Member - Jeffrey replied:

Hi Mrdesmo,
I'm running coopers at the moment at the size your thinking about,I live in the sevo area you can have a look at my st after approx4500 kms and not much 4wding on them,..but dont they GRIP I lifted my wheels momentarily negoiating ruts to small mountains..you know what I mean and when they touched down I nearly got whiplash,the blocks seem to chip easy.but I run them on a Patrol
All The Best In Health And Wealth
Jeffrey (AKA JD)

Member - Captain (WA) replied:

I had 31" BFG tyres on my 80 series (non-turbo) and went to 33" BFG (same as 285/75R16). I found the gearing change a positive thing as it always had relatively low gearing.

But there was a HUGE difference in off-road performance. In WA beach sand, where I previously had my tyres down to 20 psi just to be able to get through, I was able to get through on 40 psi (a test - not normal practise).

I changed to the 285/75R16 Cooper ST's when I got my GU and rekon they are better than the BFG T/A KO's IMHO (I previously had a great run with BFG's, but never found the KO series the same). I never found the change in gearing a problem on the GU (originals 265/70R16), in fact it was not noticeable (but I only did 35kms before changing the tyres!).

While you "may" notice a gearing change, I would not hesitate to change the tyres as the huge offroad performance gains more than outweighs it.

Cheers

Captain

Member - Don (QLD) replied:

I put 285/75/16 on my 80 Series and found them to be good.Before that i had just the standard 265/70/16. Since getting the 80 i had put a DTS Turbo on and i notice the turbo takes at about 2200rpm.Which sometimes can be a drama.No probs with the clutch yet.(touch wood).I am not sure of the legals in SA, but in Qld i think it is 15% over original tyre size. But the pros outweigh the cons.
Good luck

Member - Jeffrey replied:

Hi Mrdesmo,
I'm running st..LT 285/75R16 M+S.
All The Best In Health And Wealth
Jeffrey (AKA JD)

Member - Allan replied:

Hi Mrdesmo, I have 285/75x16 tyres and I blamed them for making the chronic turbo lag you describe worse. I eventually had the injector pump adjusted while on the dyno. It is now a totally different vehicle to drive with far better low down torque. The larger tyres actually improves gearing (I always thought they were a bit low geared).
Don't be afraid of the 285/75's and don't put up with the turbo lag - it can be cured for very little money.

Member - Dave (Pilbara) replied:

onen thing to note is the 265's are a tougher tyre. They are equivilent to 10 ply. The 285's are a lighter construction. I took this into consideration when I brought my 265 ats and have not regretted it. The other thing to note is the 265's have a very straight side wall and the footprint on the ground is almost the same as a normal 285. Ie tread width is not much less. I travle a bit on very sharp rocky roads so this was important tom it may not be to those who don't have the same usage. I run mine on a 100 series turbo and have noticed a minor difference in the take up but the 100 has far less lag than the 80.

Bob Y. - Qld replied:

G'day Jeff,

We have 265's BFG AT's on 80 series multi valve, and it has plenty of lag, so haven't gone to bigger tyres. Previously, we had a 90 model 80 series turbo, with 31x10.5R15's on it, and it would really boogy, but at cruising speed, we were always looking for the next gear.

Suppose you could always fit an intercooler, to get some more grunt.

Good luck in the new job.

Hooroo...

Bob et Joëlle replied:

We got a lot of help on the legals from the answers to our post 11692 - the insurance issue could be a bit of a problem no doubt - it is often someone else that causes the prang !

B & J