Tyres: 15" vs 16"

Submitted: Friday, Oct 24, 2014 at 01:39
ThreadID: 109910 Views:1898 Replies:12 FollowUps:3
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We have a 75 series 1993 Toyota Landcruiser Troopie. It currently has 15" rims but we need some new tyres, and we are exploring an upgrade to 16"rims.

Having had some sidewall tyre damage on the Tanami track a year ago, we're not sure that the 15" tyres with 3-ply walls are tough enough for where we go. I believe you can get 16" tyres with 8-10 ply sides.

I'm looking into second hand 16" rims for the 6 stud 75 series wheels.

My questions:
- Do I have to get 75 series rims, or what other makes and models will fit?
- What's the difference between single and split rims, and what are the benefits of split rims?
- should I go for the 265, 275 or 285 size? I guess 285 gives more clearance, but you have to climb higher to get in. :-|
- is it worth it to go for the thicker sidewalls?

Cheers
Rob
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Reply By: Member - Duncan W (WA) - Friday, Oct 24, 2014 at 02:01

Friday, Oct 24, 2014 at 02:01
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
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Follow Up By: ModSquad - Sunday, Oct 26, 2014 at 18:20

Sunday, Oct 26, 2014 at 18:20
Hello Duncan

If you have items you want to "flog" please use the Classifieds section of the website, not the forum (against rules:). No major drama just a reminder.

If you do choose to utilise the Classifieds, as you are a Member, a link to your add will be visible on all posts you make on the forum..bonus!

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Reply By: olcoolone - Friday, Oct 24, 2014 at 08:40

Friday, Oct 24, 2014 at 08:40
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.
AnswerID: 540768

Reply By: Member -Hilton Hillbillies - Friday, Oct 24, 2014 at 08:46

Friday, Oct 24, 2014 at 08:46
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.
Steve

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Reply By: Member - johntoyo - Friday, Oct 24, 2014 at 09:31

Friday, Oct 24, 2014 at 09:31
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
AnswerID: 540773

Reply By: The Bantam - Friday, Oct 24, 2014 at 10:34

Friday, Oct 24, 2014 at 10:34
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
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Reply By: pop2jocem - Friday, Oct 24, 2014 at 11:06

Friday, Oct 24, 2014 at 11:06
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
AnswerID: 540788

Follow Up By: Ron N - Saturday, Oct 25, 2014 at 18:59

Saturday, Oct 25, 2014 at 18:59
There's nothing wrong with tubed tyres, they served us faithfully for many decades.
Tubeless tyres reputedly run cooler, because there's no friction between tyre and tube.
However, I've found that shaking some french chalk (or talcum powder) into the tyre before tube installation, ensures that tyre/tube friction is at an absolute minimum.
I've proved this benefit to myself numerous times, after staking tube-type tyres at high speed - usually on freshly-graded roads, where there's debris in the material swept across by the graders.
Without french chalk, the tube is usually toast by the time you've pulled up.
With french chalk lining the inside of the tyre, the tube is nearly always useable again, after pulling up from high speed with a flat.
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Follow Up By: 671 - Saturday, Oct 25, 2014 at 21:11

Saturday, Oct 25, 2014 at 21:11
"I've found that shaking some french chalk (or talcum powder) into the tyre before tube installation, ensures that tyre/tube friction is at an absolute minimum"
------------------------------------------------
I agree, chalk is essential. The type I use comes from Rema Tip Top. I don't know if it is any better or not than any other type but it does come from the world's leading manufacturer of tyre repair equipment so I know it will work.

Another thing I do is seal around the ring and valve hole with roof and gutter sealer. That will prevent the entry of sand and water.

Heat should not be a problem. The tyre manufacturers know exactly how hot their tyres are going to get at all speeds, road conditions, loads, factory recommended pressures and atmospheric conditions.

The first trip I did with my current set was in the Vic. High Country in blazing heat in January. I had to drive all the way from Sydney to Bright before I saw my first dirt track. I could have fried an egg on the tyres but I had no problems at all with them. They were just doing what they had been designed to do.
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Reply By: gbc - Friday, Oct 24, 2014 at 12:33

Friday, Oct 24, 2014 at 12:33
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.
AnswerID: 540795

Reply By: Member - DrRob - Friday, Oct 24, 2014 at 12:47

Friday, Oct 24, 2014 at 12:47
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
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AnswerID: 540798

Reply By: TomH - Friday, Oct 24, 2014 at 17:26

Friday, Oct 24, 2014 at 17:26
Here is a comparator to work out size difference and alteration to speedo


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

Does offset and all.
AnswerID: 540812

Reply By: Bigfish - Friday, Oct 24, 2014 at 17:35

Friday, Oct 24, 2014 at 17:35
Put 33 inch on my troopy and speedo was spot at 100kph.Standard tyres read about 6kph lowr.....

just saying
AnswerID: 540813

Reply By: 671 - Saturday, Oct 25, 2014 at 01:45

Saturday, Oct 25, 2014 at 01:45
" 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.


AnswerID: 540836

Reply By: Member - Phil G (SA) - Saturday, Oct 25, 2014 at 21:42

Saturday, Oct 25, 2014 at 21:42
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.
AnswerID: 540863

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