Weight

20-inch BMX bikes are lighter because the frames and wheels are smaller and thus require less material.

The table below compares the weight of popular 24″ and 20″ BMX freestyle/street bikes.

Conclusion: On average, the 20″ BMXs in the table are 0.45kg/1lbs lighter – a 3.85% difference.

The next table compares the weight of race 24″ and 20″ BMX bikes:

Conclusion: On average, the 20″ BMX race bikes in the table are 2lbs/0.9kg lighter. This a 9.8% difference that couldn’t be easily ignored.

3. Maneuverability

Smaller tires increase the maneuverability of a bike. Hence why 26-inch MTBs can make tighter turns than 29-inch models.

The same applies to BMX. 20″inch tires offer greater precision – a quality appreciated during the performance of freestyle and street tricks.

4. Control and Domination

Smaller bicycles are more “playful” and easier to toss around.

In consequence, 20-inch BMXs are better suited for more technical tricks such tail whips, 180, 360…etc.

5. Shorter Chainstays

20″ inch BMX bikes have notably shorter chaintays. This is possible because the tire is smaller and thus does not require as much clearance as 24″inch wheels.

The table below compares the chainstay length of the bikes in the examples above:

Conclusion: On average, 24-inch BMX bikes have 2-inches/5.08cm longer chainstays than 20-inch models.

This is a significant difference that has a noticeable impact on riding.

Shorter chainstays put the rear wheel closer to the bottom bracket and the rider’s center of gravity.

As a result, the rider doesn’t have to move back as much to lift the front wheel.

Ultimately, shorter chainstays greatly facilitate the performance of bunny hops and manuals which are the foundation of the sport.

Another benefit of shorter chainstays is extra maneuverability when cornering.

If you want to learn more about the differences between shorter and longer chainstays, consider reading the dedicated article on the topic.

6. Lower Bottom Bracket

20″ inch BMX bikes tend to have bottom brackets closer to the ground.

The table below compares the bottom bracket height of BMX models from the previous data blocks.

*BBH – bottom bracket height

Conclusion: On average, the 20″ BMXs in the table have 1.23″/31mm lower bottom brackets.

Lower bottom brackets have the following benefits:

• Stability (the rider’s feet are closer to the ground)
  
• An opportunity to run shorter chainstays

A high bottom bracket combined with shorter chainstays is harmful because it offers too much leverage.

As a result, rider loses the ability to feel where the rear wheel is and could easily loop out during manuals. For that reason, shorter chainstays come with lower bottom brackets.

7. Stronger and Lighter Wheels

The smaller the wheel, the stronger it can potentially be.

When all other parameters are equal, a 20-inch wheel is tougher than a 24-inch one.

The extra strength is greatly appreciated in the world of BMX because the wheels are subjected to extreme “treatment”.

In addition, 20″ wheels can be lighter than 24″ while being just as strong.

This is possible because 20″ wheels require shorter spokes, rims and smaller tires (less rubber).

If a 20″ and a 24″ wheel are made of the exact same materials and equipped with identical tires, the 20″ wheels will be lighter and stronger than the 24″ model.

Having said that, 24″ wheels and even 26″ can be built super strong – to the point where they can take an unbelievable amount of abuse.

8. Faster Acceleration

The smaller the wheel, the easier it is to get is spinning to a certain RPM (rotation per minute). Thus, 20″ wheels offer better acceleration.

However, 20″ wheels are not faster than 24″ by default wheels because speed is ultimately decided by the gearing of the bike.

If two bicycles have identical gearing, then the one with the larger tires will be faster overall because each rotation of the tire would result in greater travel distance.

Example:

Bike 1 has 20″ wheels, a chainring with 25 teeth, and a rear cog with 10 teeth.

Bike 2: has 24″ wheels, 25T chainring and 10T cog.

The gear ratio of both bikes is 25/10=2.5. This means that one turn of the cranks results in 2.5 rotations of the rear wheel.

If the riders are spinning the cranks at 80 rpm, then the rear cogs and respectively the rear wheels of the bikes will be making 80×2.5= 200 rotations per minute.

However, the traveled distance will be greater in the case of 24″ wheels because they have a larger circumference when both wheels are equipped with tires of the same size.

If both models use 2-inch tires, the circumference of 24″ wheels is approximately 1911mm whereas that of 20″ wheels is roughly 1594mm.

To find the distance that a bike will cover with a certain set of wheels, we have to multiply the wheel’s circumference by the rotations of the rear wheel per minute.

In one minute and at 80rpm, the bike with 20″ wheels will be covering 318.8m. The speed will be 19km/h or 11.8m/h.

Meanwhile, in one minute and at 80rpm, the bike with 24″ wheels will be covering 382.2m and moving at 22.9km/h or 14.2m/h.

9. Greater Tire Choice

When shopping for tires, you will have a lot more options if you’re running 20-inch wheels.

10. Better For Shorter Riders

20″ BMXs are smaller overall and thus more suitable for shorter riders who would have a harder time perfuming the same tricks on bigger bicycles.

11. Grinding on Short Ledges

You can’t grind a ledge that’s significantly shorter than your tires.

For that reason, 20″ BMXs provide more opportunities for grinding than 24″ and 26″ models.

12. Easier To Resell

The greater demand for 20″ BMX makes it easier to sell parts and bikes on the second-hand market.

What Are The Disadvantages Of 20″ BMX?

The main disadvantages of 20″ BMXs in comparison to 24″ models are:

1. “Twitchy” Handling

By default, bikes with smaller wheels are considered twitchier.

A bike with a “twitchy” a.k.a. nervous front end is a bit a more difficult to control at times. The bike feels “insecure” and less “confident” of where it’s going.

Having said that, this property could also be seen as a positive in the world of BMX because a twitchier bike is also a more responsive one.

2. Small

At the end of the day, BMX bicycles are small by adult standards. If you’re a huge guy, you may feel weird riding a 20″ BMX.

3. Uncomfortable For Cruising

There’s a reason why 24″ BMXs are often referred to as “cruisers” – they are simply better at cruising than 20″models.

24″ bikes come with larger tires which store more kinetic energy. As a result, they roll for longer once you get them up to speed. The larger tires are also better at coping with obstacles on the road.

What Are The Advantages of 24″ BMX Bikes?

The main advantages of 24″ BMX bikes are:

1. Better Fit For Larger Riders

24″ BMXs have larger frames and wheels. For that reason, taller riders may feel more comfortable and less “claustrophobic” on 24″ models.

2. Less Shocking Transition From MTBs

If you’re riding a mountain bike with 26″, 27.5″ or 29″ wheels and plan to enter the world of BMX, a 24″ model would make the switch a bit less shocking.

That said, you could go straight to 20″ BMXs too. If you practice consistently, you will adapt quickly.

3. Higher Top Speed (Potentially)

As previously mentioned, the larger wheels of 24″ inch bikes have the potential for greater speed in comparison to 20″ models.

(If two bikes have the same high gear, the one with the larger wheels will be faster in that gear.)

4. Stable Handling

The larger 24″ tires make the handling of the bike a bit more stable. The trade off is precision.

5. Better For Trails

If you intend to hit off-road sections, 24″ inch wheels will facilitate the task as they have an easier time rolling over obstacles.

6. Better For Commuting

If you plan to run errands on your BMX, a 24″ model would be better suited for the task thanks to it’s more forgiving tire size and larger frame.

The comfort could be increased by installing a longer, lay-back seat post.

Ultimately, however, BMX bikes do not make the best commuters due to the lack of gearing and the small dimensions.

What Are The Disadvantages of 24″ BMX Bikes?

1. “Master of None”

The greatest strength of 24″ inch bikes is also their weakness.

24″ inch models are a transition. As such, they’re neither as maneuverable and as “whip-able” as 20″ BMXs nor as fast and shock absorbing as 26″ wheels.

Thus, they’re a jack of all trades and a master of none.

2. Harder To Bail Out

The larger dimensions of the bike make it harder to get away from it when you fail a trick.

3. Reselling Could Be Difficult

Most dedicated BMX riders are on 20″ and 22″ wheels. Hence why the 24″ BMX market is so small. As a result, it’s bit harder to find or sell a 24″ BMX.

4. Fewer Choices

If you want to buy a standard BMX you can choose one of many brands.

But if you’re after a 24″ model, your options are a lot more limited.

Having said that, the fact that many children’s bikes use 24″ wheels is beneficial because this increases the demand for tires and inner tubes of that size.

FAQ: Are 24″ BMXs harder to bunny hop?

All tricks take a bit more effort when the bicycle is larger.

The shorter chainstays of 20″ BMXs and the smaller frame make it easier pop the front wheel and then follow with the back one.

However, 24″ BMXs are trick ready too. Their chainstays may be longer, but the higher bottom bracket compensates somewhat.

Virtually every trick apart from something “hyper-niche” that could be done on a 20″ BMX can be replicated on a 24″.

The Profile of a Potential 20″ BMX Buyer

The potential buyers of 20″ BMXs usually but not always fall within the criteria below:

1. A strong desire to learn technical BMX tricks

2. Ambitions to become a rider with a large variety of skills and get sponsored and/or compete

3. Short to average stature

The Profile of a Potential 24″ BMX Buyer

The potential buyers of 24″ BMX often share the following characteristics:

1. Larger rider who feels a bit compressed on a 20″ bike.

2. A weaker desire to perform ultra-technical tricks.

3. Recreational riding

4. MTB background

5. Plans to use the bike for pedaling (e.g, commuting, cruising…etc.).

6. Dirt track riding

FAQ: I am an older guy. Should I buy a 20″ or 24″ BMX?

Older riders are often advised to get a 24″ bike because it feels a bit softer. In reality, such a requirement does not exist.

Seasoned men can ride 20″ too. There are larger 20″ frames with extra stand over and higher bars reducing the strain on the back.

Many older guys who get back into the sport regret buying 24″ models because the larger size makes it noticeably more difficult to pull some tricks.