Purpose-built vs. a converted e-bike

What an exciting time it is to be alive with so many e-bike options to choose from! With lots of options, though, can come lots of confusion in finding the right system for you. That’s where we come in! We aim to help arm you with the information you need to decide on the right type of e-bike for you. In this article, we are discussing the difference between converted electric bikes that use a conversion kit and purpose-built electric bikes, like a Bosch powered Xtracycle. We will examine the pros and cons of each and how to decide which configuration is right for you.


If you already have a non-electric bike and are looking for tips on converting it with an e-bike kit, check out our article “All you need to know about doing e-bike conversions”.

IMPORTANT NOTE: When shopping for an e-bike conversion kit, Xtracycle only recommends kits with a max 20 MPH assist. We recommend against kits with an assist higher than 20 MPH or any kit (regardless of max assist level) with throttles.

Let’s dive right in!

Converted vs. purpose-built: what’s the difference?

A converted electric bike is a non-electric, also referred to as a “mechanical” bike that has been electrified using an e-bike conversion kit. This kit typically includes a motor, a battery and electric controls. Converted e-bikes maintain their ability to revert back to a non-electric bike once the conversion system is removed. Here is an example of a converted Xtracycle EdgeRunner using a rear hub Bionx motor:

A purpose-built e-bike is a bike that is meant to be sold as an electric bike. This means the bike has a custom frame made to fit a certain e-bike motor and that the electrical components are integrated into the frame design of the bike. Often times, a purpose-built e-bike can only ever be an e-bike and cannot be retrofitted to become a non-electric bike. Here is an example of a purpose-built Xtracycle EdgeRunner with a Bosch system:

A big difference between the frame of non-electric bike and a purpose-built electric bike is in the bottom bracket area. Let’s take a closer look since this difference plays a role in the pros and cons of each system:

On a non-electric bike, the bottom bracket shell is a hole in the frame meant to house the bottom bracket (what connects the two pedals within the bike frame) and allow it to smoothly rotate as you pedal. E-bike conversion kits are intended to be installed on bikes with bottom brackets. With a mid-drive system, the motor utilizes this bottom bracket shell and installs into that hole along with the crank arms. With hub drive systems, that bottom bracket remains unaltered.

On a purpose-built electric bike like an Xtracycle Bosch bike (shown here) and the Xtracycle Shimano bike, there is no bottom bracket nor bottom bracket shell. In its place is something called a node. This node is a custom fitting or cut-out in the frame intended to securely hold a specific electric bike motor. Once the motor is installed, the crank arms install directly into the system and it is the internal gearing of the system that turns when you pedal. When the motor on an electric bike is removed, the bike is non-functional because there is no place to install crank arms and pedals.

Buying a purpose-built e-bike: pros and cons

PURPOSE-BUILT E-BIKE: PROS

  • YOU HAVE A FULLY INTEGRATED ELECTRIC BIKE: When you purchase a purpose-built e-bike, you are buying a bike that was engineered specifically to be an e-bike. This means that choices were made for that bike knowing that it would have more power than what the human body can exert. For Xtracycle Bosch powered bikes, this means reinforced framing, stronger brakes, a frame custom built to the Bosch motor node, stronger rims, a stronger e-bike specific chain, pre-installed lights connected to the motor, just to name a few.
  • YOU HAVE TWO COMPANIES WHO WILL BE OFFERING CUSTOMER SUPPORT: Most purpose-built e-bikes come with the support of two companies: the bicycle manufacturer who made the frame and the company who made the electric motor and components. For Xtracycle Bosch powered e-bikes, this means you have the support of Xtracycle staff if something goes wrong on your bike AND you have the support of Bosch for their components.
  • YOU ARE PICKING FROM SOME OF THE BIGGEST, MOST REPUTABLE E-BIKE SYSTEM MANUFACTURERS: Most purpose-built electric bikes come with a motor made by a highly reputable company, like Bosch or Shimano. While these highly rated, reliable companies offer systems made for bikes with nodes, they do not make comparable conversion kits for non-electric bikes.
  • IT CAN BE EASIER TO FIND A SHOP TO SERVICE YOUR BIKE: Many of the systems found on purpose-built e-bikes are from global companies. Because of this, it can be easier to find a shop certified to work on your system or work with the original manufacturer to get an issue resolved.
  • THERE ARE FEWER DECISIONS TO MAKE WHEN BUILDING YOUR ELECTRIC BIKE: Once you have decided on the brand to go with, there are typically fewer options to have to wade through when building up your bike than if you were to start from scratch converting a bike. With Xtracycle Bosch bikes, this means we have narrowed down the options of motors and batteries. Our knowledgeable staff is available to help customers choose among those options to build the best system for their needs.
  • ALL THE HARD WORK OF BUILDING THE BIKE HAS ALREADY BEEN DONE: Since your bike comes pre-built and ready to roll, there is no need to bust out the build tools and get greasy. You can just enjoy your new electric bike! If you purchase your Xtracycle through our Big Box of Happiness program, you can have your new bike unboxed and ready to ride in minutes!

PURPOSE-BUILT E-BIKE: CONS

  • PURPOSE-BUILT E-BIKES TEND TO COST MORE THAN CONVERTED BIKES: Because of their custom design, specialty tooling, engineered enhancements and powerful electric motor packages, purpose-build e-bikes tend to come at a higher cost than bikes with electric conversions.
  • YOU ARE LOCKED INTO USING ONE SYSTEM: Owners of purpose-built bikes can only use the system their bike frame has a node to fit. More often then not, competing e-bike system brands don’t use the same node shape. For example, a bike frame made to be used with a Bosch motor cannot be fitted with a Shimano motor since the node for each motor is different. This means sticking with a trustworthy system is paramount.
  • YOU ARE LIMITED IN YOUR CUSTOMIZATION CHOICES: With a purpose-built e-bike, your only options for upgrades are those offered by the company. If you wanted a more powerful motor or higher capacity battery than what is offered by the company, you would be out of luck.
  • YOUR BIKE CAN ONLY BE AN E-BIKE: Since purpose-built e-bikes have no bottom bracket shell, an e-bike can only ever be an e-bike. Most systems work with the power turned completely off, however, the magnets and gears within the electric system will create more drag than that of a non-electric bottom bracket and bearing system, which can make the powered-down e-bike feel harder to pedal.

Buying a bike to convert: pros and cons

E-BIKE CONVERSION: PROS

  • SAVE MONEY: Buying a mechanical bike and converting it with a kit can be lower in cost in some cases than buying a purpose-built e-bike. This can be important if you have a smaller budget or if you do not want to apply for financing. Converting a bike you already have or a second-hand bike can make that investment lower in cost.
  • YOU ALWAYS HAVE THE OPTION OF REMOVING THE SYSTEM TO HAVE A NON-ELECTRIC BIKE: As mentioned above, when you buy a non-electric bike and convert it, your bike forever maintains the ability to become a non-electric bike in the future. If you later decide you no longer want an e-bike or if the electrical system brakes and you can’t replace it, you can simply uninstall the system and you will have your regular, non-electric bike again.
  • YOU AREN’T BEHOLDEN TO ANY ONE E-BIKE BRAND: When a rider converts a regular bike, they have various options of systems to pick from since their frame isn’t custom built to only work with one system. The only limit for a person doing a conversion is the compatibility of a system they want with the bike they have (i.e. bottom bracket size). This also means if your needs change, you have the ability to remove one system and buy another kind to install instead.

E-BIKE CONVERSION: CONS

  • YOUR BIKE MIGHT NOT FEEL LIKE A “REAL” E-BIKE: Since you are taking a regular, non-electric bike built to withstand human propulsion only and asking it to become a powerful, motor enhanced electric bike, this can make an e-bike conversion feel, sound and ride differently. The frame might flex a little more or the bike might develop some creaking sounds from the added stress on the frame.
  • IT REQUIRES SOME DIY KNOW-HOW: Most e-bike kits are made to be user friendl when it comes to installation which requires some tools and a little bit of bike maintenance know-how. Alternately, you can have the system installed by a bike shop but this comes with its own downside if it’s a system their mechanics aren’t incredibly familiar with.
  • QUALITY BETWEEN CONVERSION KIT COMPANIES CAN VARY: Because there are lower cost and lower quality kits out there, finding a quality e-bike conversion kit will take some research on your end. The key is: find a system that has a good reputation and accessible customer support!
  • SERVICEABILITY MIGHT BE AN ISSUE: If you aren’t able to service your system yourself, it might be challenging to find a bike shop that can help you. That said, if you do your research into conversion systems with great customer support, you should have a system from a company that will do their best to offer support remotely.
  • THE SYSTEM WON’T BE AS SEAMLESS AS A PURPOSE-BUILT SYSTEM: The conversion system won’t be as well integrated with the other components of your bike as it is on a purpose-built e-bike
  • WHEN BUYING A KIT, YOU HAVE A LOT OF OPTIONS TO PICK FROM WHICH MEANS A LOT OF RESEARCH ON YOUR PART: With all of those various options comes the down side of needing to know what to pick and that typically means doing more research.