mmaaxx wrote:Can anyone here please tell me according to NCOP what is the largest tyre I can legally fit to a 98-2004 IFS hilux as I know a few people with them and no one knows what the stock diameter of the split rim was?
I inquired with bob jane and the 7.5x16 split rim road gripper was stated as 29.4" . does that mean I cant go bigger than 31.4" ?
Do I go by the "actual tyre diameter on the spec sheet or do I go by the size printed on the side of the tyre as they are not allways the same?
Bloody confusing!
There's previous threads about NCOP and the vagueness of the tyre sizes.
There's some question over the interpretation of that clause that I have not been able to get a clear answer on. Since QLD has not instigated NCOP there hasnt been too much point chasing it further. However, it is something that we've discussed here before on a number of occasions.
It has a reference somewhere to original fitment that can be interpreted in a number of ways. For instance, if you had say a Bridgestone Desert Dueler 7.50R16 as original fitment back in 1988 on your 4wd.
Now, say that original compound and size is no longer available and you cant find out the original diameter specs.
1) Does this mean that you have to use the original one as your base size - even though you (nor Mr Plod) cant find details so you cant tell how big it is, and therefore how much total size is actually legal?
2) Can you use the nearest current equivalent available now - say the Bridgestone Desert Dueler 604V 7.50R16 at 809mm nominal (31.85"). And then add 50mm to that - meaning 33.85".
3) Or any Bridgestone 7.50R16? 811mm.. (31.93")
4) Or any 7.50R16 - because these can vary by up to an inch either way. I can find 7.50R16's up to high 32" (+50mm would allow most 35"s and 315/75/16) and as low as mid 30"s.
5) Or do you Base it on the default size in the tyre and rim manual? (Which only a few tyre fitters would have access to). I believe the figure in this case is 31.7" or 805mm for a 7.50R16, meaning 855mm legal.
Given 1) we have no clue so we just have to wing it. It's really a non answer unless said tyre is still available today in the exact same construction.
2) and 3) are at least measurable, but most manufacturers (Thanks Bridgestone who do) do not state diameters on product pages or websites now. Go check a few out to find out.
Note that there may be differences in size between our version of a tyre, the US version and the Japanese version......
4) with no product spec sheet to back you up, proving their size is ok (unless you keep a 7.50R16 spare) would be hard unless you had that specific 7.50R16 there. If it's your spare and it doesnt match the other tyres, they will ping you for that anyway.....
Also, some manufacturers deliberately make tyres oversize... great for us but not something you're likely to get away with just because Shonkycorp (TM) make a 7.50R16 that's 36 feet high.......
5) My expectation is this would be the most likely source of our size limit, but damn hard to prove since we dont all have access to this manual.... especially when pulled over at a roadblock coming out of a comp after a dirty weekend.
A manufacturer would not support you in your court case..... it's an insurance liability issue they really would not want to get into.
And traffic cops and transport departments tend to take a policy of guilty unless engineering docs stand up to intense scrutiny, and have been known to "de-engineer" vehicles on the spot anyway.....
As such you're probably stuck using the minimum of the above 5 and then adding 50mm.
If anyone gets a clear interpretation of how this should be interpreted in writing from any state's transport department please scan it and put it up here so we can all carry a copy