Grandtrak A/T 1 failed miserably
Submitted: Monday, Jan 26, 2004 at 20:00
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Goran
Here is some
feedback on my experience with this tyres, for the benefit of the
forum members. I had Grandtraks AT1 for 4 years, 40.000k with only one
puncture and excellent wear. I always run correct pressures (depending on the terain) and rotated them every 10.000 k. At 40.000 i had 40% tread left. I just got
home from
Broome (1200k round trip from
Port Hedland) and had 3 Grandtraks from my set FAIL. The tread separation fairlures on all of them (34psi press).
They where failing fo bits all over the tarmac. My recomendation to people here is to stay clear of Dunlops AT1 and AT2.
Reply By: chrisfrd - Tuesday, Jan 27, 2004 at 10:11
Tuesday, Jan 27, 2004 at 10:11
bleep ! 34PSI is very low. Are you American?
The wanker-Yankers love to run very low tyre (tire) pressures like that. I had a trip in the US a few years back and they thought that their tyres were over-inflated at 34PSI!
I pressurise my tyres to 45PSI in a 3.0TDI GU 2 Patrol running 275/70 ish Bridgestones. I've done about 45000K's so far and they haven't been a problem. The idea with tyre pressures is to get the best COMPROMISE. Don't over-inflate, otherwise you will have poor tyre wear (the centres will go out of the tyre) poor wet weather performance. Braking won't be and issue, as the contact patch only varies by about 15% on even the best tyres. (unless they are totally flat)
If you under-inflate, you will have exactly the same problems as the wanker-yankers over in America. Which you did!
Also, remember that inflation pressures and vehicle weights have a bearing on vehicle speed. If you were doing 100Km/h on tyres at 45PSI, expect to only travel at 60-80Km/h at 35PSI and so on, for the same weight and terrain.
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Follow Up By: Goran - Wednesday, Jan 28, 2004 at 00:16
Wednesday, Jan 28, 2004 at 00:16
No, i am not an American. I ran my tyres at 40psi when i first got them, but even at that pressure centres where wearing out fast. That is why i dropped the pressure to 34psi. Wear on this Grantraks is perfectly even across the thread which to me means tyres where not underinflated. I could be wrong about this but in my opinion poor tyre construction is to blame. Consider this, Dunlop Grantrak AT1 Max recomended pressure is 50psi at max load of 1420kg. GVM of my 4x4 is 2200kg.
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Follow Up By: David N. - Wednesday, Jan 28, 2004 at 10:36
Wednesday, Jan 28, 2004 at 10:36
I would tend to agree it's poor tyre construction to blame- that was also indicated by your tyres wearing in the centre at 40 psi.
I also agree 34 psi is LOWWW!
Many people in all sorts of vehicles from small four cyl Front wheel drives up run tyre pressures much too low.
Leaving out soft surfaces such as sand, your tyres will at HIGHER pressures.....
1. hold the road better,
2. handle and stop better
3. last longer
4. handle better in the wet (aquaplaning speed is directly proportional to inflation pressure)
5. run cooler
6. save fuel
The only disadvantage is rougher ride. That is one major reason the yanks run such low pressures.
This all assumes the tyres are built properly in the first place.
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