reducing 15mm thru axle fork to 12mm

[joejack951]

Because this is Weight Weenies...

[NickJHP]

Needs to be road tested but here it is in the flesh. Currently designed to fit my Hong Fu fork (10mm thru hole drop out thickness, 15mm threaded dropout thickness) and to use a standard 12mm x 125mm long thru axle with 12mm of threads (https://www.jensonusa.com/Rockshox-Maxle-Stealth)

Note that the threaded adapter is slightly backed off from being fully threaded into the dropout. I expect that there will be some variation in dropout thickness so the plan will be to use shims under the outside flange to get the inner portion just flush with the dropout. I plan to include a few shims with each set for this purpose.

Price? Probably $30 shipped for the pair of parts.

I'd definitely be interested in a pair of the adapters. I have a Niner RDO fork that uses a 15mm thru axle (M15x1.5), but all my other bikes with thru axles use 12mm, so I can't easily swap any of my other wheels onto the bike with that fork.

[joejack951]

I'd definitely be interested in a pair of the adapters. I have a Niner RDO fork that uses a 15mm thru axle (M15x1.5), but all my other bikes with thru axles use 12mm, so I can't easily swap any of my other wheels onto the bike with that fork.

What are your dropout thicknesses?

[crazybaboon]

I’ll also have some, again for a Niner RLT RDO fork

[AZR3]

I'd be interested for my Exploro too

[joejack951]

Loving the enthusiasm/interest but I need dropout thicknesses, guys! Hoping that cross/rigid MTB forks are fairly consistent around 18mm per leg. That would make the kit very easy.

[KyleH]

Loving the enthusiasm/interest but I need dropout thicknesses, guys! Hoping that cross/rigid MTB forks are fairly consistent around 18mm per leg. That would make the kit very easy.

Joe I’ve got a Parlee fork with 13mm thick fork dropouts. Would love a set of these!

[NickJHP]

Loving the enthusiasm/interest but I need dropout thicknesses, guys! Hoping that cross/rigid MTB forks are fairly consistent around 18mm per leg. That would make the kit very easy.

On my Niner RDO fork the threaded side dropout is 15.8mm thick and the other side dropout thickness is 10.5mm.

[joejack951]

Thanks, Kyle and Nick!

Since the Niner fork has nearly identical dropouts to my Hong Fu, would NickJHP and/or crazybaboon be willing to try these prototypes out and give some feedback? All I ask is to cover shipping.

Kyle, the threaded insert I have could likely be trimmed down to fit your fork but the thru hole side will be quite short. It may not be that big of a deal depending on the geometry of your hub’s end caps.

[KyleH]

Yeah I’d 100% be able to trim the one side. The hub end caps are substantial enough that I don’t think it would be a huge deal with the shorter hole side. Let me know if you want another beta tester!

[crazybaboon]

I’d love to test them, should be able to trim them if necessary

[joejack951]

Anyone interested in beta testing please email me at jjpandellc at gmail dot com and I’ll send you a Paypal invoice for shipping. Include your address so I can calculate that beforehand. I have 7-8 sets available. These are designed to work with a 12mm x 1.5mm pitch x 125mm long axle with 12mm of threads. Please do not attempt to use these with a 118mm long axle.

[maximvanwijk]

Looks great! In the mean time I have updated my hub to take 15mm TA, so no need for me right now. Good luck with testing, production and further development of this kit.

[joejack951]

Hey guys, sorry for the silence. I will be sending out shipping invoices for everyone who responded as wanting a beta test set. I really appreciate your feedback.

I took my bike on its maiden voyage with the 12mm conversion kit installed and all went well. No weird noises, no issues with disc alignment, etc.

One minor issue I encountered during installation is that with the acetal shims under the threaded adapter (to adjust the adapter to be flush on the inside of the fork dropout) is that the adapter wants to unscrew from the fork when proper torque is applied to the thru axle. There are a couple of solutions, the simplest being using some threadlocker on the adapter, the more permanent the better depending on how frequently you'll be wanting to revert back to 15mm threads. The second option is for me to source some stainless shims which will offer a much higher friction force to resist the torque from the thru axle. With no shims installed, the adapter goes nowhere even at max specified torque for the axle. Third, you can hand trim the adapter to the right length by slowly removing some of the 'skirt' until it is just flush with the dropout when tightened. A little sub-flush won't hurt anything most likely but my preference will always be as flush as possible.

Another even more minor issue is with the o-ring on the thru hole insert (to keep it from falling out during wheel swaps). My drop out had a sharp edge to kept the insert from sliding in no matter how much lube I added or how hard I pushed (within reason). I took a sharp knife blade and lightly scraped the ID to remove the sharp edge and the insert snapped right in.

Some more pics (ignore the scratches on my adapter from stepping on it while it sat on the garage floor):

[spud]

what a great solution, this will allow lots of people to update their bikes to share wheels across different bikes.