04 STi to 05 STi hub swap.

[javid]

We are about half way though with the swap, I will have some one post pics soon. We should finish up tonight. Many thanks to Subaru of Gwinnett for parts and for helping to figure this out. Also have to thank Nasioc's Ver. III and driveshaftshop.com for useful info. Mucho thanks to everyone at TopSpeed. Doug is loaning me some rear rotors and his wheels and tires (my only set of 05 wheel have victos on em) to get to the track this Monday, Will helped my incompetent ass with the tear down, and Jason for some trick bushings and staying late. Lastly, Tom Hoppe is the MAN!!!! <-- stayed up late to get most the swap down and is comin back for more wrenching and tomfoolery tonight. You rock buddie.
Down to business.....

Why swap: Wheel selection of 5x114.3 bolt pattern and SUPERIOR front hub and bearing.

For serious Auto-X'ers, DE, or club racers, there are only a couple production wheels wider than 8.5" for the 5x100 bolt pattern and custom will run $2k+. 5x114.3 has 'any' width wheel and many can be found in the cheap, light, and strong category.

The 05 bearing in the front is larger / stronger which will prolong life and resist knock-back longer. Plus the hub and bearing come as one sealed unit, which I call a unit hub, which bolts to the knuckle. Replacing a unit hub should take ~30 mins.

Will it work on WRXs/RS? Haven't reviewed all the changes but I think it will be just as easy. Edit: I understand that the axles are thinner, if the outer axle is also thinner then WRX/RS owners will need to swap axles....

What's different / what do you need.
Front:
2 - Unit hubs. ~$200
2 - 05 knuckles (subaru calls em housings) ~$200
8 - bolts to attach the unit hubs to the knuckle. These are not immediately obvious; usually when you are replacing the 05 unit hubs you would already have the bolts. ~$10 maybe
2 - 05 uprights. I had JICs going into this mod, so I just screwed on the new 05 uprights. If your not as lucky as I, you could buy take offs or upgrade... ~$depends, most coil over manufacturers will let the uprights go for $200-$300.
2 - rotors. Its hard to find take offs, but I did. I will upgrade to two-piece rotors very soon; these should reduce the heat transferred to the hub which I believe is the main contributor to flex and failure. Take offs $100-$200. New $350-$650. You might as well get two piece and keep your pimp new bearings happy.
2 - wheels. ~$350 and up for a pair

Rear:
The rear is essentially the same design as 04, except the PRESS IN hub has a different bolt pattern. The rear on an 05 has a larger track which is only from slightly longer axles and links. The sub-frame is the same and the knuckle is the same part number. So you should only need:

2 - press in hubs. You will pull the 04 pressed knuckle and hub, bring it to your mechanic, to have them pull and rebuild with new bearings and the 05 hub instead of the 04. ~$200
2 - new bearing sets, pretty obvious from the above. might as well invest in some upgraded grease. ~$150 for the pair I think.
2 - rotors. New $220+
2 - wheels $350+

Some random info:

The rear axles and links for 04 to 05 are different lengths the 05's being slightly longer. This produces a looser but predictable rear end. autoXers may want this but buying spacers would be much cheaper...

Both the rear and front axles are different part numbers between 04 and 05. I believe that the rears are just a little longer. I know that the fronts have a different mechanical attachment to the tranny (04 can't go in 05 tranny and visa versa), they have different spline counts on the main axle bar (piece between the CVs), the spine count on the outside of the axle is the same (so 05 unit hubs will fit on 04 axles).

Some very experienced enthusiasts thought I would be fine just re-drilling my rear rotors. Aftermarket rotors range from 220 to 450 a pair for 1 pieces.

This conversion isn't for everyone; probably only makes sense for the autoX / road race crowd, however there are many. Like many conversions, planning / timing can be very important and save you money.

Knowing that the rear links were different lengths, I bought some adjustable lateral links (Poltec). however 04 rear links will work with 04 axles, your track will be ~1/2 inch narrower than an 05.

Even if you don't up grade links, this conversion would be a good time to upgrade some bushings, especially the rear trailing arm bushing, it is in the rear knuckle and is easy to remove with a press ONLY if the bearing has been separated and the dust/e-brake shield is removed. Else your must drill the old bushing out.

For a WRX or RS: I think axle/hub engagement is the big question. I believe that the bearing has been the same in the rear for some time... Someone on the board may know more. I have spare hubs at each end now though so if some one local has there axles.

5-29-05 Update:

Well we finished up late Friday. Big thanks to Subaru of gwinnett and the SE subaru warehouse for pressing the new rear hubs and bearings and rushing the 8 hub bolts over. Every thing went together fine. Except the front wheel speed sprocket on an 04 is in a different place than the 05 . I believe that the teath are the same but the 05 is closer to the end of teh axle. This means that with the center diff in auto, it sees infinite slip and locks the center diff and of course ABS is not happy. So for now, I pulled the ABS fuse and bump the center diff into manual every time I hop in. ABS and auto mode would be nice, and I have a few options to investigate to either get the sensor over the sprocket or press another sprocket on teh axle under the sensor, I should have answers on this in a couple weeks.

General 04 vs 05 info: thread

Buy my old stuff: here

gregr01: Depending on the brakes (heat), grip, and driving, the 04 bearings will last about 4 or 5 track hours before they start to flex very badly and fail. After 10 hard track hours they may be destroyed....

Update 5-03-05
I have had a few inqueries on the front hubs and knuckles. Once I get pics up they should be sold quickly. So If your doing a conversion, you shouldn't have trouble finding 04 STi owners that want a spare set of hubs to build up.

I had the rear rotors re-drilled for the new bolt pattern. I was a little worried but this should be a cheap and simple job for any decent machine shop. They slipped right on and the is no issue with balance.

So the only thing left to do is get a wheel speed gear made and pressed against the existing one. I will probably start this process (bring axle to shop, order gears, bore them out, etc) next week. Odds are I will have 10 or 20 gears made once mine are fitted and tested. Maybe a month till they're available.

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[gregr01]

Did you experience a failure of any '04 hub components prior to the conversion?

[King Of Imports]

Can you verify or know where we can learn whether the axles are the only parts required to gain the additional track width in the rear?

Also, wouldn't you also want to increase the width of the front track as well? It seems to me the car would not handle as well with a wider rear track unless the front was widened the same amount or more than the amount we would widen the rears. From what you have indicated, it does not seem like we can widen the fronts because the 05 axles are different from the 04 axles where they meet the transmission.

And one more thing to add to your wonderful writeup, STi just released competition GDB-E Type (that is 2005 in our country) competition hubs in Japan. No idea what the differences in design are.

Kevin
www.kingofimports.com
King of Imports, LLC

[stimpy]

Interesting. I was throwing around the idea of converting my L wagon to the 5x114.3. It sounds possible and yet not possible.

I was told that the front uprights differ between the 2004 and the 2005 STi where the 2005 STi is a wider piece. If that is the case, and it sounds like it is, then the older cars are going to have issue with doing this and be severely limited due to suspension options. I didn't expect the hub assembly itself to be drastically different and incompatible with the existing hub. The rear, as I suspected, is merely just a bearing and hub away.

Thanks for the work

-Jon

[javid]

Kevin, my 2004.5 setup has the same track front and rear as an 04. I DID NOT need new links, but installed some pillow ball poltecs that I bought just incase. The knuckles from 04 to 05 are the exact same as is the subframe. On the 05 both the links and axles were lengthed to produce a looser but predictable rear end (widening track on a macpherson setup is very different than on a multilink setup).

Provided the upgraded hubs that you have heard of aren't uber expensive, they may be worth it. The redesigned 05 unit hubs that I installed have MUCH bigger bearings than the 04. Its still pretty soon to tell but no one in an 05 is reporting bearing flex or failure.

stimpy: I recently learned that the RS and WRX axles are thinner than the sti. It this difference is also present in end of the axle out side the CV, then the new unit hubs won't it. The end of the axle may be the same. The Leg may have thick sti like axles...

[King Of Imports]

Was the front axle widened as well on the 05s?

[javid]

My understanding is no, but alot was changed: attachement to the tranny is completely different, spline count on the main axle (between the CVs) is different, as is the length on the main axle, but the overall track is the same I believe.

Anyone else know?

[petawabit]

woops double post

[petawabit]

are the part numbers for the control arms the same for the 04-05 sti? I don't think the extra track is gained from the axles,but rather something holds the hub to the axle, like a control arm or steering rack.

This doesn't seem too bad as it seems. I'm wondering how the spacing on the uprights would effect the gc chassis. Other than that, it seems like it would fit fine without problems

[javid]

My understanding is that the 05 front track didn't not change. Don't know about part numbers.

[Soon2Bgreat]

Disregard this, misunterstood a post

[petawabit]

Originally Posted by javid

My understanding is that the 05 front track didn't not change. Don't know about part numbers.

in one of your links above with the differences in the 04 and 05, someone stated that is has a wider steering rack. I think this was stated in EVO?
Would you think changing to the 05 hubs were worth it?

[petawabit]

also, for the rears, you do not need to change the strut upright to bolt onto the hubs?

[javid]

As for the rack I have not read that it is a different width. It bolts to the subframe in a different manner. After the swap there was no noticeable difference in toe so I would guees that even if the rack was wider then tie rods absorbed that difference.

Was it worth the swap? yes, I track the car alot and the bearings would go fast and the knockback was getting dangerous. Also the wheel selections / cheapness is great. Worth forces one to consider cost. I planned the swap, I needed new front rotors for a couple months but held off, also waited to get new wheels until the swap.

For the rear you don't need new uprights, the 04 and 05 struts are the same in the rear.

[root]

I noticed you list some rough price estimates on a piece by piece basis, but was curious if you have a final all inclusive total that this process costed you?

[petawabit]

Originally Posted by javid

As for the rack I have not read that it is a different width. It bolts to the subframe in a different manner. After the swap there was no noticeable difference in toe so I would guees that even if the rack was wider then tie rods absorbed that difference.

Was it worth the swap? yes, I track the car alot and the bearings would go fast and the knockback was getting dangerous. Also the wheel selections / cheapness is great. Worth forces one to consider cost. I planned the swap, I needed new front rotors for a couple months but held off, also waited to get new wheels until the swap.

For the rear you don't need new uprights, the 04 and 05 struts are the same in the rear.

yeah, seeing as to whats involved, it's not too much if you have most of the items transferable. for me, all I would have to convert are the rims(can sell my old ones and buy new rotas and still be ahead for now), convert the front upright, redrill or get new rear rotors, and get the hub assemblies in the front and the press in one in the rear. have you tracked the new setup and felt a difference in the stiffness of the new wheel bearings?

[King Of Imports]

Originally Posted by javid

Every thing went together fine. Except the front wheel speed sprocket on an 04 is in a different place than the 05 . I believe that the teath are the same but the 05 is closer to the end of teh axle. This means that with the center diff in auto, it sees infinite slip and locks the center diff and of course ABS is not happy. So for now, I pulled the ABS fuse and bump the center diff into manual every time I hop in. ABS and auto mode would be nice, and I have a few options to investigate to either get the sensor over the sprocket or press another sprocket on teh axle under the sensor, I should have answers on this in a couple weeks.

Any word yet?

[javid]

Originally Posted by root

I noticed you list some rough price estimates on a piece by piece basis, but was curious if you have a final all inclusive total that this process costed you?

mkay.

I sold my bbs wheels n tires for 750, they were scratch and tires were spent.
Bought some used 17x9 5Zigens and 255 RA-1s for a total of 1350

= -600 for wheels and tires.

-200 for take off rotors
-30 to redrill the backs
-400 for front hubs and knuckles
-240 for rear bearings and hubs and labor to press them in.

so -1500 to get the swap done.

I am confident I can sell my front rotors for 150 or so and the front hubs and kunckles for 200. Either would be great spares for any sti owner that spend time at the track.

[javid]

Originally Posted by petawabit

have you tracked the new setup and felt a difference in the stiffness of the new wheel bearings?

Haven't tracked it no, however there was a huge difference just on the street; my old bearings were completely shot.

[javid]

Originally Posted by King Of Imports

Any word yet?

Nope just bad news and more bads news. 3 weeks ago I tore soethin up in the steering rack. This weekend I am leaving town for work for at least a few weeks. I am going to try and pull an axle before I leave and drop it off at the machine shop....

[petawabit]

Originally Posted by javid

Haven't tracked it no, however there was a huge difference just on the street; my old bearings were completely shot.

difference between 04 and 05 hubs WITH good bearings?

[javid]

I haven't had the opertunity to push the new bearings but a few freinds of my that have 05s and are active in motorsports have confirmed they can put up with alot more than the 04s...

[veightkiller]

eh!?!?! where's the pix?? i want to see it?

[javid]

With 275 V710s on 17x9 ET35.
Now it sports 255 RA1s on the same rims.



The front is charge speed fenders andthe rear was rolled and stretched about 1" at the top.

[javid]

I had no rubbing issues with the 710s and I will be running much more camber than those pics (just after the install w/o alignment). Eventually I would like to run 275 or 285s on 18x9.5 rims for dry track events.