tyre Pressures - Nissan-Navara.net
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post #1 of 31 (permalink) Old 13-05-18, 12:59 PM Thread Starter
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tyre Pressures

afternoon gentlemen, I have a v6 with 18" alloys with grabber tyres on , I put 39 in the front 45 rear. is this correct ? someone mentioned to me that those pressures
are for 17" with normal tread tyres. any help would be appreciated.


regards dave.
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post #2 of 31 (permalink) Old 13-05-18, 04:10 PM
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If you are running fully laden, yes. If not those pressures will make the ride very harsh. 38 all round is a good compromise.
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post #3 of 31 (permalink) Old 22-06-18, 04:43 PM
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If you are running fully laden, yes. If not those pressures will make the ride very harsh. 38 all round is a good compromise.
I have a Pathfinder with 18in rims and recently swapped road tyres for Grabber AT3s. Nissan recommend 35psi front and 35-40psi rear (increasing to 44psi when fully laden). On the road tyres I ran 35 front and 40 rear upping to 44 rear when towing caravan with fully laden truck. On the AT3s I started with 35 all round, then quickly increased that to 40 rear when I checked the fuel consumption. But am still losing 2 to 3 mpg on the Grabber AT3s. I can't drive any more sedately than I am at present so am faced with 3 options: put up with it, play about even more with the pressures, or get it remapped. Is 2 to 3 mpg loss normal when swapping to AT tyres? Any comments welcome !!
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post #4 of 31 (permalink) Old 22-06-18, 05:06 PM
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I'm guessing losing only 2-3 mpg is probably very good, compared with standard road tyres, even with optimal pressures.

A remap, depending who you believe, is unlikely to improve mpg and runs the risk of clogging the DPF - just an observation and not based on proper science or big statistics... I heard Billcar no longer offer remaps for towing vehicles, owing to DPF issues, but I'm not certain.

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Last edited by freemansteve; 22-06-18 at 05:10 PM.
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post #5 of 31 (permalink) Old 22-06-18, 07:15 PM
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I have a Pathfinder with 18in rims and recently swapped road tyres for Grabber AT3s. Nissan recommend 35psi front and 35-40psi rear (increasing to 44psi when fully laden). On the road tyres I ran 35 front and 40 rear upping to 44 rear when towing caravan with fully laden truck. On the AT3s I started with 35 all round, then quickly increased that to 40 rear when I checked the fuel consumption. But am still losing 2 to 3 mpg on the Grabber AT3s. I can't drive any more sedately than I am at present so am faced with 3 options: put up with it, play about even more with the pressures, or get it remapped. Is 2 to 3 mpg loss normal when swapping to AT tyres? Any comments welcome !!
Are the grabbers the same size? Reason being that if they are larger you will get an mpg drop, not a real drop, just that the car doesn't know it is going further for each tyre revolution.
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post #6 of 31 (permalink) Old 22-06-18, 08:12 PM
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I run Grabbers on my D22 and I find the mpg isn't that good, I am thinking of changing next time to the new Mitchellin Cross Latitude tyre to see if that makes a difference

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Driving a 2003 D22 and loving her, bottom end and oil pipe mod, Monroe shocks all round, Old man Emu rear springs fitted and running on Vredestein Quatrac 5 all season tyres
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post #7 of 31 (permalink) Old 22-06-18, 08:13 PM
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Yes - never trust the 'computer' mileage. It is calibrated(-ish) to the standard tyre circumference at standard pressure. Always measure mpg based on what the fuel pump reads on a fill up, against actual mileage covered.

Nevertheless some tyres types do have a higher rolling resistance and will affect MPG even if identical in circumference...

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post #8 of 31 (permalink) Old 22-06-18, 08:45 PM
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Originally Posted by landmannnn View Post
Are the grabbers the same size? Reason being that if they are larger you will get an mpg drop, not a real drop, just that the car doesn't know it is going further for each tyre revolution.
Good point, thanks, but yes the Grabbers are identical size - different speed rating but that's the only difference.

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General Tire Grabber AT3
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post #9 of 31 (permalink) Old 22-06-18, 08:58 PM
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Originally Posted by freemansteve View Post
Yes - never trust the 'computer' mileage. It is calibrated(-ish) to the standard tyre circumference at standard pressure. Always measure mpg based on what the fuel pump reads on a fill up, against actual mileage covered.

Nevertheless some tyres types do have a higher rolling resistance and will affect MPG even if identical in circumference...

Yes, I suspect rolling resistance too. The Grabbers seem to sit more square, so a bit more tyre in contact with the road. And I doubt that increasing the pressures is going to make much difference to the way they sit but, on the other hand, I'll be grateful for that extra grip when off-road . Trying to keep a positive spin on things (apologies for the pun).

Pathfinder R51 Tekna 2.5 dCi 190PS auto in black
General Tire Grabber AT3
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post #10 of 31 (permalink) Old 22-06-18, 09:45 PM
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Well, you let that pun slip, so get a grip, man.
Don't slide off, when the pressure is on, just stay in the groove...

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