Thread: Big Tyres: Pros and cons

Pros & Cons ... depends on the vehicle the tyres are fitted too as well ...

Years ago I owned a S111 SWB canvas top 2.25L, fitted with Wrangler 7.50 x 16 on std LR rims.
Mate had a IIa SWB hardtop with a 202 conversion and 31x10.5x15 tyres on sunraysia rims.

Using sand driving as 1 specific example. Stockton Beach ... both of us could travel anywhere on Stockton. Beach front, climb the dunes, soft powdery sand, etc ... both vehicles were pretty capable in this terrain.

For ****s & giggles one day we swapped wheels between the vehicles and tried driving stockton ... wasn't going to happen !!

My SIII with the big tyres (which looked the goods now with BIG tyres) didn't have enough guts to properly drive the bigger tyres in the sand (even aired way down). Had to wring it's neck to make progress and the slightest soft slope would severley impeed progress. Worked OK in the bush though.

The IIa fitted with the 7.50 x 16's just dug holes everytime the clutch was released. Due to the 202 having nothing at low rpm, you needed some right foot to make progress, and the narrower tyres just spun and dug holes and kept getting stuck.
Again, it worked OK in the bush.

If I drive my D2 in the dunes, pretty much it leaves a nice clean tyre tread print behind me wherever I drive. The TC is slipping and preventing the tyres from spinning ... A manual vehicle tends to wheel spin more due to the solid drivetrain and chew the loose surface causing the tyres to sink in more rather than float over the top.

So larger tyres have their place ... but the terrain and vehicle (& transmission type) have a large bearing on what works and doesn't also. There's no 1 size fits all.

... my 0.02c

Too many of the countering comments change too many variables in this thread. For meaningful comparison - gotta focus on one difference.

OP asked about "big". As I wrote before that can mean taller, wider, or both.

Seems all agree taller means more ground clearance and that's nearly always good.

So why not lock that in and focus on "big" that assumes tall. Only one variable, width.

i.e. Discuss the relative merits of:
- tall&narrow (some passionate proponents here saying this is good for ALL situations and wide is for posers)

VS

- tall&wide

Then a measurable and meaningful conversation can be held

Can we agree that 6-8" wide is narrow. (Eg 235/85/16)

Can we agree that 10-12" or more are wide.

Originally Posted by Fluids

For ****s & giggles one day we swapped wheels between the vehicles and tried driving stockton ... wasn't going to happen !!

My SIII with the big tyres (which looked the goods now with BIG tyres) didn't have enough guts to properly drive the bigger tyres in the sand (even aired way down). Had to wring it's neck to make progress and the slightest soft slope would severley impeed progress. Worked OK in the bush though.

And to point out, airing down, although improving traction, increases rolling resistance.
You will need more power and fuel to push that tyre along.
Interestingly, some of the energy from that excess fuel you are burning is transformed into heat in the side walls.
While we're talking about rolling resistance, generally wider tyres have greater rolling resistance. That is why putting wider tyres on will increase fuel consumption.
The tyre manufacturers are trying to develop tyres from materials with reduce rolling resistance. That is why you are hearing "Siica Technology" in reference to tyres nowdays.

if you take width in relation to diameter

The Hankook Dynapro MT 37x12.5R17 ****** tyres on my truck
37" diameter, 10.5" tread width 37/10.5 =3.5


The Toyo M55 235/85R16 tyres on my caravan
31" dia, 8" tread width 31/8=3.8

so the 235/85R16 are looking good !!

Taller / skinny = the bigger number is better as far as this argument is concerned.

Interco TRXUS 37x12.5R17 have merit, but at $655 each ??
37" dia, 9.3 tread width 37/9.3 = 3.9

Perhaps I've just found my next tyre
http://opw.com.au/tyres/interco/trxus-mt-page-3.html


anyone know the diameter and tread width of a 1920's Dodge
lets say 36" diameter 3" wide 36/3 = 12 Whoah! no wonder the old Dodge is king off road ,
would like to see any modern 4x4 try to follow the Dodge, and its only 2WD !!

[ame]https://www.youtube.com/watch?v=nq2jY1trxqg[/ame]

Love the rollover recovery :sly:

Sent from my Nexus 7 using AULRO mobile app

Originally Posted by Tombie

Because you can have narrow tyres with large rolling diameter

Larger rolling diameter plays a reasonable part in capability regardless of width...

Yep,

4WD Monthly (as it was known then) did a story about this 10+ years ago.

The contact patch was bigger on skinnier tyres when aired down, without the plough effect.

I've had 31 x 10.5 x 15 on my POS for years, but it is less than ideal, on or off road.

Mega grip on dry tar, aquaplane in the wet.

When I can conquer inertia all will be different..........

cheers, DL

I was looking at a Harley at the weekend which had a really wide donut on the back and a tall skinny tyre on the front. Can't see either being much use off the bitumen though.

Wow great thread. I have been in discussions with a couple of mates about exactly this issue.
One mate has a patrol with 2 inch lift and 285/85/16 muddies on it.
Other mate has a prado with 2 inch lift and road tyres quite thin. 225 ish.....
I have a 2 inch lift disco 1 with 235/75/15 AT.
My AT are total crap. Not to mention 15s!!!!
I planned to go 285/85/16 muddies but after reading this thread im not so sure.
Perhaps i should go thinner and not need to put in those over priced guard flares?