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Checking: Koolux BK6S 4.0 Electric Bike
Why Buy From TrailSurge?UK showroom, product support & aftercare
Buy your Koolux BK6S 4.0 Electric Bike with UK-based support
TrailSurge is a UK retailer with a showroom and workshop in Nuneaton. Our team can help before you order and continue supporting you after your Koolux BK6S 4.0 Electric Bike arrives.
UK-based customer support before and after your purchase
Showroom and workshop in Nuneaton
Help with product questions, setup, parts and aftercare
Tracked UK delivery with support if you need help with your order
Speak to a real member of our team before placing your order
Why buy through TrailSurge?For the best UK-based support and aftercare, we recommend buying through TrailSurge rather than ordering directly from overseas manufacturers or China-based sellers, where returns, warranty support and parts handling can be more difficult.
Need help with the Koolux BK6S 4.0 Electric Bike?Ask our team a question before ordering.
TrailSurge Warranty+✓
BEST WARRANTY IN THE UK
Stronger cover. UK support. Real help when you need it.
TrailSurge Warranty+
Extra protection, backed by our UK team
For the first 12 months, TrailSurge Warranty+ gives you direct UK support on eligible faults affecting the main factory-fitted components — with practical help to get you back up and running.
UK-based fault support
Major factory-fitted components covered
Repair, parts or another suitable solution where eligible
Typical component cover:
Eligible faults affecting major factory-fitted components, including the frame and forks, motor and drive system, controller, battery and BMS, charger, wiring, display, gears, brakes, and factory-fitted sensors or controls.
+Koolux manufacturer warranty
Warranty period
12 months against manufacturing defects.
What’s covered
Confirmed production faults affecting the original frame and factory-installed electrical or mechanical components.
Road use notice: This bike is over 250W and is for private land/off-road use only. Need a UK road-compliant option?
View road legal e-bikes
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Description
Quick Summary The KOOLUX BK6S 4.0 combines rugged fat‑tyre traction with a powerful 750W motor and a high‑capacity 48 V 13 Ah battery. Designed for both urban streets and off‑road paths, it delivers stable handling and dependable performance.
Smooth Power Delivery The 750W hub motor offers responsive acceleration and smooth pedal‑assist across seven levels, letting you tackle hills and headwinds without strain. A thumb throttle provides instant power when you need a boost.
Comfort & Control Wide 4.0″ tyres and front suspension absorb bumps and maintain grip on loose or uneven surfaces. Dual mechanical disc brakes ensure consistent, controlled stopping power in all weather.
Smart Battery System A lockable, removable 48 V 15 Ah battery provides long-range capability and convenient off‑bike charging. Built‑in protection circuits guard against over‑charge, over‑discharge, and overheating for safe, reliable use.
Tech You Can Trust The clear backlit LCD displays speed, battery level, distance travelled, and assist mode at a glance. Simple handlebar controls let you switch assist levels and monitor ride data easily.
Built for Everyday Use With its durable frame, fat‑tyre stability, and straightforward folding rack mount design, the BK6S 4.0 is ready for daily commutes, weekend adventures, and everything in between—wherever you choose to ride.
Yes. The frame and stem fold to approximately 96 × 38 × 75 cm. That helps with boot or shed space, but it remains a substantial 20-inch fat-tyre bike, so check the vehicle opening and lifting height before relying on the fold.
Yes. The lockable battery can be charged on the bike or removed and taken indoors. Support it securely as it slides out, use the supplied charger on a dry, stable surface and make sure it clicks and locks fully back into position before riding.
The standard BK6S 4.0 uses one battery and is the simpler choice for typical rides. The BK6S Pro carries two batteries with 23.4Ah combined capacity, giving it a longer-distance focus but adding cost and weight.
Published guidance places it around 165–195 cm, but height alone does not guarantee comfort. Its 20 × 4-inch tyres and folding frame still create a fairly tall, broad bike. Check that you can stand over the frame, reach both brake levers and achieve a safe knee bend at the lowest suitable saddle position.
The Koolux BK6S 4.0 Electric Bike arrives mostly assembled. Final setup normally includes aligning and securing the handlebars, fitting the pedals and completing essential safety checks. Allow approximately 20–30 minutes, or select our professional assembly and PDI service.
The Koolux BK6S 4.0 Electric Bike is not fully waterproof. Avoid prolonged exposure to heavy rain, and never submerge or pressure wash the bike or its electrical components. After riding in wet conditions, wipe the bike dry and store it in a dry, sheltered location.
