Any interest in pre 88 custom hubs?

[Crazyswede]

Discussed the idea of making hubs up for the early 900's to allow vented rotor usage and two bolt patterns for new and old wheel usage. Likely costly but might look into it. Could even explore a 3rd bolt pattern depending on space.

[MattWatson]

What about modding an existing hub on a semi production basis?

This is from an xr4ti, but we turned the hub down and then machined a disc with register for the rotor and wheel. It would be much cheaper than a new hub casting. It converted to the old pattern as well. It was an interference fit with extra long studs that engaged both the old hub and disc. You could easily zap a few welds on too.

[Crazyswede]

Think thats similiar to the idea...i didnt mean making a whole upright assembly...just the wheel flange piece.

[Jon1]

We might be able to use the idea in the photo that Matt posted to add an additional flange (behind the existing flange) with studs or tapped holes for the other bolt pattern.

[Crazyswede]

the hubs in that photo have a lot more material on them vs the stock Saab ones that make me nervous due to their thickness. i wouldn't want to turn the stock ones down at all we might be able to have a form fitting collar machined to fit to the back..but I'd want to do some stress analysis on the stock hub due to its thickness again..would hate to build a protect that lead to wheels shearing off the car.

[Geoff]

I've thought about this a bunch of times over the last 12-15 years. Never did anything about it though

I've always thought about building new hubs out of steel rod but recently thought about modifying existing parts.

The stock hubs are thick where the stud presses in, but too thin in other areas to support a drilled/tapped hole with a wheel bolt through it (at least for my comfort). I suppose one could drill it to 4x108 and weld nuts on the back. But to have the ability to run two different wheel bolt patterns the 4x114 studs would have to be pressed out and bolts would have to be used. I think the hole for the studs is too large to tap to fit a wheel bolt, but not sure. It could be drilled and helicoiled but the thickness of the hub (at the OD of the hub) is kind of thin. Or maybe just weld a nut on the back there too.



Another option would be to convert to '88+ hubs, uprights, rear axle etc. and then pop 4 holes (4x114 pattern) in each hub and tack a nut on the back side. Might be good for a street car (later brakes and all that) but on a race car it might not be ideal (since we have all the Wilwood stuff available for the early hubs/uprights)

[BIRDIEMANGO]

I WAS ALSO LOOKING AT THIS...BUT USING SAAB PARTS BIN....

THE FRONT WHEEL BEARING IS THE SAME FOR BOTH 114.3 PCD&108 PCD FLANGE FITMENT....

SO MY IDEA WAS TO,SEE IF I COULD FIT A 114.3 PCD FLANGE INTO A 108 PCD HUB,SUCH THAT I COULD UTILISE THE 108 PCD FRONT VENTED DISCS,BUT KEEP THE 114.3 PCD.....WITH LITTLE MACHINING?

I NEED TO PRESS OUT THE FLANGES,AND COMPARE DIMENSIONS....

THE CONSTANT VELOCITY SPLINE WILL FIT EITHER FLANGE....

ANOTHER ONE ON THE LIST OF 'TO DO........'

MEANWHILE,THESE ADAPTOR PLATES TURNED UP IN SWEDEN.....WHICH SOLVE ANOTHER PROBLEM,ON ANOTHER PROJECT,BUT NOT THE BRAKES....

MANTON.SE

[Jon1]

Hey Julian, I had the same idea; using adapters to mount the older bolt pattern to the newer hub to utilize the newer brakes and still be able to use the older wheels. I fabricated an adapter out of wood that uses the M14 1.5mm pitch bolts to secure to the hub with the 1/2"-20 studs to mount the wheels. A Soccerball wheel will fit using the original wheel bolts but most other wheels need a flat head screw to mount to the hub for clearance. I am having trouble sourcing a M14 1.5mm pitch flat head screw.
The adapter should be 1/2" thick for brake to wheel clearance (at least on the soccerball wheel) and to have the strength needed for the mounting screws. There isn't enough thickness to use socket cap screws and I can't find low profile socket cap screws.
I mounted this on an 89 SPG with 16" Aero wheels. The soccerball wheel (ET40) stuck out of the wheel well the same distance as the Aero wheel (ET27).

[Jordan]

So what is the problem with pressing the old hubs into the new uprights? I think that is what birdie is saying, no? Has anyone tried it?

[Jon1]

Jordan, the dimensions on the hubs are different, but the real issue is the brake rotor/caliper mounting. You can't use the 88 and up rotors and calipers on the 86/87 hubs.
My idea was to use the 88 and up assemblies and just use an adapter to mount the 114.3 wheels. It does work.
Seth took some photos of the early hubs; solid rotor, 85 and earlier, vented rotor, 86/87, vented rotor 88 and up to show the differences.

[99Super]

Hey Birdie, I didn't see those spacers on the web site, what did you have to pay for them?

I had some similar ideas a while back to use the 88> rear axle/brake caliper, but use 99/early 900 hubs and rotors and adapt the fit in the bearings. Thoughts on that one?

John

[Mezzanine]

Hey Birdie, I didn't see those spacers on the web site, what did you have to pay for them?

I had some similar ideas a while back to use the 88> rear axle/brake caliper, but use 99/early 900 hubs and rotors and adapt the fit in the bearings. Thoughts on that one?

John

John, if you're using the adapters in the rear and no adapter in the front, then you'd need wheels with different offset for front/rear... That or add huge spacers in the front to match the rear and then get rims with big offset. If I have my head around this correctly, it would be a pretty significant amount of offset needed to make up for those spacers. I'll be the first to admit that I get wheel offset confused regularly though.

[BIRDIEMANGO]

So what is the problem with pressing the old hubs into the new uprights? I think that is what birdie is saying, no? Has anyone tried it?

IF I GET CHANCE THIS WEEK,I WILL NIP ROUND TO THE WORKSHOP,AND PRESS OUT BOTH FLANGES,FROM THE WHEEL BEARINGS,SO WE HAVE A DIRECT COMPARISION........

I KNOW,IT WON'T BE A SIMPLE SWAP OVER,THERE WILL NEED TO BE SOME SERIOUS MACHINING.....

I HAVE BOTH FRONT BRAKE DISCS(ROTORS)FROM THE FRONT HANDBRAKE SETUP,AND ALSO THE LATER 108 PCD FRONT DISC SETUP,TO DO ALL THE MEASURING....

JON1,HAVE YOU ANY PHOTOGRAPHS YOU CAN POST UP,SO I CAN GET MY HEAD AROUND,WHAT YOU ARE SAYING.....

99SUPER,I SAW THESE ADAPTORS 114.3>108PCD FOR SALE AT THE TROLLHATTAN SPORT&RALLY FESTIVAL......NOT CHEAP,BUT THEY HAD NEVER BEEN FITTED,SO I COULDN'T RESIST.....


MEZZANINE,
YEP,THE REAR AXLE FLANGES COULD ALSO BE DRILLED,AND/OR MACHINED TO SUIT,EITHER 108 OR 114.3 GOING EITHER WAY....BUT 'TRACK' MEASUREMENTS(FRONT&REAR) I THINK WOULD HAVE TO MIMIC THE ORIGINAL GEOMETRY,OTHERWISE YOU START CREATING HANDLING PROBLEMS....

WHEEL OFFSET IS A NIGHTMARE ONCE YOU START TO GO FOR WIDE WHEELS....

MOST 114.3 PCD WIDE WHEELS HERE,ONLY HAVE A CENTRE BORE,OF AROUND 64-66MM,SO TOO SMALL FOR SAAB 99/900 71.6MM.....

I AM FOREVER GETTING WIDE 114.3PCD WHEELS MACHINED TO FIT,OFFSET FOR 7.5 J 15 OR 16 INCH RIM, CAN BE A MAXIMUM OF 35MM,GIVING A BACKSPACE(REAR OF MOUNTING HUB ON WHEEL,TO REAR OF RIM) EQUAL TO OR<135MM......

ANY MORE THAN THIS,AND YOU NEED SPACERS,BUT START TO RUN OUT OF THREAD,ON THE WHEEL STUDS.....

SOME 'JEEPS' (MAYBE CHEROKEE?) ALSO USE 1/2 UNF LONGER STUDS,I HAVE TRIAL PURCHASED SOME OF THESE,BUT THE SPLINE SIZE IS WRONG FOR THE SAAB FLANGE,MEANING THEY WOULD NEED TO BE WELDED IN......

[Jon1]

http://www.nysocphotos.com/Jon-Williams-Garage/Saab-Wheels/5650800_bm2pWm#!i=3127961082&k=KB4VLPz











The adapter needs to be 1/2" thick. The wooden prototype is actually 11/16" thick. I only installed two lug bolts and only two 1/2" studs, but you get the idea. The M14 1.5mm lug bolts would be replaced with flat head screws (tapered head). The 1/2"-20 wheel studs would be replaced with 1/2"-20 high strength threaded rod (B7 or other) with an interference fit into the adapter and a clearance fit where the lug nut attaches.
The center bore is sized for the 88 and up hub. The protrusion into the Soccerball wheel is the smallest opening of the 114.3 bolt pattern. A hub-centric ring could be used for the larger center-bore wheels. No modifications to the wheels or lug nuts would be needed.
The wheels and adapters could quickly be removed and the original wheels could be remounted.

[99Super]

Hey Birdie, I didn't see those spacers on the web site, what did you have to pay for them?

I had some similar ideas a while back to use the 88> rear axle/brake caliper, but use 99/early 900 hubs and rotors and adapt the fit in the bearings. Thoughts on that one?

John

John, if you're using the adapters in the rear and no adapter in the front, then you'd need wheels with different offset for front/rear... That or add huge spacers in the front to match the rear and then get rims with big offset. If I have my head around this correctly, it would be a pretty significant amount of offset needed to make up for those spacers. I'll be the first to admit that I get wheel offset confused regularly though.

No adapter in this case, just use the earlier 4x114.3 rear hub with the later rear axle. I plan to buy an 88> axle out of the yard this weekend and start on this...

John