I’d assume many of you, like me, have a 15mm thru-axle gravel fork that you would like to convert to 12mm. Every time I review gravel or all-road wheels, they come in 12mm and I have to spend time searching and ordering 15mm cups for the hubs. Let me tell you, it’s a waste of time. I looked for a while for a conversion kit to change my 15mm fork to 12mm but never found anything. The other day, I stumbled upon an eBay seller who makes a handy 15mm to 12mm conversion kit for just about every fork on the market. The account is JJP&E and it really is as simple as you’d imagine! Check out an in-depth look below…

Here’s the copy from the seller for my specific kit:

“15mm to 12mm Fork Thru-Axle Conversion Kit for most road, gravel, and cyclocross forks including Niner (non-MTB), GT, Jamis, Kona, Norco, Felt, Ridley, Raleigh Roker, Rose, Whisky #9, TRP, Otso (Lithic Hiili fork), All City Cosmic Stallion (w/ Whisky #9 fork) and Gorilla Monsoon, Lynskey PRO CX (not PRO GR), Genesis, Hong Fu, Carbonda, Hoy Alto Irpavi, Principia, Prologue, Rapide, Crust Evasion, Tomac Mesa Verde, and Viner Super Prestige. Use 12mm wheels in a 15mm fork. Converts 15×100 forks to 12×100 standard! ”

I wasn’t sure at the time, looking through the many options, but I emailed him, asking him which kit my Whisky fork would take. He replied fast and I ordered the correct kit without having to guess.

The Kit includes the following:

-Thread adapter: M15x1.5mm pitch external thread, 15mm long, M12x1.5mm internal thread
-Thru Hole Insert: 15mm OD x 12mm ID, 10mm long
-Axle: 12mm x 130mm long, M12x1.5mm threads, 2mm spacer (optional, for fine tuning length)

Note that thread adapter and/or thru hole insert may require trimming to fit your fork. A file, coarse sandpaper, or a rotary tool can be used to trim the adapter/insert to be 0.25-1mm sub-flush with dropout. On my Whisky fork, I didn’t have to do anything but chase the paint out of the threads.

It is recommended that you use a blue threadlock to keep the threaded insert from removing. It’s unlikely but I like the added security.

JJP&E’s kits are between $60 and $70 depending on the complexity of the parts. Head to their eBay store to check more kits out. I bought mine and was so stoked on how well it worked that I had to share!