kieronf
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Getting mine shod in new Grabber At's tomorrow (255/55/18/109V). Any recommendations as to pressures would be most welcome.
Air pressure for Grabbers
- Thread starter kieronf
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Fur Trapper
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the air pressur is on the side of the tyre use the manufacturer recommendations . simple
kieronf
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yep, but everyone here has tried and tested pressures for various tyre brands. I've been running at 28 front 36 rear, just wondered what worked best for these tyres when fitted to a P38...............
StuckAgainSteve
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kooky_guy
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I found that 30 on the front works better on my GG AT2s. I'm on 18 inch rims and they tend to tramline on 28. Keep 38 on the rear though.
James R
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So why are there pressures on the side of the tyre? What if you fit tyres that fit perfectly well (such as a slightly bigger tyre) but are not mentioned in the manual for the car? What do you do then? Genuine questions : not being snide.
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on tyre - max pressure before it goes bang.
what do yu do.... do the chalk test.
what do yu do.... do the chalk test.
StuckAgainSteve
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Absolutely, marked on the tyre is max pressure and load. The tyre pressure is determined by the air pressure required to maintain the correct footprint given the average axle weight the tyre has to cope with divided by two.
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Just look at hand book. 8J/255x55x18. 28 psi front 38 psi rear.
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kieronf
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Tyres on car - chalk test at fitters suggested 28 front and 36 rear for best footprint. As an aside, the tyres they took off were all at 6psi higher than the garage air guage I regularly used had suggested.
The meter at the tyre fitters was done by trading standards ( I think it was them) only last Tuesday and so is bang on. Just goes to show these bloody garages don't calibrate their guages too often.
The meter at the tyre fitters was done by trading standards ( I think it was them) only last Tuesday and so is bang on. Just goes to show these bloody garages don't calibrate their guages too often.
kooky_guy
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I have a similar problem with my own guages. I have 3 and they all show different readings - no idea which one is right if any. Anyone recommend a decent reliable guage?
StuckAgainSteve
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Pencil gauges are the most reliable and accurate - most consumer digital gauges are not very accurate. If I remember rightly a Halfords Professional pencil gauge won a group test against much more expensive kit. The Halfords gauge was under a tenner at the time. yes, you guess with a pencil gauge to the nearest pound or two coz they are not easy to read. A digital gauge will give you a comforting 38.35 - great - 'cept the figure usually isn't worth the silicon it's displayed on.
tony2
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I have Grabber AT's fitted and running them 30 front 34 rear. All ok so far.
StuckAgainSteve
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Dunno if it's my imagination, but I haven't felt or heard the ABS kick in since switching to Grabber ATs, the Pirelli Scorpions were always scrabbling for grip over wet drain covers or whathaveyou. I expected the Grabbers to be inferior on tarmac but better off road - it seems to me they're better on-road as well!
kieronf
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Nope, me too, the Grabbers are proving to be an excellent tyre on tarmac - stable and predictable in corners and much less road noise than the Toyos it had before.
lowfat
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Regarding tyre pressures and handbook values, the prosecutions case against a driver involved in a fatal loss of control.Hinged on the incorrect pressures found on the vehicle,compared to the vehicle handbook.
So disregard the vehicle handbook at your own risk......
So disregard the vehicle handbook at your own risk......
James R
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But what do you do if the size of tyre you are using are not in the manual. Ah, got you there!
Fur Trapper
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Fook the manual The air pressure is on the side of the tryer from manufacture, that is what you HAVE to use. The book is old compared to what the tryer design is, with different rubber compounds and different ply/belting material that is why the manfacture has to put the psi specs on there tryers
James R
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But I thought someone earlier in the thread said that the pressures shown on the tyres are the maximum pressures not the recommended pressures? How would the manufacturer know which tyre would be used at the front or rear of a car where sometimes the pressures are different?
kooky_guy
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They are the maximum pressures. How will the tyre manufacturer know what the tyre is being used for?
FT, by your logic, front and rears would need to be at the same ridiculously high pressures.
So it sounds as though we're liking the new GG AT? Anyone tried them offroad yet?
