If you're like most people who get into e-bikes, at some point you start thinking — "how fast can I actually go?"
You hit the factory speed limit — usually 25 km/h (15.5 mph) or 32 km/h (20 mph) — and realize the bike’s still got more in it. You’re pedaling hard, the motor cuts off, and you’re left wondering if there’s a way to squeeze a bit more out of it.
The short answer is: yeah, you can get more speed out of most e-bikes, but it depends on a few things.
In this post, I'll walk you through what controls your top speed, what changes when you tune your bike, and the safest ways to unlock a bit more performance (including a simple mechanical tuning option like SPEEDi — more on that later).
If you're keen to go a bit quicker and get more out of your rides, let’s get into it.
What E-Bike Top Speed Actually Means (And Why Limits Exist)
Before we get into ways to increase your e-bike’s speed, it’s worth understanding how top speeds work in the first place.
When we talk about an e-bike’s "top speed," we’re really talking about the speed at which the motor will stop assisting you — not the absolute maximum speed your bike can go.
Pedal-assist e-bikes (which is what most people ride) have a built-in limit where the motor cuts off assistance. You can still go faster by pedaling harder or going downhill — you’re just on your own past that cutoff.
Those limits are mainly about laws and regulations, not what the bikes are physically capable of. Governments set these limits to keep e-bikes in the same legal category as bicycles, which means no registration, no motorbike licenses, no insurance requirements.
That’s why you see common assist limits like:
- 25 km/h (15.5 mph) in Europe and the UK
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32 km/h (20 mph) in most parts of the US
Without those caps, your e-bike could legally be treated like a moped or a motorbike (and nobody wants to deal with all that paperwork just to ride to work or hit the trails.)
How to Increase Your E-Bike’s Speed (Safely)
There’s a few different ways to bump up your e-bike’s assist speed limit.
Some people go down the path of software hacks, tuning chips, or full-on motor mods, but that stuff can get messy pretty fast.
If you want the full rundown on all the different tuning options (and the pros and cons of each), check out this guide we put together here.
But if you're after something simple and a way to go faster without messing with your motor or electronics, mechanical tuning is the safest bet.
This is where we’ll shamelessly plug our SPEEDi for a sec.
SPEEDi is a mechanical device that increases your e-bike’s assist limit. No software. No rewiring. It just changes how your speed sensor reads the wheel rotation, so the motor keeps helping you a bit longer (we’ll go into the details a bit later).
One of the most common questions we get is: How fast can I actually go with SPEEDi installed?
The short answer: SPEEDi increases your e-bike’s assisted speed by around 1.5x.
If you’ve got a standard 25 km/h (15.5 mph) e-bike, with SPEEDi installed you’ll see support up to around 37–38 km/h (~23 mph).
However, your final speed depends on multiple variables. Let’s break them down.
What Affects Your Top Speed (Even After Tuning)
Your Pedaling Effort
SPEEDi removes the speed cap, but it doesn't make your motor any stronger. You still need to put in the work.
If you stop pedaling, your motor stops helping — tuning or not. You’re still the engine past a certain point.
Motor Power and Software
Most e-bikes run 250W motors (like Bosch, Yamaha, and Brose), and with tuning, they’ll usually assist you nicely up to that ~37–38 km/h (~23 mph) range.
Some bigger motors — like those on S-pedelecs (500W–750W) — can help you push closer to 50 km/h (~30 mph).
But even with tuning, your motor’s original design and software still matter. SPEEDi doesn’t boost your motor’s actual power — it just lets it keep helping you a bit longer.
Gearing and Cadence
This is a big one. At higher speeds, your pedaling speed (cadence) can become the real limiter. If your gearing is too low, you’ll be spinning your legs like crazy without actually going any faster.
If you’re serious about tuning, swapping to a bigger front chainring can help:
- Standard Bosch setups often run 15–16 teeth.
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Tuning setups might use 19–22 teeth, depending on your terrain and riding style.
(Heads up — if you do swap chainrings, you might also need a longer chain.)
Aerodynamics and Rolling Resistance
At around 30–40 km/h (18-24 mph), wind resistance becomes a problem.
Getting into a more tucked riding position (like roadies do) and running smooth, higher-pressure tires can make a difference. Otherwise, you’ll feel like you’re pedaling into a brick wall no matter how strong your motor is.
Why 1.5x Your Limit is Actually Enough
If you’ve been doing any research into de-limiting your e-bike, you’ve probably noticed a bunch of different tuning options out there, and they all claim different top speeds.
Some of the electronic hacks and dongles promise crazy numbers like 60–70 km/h (37–43 mph), while others just extend your limit a bit.
With SPEEDi, the increase is about 1.5x your factory limit, which is on the lower end compared to some of the software mods and devices.
But there’s a good reason for it (technical explanation incoming…)
When I designed SPEEDi, I built it around a 1.5/1 gear ratio (instead of something bigger like 3/1) to make the whole thing stronger and better aligned.
- Mounting the ring gear up against the disc means it stays properly braced and keeps its strength.
- Mounting the sun gear directly onto the end cap means it’s perfectly concentric.
- That also makes it a lot easier to install and uninstall compared to more complicated setups.
(PS—if you want to learn more about how it actually works, check out our full product info page.)
Basically: It’s simpler, stronger, more reliable, and it does exactly what you need without overcomplicating things.
And out in the real world, even riding hard, I rarely hit the new limiter anyway. Once you bump your assist limit up by 1.5x, you’re already pushing into the limits of gearing, motor power, and wind resistance. You don't need more speed than that — what you get is enough to make the bike ride the way it always should have.
And it’s the same story we hear from riders over and over again: 👉
Check out more sweet reviews here!
It’s not about turning your bike into a motorbike. It’s just about being able to jump on and ride your bike how you want to (without slamming into an invisible wall — that’s a real vibe killer.)
Is It Legal to Unlock Your E-Bike's Speed?
Well, it depends where you are. And I am not qualified to give you legal advice, so make sure you do your own research and take this next part with a grain of salt.
In Europe and the UK, legal e-bikes are capped at 25 km/h (15.5 mph).
In the US, most Class 1 and 2 e-bikes are supposed to stay under 32 km/h (20 mph).
If your bike goes faster and you're riding on public roads or bike paths, technically your bike could be considered a moped or motorcycle. That can mean:
- Needing registration
- Motorbike helmets
- Insurance
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Road riding only (no bike paths)
As laws usually go, violating them can lead to fines, legal liability, and even criminal charges if an accident occurs. Check your local laws and use your common sense.
Additionally, modifying an e-bike can void its warranty.
This is another can of worms and something that a lot of people (fairly) have strong opinions on. Here’s a couple of important points
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If your bike is already out of warranty, you don’t need to worry about this.
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Tuning with a mechanical device (like our SPEEDi) means it’s much less likely to be detected. Because it’s easily removable and you aren’t messing with any of the electronics or computer, it’s harder to detect. So if you want to tune within your warranty period, this will be your safest bet. However there is still a chance it can be detected. Bike computers are getting really smart, and we do get the odd bike that will somehow detect tampering and throw a code. At this point, the SPEEDi being detected by your bike is very inconsistent and uncommon.
Real Risks (And Why People Still Do It)
Let’s not sugar-coat it, there are some risks to tuning.
- Brakes and Handling: Your bike’s brakes and frame were designed for certain speeds. 40+ km/h puts more stress on everything.
- Motor and Battery Wear: The motor’s helping for longer, and the battery's draining a bit faster. That’s just how it goes.
- Error Codes: Some newer bikes have software that could throw an error if they detect something weird. With SPEEDi it’s rare — but not impossible.
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Warranty Risks: If any tuning gets detected, there’s always a chance it could void your warranty.
But here’s the thing: Most people who tune aren’t smashing their bikes full throttle everywhere. You're riding a bit harder and faster, sure, but you’re still pedaling, and you're still using your bike like a bike. It might wear stuff out a bit quicker — chains, tires, brake pads — but if you’re riding a lot, that’s happening anyway.
In my opinion (and our 4000+ customers) it’s worth it for the better ride. The bike rides like it should. The motor doesn’t give up on you right when you’re pushing hard. It just makes the whole ride more enjoyable.
Should You De-Restrict Your E-Bike?
If you’re just cruising bike paths at 20 km/h, you don’t need to bother.
Remember that the SPEEDi doesn’t actually boost your speed, it just assists you 1.5x past your existing limit. If you’ve never felt like you’ve hit your built-in speed limit before, then looking to push past that by tuning your bike is probably a waste of time, as you’ll never notice a difference.
But, if you’re the sort of rider who’s pedaling properly, riding open trails, or commuting and wanting a bit more speed — tuning makes a massive difference.
When I first tuned my own bike, the biggest thing I noticed wasn’t the top speed, it was how much better the whole ride felt.
No sudden cutoffs, just smooth, consistent assistance that matches what you’re putting in.
And that’s exactly what so many of our customers say too.
Final Thoughts
Tuning your e-bike, when done smartly, gives you more speed, more fun, and a better ride (ideally without wrecking your motor or hacking into your electronics.)
Mechanical options like SPEEDi make it simple. No wires, no software tricks, just simple mechanics.
And if you ever want to go back to stock, you can pull it off in a few minutes.
And if you've got any questions, flick us a message.
— Neale
About NLS Components
Neale is a mechanical engineer and lifelong mountain biker, and the creator of SPEEDi. When he’s not in the workshop, you’ll find him out testing gear on New Zealand trails.
