Should You Derestrict Your Electric Mountain Bike?

Derestricting or ‘tuning’ your electric mountain bike to make it go faster, sound pretty cool. It means that your bike will still assist you above 15.5 mph or 25 km/h, so you can get faster to your favorite trail. Should you do it and what happens if you derestrict eMTB?

Derestricting your electric mountain bike is not advised. Research has shown that doing so will result in extensive wear and tear of vital components of the bike. Using it on a public road is illegal and the financial and legal consequences of getting into an accident are huge. It should only be used on private land.

Reading this article will prevent you from making a hasty decision which may get you into all kinds of legal problems and can end up costing you a lot of money. Based on my own experience, I’m going to give you all the information you need so that you can make the right choice.

How Fast Will An Electric Mountain Bike Go?

In theory, an electric mountain bike will go as fast as you can peddle. But after the speed limit, the bike stops assisting you and it gets quite a bit more difficult to get it past that speed. That’s because of the extra weight of the bike and the drag of the motor. The speed limit for electric mountain bikes is no different from the speed limit of other e-bikes.

The speed limit is set by the government and isn’t the same everywhere the world. In Europe, UK and Australia, it is 25 km/h or 15.5 mph. In the US, it is 20 mph or 32 km/h.

Why Would You Want To Derestrict Your Electric Mountain Bike?

The first time you get on your electric mountain bike, you feel invincible. Every steep climb you dreaded in the past, now becomes a whole new experience. You start testing out the different modes until you find a setting that best suits your new riding style. You’re now so much faster and more stable than you’ve ever been: it feels awesome.

This until you find yourself on a public road on the way to or from your trail, and suddenly your bike doesn’t feel as fast anymore: you’ve hit the speed limiter. You can still go above 15.5 mph or 25 km/h, but it takes so much more strength than it used to on your non electric bike. People on city bike are passing you by…

The story above is my personal story. I was quite a bit disappointed as I lived fairly far away from my local trails. Since I used to travel on my non electric bike at around 18 mph or 29 km/h on the public roads, I was now slower. I had heard about the possibility of derestricting or tuning an e-bike and it suddenly sounded quite appealing.

How To Derestrict Your Electric Mountain Bike

First of all, don’t think of tuning an eMTB the same way you think of tuning a car: there’s no power gain and it can’t be done by a laptop on a rolling road. After tuning, the bike still delivers the same amount of newton meters that the manufacturer mentioned in the brochure. But you can compare it with removing the speed limiter of your German car so it will go past 250 km/h on the Autobahn.

For derestricting your electric mountain bike, in most cases you need hardware in the form of a tuning device. There are a few options here where we will get to further down the line. The device will trick your bikes computer into thinking that you’re doing a lower speed than you are actually doing. It alters the magnetic impulses from the magnet on your wheel, after which the computer then calculates a lower speed. The result is that your bike ‘thinks’ that you’re travelling slower than you actually are, and will still assist you after hitting the factory limiter. Most tuning devices will even display the right speed and mileage on your bikes display.

You can find tuning devices for all the popular motor brands like: Bosch, Brose, Shimano and Yamaha. There are several types and manufacturers to choose from and a device will set you back between €130-190 or $135-200. The differences between the tuning devices are usually the way they are mounted, the maximum speed they will allow and how you operate them. For the less known motor-brands, you can also find tuning devices, but your options are limited.

Externally Mounted Tuning Devices

When browsing through the options for your type of motor, you will come across tuning devices which are externally mounted. It consists of a plastic box and a magnet for your spoke. It is a simple, fast and effective way of tuning and they are usually mounted on your chain stay. If you actually use your mountain bike under heavy conditions, then you should look further. They are not robust enough for dealing with crashes, hitting branches or coping with a lot of dirt.

Internally Mounted Tuning Devices

The most professional way of derestricting a mountain bike, is via an internally mounted device. It’s an invisible and robust solution which is suited for heavy use and works best with your bikes software. It consists of a ‘dongle’ with a few cables attached. You don’t have to be a mechanic to fit one of these, but some experience with tools is needed. The casing around your motor needs to be removed and you reconnect a few connectors. It’s fairly idiot proof, but you need to find a space around your motor or within your frame for the dongle to sit comfortably.

A professional bike shop will not sell this device or help you with fitting one, so you have to decide for yourself if you are capable of performing this job. If cables get jammed or plugs come loose, your electric system will stop working and you have to get home on your own power.

Software Modifications

For some motors it is possible to remove or adjust the speed limiter with just software. In some cases the bikes software can even be changed to the US version, which means that the limiter moves up to 20 mph or 32 km/h. The downside of this form of tuning is that it is permanent and in most cases can’t be turned off temporarily.

Updating Your Electric Mountain Bike

As with almost anything electronic, even your mountain bike can receive an update. Manufacturers are constantly collecting date so that they can improve their products. Since every electric bike has a control unit, they can alter the software to make the motor more efficient, more powerful or to fix bugs. They are also constantly improving the way the control unit registers whether there is a tuning device present or not.

Between manufacturers of e-bike motors and manufacturers of tuning devices, there’s is an ongoing cat and mouse game; the manufacturer of the motor designs software for the bike to operate which isn’t easy to tamper with, and the manufacturer of the tuning device tries to ‘hack’ the motors software and stay under the radar. Eventually, the motors manufacturer discovers this and will adapt its software so that it will detect tuning devices sooner. The advice is always: do not update your e-bike after a tuning device has been fitted.

What Happens If Your Software Detects That You Ride Derestricted?

The outcome of your system thinking that something is off, differs from brand to brand. In all cases, you will get an error code on your display usually followed by limp mode (reduced power). This can be undone in various ways and also differs from brand to brand. In worst case scenario, you have to see your dealer to get it back to normal mode. He, and therefore you, will not be happy if your bike is still under warranty. More about that further on.

Also, if you bring your derestricted electric mountain bike to your bike shop for maintenance, always let the mechanic know that you ride with a tuning device. If you don’t, they might update your system if there’s an update available. If they don’t update but still check your system for faults, they will still find out. This is because your bike collects data from how the motor gets used. It registers how much power you are using during your ride and what modes you are your favorite. Tuning your mountain bike is your responsibility, so don’t drag other people in! If your are transparent about it, it might not be a problem.

How Do E-Bike Manufacturers Try To Put A Stop To Tuning?

If a good tuning device does not get detected by the bikes software, then a manufacturer should not find out about it and they would have no reason to up their game and stay ahead of the tuning devices, right?

That is not the case. Manufacturers will collect data from dealers and bike shops and work together with the police in identifying tuned e-bikes. The are constantly evaluating if the current standard for detecting anti-tampering is still enough.

Why Do Manufacturers Don’t Want You To Derestrict Your Bike?

Since there are regulations about the use of electric bikes, you can’t just do whatever you want with it. Even if you don’t use it on public roads. This is because manufacturers of course know about this legislation and build bikes accordingly. If you tamper with it and something goes wrong, the manufacturer doesn’t want to be held responsible for selling a faulty product. This goes for mechanical damages as well as legal consequences in case of accidents.

The dimensions of the components on your bike have been carefully calculated and selected by the manufacturer. Those components should perform accordingly to what the manufacturer says the bike is capable of. The safety of a tuned bike can not be guaranteed. It’s components and the bike itself is exposed to greater stresses and it is difficult to predicts what the consequences are.

If something does fail on a stock bike within the warranty period which can’t be traced back to you using it incorrectly, it will be repaired at the manufacturers expense.

The Consequences Of Having A Derestricted Mountain Bike

If you’ve done all your research and you decide to go for it, then you should be aware of the financial consequences as well as the legal consequences. Especially the last one I don’t want to leave unmentioned.

Financially

As touched upon briefly, manufacturers can’t guarantee what will happen to your bike when you put it through the higher stress that comes with derestricting it. Even if the power of your bike doesn’t actually increase, you are using this power at higher speeds and thus higher revolutions. This will wear out your components faster. This goes for basically every main component of your bike, but in general, these parts wear out noticeably faster on a tuned bike:

• Crank bearings (part of the motor)
• Drive train: chain and cassette
• Wheel bearings and freehub bearings
• Brakes: discs and pads
• Control unit
• Battery
• Tires

It is important to mention that riding your stock bike at speeds above the factory limiter (i.e. downhill or on a long stretch of road), does not have the same impact on the components as with riding the same speed on a derestricted bike.

Your manufacturers warranty policy states that the warranty is void when modifications have been made to components. Knowing this, you can’t hold your bikes manufacturer responsible for when one of the above mentioned components go boom within the warranty period. E.g., if the motor needs replacing, it will cost you around €650 or $685; a new battery will be €600 or $635.

Interesting fact: in most parts of the US, electric mountain bikes are limited at 20 mph or 32 km/h. This is 5 mph or 7 km/h faster than elsewhere in the world. There are no mechanical differences between the US version of an electric mountain bike and the version sold in other parts of the world. This does mean that your bike is capable of coping with a bit more stress, but this doesn’t change a thing about the aforementioned.

Legally

If you accept the financial consequences and are you ready to order a tuning device, there’s is a way more important consequence that you have to think about first: the legal consequences. By derestricting your electric mountain bike, you turn it into a moped which needs to be insured and taxed. And for a moped, the rules on public roads are completely different.

With greater speeds come greater risks. If you ride your derectricted bike on public roads and you happen to get into an accident with a pedestrian, a car, a cyclist or any other road user, chances are that you’ll receive a huge fine, end up in prison and/or become liable for all the the costs involved. This could mean that you have to pay for the other party’s long term medical costs. If you think that nobody will find out about your secret modification, you are wrong. The police or insurance companies will perform an investigation and if there’s a suspicion of tampering with the speed limiter, you are held responsible.

Faster Electric Mountain Bikes From Factory?

If you legally want to go fast on a mountain bike, you can go for a so called s-pedelec (speed pedelec) mountain bike. These bikes will assist you up to 45 km/h or 28 mph and are classified as a moped. They usually come with some kind of number plate. If you are looking for a speed pedelec, you will notice that the mountain bike variant is quite rare. Since you are not allowed to take a moped out in the forest, country roads or on bike trails, you are also not allowed to do this with a speed pedelec. This makes them quite useless as a mountain bike.

Also if you look at a the specs of an s-pedelec mountain bike, you’ll see that most of them weren’t build to excel in bike parks. The only case in which you might want to ride a bike like this, is if you live in a rural area with bad roads.

Alternatives For Derestricting an Electric Mountain Bike

If you have decided to refrain from derestricting your electric mountain bike, you might still be annoyed. Before you feel like electronic mountain bike are not for you, you should at least give the following tips a try.

Try A Different Mode

If you ride in a faster mode for most of the time, you might want to think about switching to a lower mode of assist, like Eco. You then have to put in more effort to go fast, but you won’t be hitting the limiter constantly. It ‘ll also give you a good workout.

Switch Up Your Routes

Electric mountain bike are extremely capable machines. You can ride very technical and steep sections without problems. If you are used to riding more open and faster trails on a non electric bike, it might be time to try the more difficult stuff with lower speeds.

Try A Bike With A Different Motor

Since technology evolves, so do electric mountain bikes. Each motor has different characteristics and some motors even have almost zero drag above 25 km/h or 15.5 mph. If you live in an area where there are not many technical and steep trails, it might be best for you to test out some bikes at your local dealer to find the one with the least drag. It means that you’ll find it less difficult to peddle above your speed limiter.

Conclusion: Should You Derestrict Your Electric Mountain Bike?

First of all, lets summarize all the above in the form of pros and cons of derestricting your electric mountain bike.

It goes without saying that there’s more to derestricting your electric mountain bike than just you placing a tuning device.

My Advice

I hope that this article has given you insight in what derestricting an electric mountain bike will do for you, your bike and the people around you. It is a great way of achieving some immense speeds on your bike which can make your ride much more exciting. But in my opinion, the pros do not outweigh the cons.

Sure, it is cool to tell people that your bike does some pretty hefty speeds, but you are not alone in this world. If things were to go wrong (even if it was not because of speed), you can get in quite some trouble. Even if you don’t use it on public roads, other people often don’t expect you to travel at speeds that derestricted bikes can achieve. Which may result in collisions with hikers or other mountain bikers. You don’t want to get other people hurt because of your decisions. I would only do it if I owned a private land with no people around, and if I was able to cover the extra maintenance costs.

If that speed limiter is really bothering you that much, you may want to rethink if an electric mountain bike is the most suitable bike for the task. Or you should move to the United States and benefit from their higher speed limit for e-bikes.

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