Wide Vs Narrow off-road tires.

Brodie Allen · Guru

Wide Vs Narrow off-road tires.

Possum3 · Guru

www.youtube.com/watch

Cuppa · Guru

Another thing not mentioned in the video is that narrower tyres can be much better at cutting through a sloppy crust to a more stable surface below it.

FWIW my car is an ex Telstra vehicle used exclusively in central Australia, based in Alice Springs, until I bought it. It came to me fitted with 'pizza cutter' tyres 245/75R16

I had no doubt that Telstra knew what 'worked' out there in the desert, but I wanted to change the tyres for two reasons. They were fitted to split rims which I wanted to change to tubeless & after I had converted the canopy to a camper & had the GVM increased, I was needing to run the 245's at maximum pressure to carry the weight. 65psi IIRC. This seemed to me to be far too high for off road use & a 'blow out' waiting to happen.

I got new mine spec rims (to provide adequate load carrying capacity) & new tyres. All the 4x4 boys told me to buy 285's, but I resisted & instead bought 265/75R16's. Several years on & two sets of tyres I still consider that this choice was by far the best compromise.

Difference in tyre diameter was around 1" & with a slightly higher sidewall compared to the 245's

They allowed me to run the tyres & carry the weight without ballooning out to much at 40 to 45 psi in the rear & 30 to 36psi in the front. They have done all I've asked of them including a lot of desert tracks & corrugations as well as plenty of gnarly rocky & boulder strewn 4wd tracks. I don't believe going wider would have been of any benefit other than looks which I don't really care about. That said I have done very little mud driving - not my thing if I can help it.

The width vs length of the contact patch in the video did surprise me. I too have always believed that the contact patch just got longer at lower pressures.

Those KM3's look like a good option!

-- Edited by Cuppa on Sunday 6th of August 2023 02:31:23 PM

Are We Lost · Guru

Possum, the link you pasted is a different video from what Brodie pasted. But it's also worth a look.

Here is Brodie's reference converted to a link

I agree with Cuppa's point that when there is a firm surface underneath the narrower tyres will more easily penetrate the soft mush and therefore get better grip. Sometimes wide will be good, sometimes narrow. On the beach, wide will always win.

The part about the video I don't like is that it is mostly based on the premise that wider tyres do not contact the road all the way across. Well that seems logical if you don't have rims to suit. Wide tyres on standard rim is naturally going to result in a rounded tread surface. If the rims had been changed to match the wider tyre size it would have been a very different result.

Real world comparisons in usage would be useful.

Aus-Kiwi · Guru

Tyres aspect ratio plays into it also . Percentage tread to side wall .

Whenarewethere · Guru

Narrow & larger diameter tyres are better (& cheaper).

Having said that, an additional 25mm width has prevented any further kissing kerbs on our car. So there is value there from some perspectives.

We always let tyres down in the outback to suit the roads. Our car is not suited to "obstacle courses". Nevertheless with 3 compressors onboard (had quite a bit of fun embarrassing serious 4WDrivers without basic equipment) we can air up a 70 litre tyre volume from 20 to 35psi per corner in 28 seconds (deflation 60 seconds per corner).

If one looks at "prehistoric" car footage in remote areas around the would. It is interesting than they could get to areas on utter goat tracks. But if you look at the wheels, even though they were very narrow, they were very large diameter.

One of the issues today is the shear amount of power the typical vehicle has & if your car is 2wd drive you will spin the wheels. My car 1972 vs 2007> (I have a 2013) are both 2.0L, each are 56 vs 177kW respectively, today that is pathetic. Power output a hundred years was almost in single digit.

If we had tyres from a century ago they would have been shredded being made from natural rubber.

Plain Truth · Guru

Our previous vehicle was a 80 series Land cruiser diesel.Around town we ran Bridgestone All Terrain on wide rims.

When on trips we ran Bridgestone Mud Duelers on 750 x 16 split rims,great in mud,no problem in sand.

Did Fraser Island and Simpson Desert with no problems,fantastic in the Vict. High country.

Couple of photo's in the desert,Big Red no problem.Skinny tyres or pizza cutters are OK

pizza cutter2.jpg pizza cutter1.jpg

-- Edited by Plain Truth on Sunday 6th of August 2023 06:25:16 PM

Basher · Senior Member

Sometimes l think you can over complicate things.
Unless you are doing something out of the NORM, go with the flow.
Basher

Brodie Allen · Guru

Wide tires can also be a problem in the wet with reduced traction (compared with pizza cutters) the faster
you go with increased propensity for hydroplaning.

B

Cuppa · Guru

Plain Truth wrote:

-- Edited by Plain Truth on Sunday 6th of August 2023 06:25:16 PM

It doesn't change what you said about tyres, but I believe the dune shown in your photo is incorrectly labelled, although if I am correct about that, you would be far from the only person to ever have made that mistake. I believe the photo shows the first dune you come to on the road out from Birdsville, & the the shot is of the dune on the opposite side to the road with the vehicles pointing toward Birdsville? That being so this is the Dune known as 'Little Red'. 'Big Red' is the next dune to the north west as you follow the track into the Simpson Desert.

Plain Truth · Guru

big red.jpg

Cuppa · Guru

Plain Truth wrote:

Same mistake we made! :) Sign points to big Red, but it's not big Red in the photos. We were informed of this back in Birdsville. Google Maps concurs.

-- Edited by Cuppa on Monday 7th of August 2023 12:48:21 PM

Plain Truth · Guru

We came out of the Simpson on the Qaa Line as shown in this photo with Big red in front just as Google map shows

capture bigred1.jpg Capturebigred google.JPG

Brodie Allen · Guru

Whats this got to do with tires.

Who cares where it is?

B

Cuppa · Guru

Plain Truth wrote:
We came out of the Simpson on the Qaa Line as shown in this photo with Big red in front just as Google map shows

I should have known better than to suggest you were incorrect. biggrin

Fact is it is such a commonly made mistake that even labelling on some Google Map images is wrong , due to folk having labelled Little Red incorrectly.

Is the dune you are referring to as Big Red the first one at the end of the road from Birdsville? Or the second one from the end of the road from Birdsville?

Map below from Exploroz Traveller https://www.exploroz.com/places/14098/qld+little-red

yobarr · Guru

Brodie Allen wrote:
Whats this got to do with tires.

Who cares where it is?

B

Who cares? It's a direct continuation of an interesting discussion that I, for one, am finding most informative. We have a couple of very experienced travellers sharing their adventures from which we all can benefit. Can't be bad, surely?

If you don't like it, read the jokes section instead, and lighten up a bit! Have a GREAT day. Cheers

-- Edited by yobarr on Monday 7th of August 2023 02:14:11 PM

Plain Truth · Guru

Sadly Cuppa doesn't want to understand again.

We came from Mt.Dare not from Birdsville end.This should clear the matter up,we were nowhere near little Redhopefully.

Cuppa · Guru

Why do you always seem to need to become unpleasant & accusatory PT?

Not a matter of me 'not wanting' to understand.

I'll just accept that you know where you went & that you couldn't possibly be mistaken. It's really not that important.

Craig1 · Guru

Back to tyres, My late father had a 1959 Land rover to travel from Arthur River Ferry to Temma on Tassie West Coast, in early 1960's. He frequently got bogged with it full of Tassie crayfish, sometimes towed a trailer when he had a good catch. Standard for then tyres.

A farmer who lived south of the river had a Thames Trader 2t tray truck with really skinny wheels, tyres, but around 20" dia. Somehow this old thing just waddled through the slop and did not get bogged.

Dad upgraded to a Willys tray fwd and with track improvements seldom got bogged after that.

dogbox · Guru

i remember seeing one of the LEYLAND BROS. episodes when they first tried the wide tires an they ended up going back to the real skinny tires DUNLOP MAJORS i believe, the ones that looked like they were off of a tractor. the problem they had with the fat tires was sticks punching thru the side walls, got worse as the tire pressure was lowered.