31 replies to this topic

[Dr Terry]

Most failures occur at the wheel bearings.

 

That's the weakness of the Ford 9-inch set-up. Those who have done lots of km's with a Ford 9-inch will know what I'm taking about.

 

XW-XA rear wheel bearings are slightly smaller than the old single ball one used in FE to HG Holdens.

 

Dr Terry

[TerrA LX]

^ this is true what Dr.T has said but I think where you are going with this is big wide STICKY tyres tend to snap axles and put extreme load on the centre carrier (hemisphere) and crown and pinion.
You will find most guys with a 9inch with a bit of power who love to have fun are upgrading the centre (to LSD, locker or spool) and opting for billet axles.

Does your question refer to this or directly at a registration (load carrying) point of view?

Edited by TerrA LX, 20 February 2015 - 04:20 PM.

[Bigfella237]

The wheel bearing is usually the first to fail but there are other problems with a semi-floating axle, because there's only one bearing per side the drive axle itself ends up supporting some of the load causing it to flex and run in a slight bow shape, which in turn places extra load on the side gears in the diff centre and on the carrier bearings as well.

 

It's not only wider offsets that cause this but also the width of the rim itself, the wider the rim/tyre the more leverage is placed on the axle when all the weight is supported on one extreme edge, such as when pulling into a driveway diagonally.

 

A full-floating axle is a much better setup for carrying load, with two wheel bearings for each wheel instead of just one the drive axle is now, as the name suggests, fully floating. It carries none of the vehicles weight at all and therefore cannot transfer any of that load to the diff centre, its only job is to turn the hub.

 

Add to this that full-floating wheel bearings are usually much more 'heavy-duty' than standard car bearings and so can carry more weight anyway. A lot of (real) 4WDs and most trucks use a full-floating setup, as do most drag cars.

[EunUCh]

?? is that why they try to have the center line of the rim with vertical lines more or less over the center line of the load bearing (bearing) part of the 

system...the more out we go with those lines,the strain and force applied which causes twisty/flexy things to happen from one end to the other? 

[BIG KEV]

I have my LH ....The 6LR Project Engineered with 18 x 10 and yes its tubbed and has NO flairs

[BIG KEV]

Diff is being made in a few weeks .....the Engineer never said any thing about floaters ....just ask if I was using Ford big bearings

[N/A-PWR]

what are the Chevy C30 diffs like?

[Rockoz]

Full floaters on the last of the Toranas at least.

Definitely on the Commodores.

Plus on the front they ran a different bearing set up.

They ran an adaptor that fitted over the existing stub axle and used bigger bearings.

May have use it on the last of the Toranas as well.

[Bigfella237]

I haven't checked recently but I'm pretty sure McDonald Bros do those larger front bearing adapters and hub kits as well as full-float kits for diffs.

 

9" diffs also came from the factory as fully floating in the larger F-series trucks, anything with dual wheels should've had f/f axles.

 

just back on the 9" diff for a sec...the XW,XY GT HO's had a different wheel bearing to the "std run of the mill" 9" a HD version

 

I see might be over 10 inch then. F100 had the big bearings too tim

 

I know some of the early Fairlanes and LTDs had the big semi-float bearings too at least. I found this on Google which may help identify which bearing you have:

 

 

If a LX Torana has 18x8 with a 120mm backspace/108mm frontspace, on the front and 18x10 with a 100mm backspace/178mm
Frontspace. ~ And has anyone ever managed to get this big rim combo engineered?

 

I think VIC is more or less using the NCOP aren't they? So it would depend on several things, 8" front & 10" wide rear rims should not be a problem, the rim diameter shouldn't be either, but the NCOP is all about tyres, for an LX Torana:

 

the tyre width cannot be more than 30% wider than an A9X tyre (roughly a 205/70R14), see table LS2 below

the overall diameter of the tyres must be within -26mm to +15mm of an A9X tyre (a 205/70R14 measures 642mm)

the aspect ratio of the tyres must not vary by more than 10% front to back

if different width tyres used front & back, the smaller cannot be less than 70% of the larger

 

NCOP Table LS2 says a 205mm wide factory option tyre can be replaced by a 265mm wide tyre on a maximum width rim of 10" (with a 60% or less aspect ratio).

 

 Table LS2.JPG   137K   4 downloads

 

Lastly the track measurement / rim offset. The track measurement cannot be decreased at all and cannot be increased by more than 25mm over an A9X (which we believe has a track measurement of 1470mm).

 

However, where a replacement axle assembly has been fitted, the factory rim width and offset figures of that axle are used as base figures, not that of the vehicle it's fitted to (try explaining that to a copper on the side of the road).

 

You would need to take some front & rear hub-to-hub measurements of your actual vehicle to figure out the legal rim offsets allowed.

[Bigfella237]

Minor correction/addition to the above:

 

A9X front track we believe was 1470mm with a rear track of 1443mm

[76lxhatch]

How on earth did all those group C cars of the 70's get away with huge wheel offsets and standard rear axels. I've never seen any wheel bearing failures on any cars I've known of with huge wheel offsets. the bloke across where i used to live had a HR with 13x10 rear rims with a redickulas offset, never suffered any failures ever. I've also done the big offset thing and nothing ever failed either. I'm sure there is an explanation for this.
Regards

The wider you go, often the offset isn't as different as you think as the wheel is wider both inboard and outboard. The issue with riding on the wheel edges is valid but mostly tends to only occur in low speed/low load situations. Also the wheel alone is only half the equation, you need the opposing force (cornering or mass).

A factory Torana Banjo bearing is the same one used on a one tonner Salisbury (they have a wider retainer but same bearing), so its obviously capable of handling more than a small offset 13x5" wheel and a Torana's weight to begin with.

Bearings tend to be an item that lasts forever if it never sees the wrong conditions, but will fail in an instant if it does. Having the retaining components installed correctly so that the correct preload (or clearance) is set, using good oil, can have an effect. Race cars are maintained and components replaced on a regular basis too.

I also wouldn't be surprised if the HR only ever saw straight line activity and wasn't exactly heavy, you need a lot of weight and/or hard cornering to load up the tapered bearings.

[WhaleOilBeefHooked]

Dodge Viper, Lamborghini, Ferrari & Porsche have worn 275's & larger from factory......

[EunUCh]

It's not that hard to comprehend.

Quite some time ago Transport Industry Consultants Pty.Ltd (TCI) did tests on a 9inch and found that there was no greater load on the fracture area, (bearing area,but not the bearing itself) going from a 6 inch rim to a 10 inch rim.

 

The main problem arose from large offsets (deep dish,some people may remember the fitting of deep dish rims as being "frowned upon".

The reason being that the load bearing center line ended up further away (out) which put undue and sometimes excess load in 

the area of where they failed.This would also have some effect on the rest of the the axle and probably the diff. center when simple

load/leverage/fulcrum (see-saw effect) type pictures are drawn.

"If' this would affect the diff itself to the point of failure... ???....but it would certainly load the side gears more than what they were designed to handle due to more weight away from the axle flange causing more bend in the axle,might be ok to a certain point 

but bumps and heavy load might be a different story.