4x4 tyres

 Hi folks, chasing some advise.

Purchased a vehicle with 20" rims and i would like to put some A/T tyres on it.

I know people say get rid of em and put 18's on but that would mean buying 5 new wheels, cladding them with rubber and having 5 20" in the shed doing nothing.

Has anyone changed out their 265/50R20's for say BFG's 275/55R20's.

If so or you know of someone that did, how do they go and is there any problems.

It means i get a bigger sidewall to play with lowering the pressure for the beach and a slightly wider tyre.

Your opinions will be appreciated as usual.



Cheers & Stay safe

Posts: 675

Date Joined: 21/05/12

 imho set of cheap white (now

Fri, 2020-08-07 17:32


set of cheap white (now even black) steelie rims

285 18 is common around the paddock - well more so than 19' or 20'

its the difference of getting something 2nd hand that will get u home, even on stations

mate with a navara waited 3 days in derby to get tyres if he had 18 inch he would have been an hr 

the only stock was in perth in  the whole north end  carnarvon to kununarra

those 20 inch rims will sell on gumtree in a hurry

Posts: 4225

Date Joined: 01/02/10

 I had a set of 20's on my

Fri, 2020-08-07 17:49

 I had a set of 20's on my last 200 series. Weren't as bad as I thought they would be. Still beach launched a few times with it. I was running 285/50/20. 


Does anyone know where the love of god goes, when the waves turn the minutes to hours?

ranmar850's picture

Posts: 2683

Date Joined: 12/08/12

Lower the profile, the more punctures. period.

Sun, 2020-08-09 09:05

 Larger diameter rims will always require a lower profile. Lower profile means you gain less by way of traction when you deflate, because of less sidewall bag. So you don't gain as much caterpillar effect, which is what tyre deflation aims to achieve, not getting it wider. And, if you deflate a bit for running on bad corrugations, as is the usual practice, you really run the risk of destroying an alloy rim and the tyre with it.  There is just less deflection available when that unseen grapefruit-sized rock hidden in the soft corrugations slams into the tyre, the tyre squashes all the way into the rim, the rim shatters. This is not theory, this has happened to me, and the tyres still had a fair pressure in them, 28psi IIRC. That incident involved a paid recovery by tilt-tray, as the other wheel on that side hit the same rock and came off the rim,  without damaging the rim. this was on 55 series, IIRC. Not a believer on alloys for off-road. Have a look at this video--lays it out in a simple manner. www.youtube.com/watch  

The only place 20" rims belong on any vehicle which has more than the lightest and most casual off-road use , is on the big yankee trucks, where you can run a decent profile tyre. IMO, I wouldn't go below a 70 profile for any real off-road work, including difficult beach work. 75 is the go if you can get that on you vehicle/rim combination. Current Hiluxes are 65 on 17's, I'd fit 70's to them if it is legal. My new D-max had the stock rims swapped  before delivery for black steel 16 x 8's on 70's,  biggest I could legally fit. 50 profile is for show ponies.


Oldbull's picture

Posts: 138

Date Joined: 21/09/15

Ever seen a Suzuki bogged on a beach?

Sun, 2020-08-09 09:47

 Up at Luck Bay there was a Suzy with 16 inch rims but 55 profile tyres.  Tyres would not bag out.   I have a lte model 100 series cruiser with 17 inch rims running 275/65 ATs.  Even that needs 14psi to be a starting point on a beach yet early model 100s with 16 rims and 70 profile can start at 16-18.  Yep lower profiles are fine for bitumen but crap for beach and offroad.

Deckie's picture

Posts: 1289

Date Joined: 03/04/09


Sun, 2020-08-09 14:48

 Thanks for your input. 

The 275/55R20's are 1 1/2'" larger in outside diameter, would that not give me a little bit more buffer room and more chance if the tyres were deflated.

I will be going from a 30.4" tyre to a 31.9" tyre.

Your thoughts....


Cheers & Stay safe

Posts: 438

Date Joined: 28/10/08

Lower profile

Sun, 2020-08-09 18:17

 Lower profile = harsher ride = less bag out when deflated

I'd sell the rims.

ranmar850's picture

Posts: 2683

Date Joined: 12/08/12

Going to a larger diameter

Sun, 2020-08-09 20:56

 Will give you a larger circumference, obviously. So each revolution of the wheel travels further. So you are effectivey raising your gearing. Your speedo will be closer to accurate, usually. But more speed for the same rpm is not necessarily a good thing. Mostly it will actually coast you fuel , because, as most vehicles nowadays are geared sky high in top, you are over-gearing. Performance and fuel consumption  can actually suffer, towing will suffer,  depending on the vehicle. Ask anyone who went from 31's to 33's. 

Work it out     30.4" dia =95.5" circumference

                     31.9" dia = 100.21"  circumference

So with the higher profile, you are travelling an extra 4.71" per revolution. Which is nearly a 20% increase in gearing. BIG difference, considering you already have at least one overdrive gear, probably 2, if you have an 8 speeder. All up IMO, you'd be better off going to a 18" rim and keep your original circumference. by getting a higher proflile tyre. 

Deckie's picture

Posts: 1289

Date Joined: 03/04/09


Mon, 2020-08-10 07:15

Thanks for the info folks. Looks like there will be another set of 20's on the market soon. need them for April next year so i will run these ones till then.
Again thanks for your input...


Cheers & Stay safe

Posts: 675

Date Joined: 21/05/12

 just remember in sand - its

Mon, 2020-08-10 16:12

 just remember in sand - its not the width of the tyre - but the diameter 

here is 1 link 

there are more if u search


commonly made mistake is to go wider tyres

Deckie's picture

Posts: 1289

Date Joined: 03/04/09

Wide enough.

Tue, 2020-08-11 07:30

Yeah the tyres are wide enough. The extra sidewall height will give me a slightly larger foot print when lowered in pressure as they are a slightly bigger diameter.


Cheers & Stay safe

Jackalchub's picture

Posts: 536

Date Joined: 10/03/12

 I'm running 16s.. 285/75..

Mon, 2020-08-10 16:43

 I'm running 16s.. 285/75.. It's like having a new car compared to stocks