Hi form the Barossa SA!

Hi all.. New to this forum, but not forums in general!! Sadly I don't have the funds to run an OKA, but do run something similar.... A Land Rover 101 Forward Control into which I've fitted a Cummins 5.9 turbo diesel!! I thought Id come have a look around and get some opinions re truck tyres! Im currently running 16" rims and expensive Michelin 255/100 R16 XZL's.. They area great tyre but fairly soft. Im thinking about purchasing some 19.5" truck rims with 285/70 R19.5" drive axle tyres, and would like to know what OKA owners who run these types of truck tyre think. Cheers for now!

Good Day Sitec welcome to the Oka forum.
Your 101 is also a unique vehicle and I understand it has very good off road capabilities so it will probably hold its own in Oka company.
You will get many different views on the different sizes of tyres and rims on this forum but my experience is only with the 285/70.19.5s so I will say this from experience ,I have travelled extensively in desert areas of West Aus and have found them quite capable of getting me where I want to go pressures are always the key whatever you run but myself and 2 other members with our wives have just completed a pretty tough journey in the Great Sandy Desert which involved multiple sand dune crossing making our own trail I managed to destroy 4 tyres but I attribute that to the fact I wasn't picking up the air loss through stakes and once you run flat on a tubeless and the tyre leaves the bead you then have the rim of the wheel run over the wall of the tyre and fracture it ,the lesson in this for me was don't run with the a/c on and the windows up my 2 companions suffered one stake between them so apart[no A/Cs] from my misdemeanours up until this trip I have had 5years of travel in similar areas without even one flat and as the 19.5 inch tyres are a rated truck tyre they are pretty tough and I personally wouldn't use anything else but there will be plenty on this site that will say otherwise.
I run 65 to 70 psi on the bitumen and drop that to 50 on good gravel roads and I think I can speak for my companions too this last trip 28 in the fronts and 32 in the rears got us every where we wanted to go.
Their cost is not much different to normal 4wd tyres I replaced the lost 4 for a little over $400 each but there are only now about 3 brands that are readily available and one of them is Michelin and they are twice the price the 305s appear to be easier to obtain but I.m not sure of cost.One of my companions this year had 305s and no problems.

Hope this helps a bit cheers Dave

Hi Dave. Yeah, it does, and its what I wanted to hear.. A lot of the 101 guys have said that the ride will be harsh and that its not the way to go, but what you say is about what I was expecting/hoping for. The tyres will work out cheeper than the Michelins at $700 a corner, and the bigger rim will give me room for a decent disk and calliper conversion on the front axle.. Truck tyres are also rated at more than 100kmh which is what the XZL's are rated at. With the Cummins up front, the 101 is capable of a lot more than 100!! Cheers again!

Tyres are a real personal thing.

There appears to be roughly two camps now a days with OKA`s owners.


19.5 with different profiles.

16 inch on Alloy Rims with anything from 34 odd to 38 inch.


Some still have original 16 inch tyres, but the cost of the XZL/XML make it an expensive exercise at around 1000k plus.


With the other options its around 350 to 400 odd per corner.


Love to see some more pictures and here more about your conversions. A lot of OKA owners are converting over to the 6bt.

Hi Outback Jack. Yeah, the cost of the XZL's is a bit frightening!!! As for the Cummins fitment, I've got a thread on the AULRO forum. I could put the link here if that wud b ok with the mods.. I bought the Cummins 6bt and ZF 5-42 gearbox out of the UK as it worked out a lot cheeper than buying just an engine here. Now its in and tested, it has transformed the 101! I've covered approx 10000 kms since the conversion and love it. Fuel economy is between 11.5 and 12lt per 100kms which is good for a vehicle of the 101's/OKA's size. I've used the older engine with a Bosch rotary VE pump. Other options are the 'P' type pump which is good for big power.. I would think the later Cummins Paccar common rail (Iveco Tector) engine would be good in an OKA. Its just over 6 litres, the same size as the 6BT as it shares the block, but runs ECU controlled fuelling.. Will post a link up shortly if mods r happy with that.


Here's a shot of the 6Bt in the 101.

Dont think the mods will have a problem with the link.

OKA`s was designed/engineered by mostly English people from what I understand.

Some things are even borrowed from the Landrover. Things like fuel caps, reverse switch on the gear box etc.

VE pumps are the cheapest option and you dont really need a P pump unless you want big power.

The OKA gearbox comes from the UK and is used in other vehicles with Cummins 6b engines.

Hi all. Here's the link to the thread on fitting a Cummins 6Bt into a 101 Land Rover. Mods, move it as you see fit if its in the wrong place/not fitting etc!

www.aulro.com/afvb/101-forward-controls-...esel-into-101-a.html

Nice conversion Sitec! I had a 101 with the P76 engine which gave it "adequate" performance but appalling fuel consumption. I should have gone diesel.

The Oka has much softer front springing than the 101, despite the paucity of leaves on the Landie. I started with 19.5's on the Oka and then went to 16's. There was a noticeable improvement in ride quality, especially on rocky surfaces. I have never tried it, but I think 19.5's on a 101 could give a very hard ride up front.

I also suspect that heavier wheels on the 101 could be asking for trouble with the shockers. The Oka has multiple leaves which cause a bit of friction to help along the shockers, but the 101 doesn't have multiple leaves hence the shockers work quite hard. I feel that alloy wheels with 16 tyres might look daggy on a 101, but would possibly improve the ride and prolong shocker life. 285/75/16 tyres are readily available and cheap - I use Goodyear Duratrack on the Oka at about $330 a corner, on Eagle Alloys at about $250 a corner.

Cheers! Yeah, it's worked out well.. As for the ride, with the Cummins up front and the twin spares hung off the rear, the ride is pretty good.. We drove from the Barossa to Wombat State Forest in Vic and back last month. 100kmh all the way! Re wheels, yeah, the ride is one thing Im worried about. Trouble is the 16" wheels are tiny and the swivel housings huge, so it leaves me little room for a decent brake disk, and I don't think Im going to get decent kms out of the Michelins.. With the truck tyres I'll get meter kms, less noise and at half the cost.. 285's won't give me the diameter I need. There's a few on the forum running massive muddies on wider rims on their 101's, but its not a look Im a fan of.. Decisions decisions!! This is a close up of my setup at the mo.

Ditto Paul's comments, was very interesting as I've got a 6bt sitting on the floor pretty much ready to go in the Oka.
I would imagine that you will find the 16" alloys with 315's like we have will make a huge difference to the handling and ride as we found it transformed the Oka, plus tyres are much cheaper than the Michelins and seem to be pretty robust.