So, I’ve read this entire thread and I’m still not convinced which way to go. I’ve also been reading here and on various tyre websites about ‘LT’ vs ‘P’ rated tyres and that also leaves some room for doubt.
I am getting a 2” CRDSTU lift on my 2011 GC Laredo 3.6 and I want the larger 65 series tyre on the Laredo 18” rim. I’m tossing up the 275 vs the 265 not for the slightly larger diameter but for the higher load rating.
For example in the Yoko Geolandar ATS G012 (which is NOT an ‘LT’) which I’m considering, the 275/65 has a load index of 123 (1550kg/tyre) vs the 265/65 at 113 (1150 kg/tyre) which would indicate that the 275 would have a much stiffer sidewall and should hopefully be better in terms of overall strength and when lowering tyre pressures.
The load ratings above bring me back to the LT discussion:
We know that ‘ply rating’ doesn’t actually mean layers of cotton anymore but is an equivalent load rating for LT tyres however this from an American (I think) website:
http://www.tirerack.com/tires/tirete....jsp?techid=55
There’s quite a bit about construction etc but specifically:
LT-Metric, LT-Flotation and LT-Numeric Light Truck Tires
Load Range Ply Rating Abbreviated Maximum Load Pressure
B 4 B 35 psi (240 kPa)***
C 6 C 50 psi (350 kPa)***
D 8 D 65 psi (450 kPa)***
E 10 E 80 psi (550 kPa)***
F 12 F 95 psi (650 kPa)***
***Selected large LT sizes are designed with reduced maximum load pressures
Euro-Metric Commercial Vehicle/Van Tires
Load Index Maximum Load Pounds Maximum Load Pressure
116/114 2,705/2,600 69 psi (475 kPa)
118/116 2,910/2,755 75 psi (525 kPa)
121/120 3,195/3,085 83 psi (575 kPa)
So with all of that in mind:
Is an ‘LT’ construction technically no different to a non ‘LT’ (I wont refer to it as ‘P’ for the sake of the argument) that has a load index of equivalent weight per tyre? It is after all just a measurement of the relative loads the tyre can take, and in the example of the 275 Geolandar above its load index 123 is well above those in the Euro-metric commercial table above.
And if that is the case then what is the argument for saying that LT is more damage resistant than non-LT apart from the actual load rating? Is it not then down to the individual manufacturers tyre construction method?
Last thing – If one was to go with 275/65 would it be ok to use a 265/65 as the spare (for reasons of getting the wheel well closed)? The difference is about 13mm in diameter. Is that likely to make any difference at all to the road manners, ESC or safety of operation? I know others have mentioned 255/70 as an option for the spare but I’d rather have an A/T spare than a H/T which seems to be all that can be had in that size in Oz.
Thanks.