52 replies to this topic

[Bigfella237]

No, they don't have to be engineered so long as the width and offset of the rim and the overall diameter of the tyre stays within the tolerance allowed.

 

Again, read VSI09 as I already pointed out in an earlier post... everyone has a different opinion on what's legal, but the only one that matters is that of the NSW RMS!!!

 

Seeing as you're in NSW, read the official answer:

 

http://www.rms.nsw.g...vsi-09-rev4.pdf

[Bigfella237]

Just to clarify, if you want to avoid a trip to the engineer, this is the clause you need to adhere to:

 

Minor changes to wheels

Wheels up to 26mm wider than the largest optional wheel recommended by the vehicle manufacturer for the vehicle can be fitted without the need to notify the RTA.

 

The outside diameter of the wheel and tyre combination must be no more than 15mm over the largest diameter wheel and tyre combination specified for the vehicle and not more than 15mm below the smallest diameter wheel and tyre combination specified for the vehicle.

~

Wheels that exceed the diameter and width limits for minor wheel changes must be assessed by a signatory.

 

Does it say anything about rim diameter there? No, the only thing they care about is overall diameter (ie the rolling diameter of the tyre).

Edited by Bigfella237, 20 February 2015 - 01:48 PM.

[Bigfella237]

I assume a UC would have had a largest tyre option of a CR70H13, which is a 205/70R13 in modern terms? This is more a guess as I have no idea what came out on a UC, probably the SL/E would've had the largest tyre?

 

A 205/70R13 has an overall diameter of 617mm, so if you're allowed 15mm under/over that, then you need a tyre with an overall diameter of no less than 602mm and no more than 632mm.

 

If you're talking about LH/LX then that's a different story thanks to the L34 and A9X, which came out with a DR70H14 or a 205/70R14 in modern terms, these have an overall diameter of 642mm, which gives you an extra inch (or 25mm) to play with.

[Collo]

Thanks guys, my torana has commodore stud pattern on it so it fits the old Commodores, will most likely be getting hotwires though I'll post a link of them

Just out of curiosity, are you sure it's Commodore pattern and not HQ?

[Bigfella237]

Just to satisfy my curiosity, where did you even find 13" Commodore wheels? The only ones I know of with 13's were the very early 4 cylinder poverty packs and they'd have to be pretty hard to find these days?

 

 

This is only picture I have of if, btw it is fully legal and meets the required departure angle ( in pic. It dosnt look like it but we pumped up wheels fully and bolted it on more and is legal

[EunUCh]

Just from a personal experience type thing,a 195/60R14 has a very close "roll out" or circumference as the original 13 inch rim/ tyre combo on the UC.

A 205/55R14 would be better width wise  but the numbers don't seem close enough to keep speedo at least within reason...for me anyway.

 

your right,the como rims were on the poverty pack 4 cyl como...still the odd one kicking around.

There is/was a good thread around here explaining the ins and outs of what happens to the geometry of the suspension when well oversized wheels were fitted.

[Bigfella237]

Thanks Bomber, I assume you meant 13" 4 cylinder commo rims were torana pattern?

 

If so, that just adds to the confusion!

[Ice]

Hey slr, yes I'm sure it's commodore stud pattern , well that's what my engineer friend said haha. I wish I could just get them passed with 13,s on and than take them off and put 17 on :,(

Use whats on there now when passed do want ever you want

[Bigfella237]

I thought they were 14s.

You seem to like googling before you post a lot mkre than i do so i will assume im wrong.

 

I didn't google it, I still own two VH Commodores and I scrapped half-a-dozen more to build rally cars back when I was young and stupid.

 

To the best of my knowledge, only 4 cylinders of that era had 13" wheels (although I'd obviously forgotten they were Torana PCD), everything else had 14" steel wheels except the SS and SL/E, which were 15" alloys?

 

Although there may have been some mixing and matching with different models, I have a vague recollection that the povo pack SS might have had 14" rims as well and possibly that the SL/X had 15"?

 

Ah who cares, back to Torana's!

[EunUCh]

From the tyre placard of sedan.

Hatch may have been different ?

forget how to decifer hyroglyphics to modern stuff

 

5.5JJ                   AR78S13

5.5JJ ,  6.0 JJ      BR78S13

5.5JJ ,  6.0 JJ      BR70H13

 

so long as the current NCOP guidlines are not exceeded,no problems,as already said they go on the Overall diameter of the 

wheel assy.  the bigger the rim...the lower profile tyre you will need to fall within the guidelines,,otherwise it needs to "signed off".

 

[EunUCh]

^ that needs changing as well,17's with 9/10ths of frokall sidewall give during decent steering loads considering suspension of the day?..they just let go without warning under certain circumstances...have seen a como go off a range and sideways into a tree because the owner wanted big rims with low profile rubber..on a dry day at that...lucky he had no passenger or else another funeral.

The reason they specify certain things may well have been overlooked by keeping the the overall diameter but the sidewall has just a tad to play in "feel" and control as well.

Nevertheless...they are the experts and know best...  

Try finding a V8 supercar with 45 or 35 series or less rubber?

[Bigfella237]

From the tyre placard of sedan. Hatch may have been different ?

forget how to decifer hyroglyphics to modern stuff

 

I think the metric equivalent of those would be:

 

AR78S13 = 175/75R13 with an overall diameter of 593mm (23.33")

BR78S13 = 185/75R13 with an overall diameter of 608mm (23.93")

BR70H13 = 185/70R13 with an overall diameter of 589mm (23.20")

[EunUCh]