reducing 15mm thru axle fork to 12mm

Discuss light weight issues concerning mountain bikes & parts.

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AZR3
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by AZR3

joejack951 wrote:
Sun Dec 22, 2019 11:36 pm
Got the 3T Luteus II fork in the mail today and was able to finalize the threaded insert dimensions. I'm releasing a similar threaded insert design for Focus Mares RAT forks at the same time. Both kits will yield some weight savings with the Focus kit cutting about 50 grams off the RAT original equipment parts. The 3T thru axle is a real porker at nearly 60 grams so replacing it with any decent weight 12mm thru axle will save some grams there.
Sweet! My wheel options will be much better soon :thumbup:

joejack951
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by joejack951

For anyone looking to convert a Santa Cruz Stigmata 15mm fork, here is the kit I’ve been putting together until I get my own axle production going. I am using a 160mm Maxle, cut down to 152mm with roughly 8mm of new threads added (replacing the 8mm removed in shortening the axle). Both the thread adapter and thru hole insert need a little custom length tuning to match the 24.5mm fork ends but nothing a few swipes across a sharp file can’t fix.

Still a couple weeks out on the 3T and Focus kits but getting closer every day. On the 3T kit, I added an o-ring to the sleeve that fills out the 15mm thru hole portion of the leg that accepts the threaded insert (same design detail on the thru hole insert for all kits). I haven’t seen it mentioned but having a loose insert on that side seems like an important-but-soon-to-be lost-during-travel piece waiting to happen.

I’m also looking into special centerlock rotor shims now that more and more wheelsets can be shared amongst bikes. I’ll share details on those once I am further along. Hint: they’ll be better than off the shelf shims.
Attachments
ECD8E00E-63DD-44F1-B4B6-220A3D73625A.jpeg
Last edited by joejack951 on Thu Jan 16, 2020 3:01 pm, edited 1 time in total.

by Weenie


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joejack951
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by joejack951

3T Luteus II 12mm thru axle insert:

Image

Focus Mares 12mm thru axle insert:

Image

Both options are now available to ship.

3T Luteus II fork kit, which includes a 13mm long thru hole insert for the other side, works best with a 130mm long axle. Robert Axle Project LIG519 will fit as-is.

Focus Mares kit, which includes a 15mm long thru hole insert for the other side, needs a 138-140mm axle. Robert Axle Project LIG510, 145mm long axle, trimmed to size is the easiest option here.
Last edited by joejack951 on Thu Jan 23, 2020 4:19 pm, edited 2 times in total.

joejack951
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by joejack951

I'm posting this measuring template in hopes that it will solicit input from Weight Weenies to help make it easier to use. In the event that it is refined enough already, I hope it can also help anyone interested in a conversion kit select the kit they need without a bunch of back and forth emails. Let me know what you think after giving it a try: https://www.scribd.com/document/4460642 ... g-Template

Note: Template has been updated as of 2/7/2020.
Last edited by joejack951 on Fri Feb 07, 2020 8:40 pm, edited 1 time in total.

joejack951
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by joejack951

I received a request recently for a conversion kit for the new Fox gravel fork: https://www.ridefox.com/content.php?c=openproject

Anyone else interested in this kit? I’m going to be sorting out the details and beginning production of thread inserts hopefully this week with parts ready by mid to late February. The same kit could potentially be used with any Fox fork that has a 15mm axle with M14x1.5mm threads but I can’t say how smaller diameter will affect the suspension. At 40mm of travel on the gravel fork, I’m less concerned. Plenty of Lauf Grits are using my kits now with positive feedback.

joejack951
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by joejack951

Amazon ordering is available for the most popular kit: https://www.amazon.com/dp/B084BN3BPW (15+10 kit for Niner, GT, Scott, Jamis, Kona, Norco, Rose, Whisky, etc.)

joejack951
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by joejack951

I had a good data-gathering experience this past Friday at a local shop, Garrisons Cyclery. The owner happened to be rebuilding a front wheel for a Stigmata owner as the bike had a 15mm fork and the wheel he was given had a 12mm-only hub. While I was a few days too late showing up in that regard, it was still a good visit.

Adding to the list of applications that are currently available:

Rockshox forks: I measured a handful and they are nicely consistent in using 24.5mm wide thru hole dropouts and 24.2mm wide threaded. So the current 25+25 kit fits and in the case of a Boost fork, a standard 160mm long Maxle Stealth rear axle is a nice fit. 100mm forks will still need a customized axle solution as I've been making for the Stigmata/Lauf applications.

Moving forward, I'm going to make a running change to the 25+25 kit to go 24+24 which is a decent compromise to allow for a drop-in conversion on a range of forks. I still have a good amount of 25+25 kits left so I am looking into modifying them all which ought to make installation much easier anyone considering this conversion.

Fox forks and Trek Domane forks are two new applications that both require special inserts which I plan to produce. More details once I get further along there. I have all the necessary details for the Fox application now and am waiting on a Trek fork to arrive (tomorrow) before I draw that design.

Axles...they are coming. Mainly because no one buys a 3T Luteus II or Stigmata/Lauf kit without an axle. And while modifying Maxles has proven to work just fine, I'd rather produce the 'right' axle than modify. They'll be better finished (fully anodized) and cheaper to boot, and require far less of my time.

Once again, I appreciate all the help from this forum and happy to filling a hole in the market!

2rismo
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by 2rismo

joejack951 wrote:
Mon Feb 24, 2020 4:00 pm
Fox forks and Trek Domane forks are two new applications that both require special inserts which I plan to produce. More details once I get further along there. I have all the necessary details for the Fox application now and am waiting on a Trek fork to arrive (tomorrow) before I draw that design.
Awesome!

Is there a list somewhere of forks that the initial prototype fits succesfully?

joejack951
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by joejack951

2rismo wrote:
Mon Feb 24, 2020 10:12 pm
Awesome!

Is there a list somewhere of forks that the initial prototype fits succesfully?
Well, I'm pretty far beyond the initial prototypes at this point :) I still don't have everything covered, but I am getting closer. What's easier for me to do at this point is to list the known applications where I do NOT have a solution and am NOT in the process of producing a solution either. Basically, I know what the solution is, but I need to figure some things out in order to actually produce it.

Those applications are:
1. Trek forks other than the Domane Disc (Boone, Crockett, [Bontrager] Bowie)
2. Some random open mold carbon fork that uses the same 15mm axle with M14x1.5mm threads as the Trek forks above. This fork uses an insert that could be swapped but once I get the Trek solution sorted, the same thread adapter can be used for it.

In Process applications:
1. Fox Step Cast forks - as far as I can tell, all of the lowers for these forks are identical aside from Boost/non-Boost spacing
2. Trek Domane Disc

'Special' Applications:
1. 3T Luteus II fork (3T Exploro, Open UP) - I have a kit for this where replaces the stock hex-shaped M14x1.5mm threaded insert with an M12x1.5 thread insert plus a thru hole insert.
2. Focus Mares - same as above except this fork has a RAT axle rather than an M14x1.5mm thread axle. New insert makes it M12x1.5mm.
3. Salsa Warbird (possibly other models) - 13mm thread adapter needs the flange removed and the adapter needs to be Loctited in place due to the tapered exterior of the fork leg. Loctite 222/242 works well here
4. Specialized Diverge - cone washer on stock 15mm axle needs to be transfered to thru hole insert. With that done, the fork can now use a standard flat M12x1.5mm axle. The thread adapter for this fork has M15x1mm threads to match Specialized's unique choice here.

Everything else takes a standard kit perhaps with a little trimming. Brands of bikes/forks that are using my kits that fall into this category include (but are not limited to):

Niner, GT, Scott, Jamis, Kona, Norco, Felt, Rose, Whisky, TRP, KTM, Genesis, Hong Fu, Carbonda, Otso, Viner (all 15+10 bikes, kit is available on Amazon with free Prime shipping)
Parlee, Raleigh (13+13)
Merida CX forks (19+19)
Santa Cruz, Lauf, Rockshox, Bearclaw, Soma Wolverine v3 (25+25, soon to be 24+24)

There are a few stragglers here and there but not many. If anyone has info about a fork not in this list, or a correction, I'm all ears!
Last edited by joejack951 on Sun Mar 01, 2020 7:30 pm, edited 2 times in total.

2rismo
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by 2rismo

Very comprehensive. Can't wait for the Domane Disc version.

Interested in stocking them here in Australia if you think that would work.

joejack951
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by joejack951

2rismo wrote:
Tue Feb 25, 2020 2:38 am
Very comprehensive. Can't wait for the Domane Disc version.

Interested in stocking them here in Australia if you think that would work.
Of course! I'll send a PM so we can take this discussion offline.

joejack951
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by joejack951

Thanks to a new printer purchase, I'll be checking my design of this Trek Domane Disc insert later today. I plan to only make the threaded side as the existing 19mm long thru hole insert is a perfect fit for the other side and far less expensive to produce. Less labor to swap from 15mm to 12mm, too, as only one nutted-insert will need to be exchanged. This kit will use a new JJBP 140mm axle.

Fox Step Cast insert was printed for the heck of it. With a thin washer this kit will use the same 152mm axle as the Stigmata, Lauf, Rockshox, etc. kits.

Late March availability seems likely.
Attachments
trek insert.jpg
fox insert.jpg

joejack951
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by joejack951

I put this graphic together in an attempt to illustrate how I am calculating axle lengths for these new applications. This particular graphic shows the Trek Domane Disc conversion kit which includes a 19mm thru hole insert, special thread insert, and a 140mm axle.

Image

2rismo
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by 2rismo

Standing by ready to test. :)

by Weenie


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joejack951
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by joejack951

2rismo wrote:
Tue Mar 17, 2020 1:29 am
Standing by ready to test. :)
I know.... :D

I'm running a little behind schedule (shouldn't be a surprise) with mid/late March turning into early April. On the plus side, everything that was in the works will be done at that time (axles, Fox and Domane inserts), barring any additional extreme circumstances.

For now, here's a little in-process sneak peak at the axles (130, 140, and 152mm).

Image

Image

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