Sigma-galant.com

Im not claiming this as my own idea,
I got the idea from another member.

But i have taken the photos as i have gone so i thought i would post it and it may help others.

Basically i have some struts out of the GJ-GH Sigma

My aim was to try to fit a disk and caliper package that was a straight bolt on unit.
However after asking the questions, and going to wreckers and brake parts suppliers had had any luck.
then another member showed me his setup, and while is not a direct bolt up situation,
It does require some basic machine work.

It is very cheap!
And so the minimal costs involved if you had to get a shop to machine them for you would be bugger all.

Perfect for Rally cars, And Circuit Cars.




The best part is, The Mounting surface is exactly the same distance from the strut with the new Hub and disk, as the standard Sigma.
So it doesnt upset the wheel track!

Sigma


New Hub and Falcon Disk




Many may know that the GJ-GH Sigma strut has a Stub axle with Bearing ID (Inside Diameter) surface on the Inner Bearing (Nearest the Shock) of 31.7mm,
and the outer Bearing mount surface Diameter is 19mm.

Which means it shares the same Stub axle diameters as the Holden Commadore.

So i went to my local Camping and trailer shop,
and looked at their selection of Trailer hubs.







The choices you have here are a Ford 5 stud pattern, and you can have it with either Holden, or Ford wheel bearings.
or a Holden 5 stud pattern, and again either Holden or Ford wheels bearings.

But as i said the Sigma struts I am using have are a straight swap to Holden bearings.

I originally brought the Holden stud pattern hubs, (for ease of finding wheels)
then went straight to a Brake supplier, only to find that the hub wouldnt go straight into the inside of the Commadore disk,
and so i would have to machine the Outside diameter of the hub down, and i was worried about weakening the strength of the Hub and wheel studs if i took too much meat off, and machined too close to the studs the steel might crack.


So I ended up with the Ford 5 stud pattern and Commadore bearings - Around $35 each with Bearings.

Now bare in mind, that because I have choosen to use the Ford stud pattern as it means little other changes to the hubs themselves,
and strength by using 5 instead of 4 studs,
you could just as easily get a machine shop to knock the 5 studs out, fill in the holes, and redrill to suit whatever stud pattern you like,
just make sure you will be able to buy a floating brake disk to suit your stud pattern.

4 X 100 would be easy, im not sure about 4 X 114.3??




I cleaned up the Sigma strut and stub axle,



Slid the Holden Inner wheel bearing on then rested the Hub over the bearing.

Even with the Air guide sheild still on and standard Caliper Bracket, the Hub does not foul on any part!





However the Outer bearing sat too far out and wasnt seated on the stub axle properly, it was hanging out onto the thread too far.

















I then measured the distance that the bearing needed to come in on the stub axle to allow it to get as best location on the stub axle as possible.

The Outer Bearing Outer Race had to be bored in 4mm



So i knocked to outer bearing outer race out from the back of the hubs,








To set the Hub up in the lathe i set the Dial gauge off the very front of the hub as it is a machined surface, and the inside of the outer bearing Outside race.
I then set the Borig bar to the same as the Outside Diameter so it kept the interferance fit for the outer bearing race, and simply bored the shoulder back 4mm.



I also checked the Disk mounting surface and found it to be slightly warped, so i gave that surface afew light skims also.




I then pressed the outer Bearing race back in to the new shoulder.


Due to the Difference between the New hub and the factory disk,
i needed to replace to inner seal.
I just had to goto a local bearing supplier and gave them the ID of the new hub, and the OD of the Sigma Sealing surface and he was able to match me up a seal off the shelf.
Part number - NAK TC 1.750 2.328 0.2506




Just have to pack the bearings with grease, and fit it up.

So that is the Hubs, now if you choose to follow the path of using the Ford 5 stud pattern.

I found that RDA have Falcon front disks Vented and Slotted, for $200 for a pair.

297mm X 28mm
and no the factory Sigma Calipers arent going to fit over them







I tried both the AU and BA disks and found that the BA disk braking surface sits further out, away from the Strut.
Giving you more clearance away from any steering and suspension parts.

BA disk on left, AU on right




BA Disk on the hub showing clearance to Strut


AU - AU disk is actually touching the sheild,so it would have to be removed




Here is the Disk mounted on the hub.



Here are the BA Falcon Twin piston Calipers mounted on the disk




I chose not to use the Standard Trailer wheel studs that came with the hubs,
I went to the local Ford Dismantlers,
They had BA Falcon wheel studs already removed and in a container, $1 each with the Wheel nuts
To fit them you will need to drill the stud holes out with a 14 or 14.25mm drill bit.
Make sure you use a Pedistal drill and have the hub secured properly, dont hand drill the hole or very likely will drill them oversize.

This is an awesome idea Dan and very well explained with great pics. How do the calipers mount to the strut?

What is keeping the disc hub-centric to the hub? The centre of the disc looks too big to locate on the hub itself without machining up a spacer/sleeve to suit. Or will it locate on the larger diameter section of the studs?

Galant_GT0 wrote:This is an awesome idea Dan and very well explained with great pics. How do the calipers mount to the strut?

Thanks mate, lots of bits and pieces and photos in my little bit of spare time over a month or so, glad i was able to put it together in away that was understandable.
With the calipers I am using, i will be machining up a set of caliper brackets.
I will be making them with mulitple locating holes, so i can adjust where i want the caliper to sit on the strut depending on what i need to clear for Sway bar, steering etc.
Once i am happy with them, i may make some copies.
I would certainly be happy to send people a copy of a drawing so they can make their own or get someone to make them.

C_Fernance wrote:What is keeping the disc hub-centric to the hub? The centre of the disc looks too big to locate on the hub itself without machining up a spacer/sleeve to suit. Or will it locate on the larger diameter section of the studs?

Ahh thats what i forgot to brush on.
I also machined the hub to allow for a spacer to slip on later if needed.
I was going to fit the studs and see how much movement the disk has, and i have to find some wheels, to i will be making a spacer to carry the load on the centre for them instead of all the weight on the studs.

DanTurboLancer wrote:However the Outer bearing sat too far out and wasnt seated on the stub axle properly, it was hanging out onto the thread too far.

Was there enough steel to machine out the front bearing instead of the rear?
I'm just thinking of the amount of FWD rims that you would now be able to use with the extra positive offset.

Cheers.

I love the idea, in fact this idea has now sold me on what diff I will be using and having the 5x114.3 pcd all around I will be your first customer once the drawings are complete
It will open up a massive range of wheels both new and old school

Superscan811 wrote:

DanTurboLancer wrote:However the Outer bearing sat too far out and wasnt seated on the stub axle properly, it was hanging out onto the thread too far.

Was there enough steel to machine out the front bearing instead of the rear?
I'm just thinking of the amount of FWD rims that you would now be able to use with the extra positive offset.

Cheers.

Well as it is with the disk on, the wheel offset is actually the same as stock Sigma, so it doesnt change much.

To do what you are suggesting, and make the hub to suit FWD offset,
you would have to machine that outer bearing shoulder in the 4mm that i did just to line the bearings up on the stub axle,
then to space the hub wheel mounting surface out to suit FWD offset, it has to move out about 25-30mm.
Same as if you bolt on the adaptor plates onto normal RWD hub.
You could knock out the Inner bearing race and machine a Spacer to make up the gap between the Inner bearing and the shoulder.
But im not sure if the pics are clear enough, but no unfortunately there isnt enough meat to allow machining the outer bearing in that far...

You could always get some custom one off hubs made to suit.
You could speak to Stealth about that!!

Galant_GT0 wrote:I love the idea, in fact this idea has now sold me on what diff I will be using and having the 5x114.3 pcd all around I will be your first customer once the drawings are complete
It will open up a massive range of wheels both new and old school

The range of wheels is definitely a plus.

the only thing I dont like about this mod is that trailer hubs arnt as strong as std and are fairly low quality cast items

top stuff dan!! job well done!

cheaterparts wrote:the only thing I dont like about this mod is that trailer hubs arnt as strong as std and are fairly low quality cast items

I think they'll be more than suffice on a galant, the average 7x5 box trailer is rated at around 750kg then theres boat trailers and caravans

cheater has made a good point that has me thinking, but then again trailers and caravans are designed to carry very heavy loads..

Trailers don't have to turn, run any sort of camber or castor or worry about pad knock off from hubs flexing. The forces are very different and I wouldn't trust them at all.

I am pretty sure trailer hubs would be way more smashed than ours. I have a 20year old trailer with torana rims that has done more jumps tha skippy and all is sound.
I am sure we could buy car trailer hubs for phuck all and they have to be as strong.

The only way to be legally sure is for an engineer to sign off on it. The trailer hub appears to be a bit thicker then the factory hubs but you would have to do testing to work out the material properties and strength. I doubt that would end up being cheap at all to get done comercially. Maybe if you know an engineering uni student or academic who may be able to do some tests to narrow down the material hardness and strength. Don't know how well you are connected.

The thing you have to think about with the strength of the trailer hub on a car is that there are a lot of additional forces being applied to it. There are the vertical loading forces, the cornering forces and the forces being applied under braking. And all of these forces could be getting applied at the same time. Also the front brakes do 80 to 90 percent of the work so under braking alone the forces would be somewhat similar, maybe higher depending on the deceleration. Trailers typically aren't driven as many kays as a car is and if a trailer hub breaks it isn't good but it isn't as critical then if the front wheel hub breaks. I would probably be most worried about fatigue over time due to the breaking and cornering. Although most trailers are absolutely abused over their lives.

Don't get me wrong, I'm not dissing your work and I do like you ingenuity with using a prefabricated component to do this upgrade. I would just for my own peace of mind clear this with an engineer to ensure legalities.

these hubs will out perform anything that was oem on our cars

they're are rated @ around 1500kg so cornering braking camber jumping off a pyramid or what ever is not going to affect them in any way what so ever

amgis_obrut wrote:these hubs will out perform anything that was oem on our cars

they're are rated @ around 1500kg so cornering braking camber jumping off a pyramid or what ever is not going to affect them in any way what so ever

you maybe right that these hubs may perform good enough but they are not rated for the front of a car
in fact a LM bearinged trailer hub has a max rating of 500 Kg for a trailer or 1 tonne for both

a 1.6T axle has both larger bearings and stronger hubs ( 800 kg per hub runs 2 x 35 mm Id bearing )

cheaterparts wrote:the only thing I dont like about this mod is that trailer hubs arnt as strong as std and are fairly low quality cast items

I still stand by this quote - I would not use them myself on a street or race car - I would only use them to tow the car to the track

I have made hubs for track cars but used K1045 steel over cast ( the steel can be bent or dented with a sh!t load of force but doesn't break like cast )
but if you can get an engineer to sign off on them fine
then its his neck on the line

cheaterparts wrote:you maybe right that these hubs may perform good enough but they are not rated for the front of a car
in fact a LM bearinged trailer hub has a max rating of 500 Kg for a trailer or 1 tonne for both

So by what this says its the bearing thats the limiting factor, the hub itself can comfortably cope with 1450kg

http://www.alko.com.au/vehicle-technolo ... iler-hubs/

and besides aren't these exact LM bearings OEM on our cars and stuff like falcons and 90% of holdens ??


for those doubting the durability of these hubs for automotive use i suggest you take a look at an XA falcon bearing hub

I do agree with Cheater,
These are a mass produced and cheaply made Hub.
That is why i had to Machine the disk mounting surface.

I think they have been proven over the years that they can handle loads.
I personally have never heard of the hubs actually failing?? others may have?
But I have seen alot of bearing failures.

I would bet that this would mainly be caused by the Trailers being left to sit for long periods,
and never being serviced or maintained, hense the abuse.
Water and condensation entering the bearing and effecting the bearing Race and Bearing rollers and balls themselves would be the most common failure.

As they use the exact same bearing that has been used on Holden front wheel bearing from WB through to current,
I dont think load on the bearings is of any concern.

The Ford bearings are larger, and can carry higher loads, but they dont fit onto a Sigma Stub axle.


I agree that additional side loading on the cast hub, as opposed to a machined steel hub would be of interest.
But many brake parts are made from Cast from the Factory.

As I said, i have seen this exact set up already used on another members Galant.
I know it works, and i know he has never had an issue with them.



Im not saying it will pass an Engineer, but i will speak to one and find out what he says.

However it would be a cheap option for rally and circuit cars wanting a Brake upgrade...

I for one will be using this mod once it is sorted. I see no issue with load personally and don't believe there will be any problems at all. This is (IMHO) the perfect way to go 5 stud with very little messing about.
+1 IMO

amgis_obrut wrote:

cheaterparts wrote:you maybe right that these hubs may perform good enough but they are not rated for the front of a car
in fact a LM bearinged trailer hub has a max rating of 500 Kg for a trailer or 1 tonne for both

So by what this says its the bearing thats the limiting factor, the hub itself can comfortably cope with 1450kg

http://www.alko.com.au/vehicle-technolo ... iler-hubs/

and besides aren't these exact LM bearings OEM on our cars and stuff like falcons and 90% of holdens ??

for those doubting the durability of these hubs for automotive use i suggest you take a look at an XA falcon bearing hub

read alkos specs since you posted them 5 stud trailer hubs 1450 per pair = 725 each to carrie this weight slimline bearings need to be used --- 4 stud 114.3 pcd pattern 1000 kg per pair as I had quoted

and yes I have looked at XA falcon hubs a few more times than you ( they were a new car the year I started my time as a mechanic and at Coffey ford - I must be getting old and gummpy ) the drum brake models had a cast steel hub - not cast iron and the disc brake hub/disc was cast iron but it had webs inside the disc and more to the point were rated for the front of a car
xb didn't from memory didn't have any drum brake fronts and ran the same discs as the XA
XC changed there front disc for a stronger hub section needing a larger spigget hole in the wheel

LM bearings are used in GH and later sigmas all holdens after FJ untill later commodores ( not sure which models )
Lm size are 1 1/4" Id for the larger inside and 3/4" id for the smaller outside
fords used larger bearing - slimline from at least XW which are 35 mm Id and 7/8"

Galant_GT0 wrote: This is (IMHO) the perfect way to go 5 stud with very little messing about.
+1 IMO

I must say I had planed to fit 5 stud wheels to the sigma to use a commodore pattern with 15 x 7 wheels ( the largest I can use in class )
but I'll machine new hubs from K1045 with an off set flange to keep the track much the same as it is atm
and use the largest commodore pattern slide over disc that will fit under the wheel

well you'd have to agree that a disc brake XA hub would be piss weak compared to the trailer hubs, I have XA hubs on my sigma and they're a lot thinner where the studs go, plus theres no ribbing anywhere on them and they're soft as shit

and if you go back and read my post with the link you'll notice that i said the bearings are the limiting factor, the hubs themselves are good for 1450kg (or more) with the upgraded bearings

so what would a sigma hub be rated at ???

amgis_obrut wrote:well you'd have to agree that a disc brake XA hub would be piss weak compared to the trailer hubs, I have XA hubs on my sigma and they're a lot thinner where the studs go, plus theres no ribbing anywhere on them and they're soft as shit

and if you go back and read my post with the link you'll notice that i said the bearings are the limiting factor, the hubs themselves are good for 1450kg (or more) with the upgraded bearings

so what would a sigma hub be rated at ???

The thing you have to remember is that the thickness and the overall material class aren't the main deciding factor. It's like saying stainless steel is just stainless steel and that there aren't different grades at all. The sigma or XA hubs may be smaller but they could be very different properties to the overall material properties. This could explain the big size difference between the different hubs as the trailer hubs could be made of a poorer quality material and has compensated by just making everything much larger. Also trailers don't really need to worry about unsprung weight so much as cars so they engineer things to a higher standard for the application. It all comes down to the in the end the material quality and the engineering which goes into the final product.

Also Cheater just for interests sake what kinda price would custom hubs be in the end making them from the k1045 material you? Not that I could afford it but for other people it could be an option to change to a different offset providing a much larger wheel range. Especially for those already looking at a diff upgrade. I've always thought about it if I ever got the funds for a diff upgrade eventually and have the cost of rims justify the expense.

For me these hubs just make the diff choice so much easier. Basically I want an LSD and disc brakes and staying 4x114.3 pretty much means a R31 Skyline diff, hard to find in LSD and not cheap but going 5x114.3 means I will use a XF Falcon LSD, easy to find, cheap and should be strong enough in a 1000kg car.

How difficult would it be for someone with access to a lathe to produce the hubs and caliper adapter to gh strut with good quality steel?
Would have to be cheaper than the $1400 hoppers kit.