The New KASAI Dynacoil FS (Field Serviceable) Dynamo Hub

If you’ve researched dynamo hubs, you may have stumbled upon KASAI. Their Dynacoil hub has been around for a while and is fairly well reviewed, despite the fact that it looks quite similar to the Shutter Precision hub. Today KASAI introduced a brand new dynamo, the KASAI Dynacoil FS. FS stands for Field Serviceable, which is quite a breakthrough in the otherwise slow to evolve dynamo hub market.

As most of you may know, even high-end dynamos aren’t really serviceable, not even by experienced bike mechanics. Most are sealed at the factory, so if a bearing needs replaced, it requires shipping to and from the factory to be repaired, which is usually overseas. This can leave you stranded; it happened to me in Uganda. The KASAI Dynacoil FS aims to close that loophole with a fully field serviceable dynamo hub.

There are three main things that can go wrong with a dynamo hub while out bikepacking. 1. water contamination; 2. bearing wear; 3. dynamo failure. If any of these occur when you are miles from civilization, you’re kind of screwed, especially if you rely on dynamo-dependent lighting or navigational equipment. KASAI claims that their new FS hub can be fully serviced, anywhere. With just a 36mm flat wrench, you can have access to the coil assembly and hub bearings. So if you submerge your dynamo in a river crossing, you can remove the coil to inspect it or air it out. You can also replace the bearings. And if your hub just stops charging, you can replace the coil assembly for about half the cost of the hub, without having to remove the hub.

KASAI Dynacoil FS

• Compatible with 26” to 700c wheels (6v/3w)
• Meets German StVZO standards
• Achieves 72% efficiency at 10mph
• 6061 T6 AL shell/7075 AL end caps
• Teflon-insulated copper wire from Japan
• Weight: 445g to 495g

KASAI Dynacoil FS Hub Standards/Pricing

• 9 x 100mm QR Non-Disc $129.99
• 9 x 100mm QR 6-Bolt Disc $139.99
• 15 x 100mm Thru-Axle 6-Bolt Disc $189.99
• 15 x 100mm Thru-Axle Center Lock Disc $189.99
• Replacement Coil Assemblies $89.99

Unfortunately, the KASAI Dynacoil FS doesn’t come in Boost/110mm spacing. However, KASAI offers a conversion kit for the 6-bolt hub variations. The kit contains a rotor spacer and two spacers to make up the axle width on either side of the hub. Find that as well as all the KASAI Dynacoil FS field serviceable dynamo hub options over at MerrySales.com. And if you’ve had any experience with Kasai hubs, please leave us a comment below.

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