Tyre Topic: Cooper Discoverer AT3

[nj swb]

This Tyre Topic is for members to post about Cooper Discoverer AT3. Post your thoughts on grip, noise, wear, airing down, or anything else you consider of interest to other members.

Cooper Discoverer AT3.



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[kleinh17]

AFAIK Copper Discoverer AT3 comes in three flavours, which are apparently slightly different tyres and not just different specs.: 4S, LT, XLT
E.g. https://www.youtube.com/watch?v=jQSV27OaZfw

[old Jack]

AFAIK Copper Discoverer AT3 comes in three flavours, which are apparently slightly different tyres and not just different specs.: 4S, LT, XLT
E.g. https://www.youtube.com/watch?v=jQSV27OaZfw

Correct, there are 3 different types of AT3, they range from lightweight, light duty passenger construction through to heavy duty 10 ply light truck construction. Therefore careful attention needs to be paid to all the tyre soecifications when choosing a tyre.
Cooper are not the only manufacturer to do this, Bridgestone, Goodyear, Mickey Thompson, Dunlop, Pirelli and others all do the same. It can be really confusing for customers and quite often explains why people have vastly different experiences with certain tyre models.

OJ.

[Alben]

I have been running these for the last 1 and a half sets of tyres. Will check my service book to give exact timeframe and kilometres travelled and respond with some pics if anyone is interested later today. (it's too hot outside to keep working now)

[Alben]

The first set of the Coopers AT3 that I had fitted were in March 2012 and were LT275/65R18 123/120S Load Range E. (Someone else can maybe confirm for me but I have a feeling that these might be technically too large legally for the NS Pajero. I haven't checked the bulletins on vehicle modifications for a while)
They do have a larger width and rolling diameter than the standard sized tyre for the factory 18" wheels, but I found it brought the speedo needle to within 1% of actual speed instead of over reading by around 5 or 6% as previous. Another thing to consider is that our Pajero is a manual transmission so I can't comment on how this increase in diameter effects the changing of gears in the auto.
One big difference that I noticed was the physical weight of these tyres compared to the standard sized passenger rated tyres. These are alot heavier lifting the spare back onto the rear door.
At the same time as having these tyres fitted I also had internal tyre pressure monitors fitted and have run them ever since to have a real time idea of the tyre pressure and temperature.
As subjective as it is I would say that the noise generated from these tyres right through their life was very minimal. (my other vehicle runs unevenly worn out mud terrain tyres so everything is quiet in comparison)
With a loosely followed 5 tyre rotation schedule and front and rear wheel alignment checks and adjustments this set of tyres was changed after 78,390kms. The could have done more if not for a very bad rear alignment after a suspension lift scrubbed out the shoulders to finish their lives quicker than intended.
I had 4 of the tyres replaced with the same type and kept the best of the used ones as a spare, with an extra backup. I still have the old tyres in the shed so can measure and photograph the wear and what tread was left on them if anyone is interested.
I have been very happy with the on and off road performance of these, on road specially if driving through standing water or puddles I have never had them aquaplane which I put down to the tread depth possibly, and they still seem as responsive as you could ever need in a 4wd tyre.
Off road they have held up well on multiple Victorian High Country trips (some in very wet slippery conditions) and also did quite well when deflated for sand dune driving along the Vic/SA Border track. I cant remember the exact pressures that I dropped them to for the sand driving or the high country as it varied depending on the conditions of the day.
If anyone has any questions regarding them I can do my best to offer my opinion but I am not a mechanic or tyre fitter so can't get too technical. Also the current set of the Coopers has done just over 22,000kms and is not showing any signs of abnormal or uneven wear.
Cheers
Ben

[GTP]

Would someone with knowledge of these tyres (OJ?) be able to elaborate at bit on tyre construction. (LT version.) I know these are 10 ply in the LT variation. How does this relate, if at all, to side wall construction. My understanding is that this tyre is a 2 ply side wall vs say a BFG KO2 which is a 3 ply. Does this make much of a difference to side wall strength off road, or does it also depend on tyre manufacturers, and how the plys are constructed, technology etc?