Most bikes with a standard bottom bracket can take a CYC mid-drive conversion kit. CYC supports threaded BSA (68/73/83mm) directly, PressFit BB92/BB86 with an adapter, and PF30/BB30/T47 using a press-to-thread adapter. The main exception is proprietary shells like Trek BB90/BB95, where the bearings press directly into the frame and no mid-drive can be fitted. If you can identify your bottom bracket type and shell width, you can confirm compatibility in a minute.
Step 1: Identify your bottom bracket standard
Measure two things with a caliper: the shell width (the distance across the bottom bracket shell, typically 68 to 120mm) and the internal diameter. Those two numbers tell you your standard.
Compatibility table
| BB standard | Internal diameter | Typical shell width | Fits a CYC mid-drive? | How |
|---|---|---|---|---|
| BSA / English threaded | ~34mm | 68 / 73 / 83mm | Yes, direct | Threads straight in; use 3/5/7mm spacers to set chainline |
| PressFit BB92 / BB86 (PF41) | 41mm | 86.5 / 89.5 / 92mm | Yes, with adapter | CYC BB92 adapter / extended spindle version |
| PF30 / BB30 | 46mm / 42mm | 68 / 73mm | Yes, with adapter | Press-to-thread adapter sleeve to BSA |
| T47 | ~46mm (M47) | 68 / 73 / 85.5mm | Yes, with adapter | T47-to-30mm cups or reducer to BSA |
| Fat bike | N/A | 100 / 120mm | Yes, select platforms | Wide-BB (fat bike) options available on select CYC platforms; check the product page or contact support |
| Trek BB90 / BB95 | 37mm (bearings in frame) | 90.5 / 95.5mm | No, not compatible | No mid-drive fits; bearings press into carbon |
BSA, BB92, PF30/BB30 and T47 are supported per CYC specs. Confirm the exact adapter for your platform (Photon 2, Photon Pro, X1 Pro Gen 4) before ordering.
Step 2: Check clearance
Before installing, check that the motor body clears your frame: down-tube gussets, full-suspension swingarm/pivot, and external cable guides can interfere on some frames. A CYC mid-drive fits the large majority of hardtail, full-suspension, gravel, commuter and cargo frames.
Step 3: Chainline and Q-factor
CYC uses direct-mount CNC chainrings (32T and 34T on the Photon platforms) with a built-in inward offset that preserves a standard 52mm chainline and a symmetric Q-factor. On threaded frames, 3/5/7mm spacers let you fine-tune alignment so your shifting stays crisp and your knees stay happy. For more on ring choice and offset, see CYC chainring options explained.
Still not sure?
Contact CYC support with your frame make/model and bottom bracket measurements, or ask an authorized CYC dealer, and we will confirm compatibility before you buy. If you are still deciding between kits, our guide to the best mid-drive ebike conversion kit compares fitment, power and ride feel.
Frequently asked questions
Will a CYC mid-drive fit a PressFit BB92 frame?
Yes. CYC supports PressFit BB92/BB86 frames using a CYC adapter and the correct spindle version. Confirm the adapter for your platform before ordering.
Does a CYC kit fit a Trek BB90 or BB95 frame?
No. Trek BB90/BB95 frames press the bearings directly into the carbon with no threaded shell, so no mid-drive conversion kit can be fitted.
Can I fit a mid-drive on a full-suspension mountain bike?
Usually yes. CYC mid-drives fit most full-suspension frames, as long as the motor body clears the swingarm and pivot. Check clearance around the bottom bracket before installing.
How do I measure my bottom bracket?
Use a caliper to measure the shell width (68 to 120mm) and internal diameter. BSA threaded shells are ~34mm internal, BB92 is 41mm and PF30 is 46mm. Those numbers identify your standard.
Build your Drive System
Configure a complete CYC motor and battery system
Build your Drive System
Configure a complete CYC motor and battery system
Build your Drive System
Configure a complete CYC motor and battery system visualized on your selected frame for fit and reference.
Build your Drive System
Configure a complete CYC motor and battery system
visualized on your selected frame for fit and reference.
