tyres advice for offroad newbie

**AK83** · 9th April 2019, 12:05 AM

Originally Posted by Eric SDV6SE

Thanks Geoff, yes, agreed, radial and cross ply should not be mixed, however two different brand/tread/size tyres may also have different load/speed ratings that can compromise handling and stability. I wouldn't want to give the insurers any extra reason to void a claim.
....

Insurance companies can argue till their blue in the face, but legally, mixed tyres are allowed. (except for ply construction types).
Actually says so in the laws ...

"For vehicles fitted with passenger car
tyres and manufactured after 1 January
1973, all tyres fitted to the road wheels
must be of the same carcass
construction (i.e. radial ply, cross ply,
bias belted, etc) but may have a different
tread pattern"

.

Obviously you don't want to run with mixed tyres, but in an emergency(ie. running a spare) .. sometimes you may have no other choice.

Otherwise, how to manufacturers get past ADR rules using space saver spares?

To the OP, given your intended main use of the car, I'd say go with a typical AT(All Terrain) tyre biased more for highway use.
Something that is not so aggressive on the shoulder lugs, not too overly open/coarse tread pattern .. etc.
But it depends on what you want to do in your off road adventures .. where you primarily want to go(beach/desert/high country/etc).

**Nicool** · 9th April 2019, 01:22 PM

Originally Posted by Redback

The tyre width is not the problem it's the rolling diameter, the 255/60/18 is the standard size for the Disco 3, also they are both road tyres essentially.

As for your next set of tyres, that will depend on how you are going to use the car, but I would replace the spare with something the same size as the other tyres on the car and maybe in something you are going with as your next set, that way you only need 4 tyres when it's time to change.

Rolling diameter in bold

255/60-18 6.0in 15.0in 30.0in 94.4in 671 0.0%
265/60-18 6.3in 15.3in 30.5in 95.9in 661 1.6%

Thanks a lot Redback for the very informative answer, and to everyone else who replied

**arejaybee** · 9th April 2019, 03:03 PM

Originally Posted by Redback

The tyre width is not the problem it's the rolling diameter, the 255/60/18 is the standard size for the Disco 3, also they are both road tyres essentially.

As for your next set of tyres, that will depend on how you are going to use the car, but I would replace the spare with something the same size as the other tyres on the car and maybe in something you are going with as your next set, that way you only need 4 tyres when it's time to change.

Rolling diameter in bold

255/60-18 6.0in 15.0in 30.0in 94.4in 671 0.0%
265/60-18 6.3in 15.3in 30.5in 95.9in 661 1.6%

Hey Redback, will the change in rolling diameter primary affect your speed calibration? And if so is it possible / easy to recalibrate?

I realise it would also affect your overall ratio in terms of revs vs speed as well.

Edit: I should add my context which is going from full set of 255/55R19 to 265/60R18.

**LRD414** · 9th April 2019, 05:44 PM

Originally Posted by arejaybee

.... will the change in rolling diameter primary affect your speed calibration? And if so is it possible / easy to recalibrate?
Edit: I should add my context which is going from full set of 255/55R19 to 265/60R18.

Easy with the right diagnostic tool but not needed for that diameter change. In fact 265/60R18 is closer to accurate for speed.

Scott

**loanrangie** · 9th April 2019, 06:46 PM

I put monsta all terrain's in 265/60/18, they are a budget tyre but been happy with them for the 18 months. I wasn't sure what I wanted so these have been great for just over $900 for 5.

**discorevy** · 9th April 2019, 08:46 PM

Originally Posted by LRD414

Easy with the right diagnostic tool but not needed for that diameter change. In fact 265/60R18 is closer to accurate for speed.

Scott

265/55/18 will be pretty accurate for factory speed reading compared to 255/55/18
I've found the 265/60/18 to under read by 2-3% depending on brand, no problem if you're aware of it

**Redback** · 10th April 2019, 08:27 AM

Originally Posted by arejaybee

Hey Redback, will the change in rolling diameter primary affect your speed calibration? And if so is it possible / easy to recalibrate?

I realise it would also affect your overall ratio in terms of revs vs speed as well.

Edit: I should add my context which is going from full set of 255/55R19 to 265/60R18.

We have a Faultmate MS2 and have calibrated ours to suit our 265/60/18s, it's pretty close to about 1 or 2Ks out from 60kph to 100kph, we have 17" rims as well for our off road tyres these are our touring wheels as well and run tyres with as close to the same rolling diameter as we can to the 265/60/18s which are 245/70/17s so it is as close as we can get, one or two Ks out is no big deal, these two sizes are the same rolling diameter, but calculate to 0.1% out.

245/70-17 6.8in 15.3in 30.5in 95.8in 661 0.0%
265/60-18 6.3in 15.3in 30.5in 95.9in 661 0.1%

DiscoMick · 10th April 2019, 08:47 AM

Yeah, if you're going OffRoad replace the HTs with ATs in LT - there are lots of choices.
I'm running Hankooks Dynapro ATs and very happy with them.
Re price, remember that off road tyres are a heavier construction and so generally cost more than lighter HTs. I paid $265 each for my Hankooks.

DiscoMick · 10th April 2019, 08:53 AM

BTW I once spent a week tootling around Myanmar in a Toyota which had five different brands of tyre on the five wheels, fortunately in the same size, so it can be done.

**discorevy** · 10th April 2019, 09:54 AM

Originally Posted by DiscoMick

Yeah, if you're going OffRoad replace the HTs with ATs in LT - there are lots of choices.
I'm running Hankooks Dynapro ATs and very happy with them.
Re price, remember that off road tyres are a heavier construction and so generally cost more than lighter HTs. I paid $265 each for my Hankooks.

While the Hankooks on your defender may be LT , the A/T range to suit D3 /D4 / RRS are not LT's , they are rated from 110 to 114 depending on size.
That's not to detract from the Hankooks as they are a very good tyre

Thread: tyres advice for offroad newbie

Thread Tools

Tags for this Thread

Bookmarks

Bookmarks

Posting Permissions