Thread: Best AT 255/60/R18

I went for Cooper AT3 265/60/18, which are not LT construction, and generally they have been OK except when I tow my van (2.5t loaded, 250kg ball weight, measured).

The Cooper handbook says that the ideal psi increase between cold and hot should be around 3. If it is more you just increase the pressure accordingly.

I also have ‘SensaTyre’ pressure and temperature monitoring fitted to all 6 tyres for the car, plus all 6 van tyres (2 spares).

Without the van, at 38psi, all 4 tyres increase pressure by about 3psi from cold to hot over all speed ranges, so all good.

With the van, the fronts behave but the rears start freaking me out. The rears, at 44psi (max allowable pressure), increase by up to 9psi. It is speed dependent, ie the faster I go the higher the psi increase but I don’t travel any faster than 100kph on good sealed roads. The tyre temperatures are OK and don’t get excessively hot.

I spoke to Mr Cooper about this and basically got the “sh*ting dog look” from him. I also asked if I should try the rears higher than 44 to reduce the amount of increase but I was told ‘not to exceed the max allowable pressure’.

On gravel roads I drop the rear pressure to around 34 (and slow down) and I’ve punctured twice within 6 months of the tyres being new. Both times it has been the rear left and through the tread (not the same tyre). I'd thought these types of punctures were caused by the tyre still being inflated too high and not being able to comply to the terrain??

I've since looked a bit more carefully at the load ratings:
AT3 (not LT) = 110T = 1,060kg / 190kph
Zeon LTZ (not LT) = 120S = 1,400kg / 180kph
Bridgestone D697 LT = 114S = 1,180kg / 180kph

The LTZ have an impressive load rating but I would have thought that the AT3s at 1,060kg should be OK. I'm also not sure which of those two has better puncture resistance but for my next set of tyres I’m leaning very heavily toward the 697s with their LT construction.