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Why Do BMX Bikes Have Small Sprockets?

why do bmx bikes have small sprockets

Maybe you’re getting back into BMX after a VERY long time and are questioning, “Why do BMX bikes have small sprockets?”

“This is silly,” you might think.

Or maybe you’re just curious and want to learn a little bit about the history and advantages of small sprockets on BMX bikes.

Who remembers the 44/16 gear ratios? I do.

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Who remembers bending that thing super easily? I do.

Who remembers Odyssey bringing the 13T rear driver so we could run 36T front sprockets? I do.

Going from 44/16 to 36/13 gear ratio was game-changing.

But this was only the beginning.

With the introduction of a modern cassette with an internal driver, we could finally go down to the – now standard – 25T and 28T front sprockets.

Hey, BMX bikes are built for tricks, jumps, and fast moves.

And those small sprockets? They play a big part in making that possible.

Let’s dive deeper!

This post covers:

The Role Of Small Sprockets In BMX

the role of small sprockets in bmx

So, why do BMX bikes have those small sprockets? It’s not just for looks — there’s a reason behind it. Let’s break it down.

1. Weight Reduction

Smaller sprockets make the bike lighter.

And with BMX riding, every bit of weight saved matters.

The lighter the bike, the easier it is to control, spin, and lift for tricks.

You want your bike to feel like an extension of yourself, and less weight helps with that.

However, I still believe you shouldn’t complicate with weight too much.

2. Clearance for Tricks

Ever seen a rider grinding along a rail or throwing their bike into a tailwhip? Hey, you don’t want to land a tailwhip on that giant sprocket.

Small sprockets help with tricks.

With more clearance between the sprocket and the ground, there’s less chance of the sprocket hitting anything.

And this is especially crucial when it comes to grinds.

This gives riders way more confidence when going for grinds or landing tricks.

I don’t even want to remember how we did all the grinds with the 44/16 gear ratio. It was much more challenging, that’s for sure.

3. BMX-Specific Gearing

Smaller sprockets come with smaller rear cogs.

This keeps the bike’s gear ratio perfect for BMX riding.

You don’t need to pedal like crazy to get moving, but you also don’t need massive gears like you would on a road bike.

It’s a perfect balance for quick, powerful moves.

Durability & Strength Of Smaller Sprockets

durability and strength of smaller sprockets

You might think small sprockets would be weaker, but it’s actually the opposite.

BMX sprockets are tough. Like, really tough.

They’re usually made from strong materials like aluminum — often 7075 or 6061, the same types used in aerospace stuff. Some even get an extra treatment called T6, making them even stronger.

Since BMX riders put their bikes through a lot — jumps, heavy landings, grinding rails — the sprockets must handle serious impact.

The smaller size actually helps with this. There’s less material to bend or break, which means they stay solid even after some rough rides.

So, while they might be small, these sprockets are built to last!

And if you think you need extra protection, you can always pick a sprocket with a guard.

Popular Gear Ratios For BMX

popular gear ratios for bmx riding

Let’s talk gear ratios. If you’re into BMX, you’ve probably heard of setups like 25/9 or 28/9.

But what do those numbers mean? It’s actually pretty simple.

Common Gear Ratios

In BMX, the first number is the teeth on the front sprocket, and the second is the teeth on the rear cog.

For example, 25/9 means the front sprocket has 25 teeth, and the back one has 9.

Same with 28/9 — 28 teeth up front, 9 in the back.

Why These Ratios Work

These ratios are perfect for BMX because they give you the right balance between speed and control.

You don’t need to pedal as hard to get going, but you still have enough resistance to pull off tricks.

It’s all about quick bursts of power, not long-distance riding.

Plus, smaller sprockets keep the bike light and compact, which is great for stunts and spins.

That’s why most riders stick with these gear rations; they simply work.

And when it comes to trail and transition riders, a 30/9 is the more common gear ratio. Sometimes 33/9, but that’s rare.

Aesthetic & Style Factors

Let’s be real – who doesn’t like the look of a small sprocket on a BMX bike?

And we all know that BMX isn’t just about performance. It’s also about style.

Smaller sprockets give BMX bikes a cleaner, more compact look.

The whole setup feels tight and streamlined, perfect when riding in parks or on the street.

The smaller parts just make the bike look more aggressive and ready for action.

Riders love that minimal, no-fuss design.

And when popular brands and pros started pushing smaller sprockets, the trend caught up fast.

So, the small sprocket design isn’t just functional; it’s also become a key part of a sick-looking bike.

And let’s face it: when your bike looks sick, you feel more confident riding it.

Conclusion: Small Sprockets FTW!

So, why do BMX bikes have small sprockets? It’s all about balance.

They make the bike lighter, give you more clearance for tricks, and keep the gearing perfect for quick bursts of speed.

Plus, they’re super durable, handling all the jumps and impacts BMX riding throws at them.

But it’s not just about function.

Small sprockets also give BMX bikes that sleek, compact look that riders love.

Ultimately, small sprockets are the perfect mix of performance and style – everything BMX riding is all about.

Further reading:

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About Author

Rok has been riding BMX for 20+ years, and when he's not having a session, he binges on videos, new product drops and works on creating the best content (sharing tips, tricks & more to make riding bikes easier for you) for The BMX Dude.