Hi Dave,
Just to say thank you again for the weekend training in a fantastic (if in parts scary) location. I meant to tell you that I did appreciate your botanical and geographical commentary as we journeyed around.
We look forward to the photos.
Reply from David
Mandy,
Many, many thanks for your kind words, we too enjoyed the weekend. The Flinders are a magnificent part of our State and our country and I never tire of visiting them. I hope that with what we achieved that it will inspire you to roam the Outback and see it all!
What we did on the weekend I would describe as being at the pointy end of the 4WD scale. You now have a good reference for what you might expect in the most challenging conditions, so anything less shouldn’t cause you great concern. Of course we didn’t venture near any mud or sand, but what we did in the FTO program should equip you for those environments.
I was a bit rusty on the botany lesson, but glad to be of service.
Now before I sign off on this piece of correspondence I need to mention for Don’s benefit a bit about the tyres. He asked about replacements for the Road Grippers (Dunlop) you’re currently wearing. IMHO they’re junk. When 100 series L/Cruisers were made we had countless come through the courses on Government duty. I reckon nearly every time I spoke to an operator of a skinny wheel 100 they had a story to tell of tyre failure with the stock rubber. The reason is in the carcase. It’s only got a 108 Load Index (1,000kgs per tyre maximum carrying capacity) which for a vehicle we often see carrying in excess of 3,500kgs (despite having a design maximum mass GVM of 3,200kgs), puts the tyres in a perilous position because the back tyres in particular will be overloaded past their maximum design capacity with a full holiday load.
I would recommend 2 things.
- Get rid of the split rims and get a set of 5 of 16″ x 7″ steel wheels (a Bridgestone outlet will be able to source these for you). Split rims are way too heavy (affecting suspension performance and longevity), allow grit and muck to get into the wheel assembly and chafe tubes, rust on the locking rings and they’re a nightmare to manually handle. One piece wheels are much lighter, without any of the other issues and without tubes, if you were unlucky enough to get a flat you’ll get some warning. A punctured tube goes flat in an instant, a tubeless wheel not so.
- Buy our favourite Outback stalwart for big L/Cruisers, the Bridgestone D661 Desert Dueler in an LT235/85R16 size. This will suit your purposes to a tee. For one it (when fitted to the previous rims) will put a bit more rubber on the road (width-wise), 190mm Vs 235mm. This will enhance the on-road (both dirt and bitumen) safety for you by a HUGE margin (handling/steering/braking). It’ll also help the off-road, because I saw plenty of times over the weekend where it was plainly obvious that you were under-tyred and had little shear-force grip, especially in the steep descents. Additionally because this tyre has a higher Load Index (120 = 1400kgs) you’ll be able to tow your horse float more confidently Pressures. The placard on 100 series skinnies wants 260kPa/36psi front and 375kPa/54psi rear which is right for a fully laden (at GVM 3,200kgs) vehicle. The unladen is 260/260 front/rear. We recommend a 20% reduction on the high speed (< 80kph) dirt so that would become 210kPa/29psi front and 300kPa/44psi rear or 210/210 unladen front/rear. In an environment like we had on the weekend, climbing up and down hills another 10-15% reduction will offer the enhanced grip and puncture-proofness that we enjoyed over the weekend. In sand and mud you might need to further reduce depending on difficulty and aim for a pressure where the vehicle gain the necessary momentum to float through rather than bog down. Use 105kPa/15psi as generally a safe minimum pressure with broad turns and speeds slower than 40kph.
If Don wants to get an even more scientific answer on pressures tell him to take the car fully laden to a weighbridge and get the numbers for me x 3, front axle, back axle and gross and I can compare them to the charts in the TRA (Tyre & Rim Association) handbook, in any event, that’s where the vehicle makers formulate their placards from in the first place.
Happy travels!
David