Tyres: 15" vs 16"

Rob if you're in Perth I have a set of good nick Mick T's on 15's I want to flog and also a set of 4000k only used rag tyres on 16" split rims if you are interested. I had them on mt 75s Troopy

Cheers

Dunc

16 inch are becoming more popular than 15 inch especially in the outback.

16 inch is a good tyre size.

As for sidewall damage, ply makes not a lot if difference, the biggest thing is how it is constructed and what material the ply is made from.

Damage to tyres is in most cases self inflicted, so choose your line, watch where you are going and maintain good pressure for the speed and terrain.

Split rims are a waste of time and money, you have to run a tube and you can not plug and go.

Tyre width is a personal thing, 265 - 285 would be my personal choice....... any smaller or any bigger can bring in problems.

If you want a really good tough tyre have a look at the Toyo M/T........ Mick O has a big write up about them in one of his blogs.

The Toyo's are nearly bullet proof, are heavy, expensive but offer exceptional handling and comfort......yes a tyre that does nearly everything well.

G'day Rob,

I'm no tyre expert.
However if you change from 15" to 16" it will effect your speedometer, so you will have to look at that.
Also the 265,275 & 285 refers to the width of the tyre not the Hight.
So the 285 being the widest of the 3 you mentioned will have the biggest footprint, so will be the better load carrying tyre.
I hope this helps a bit.
Happy cruising.

Rob, speedo reading and gearing will be changed if your changing from what rim /tyre size the vehicle originally came with.

The way around this is to adjust the tyre profile, and there is one or two good web site calculator for this so you get the same rolling circumference.

Eample. The LC200 come in 17 and 18 rims. Toyota dont'change the gear ratio of the box, the compensate by the tyre profile (height).

You will not have a problem, just do you your home work on tyre profile for the rims and tyres you choose.

John

A couple of matters.

In either 15 or 16 inch you should be able to buy tyres with various sidewall costruction.

In either 15 or 16 inch you can buy tyres of an appropriate size and profile to get both compliant tyre size and correct speedo reading., I run 15 inch rims where my vehicle was factory fitted with 16's.....my current tyres are 3mm smaller than factory...if I went to 31x10.5R15s I would get about 10mm of lift or a 20mm diameter increase,,and my speedo would read accurately where factory standard it reads under..

In the past a lot of people went to 15 inch rims, because it gave a better range of choice of tyre types and sizes......in fact 15 inch tyres where mostly cheaper than 16s.......16 inch rims are becomming more popular I believe.

There are lots of people with strong views about split rims.....Beadall 4wd tours have a good discussion of the matter.....google on split rims and there is plenty to read.

If you are staking sidewalls.....tyre plugs are not going to help you.....you WILL get a tyre off a split rim easier and do a propper sidewall repair with a tube tyre.

You probably need to do some research on tyre types and available tyres, and then select your rims.

For example a lot of 4wd tyres are imperial flotation type tyres (EG 31x 10.5R15..or any designation like it) mostly they are soft sidewall tyres designed to belly out for flotation...move across the the metric sizes in light truck construction and there are tyres with stiffer harder sidewalls with higher load ratings.

cheers

Rob,

I have a set of the original 16" split rims that were on my '91 75 series when I bought it 20 years ago. It's a ute but same same. When doing trips into desert, stoney type country I run 235/85x 16" 10 plys. Obviously being split rims they need tubes. The advantage is that if you damage one bad enough that plugs won't do they are very easy to dismantle and repair the tube or fit a new one. All you need is a good sized screw driver to get the lock ring section off and a nice heavy rubber hammer to refit. Being 10 ply the tyre is much heavier construction and I get less punctures anyway. Some say splits are yesterday technology and that's ok. I disagree, however if you don't want to go that route the 235/85x 16" tyres can just as easily be fitted to solid 16" rims without tubes.
I also have a set of 15" rims fitted with 10.5 x 15" tyres that I usually only use if I am doing a trip somewhere that involves beach driving such as a fishing trip. As you mentioned these size tyres generally only have a 3 ply rating sidewall so from my experience are more prone to damage in rough going. The advantage is that they increase in footprint size without having to let too much air out. I very rarely go below 18 psi for soft sand.
I personally have never found it necessary to go much bigger in tyre size but I guess it depends where you want to go.

Cheers
Pop

I can pretty much guarantee there is no 16 inch 4wd tyre with 8 or 10 sidewall plies. They will be an 8 or 10 ply rated tyre which will generally be a 3 ply sidewall tyre similar to what you are running anyway so be careful not to lust after something which may not exist. That is unless of course you are looking at steel tyres like the MRF range which are generally accepted to be the strongest sidewalls the world has ever seen, not to mention heavy, ugly, uncomfortable and air optional - see your local pro shooter's ute. Personally on a troopy doing proper offroad work, a 235 85 r16 is what I'd be looking at if I had my choice.

Thanks for all the helpful feedback (and range of views). I'll follow up some of the leads you've provided, and summarise what I've found.
Rob

Here is a comparator to work out size difference and alteration to speedo


http://www.rimsntires.com/specspro.jsp

Does offset and all.

Put 33 inch on my troopy and speedo was spot at 100kph.Standard tyres read about 6kph lowr.....

just saying

" we're not sure that the 15" tyres with 3-ply walls are tough enough for where we go. "

Where are you going? If you are talking about cross country in the deserts then a heavy cross ply is the only way to go. Somebody posted a photo on this site a few years of a 7.50 x 16 MRF Superlug with zero air pressure in it. The sidewalls were so thick that the wheel on the front of his Nissan Patrol was sitting up at about two thirds of its normal height off the ground. Not even the weight of a heavy car like that could flatten the tyre.

Those tyres are at the extreme end of the scale but they are available if you want them. You won't see them in cities but you will on Outback cattle stations.

The normal steel belted radial is what you will find on about 98% of 4wds. All of them are fairly thin in the sidewalls and you can puncture them but your chances of getting one can be drastically reduced by keeping speeds low and watching where you are putting the wheels. Don't drive over rocks that are obviously sharp and avoid pieces of wood as much as possible.

As for sizes: there would not be a mountain or desert track in the country (and most likely the world) that has not been crossed countless times by a 7.50x16. They are too big for my car so I use a little 205x16 which is the standard size. My current set have been all over mountain tracks from the Snowy River area right up the Great Dividing Range to around Taree as well as the Oodnadatta, Birdsville and Strzelecki Tracks, the Gammon and Flinders Ranges, the old Ghan railway heritage trail, four of Len Beadell's roads and to the top of Big Red and back down again. There has been no problems with traction on rocks or in sand and, while they are just about worn out now, there have been no punctures.

Wider tyres just make bigger targets for things that can cause punctures.

Another advantage with these type of commercial tyres could be pressures. The factory recommended pressures for my little 205 light truck 80% mud/rock 20% street tyres look ridiculously low but they work. I drove the car from Cooma to Sydney yesterday at highway/freeway speeds on exactly the same pressures that I used on the Sandy Blight Junction road last year. I have been doing that ever since I bought them in 2007 without the slightest problems with either vehicle handling or tread wear. The low pressures may well have contributed to the lack of punctures.

Regarding split rims: they have their place but a lot depends on how far you want to go with repairing punctures. If you have no intention of ever trying to remove a tyre from a rim in order to repair a large hole properly from the inside then you don't need them. If you want to be properly prepared for any size repairable puncture (and you can get some real big ones in the bush) then I would suggest you decide on what tyre you want then find a worn out one and practice fitting and removing it from a one piece rim by hand. If you cant do it then it is time to start thinking split rims. They are designed for the easy removal of heavy tyres by hand.

Rob,
Lots of great advice above - pity it's all over the shop.

On your 75series Troopie, I'm guessing you're running the 31" tyres which commonly have a load index of 109, sometimes a little more. Its too low for what most people put in their troopie. Also I'm guessing the 3-ply tyres you speak of are BFG ATKO - which are the thinnest 3 plies - lost count of how many sidewall punctures I've plugged on BFGs. They typically stake on that elevated ridge, and they are still thin sidewalls to dissipate heat.

My suggestion is that it's good to stay tubeless (takes the common tube failures out of the equation) and 235/85R16 on a 16x7 rim are the common solution. This size is typically 10 ply rated with a higher load index of 120. Alternatively, the same size rim will take a 265/75R16 with a load index of 122. The diameter of both these sizes is identical to the original 750R16, so won't change the gearing.
The 265 will need flares - 235 won't.

As far as brands go, the only USA brand I still have faith in is Goodyear. Many of the cheap Chinese copies are actually very reliable for outback travel. Bridgestone 694/697 have a great track record on stony outback roads.