2002-2004 STI Hubs USDM/JDM fitment?

[redfogo]

I have been trying to decide where I want to go as far as brakes go. I have been looking at 07 4pot calipers as one option, but honestly seems to be the same price as 02-04 JDM/USDM STI brembos. Can anyone confirm the hub/knuckle fitment? I know both are 5x100 and seem to look the same as a USDM WRX hub. From what I read, I think I will just need to install a different CV axle end so it fits in the hub? I'm running a Forester transmission on a EJ207.

I'm not doing a donor since my local junk yards have just about everything I need cheep(aside from engine/trans/and brakes). So I'm trying to figure out my options before I commit to a hub.

[STiPWRD]

I'm using the 02 Sti JDM Brembos (5x100). The fronts fit no problem but you will not be able to directly fit the rears to a 5 speed trans. This is because the wrx and forester use 24 splines on their hubs, axles, and transmissions and the sti's use 27 splines and larger diameter. For the rear brakes these are your options:

1. Rear spindle adapter kit (this is what I ended up doing) http://www.fastwrx.com/products/rear-brembo-dba-slotted-adapter-kit-02-05-wrx. This allows the rear brembo calipers to attach to the wrx spindle and keep existing 24 spline axles and trans. The kit also comes with larger rear rotors.
2. Use an sti 6 speed trans, sti front axles, and sti rear hubs. This ensures spline count is 27 at each location.
3. Have custom axles made that have 24 splines on one end (for 5 speed forester trans) and 27 splines on the other end (for rear sti hub and brembo caliper).
4. Swap the differential in the trans from 24 spline to 27 spline (maybe go with an LSD).

Here's how mine turned out:
4362343624

[michael everson]

I had custom axles made to do what you are trying to do. Very expensive at around $1000.00
Mike

[redfogo]

I had custom axles made to do what you are trying to do. Very expensive at around $1000.00
Mike

Ouch good to know i figured just swap one end onto the other. Good to know guess I will stick to the 20006-2007 4pot WRX hubs and brakes.

[Hindsight]

I'm wondering if using the larger diameter STI axles would solve some of the axle snapping we've been seeing lately (most recently to MetalMaker).

[redfogo]

STI stuff is a bit stronger. I'm have troubles understanding how so many are breaking them though.No one is pushing that much power through them from what I have read.

[Bob_n_Cincy]

STI stuff is a bit stronger. I'm have troubles understanding how so many are breaking them though.No one is pushing that much power through them from what I have read.
The torque normally split between 4 axles.
On the 818 it is only split between 2 axles. So the axles see twice the torque as the AWD Subaru.
Also, about 2/3rds of the weight is in the rear drive axles, this along with wide sticky rubber can be more torque than axles can handle during aggressive launches.

Here is one of my launches to 205 rear tires.
https://youtu.be/j7N_-mgzewA

Bob

[STiPWRD]

I'm curious to know what material FFR specified for the axles they provide. Depending on the metal and heat treatment there's a chance they could be made much stronger and more reliable. Does anyone have access to hardness tester that Metalmaker can send his broken axle to?

[Flamshackle]

I'm curious to know what material FFR specified for the axles they provide. Depending on the metal and heat treatment there's a chance they could be made much stronger and more reliable. Does anyone have access to hardness tester that Metalmaker can send his broken axle to?

Steel hardening and the application is a real art form. Harder can mean more brittle and achieve the exact opposite of what we want. Just spit balling

[STiPWRD]

Steel hardening and the application is a real art form. Harder can mean more brittle and achieve the exact opposite of what we want. Just spit balling
Very true, there has to be the right balance of strength, ductility, fatigue resistance, corrosion resistance, etc. Sometimes there's a limit as to what can be achieved through material selection and treatment and you have to just make things larger and beefier.

[Tamra]

I'm curious to know what material FFR specified for the axles they provide. Depending on the metal and heat treatment there's a chance they could be made much stronger and more reliable. Does anyone have access to hardness tester that Metalmaker can send his broken axle to?

Isn't it the the Subaru piece that has been failing, not the FFR provided piece?

[Hindsight]

My understanding is the FFR axles are snapping right where they go into the splines of the hub, so that's the FFR piece.

[xxguitarist]

The FFR axles don't go into the hub at all, they go into the inner portion of the outer cv joint, could you clarify?

[STiPWRD]

The FFR axles are breaking right at where they go into the outer CV joint, under the outer CV boot I believe. Wayne posted a pic somewhere but I can't find it.

Edit: I take that back, it looks like Chris's axle broke inside the hub, so that would be an OEM Subaru piece. I'll try to hunt down the pics Wayne posted where I thought it broke at the FFR axle.
http://thefactoryfiveforum.com/showthread.php?10991-Metalmaker-s-build-thread-begins&p=204982&viewfull=1#post204982

[Hindsight]

Yeah sorry.... that is what I meant. If the axles went directly into the hub, you'd bigger problems!

[STiPWRD]

Not to hi-jack this thread but here are the other pics of broken axles - one that Brando posted and one that Wayne posted right below. In both cases, the FFR axle is what snapped.
http://thefactoryfiveforum.com/showthread.php?12442-Brando-s-Newbie-818R-Build-Thread&p=198079&viewfull=1#post198079

[xxguitarist]

Ok, so that's one count for Subie spline, and two votes for FFR spline.

We're planning to build up a spare.. but would be good to know which parts are failing more often.

[Sgt.Gator]

I wondered when snapped axles would start popping up. This has been a problem in the Legacy community for quite a while, but on the rear axles, not the front. The Spec B folks finally got tired of snapping axles and have come up with a super strong set that does not require swapping the hubs, like the other solutions usually do. The Spec B uses a R180 rear diff, the regular LGT uses a R160. The R160 usually breaks before the axle does, so it hasn't been a problem in the regular LGT. However the R180 is much stronger, so now the weak link are the axles.
While it's not directly applicable to our front axle snaps, the same company could probably produce what we need.

Here's a pic of the Spec B new axles:
43700..43701

The thread is here: http://legacygt.com/forums/showthread.php/ultimate-6-speed-spec-b-rear-axle-upgrade-group-buy-237940.html

Of course there is a down side to super strong axles...the weak link will probably become something inside the transmission. That would be way more expensive to fix than replacing an axle. Watch out what you wish for!