34 replies to this topic

[Shtstr]

Ok I've been searching the net for the lh lx uc torana wheel track and have found about 5 different widths for them ranging from front 1400mm to 1470mm and rear are from 1372 to 1443mm.
I need to be able to provide the info to TMR for a project that I'm doing.
So need to be able to provide proof. Can have hear say.

Edited by lcxu105, 16 December 2015 - 09:09 PM.

[Bigfella237]

I feel your pain here Dave, the only document that TMR might accept from you is a GMH service bulletin for the LH L34, which includes this page:

 

 L34 Service Bulletin - Suspension.JPG   97.77K   31 downloads

 

Which says the L34 figures are:

 

 

14 x 6.00JJ rims with +0.25" (6.37mm) offset
Standard Track Front: 57.89" (1470.4mm) (front hub-to-hub width 1483.1mm)
Standard Track Rear:  56.82" (1443.2mm) (rear hub-to-hub width 1455.9mm)
Rear = 1.07" (27.2mm) less than front

 

 

I've got a copy of the full thing here somewhere if you can't find it?

 

Apart from that, transport have their own spec sheets that they can look up and usually won't accept any figure except what those spec sheets say.

 

I've done a heap of calculations based on a measured LX SS diff width and the correct LX RTS SL/R & SS figures are:

 

 

13 x 5.5JJ rims with +1.25" (31.75mm) offset
Standard Track Front: 55.3" (1405mm) (front hub-to-hub width 1468.5mm)
Standard Track Rear:  54.4" (1382mm) (rear hub-to-hub width 1445.5mm)
Rear = 0.9" (23mm) less than front

 

(Source: LX Torana owners manual)

Edited by Bigfella237, 16 December 2015 - 09:37 PM.

[Shtstr]

Thanks for that. I will have a chat with the engineer in the morning. I will find out if they have anything on file.
The code under the NCOP I have to use is MA.
Gives me an extra 25mm on top of that. And I need every mm.

[Bigfella237]

With the LX Hatch you'll be asking for the specs on the A9X, the front track should be the same as the L34 figures above (same suspension components, same rims) but the rear may be different because of the difference between brake drums and discs?

 

As you say, there are so many different sets of figures floating around it makes it hard to know what is correct.

[Bigfella237]

DOH! What am I saying...

 

You're using the equivalent of both front and rear "axle assemblies" from the donor car, therefore the track measurements for a Torana are irrelevant.

 

From NCOP11_Section_ LS_Tyres_Suspension_Steering_V2_1Jan_2011 v3.pdf, page 47:

 

Track. Where non-original axle or suspension cross-member components are fitted,
the offset of the wheel in relation to the axle or hub assembly used must not be
increased by more than 12.5mm each side of the vehicle based on the specifications of
the axle components used. If an axle assembly is shortened then the track width limit
is taken as the axle manufacturers original track dimension, less the amount the
assembly has been narrowed, plus 25mm.

 

So your track figures will be based on the Adventra minus any amount you shorten the "axle assemblies".

 

If you want the official figures on the Adventra let me know, I should be able to dig them up on the Road Vehicle Descriptor System but I can't access that until 06:00am?

[Bigfella237]

What model is the Adventra? If it's a VZ then I've found the RVDS sheet for it...

 

(see attached)

 

17 x 7.5JJ rims with +48mm offset

Wheel Track Front: 1617mm

Wheel Track Rear: 1623mm

 

So Front hub-to-hub width should be: 1713mm (230mm wider than the L34)

And Rear hub-to-hub width should be: 1719mm (263mm wider than the L34)

 

That's only 115mm wider each side, I reckon that should easily fit under a flare, the strut towers may be a different story though!

 

Attached Files

•  ADVENTRA.pdf   23.69K   3 downloads

[Bigfella237]

Just found this post which you may find of interest:

 

When the L34 was on the hoist I measured outside of flare to outside of flare:

Front  1770

Rear   1785

~

I thought 50mm off the outside flare measurement would be ok, 25mm each side. So outside to outside of wheel is 1735mm for the rear. 

1735 - 450 = 1285   (450 is the total wheel width for both wheels)

1285 + 220 = 1505   (220 is the total back space for both wheels)

~

 

If your track is as before, then your outside of standard Adventra wheel to outside of standard wheel measurements should be (track plus 2x half the rim width):

 

Front: 1807.5mm

Rear: 1813.5mm

 

So, knowing that you can't reduce the track for the original axle components unless you narrow those components, you're gonna need some extra-wide flares, about 20mm per side I guess?

 

[Shtstr]

They want me to have the wheel track of the torana ,25mm max.

[Shtstr]

Anyone know the wheel track of the uc sl/t?

[Bigfella237]

They want me to have the wheel track of the torana ,25mm max.

 

As quoted from the relevant section of the NCOP above (please look it up yourself to verify), that is simply incorrect.

 

I'd take a copy of the NCOP in to your engineer and point that out, if he or she still insists on using the Torana figures then they can't be very good at what they do, so it's time to find a new engineer!

 

The whole point of the wheel track restriction is to maintain the distribution of load across the wheel bearings as designed by the manufacturer. The offset of the rim determines how much of the vehicle's corner weight is supported by each bearing:

 

 70221TimkenHubC_00000028548.jpg   18.9K   4 downloads

 

If you move the wheel offset, thereby changing the wheel track measurement, you move the load:

 

 what_is_wheel_offset-450x261.jpg   30.48K   7 downloads

 

Which can cause premature (and potentially catastrophic) bearing failure. This problem is compounded by the fulcrum effect, where the further you move off centre, the more leverage the load has.

 

This usually applies to Torana owners bolting on wide rims with a huge negative offset (deep dish), but is equally relevant in your situation if you were to move the rims inward to meet the Torana track specs.

 

I believe the Adventra has a uni-bearing setup on all four corners too (one big single bearing on each wheel instead of two) so I'd think the load centre thing would be even more critical?

 

I agree 100% with the NCOP, and disagree with your engineer, the track specs must be based on the axle components used, not whatever bodyshell happens to cover them.

[Shtstr]

DOH! What am I saying...
 
You're using the equivalent of both front and rear "axle assemblies" from the donor car, therefore the track measurements for a Torana are irrelevant.
 
From NCOP11_Section_ LS_Tyres_Suspension_Steering_V2_1Jan_2011 v3.pdf, page 47:
 

 
So your track figures will be based on the Adventra minus any amount you shorten the "axle assemblies".
 
If you want the official figures on the Adventra let me know, I should be able to dig them up on the Road Vehicle Descriptor System but I can't access that until 06:00am?

If you read how it is written than the moment you narrow the diff you have to use the original cars track +25mm max.

[Shtstr]

As quoted from the relevant section of the NCOP above (please look it up yourself to verify), that is simply incorrect.
 
I'd take a copy of the NCOP in to your engineer and point that out, if he or she still insists on using the Torana figures then they can't be very good at what they do, so it's time to find a new engineer!
 
The whole point of the wheel track restriction is to maintain the distribution of load across the wheel bearings as designed by the manufacturer. The offset of the rim determines how much of the vehicle's corner weight is supported by each bearing:
 
70221TimkenHubC_00000028548.jpg
 
If you move the wheel offset, thereby changing the wheel track measurement, you move the load:
 
what_is_wheel_offset-450x261.jpg
 
Which can cause premature (and potentially catastrophic) bearing failure. This problem is compounded by the fulcrum effect, where the further you move off centre, the more leverage the load has.
 
This usually applies to Torana owners bolting on wide rims with a huge negative offset (deep dish), but is equally relevant in your situation if you were to move the rims inward to meet the Torana track specs.
 
I believe the Adventra has a uni-bearing setup on all four corners too (one big single bearing on each wheel instead of two) so I'd think the load centre thing would be even more critical?
 
I agree 100% with the NCOP, and disagree with your engineer, the track specs must be based on the axle components used, not whatever bodyshell happens to cover them.

I'm not changing the hub assemblies or bearings. Will be making the lower swing arm shorter and moving the strut inboard the same amount. Also the steer rack will stay in the same position and will be shortening the rack ends so I don't change the geometry as such so no issues are caused with bump steer.

[Bigfella237]

If you read how it is written than the moment you narrow the diff you have to use the original cars track +25mm max.

 

Not sure where you got that from?

 

If an axle assembly is shortened then the track width limit
is taken as the axle manufacturers original track dimension, less the amount the
assembly has been narrowed, plus 25mm.

 

The "original track dimension" is of the "axle manufacturer", not the car manufacturer, (in this case you have to pretend that the Adventra "manufacturer" is different from the Torana "manufacturer").

 

Yes I know the wording of this document leaves a LOT to be desired, in my opinion the NCOP should NOT even mention track width, it should deal only with rim offset as it relates to wheel bearing load, but let's not get started on the syntax within these documents or we'll be here for a week!

 

What that's saying is, if you narrow the "axle" 200mm, you must also deduct that 200mm from the axle manufacturer's original track measurement, which means the original offset wheels that were fitted to that axle will still be correct.

 

As I said earlier, the whole point is to maintain an even load across the wheel bearings as was designed by the manufacturer. You cannot possibly expect the manufacturer of a circa 1977 Torana to know what wheel bearing loads a 1995 AWD Commodore should have?

 

I don't know how else to explain it, your engineer should surely know all this already?

 

The only requirement for the bodywork is that...

 

the wheels or tyres do not protrude beyond the bodywork of the vehicle when viewed
from above;

 

...and obviously that the overall width of the vehicle does not exceed 2.5 metres!

[Shtstr]

I tried to argue with them about the wording and I have been informed that is how it is and all they will except. So what ever the model car you have the widest wheel track for that model from factory is all they will except. So for lh its l34 and for lx its a9x same as l34 and for uc they only have 1 wheel track.

[Bigfella237]

As far as I can see, your engineer just doesn't grasp the fundamental principle behind maintaining 'close to factory' load distribution across the wheel bearings?

 

As I already mentioned, it seems he or she would be happy with massive positive offset rims just because they satisfy the Torana track measurements, never mind the fact that the wheel bearings, drive axles and spindles are all now under extreme load?

 

And how about the huge negative scrub radius? I really have my doubts that you will be able to shorten all the driveshafts and move all the suspension components inboard far enough to obtain the Torana track measurements and still have any kind of acceptable suspension geometry or workable CV joint angles?

 

If I were you, I'd be sitting down with other engineers and getting their judgement.

 

But anyway, that's my opinion, I've given it and wish you the best of luck!

[Shtstr]

Drive shaft will be fine and so will the supenchion. Its the department of transport who is laying down the law. Engineer is on my side. Will be starting it over my xmass holidays
The cv shafts and lower arms and steering rack are all in perfect horizontal alinement from factory. Nothing changes.

[Shtstr]

Anyone know the width of the lx torana front end width face to face on the disk?

[Bigfella237]

At the risk of starting yet another argument on the subject...

 

A standard (non-A9X) LX front-end should be roughly 1468mm from one wheel bolt-up-face (BUF) to the other, according to my notes.

 

That equals a standard front track measurement of 55.3" (1405mm) when using a 13x5.5" rim with a +1.25" (+31.75mm) offset:

 

1405 + (2 x 31.75) = 1468.5mm

[Shtstr]

And what is the a9x one then? As i belive i will end up with 1589mm face to face from what i have worked out. Adventra front 1617+97mm for both wheel offsets giving me 1714mm face to face -125mm that i have shortened it by leaving 1589mm face to face.
So going by std lx I'm 131mm to wide from what you have said.

[Shtstr]

Having said that if i use the adventra offset wheel track on the front i end up with 1492mm wheel track witch is only 7mm wider than lx a9x at 1485mm

[Bigfella237]

A9X wheel track figures are all over the place depending on the source.

 

A9X (version 1 - Source: "45 Years of Holden", Terry Bebbington and Michael Malik, 1994, pages 93 & 96):

Track Front: 57.2" (1452.88mm)
Track Rear:  56.1" (1424.94mm)

 

A9X (version 2 - Source: "60 Years of Holden", Terry Bebbington, page 338 - Basically the same figures as L34):

Track Front: 57.9"  (1470.7mm)
Track Rear:  56.82" (1443.2mm)

 

A9X (version 3 - Source: Just Holdens Toranas Collectors Series. A9X Edition, page 23):

Track Front: 59.5" (1511.3mm)
Track Rear:  57.1" (1450.3mm)

 

There is a GMH Service Bulletin floating around for the earlier L34, which uses the same stub axle/hub components as the A9X just with different control arms and wheel alignment specs, and it says L34 is:

 

Standard Track Front: 57.89" (1470.4mm)
Standard Track Rear:  56.82" (1443.2mm)

 

I myself would trust that the GMH Service Bulletin is correct, all the other figures were likely obtained by two monkeys in a parking lot with a tape measure, so who knows?

[Shtstr]

I've been working off the l34 spec with a9x rim +6.35 i think it is and gives you around the 1483 85mm mark for wheel track on a9x. So my wheel track has to be +-25mm of that 1483 85 area. So max is 1510mm and minimum is 1460mm. Currently with Adventra rims i have 1492mm so i have a bit of room to play with still. All front end components are shortened by minimum 60mm each side. Rack control arms steering rack and obvious the strut towers move inwards 60mm each too. By doing this and lowering the struts and using a 39mm less taller tyre it brings the car back to std torana height. All control arms will end up with 2 degrees down so not to much problems with bump steer.

Edited by Shtstr, 20 August 2017 - 11:40 PM.

[Bigfella237]

Yeah I think you're in murky waters, you really need to find out what track figure your engineer will accept before doing any measuring or math. I really can't stress that enough!

 

Engineers and rego authorities typically have their own set of data, which is often different from what everybody else will tell you, and they won't even hear of outside sources that say differently.

 

Also, some engineers will accept that an A9X was part of the same LX Torana model, some say that if your car was an "SL" then that's what figures should be used.

 

To further muddy the waters, some engineers will argue that the A9X came out in 1977 only so if your car is a '76 you can't use the A9X figures.

 

And then any real engineers will treat all those figures as a guideline and actually sign off on the engineering itself, as should be done!

 

It really sucks that the so-called "regulations" leave so much to individual interpretation but what can you do.

Edited by Bigfella237, 21 August 2017 - 02:38 AM.

[Shtstr]

Well they said any model of lx so that including the a9x so thats what they are getting. But as you have sai before it comes down to the original cars specification witch in this case should be Adventra but they want torana. Different interpretation of the code i guess. I will give them what they want that way it's on them if anything goes wrong.

[myss427]

When I got mine engineered years ago, had to get a letter from Holden stating the track for A9X, it came back from them at 1510mm. Or that could have been including the additional allowed 25mm?

Edited by myss427, 21 August 2017 - 10:30 AM.