tyres advice for offroad newbie

[Nicool]

hi guys,
I'm the happy owner of a 2007 Disco 3 SE (petrol V6 engine, 208 000 km) and am slowly but surely experimenting off-road (i've done a sand-driving class and will do more training in the future).
Lucky for me the car came second-hand (was 197 000km) with some pretty good tyres (or so i am told), which are 4x Discoverer H/T Cooper 265/60R18.
Under the boot i found my spare tyre to be a Goodyear wrangler 255/6R18

I must say i have limited knowledge on tyres and on which ones are good for offroad, so pardon the stupid questions but here i go:
1/ is that ok to drive for a while with one tyre that isn't as wide as the others? If one of my Coopers fail me and i switch to the Goodyear, that means i'd have 3 tyres 265mm wide whereas the 4th one will be 255mm wide
2/ would you rather have all 5 tyres on the same brand/model?
3/ the day will come where i have to change those tyres, can you recommend any tyre mode that would be suitable for offroad + general driving?
Let's be honest the car does mostly kids pickup/drop-off during the week, some highway driving on weekend, and real offroad maybe once every 6-8 weeks for a long weekend. I can't complain about the Coopers but, but 280$ per tyre seems a lot, and i am wondering if that's a bit overkill for my usage :(

cheers
Nicolas

[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%

[Eric SDV6SE]

AFAIK it's an issue driving with two different tyre makes/treads/profiles on the same axle in terms of road worthiness. In the event of an accident where you have the different spare fitted the vehicle can be deemed to be unroadworthy and as such any insurance policy you have is null and void, as you have undertaken to maintain the vehicle in a road worthy state as part of your policy.

As soon as I was able to afford it, I changed over all 5 tyres with the same make, tread and size to avoid any such issues. I kept the odd spare carcass as an emergency spare as this still has 80% tread left, and it's the same size.

Also rotate the tyres every 5000km including the spare to even out the wear, and then you'll end up with all 5 tyres worn out at the same time and not have an odd tyre left over again.

There's a wealth of tyre knowledge here on his forum, it's horses for courses and what you intend to use the car for.

With my tyre choice, I always consider who is in the car besides myself. surely it's worth every penny if the tyres are road worthy, good quality and up to the job of keeping you and the family plus other road users safely on the road.

Just my 2c for what it's worth.

[roverrescue]

Just wandering through AULRo after a day building a shed
Came across this thread and just wanna say Redback - you’re a bloody legend.
On approximately 99.85% of the Internet, the OP question would be met with disdain and ridicule....

AULRo truly is pretty unique


Anyways back to usual programming

S

[Graeme]

There are no legality issues with using tyres of different brands on the same "axle" providing that radial and cross-ply are not mixed. The R in the size (255/60R18) stands dor radial so both your sizes are radials.

The slightly smaller size of the spare wont matter if used only for short distances as the size difference will require the diff to slightly operate (differentiate) in a straight line whereas if the same size then the diff only differentiates on bends.

[SeanC]

Light truck all terrain are the most versatile. Everyone has favourites. Stick with a well know brand. Pay what you can afford and you should be fine. Five new tyres and rotate as Eric said.

[scarry]

This is Qld transports take on the issue of different tyres on same axle,NSW maybe similar.


"While a vehicle can be fitted with different tyres (eg, brand, tread pattern), the tyre construction (eg, crossply, steel radials, textile radials, etc) must not differ.

Please note: while differing tread patterns may be used the Department of Transport and Main Roads does not recommended fitting tyres with different tread patterns on the left and right side of the same axle."

[Eric SDV6SE]

There are no legality issues with using tyres of different brands on the same "axle" providing that radial and cross-ply are not mixed. The R in the size (255/60R18) stands dor radial so both your sizes are radials.

The slightly smaller size of the spare wont matter if used only for short distances as the size difference will require the diff to slightly operate (differentiate) in a straight line whereas if the same size then the diff only differentiates on bends.

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.
Interestingly in the UK it's illegal to have two different tyres on the same axle, and in continental Europe it's also illegal to run on winter tyres in summer and vice versa. Maybe I'm overly cautious but I always try to ensure the best possible tyres for the dury on my vehicles, budget permitting

[Graeme]

Its certainly my aim to have all 4 tyres the same brand, pattern and size but sometimes compromises have to be made, such as currently when one of my new tyres was destroyed so a spare from the last set is used - different brand, different pattern, LT not P although at least the same size and the only difference I note is that the old one is noisy.

[DiscoJeffster]

Come on Eric. Cars come with space savers these days. They’re nothing alike to the standard tyre. Insurance companies don’t have a leg to stand on in regards to tyres assuming the tyre meets the minimum vehicle requirements for legal tread depth, load, speed, and size as specified. You can have four completely different brands as long as they meet or exceed the requirements. And as for spacesavers, they are clearly marked with their maximum speed. Yes, exceed that, have an accident, and if they can prove the speed was a contributing factor, then yes, they may fight a payout, but in my experience, they’re nowhere near as bad as made out to be.

Now I wouldn’t, but hey, nothing stopping you. I currently have Cooper rears and Maxxis front while I finish off the Coopers and switch to all Maxxis.

[AK83]

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]

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]

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]

.... 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]

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]

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]

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]

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]

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]

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

[DiscoMick]

Thanks. I'm not familiar with the sizes for Discoverys. Mine are rated 116.
As you say, it depends on his needs and there are plenty of choices, like Cooper ATRs, Bridgestone, Kumho etc.