Troopys (and Bushcampers): why split rims?

Might have something to do with what the vehicles are used for, a hammer and tyre levers are all you need to change a tyre on a split rim... much easier than changing a standard beaded tyre.

If you had the luxury of tyre changing equipment then a beaded tyre is easier.

Most split rimmed vehicles are used in remote places like cattle stations and mining leases/sites where split rims are easier.

Give me a tubeless tyre anyday for remote travelling.... plug and go.... stuff pulling out tubes and repairing them.

Hi Candace, I swapped my Troopy's split rims for tubeless but I won't try to develop the argument for that here.

What I do suggest is that you read what Mick Hutton (Beadell Tours) has to say on his website, here.
The link is specifically about tubeless versus split rims. It is a pretty extensive treatise but if you don't want to wade through all of it, then scroll to the end where Mick gives his "My Thoughts in Short."

Mick spends about 7 months of every year leading tours off-road and is also the proprietor of Adelaide Tyre Repair, so has a fair knowledge of this issue. Definitely a bloke worth listening to on any bush or vehicle matter.

Yet for all this debate, I've been running split rims & tubes with BFG MT's on my 40 series for 8 years. In all that time along the AB Hwy (twice), Simpson, Rudall NP, CSR, Flinders multiple times, Corner Country mutiple times, Savannah Country, Connie Sue, Kimberly twice etc. etc. I've only had 2 flat tyres, and both of those were pulling into a Roadhouse or Petrol Station where I picked up rubbish (screws etc) on the hardstand .... go figure.

Candace

Toyota still uses them because there are tyres that are used in some situations in four wheel driving that are so heavily constructed that it would be impossible to get them on and off a one piece rim in the bush by hand. I doubt if some could be removed and replaced even with a tyre changing machine.

The photo of the Nissan Patrol below was posted on this site a few years ago. The tyre is a 7.50 x 16 MRF Superlug cross ply with ZERO air pressure in it. The side walls are so heavy, the weight of the car is not enough to flatten them. Tyres like that are used extensively in the Outback, particularly for cross country work on the large stations.

The photo of the punctured tyre shows a typical bush puncture. I have seen punctures like that in remote Outback areas as well as coastal mountain tracks. You can not fix something like that with a plug kit. The tyre has to come off the rim in order to fit a large multi ply reinforced patch and most likely a tube.. If you are not capable of getting your tyres off a one piece rim yourself then a split rim will make it about 100% easier.

The safety aspect is not really an issue at all providing the wheel is not damaged or just about rusted away. The first photo below shows the removable rim in place. Note how the inner surface of it forms the seat for the tyre bead and is identical in shape to the other side of the rim. It simply stretches out like a circlip and snaps into a grove around the edge of the rim.

The second one shows the size of the grove and how the rim fits into it. When you inflate the tyre, the walls slowly slide out and can not exert any side pressure on the wheel until it contacts the sides of the rim on both sides. From that point on the walls will try and push out sideways against the edges of the wheel but there is no way in the world they are going to push that removable rim up out of its grove allowing it to fly off when the steel reinforced bead of the tyre is sitting directly on top of it. You could inflate the tyre until it burst and the rim would still stay in place.

It is a bit like placing a circlip into a grove on a gear box main shaft then placing a radiator hose clamp tightly on top of it. Now try and get the circlip out without removing the hose clamp. A split rim with a tyre bead sitting on top of it is exactly the same thing.

I have worked with split rims since my apprenticeship days in the 1960s. I have never had to put them into restraining cages, get an elephant to sit on them or run out 100 metes of air line so I could stand back a bit. They have been designed to be used safely and they are safe.

Problems with water and sand entry into split rims can be easily overcome with a little silicon roof and gutter sealer from a hardware store. Simply fill the hole around the tube stem and the gap in the removable ring then smear a tiny bead right around between the ring and the wheel.

Thanks for all the information, now I understand why they chose the split rims. But you can be sure the tools needed to remove/install the tire weren't included with the Britz, LOL.

As for plug kits, unless it's a very simple nail hole in the tread, I've never viewed them as more than an emergency repair to get you someplace where you can obtain a new tyre!

I've never had to use my plug kit myself, but it helped someone else earlier this year. They didn't have a kit or a compressor and had punctured the sidewalls on two of their Land Rover tyres, LOL. Between my plug kit and a couple cans of Fix-A-Flat donated by another desert traveller, and several stops to add air with the compressor, we finally go them and their Land Rover to someplace they could get more assistance...Saline Valley warm springs =)

(Note the road described in the article wasn't the road the Land Rover had its mishap on; we were on the rougher "jeep trail" that leads in from the north ).

Incidentally, Lee's intermediate fix at the Springs was to dismount the tyre, drill a hole in the rim, and install a tube so they could drive out to Bishop, CA and buy two new tyres. ;)

Thanks again for the replies and links!

ok some facts and myths

- myth, toyota split rims pose a hazard for re inflation - total BS ive researched this extensivly by both internet and asking people that change them NOONE has ANY first hand experience of a split rim popping off during reinflation - to the best of my knowledge it has NEVER happened . the myth comes about from a few fatalities involving HV split rims which construction has no resemblance to the toyota ones
- myth - you cant let split rims down , only partly a myth, splittys will go down to 12 psi no worries but they do get unreliable letting them right down when bogged compared to a one piece (ie under 12 psi)

myth - split rims are less reliable- again only partly a myth and the main issue is the cheap chinese tubes that get put in them nowadays, if you use good qality tubes they are no more or less reliable than 1 peice

the main advantage with split rims is lost to most users - its when doing crosscountry offtrack driving because split rims will take 12 ply pluss tyres which a 1 peice wont

Now this has been a blooby good discussion on 4WDing aspects. I sick of all the caravaning questions ambushing this site.!!!

Jeff

On the matter the original poster raised about different pressures front and back.

It depends on the vehicle and how it is loaded.

if there is more weight on the rear axle than the front, it requires more pressure its that simple.

most pasenger cars ( station waggon 4wds may come into this group) have a pretty even weight distribution front and rear, so running the same tyre pressures front and rear may be appropriate.

BUT for example...hilux and landcruser utes carry most of the aditional load on the rear axle....laden and unladen the recommended front tyre pressure remains the same, but the rear tyre pressure is incerased considerably under the full load situation.

This is why when you are setting up your vehicle for a trip you need to weigh it and get seperate figures for each axle and then calculate the required pressure from the load V pressure tables.


As for the split rims debate...a lot of the discussion is emotional and the fact is most times they are relaced, is because of looks...although most will not admit it.

cheers