crooks_uk
Member Since: 04 Jul 2017
Location: Newcastle-upon-Tyne
Posts: 42
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Currently running BFG KO2 all terrains tyres in 265/65R18 load rating D. I believe that the standard pressures given by Land Rover are for a XL P rated tyre and that a D rated tyre needs to be inflated at higher pressures than stated on the door card.
Has anybody got any experience of running these tyres and recommendations on the correct psi?
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 10th Jul 2022 11:07 pm |
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crooks_uk
Member Since: 04 Jul 2017
Location: Newcastle-upon-Tyne
Posts: 42
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Is anybody running these tyres and if so, what pressures are you running?
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| 15th Jul 2022 8:16 pm |
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LT
Member Since: 31 Dec 2005
Location: South West
Posts: 23824
  
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You need to experiment.
I ran the standard size 255-60-18 ATR’s and preferred 35-36psi on the front and 38-40psi rear.
I’d start with those and see how it feels.  2006 D3 HSE (Original & still the best)-GONE
2010 D4 HSE (A bit bling)-GONE
2014 D4 HSE (Almost too bling)-GONE
2015 D4 HSE (A heated what?)-GONE
2016 D4 Landmark (Written Off)-GONE
2016 D4 Landmark (Surely the last!) PD1881 rims-GONE
2017 FFRR SDV8 Autobiography (now semi-retired)
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| 15th Jul 2022 8:27 pm |
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riverblanche
Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2226
  
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Hi,
there is a calculation that uses the data on the tyres sidewall (istr max pressure) and the Actual weight of your car to give the "best" pressure, can not remember the calculation but we used to use it work out pressures on previous cars, had a D2 much modded, winch ect and running 235/85/16 it worked out very well for that, worth trying a search 
Did a search as knew I had posted it in the past ....... 2010  calculation is on and explained on page 2 of this thread
https://www.disco3.co.uk/forum/255-55-19-g...hlight=psi
. Transit! 2019
Gone D3 HSE 2008
Another Porsche Cayenne 2022
Gone Porsche Cayenne 2020
Gone RRS HSE Dynamic 2016
Gone RRS HSE LUX 2011
Gone RRS HSE 2006
Gone D3 SE 2.7 2008
gone D2 Td5 1999
I plan on living forever and so far so good !
Club DG Mclaren stuff
.
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| 16th Jul 2022 9:17 pm |
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crooks_uk
Member Since: 04 Jul 2017
Location: Newcastle-upon-Tyne
Posts: 42
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thanks for the replies guys. Was happy running them at 33 psi front and 36 psi rear (as light load on the door sticker) but noticed that lots of Americans are running them at higher pressures because they are loaded rated D so upped the pressures a little. Will running them at light load pressures cause problems or do I need to up the pressure due to the load rating?
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| 16th Jul 2022 10:49 pm |
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scraig
Member Since: 06 Feb 2011
Location: Langley, BC
Posts: 100
  
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I'm running the 265/65/18 KO2s at 40 psi in the fronts and 42 psi in the rears - one of my buddies got those pressures from BFG.......... Stewart
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| 21st Jul 2022 10:31 pm |
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crooks_uk
Member Since: 04 Jul 2017
Location: Newcastle-upon-Tyne
Posts: 42
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Thanks Stewart. Are you running light or heavy at those pressures?
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| 21st Jul 2022 10:33 pm |
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scraig
Member Since: 06 Feb 2011
Location: Langley, BC
Posts: 100
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I'd say light load if you are referring to additional weight added for items such as roof racks, etc. When I do load up for an adventure I don't change for the few hundred kms on pavement as I tend to be airing down for off road purposes anyways. I think LT's suggestion of experimenting a bit is a good one Stewart
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| 22nd Jul 2022 9:10 pm |
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crooks_uk
Member Since: 04 Jul 2017
Location: Newcastle-upon-Tyne
Posts: 42
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thanks for the reply. Have checked with BF Goodrich and they have advised to go with Land Rover's recommended pressures.
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| 22nd Jul 2022 9:47 pm |
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scraig
Member Since: 06 Feb 2011
Location: Langley, BC
Posts: 100
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That's good to know! Thanks Stewart
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| 22nd Jul 2022 10:33 pm |
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riverblanche
Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2226
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Hi,
you can work it out if you want to know
you only have to get the Actual weight of Your car to do it 
Transit! 2019
Gone D3 HSE 2008
Another Porsche Cayenne 2022
Gone Porsche Cayenne 2020
Gone RRS HSE Dynamic 2016
Gone RRS HSE LUX 2011
Gone RRS HSE 2006
Gone D3 SE 2.7 2008
gone D2 Td5 1999
I plan on living forever and so far so good !
Club DG Mclaren stuff
.
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| 22nd Jul 2022 10:34 pm |
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Moleshome
Member Since: 15 Oct 2020
Location: Wokingham
Posts: 412
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So I've just bought some Cooper Discoverer AT3 4S in 265/65R18
Kerb weight of the disco 4 is roughly 2,500Kg
Max load 1180Kg
Max pressure 44PSI
So:
4,720 / 2,500 = 1.888
44 / 1.888 = 23.3PSI
I'm not convinced.
The process that Cooper recommend is to inflate the tyres to the manufacturer's recommended pressure with the tyre cold, drive for 25-30 minutes to get the tyre up to temperature and check the tyre pressure.
For a 4x4 you should see a 6PSI increase over the initial pressure, if you see more than that you need to add more air, if you see less then you need to let some out.
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| 5th Nov 2022 8:04 pm |
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riverblanche
Member Since: 31 Aug 2010
Location: retford'ish
Posts: 2226
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Hi,
The calculation was 12 years old when I first posted it,
so thought tyre technology may have moved on a bit
as the BFGs I was running had a max weight of 1000kg not 1180kg also the max pressure was higher 50 not 44
But
you may be surprised of the D4s weight if you get it weighed, our D2 came in at 2600kg
so D4 more like 2700kg ?
1180x4=4720/2700=1.748 44/1.748=25.17psi
Give it a try you may be convinced (or not)
but it does give an accurate start point,
had a quick search for tyre pressure calculations and found this so it may not be as far off as you think 
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OEM Tire Size 255/55R19 (XL 111) with load capacity of 2027 lbs. @ 34 psi.
New Tire Size 265/65R18 (SL 114) with load capacity of 2054 lbs. @ 27 psi.
Transit! 2019
Gone D3 HSE 2008
Another Porsche Cayenne 2022
Gone Porsche Cayenne 2020
Gone RRS HSE Dynamic 2016
Gone RRS HSE LUX 2011
Gone RRS HSE 2006
Gone D3 SE 2.7 2008
gone D2 Td5 1999
I plan on living forever and so far so good !
Club DG Mclaren stuff
.
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| 7th Nov 2022 7:53 pm |
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RRSTDV8
Member Since: 07 Apr 2014
Location: Here
Posts: 13541
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Moleshome wrote:
The process that Cooper recommend is to inflate the tyres to the manufacturer's recommended pressure with the tyre cold, drive for 25-30 minutes to get the tyre up to temperature and check the tyre pressure.
For a 4x4 you should see a 6PSI increase over the initial pressure, if you see more than that you need to add more air, if you see less then you need to let some out.
c.2psi per 10 deg C temperature change, so they're saying the tyres will warm up by 30 deg C over whatever they were when inflated. I guess as a measure of sidewall flexing, and thus correct pressure, that's a reasonable approach. Visiting from rrsport.co.uk
2012 RRS SDV6
2008 RRS TDV8
"When you fire that first shot, no matter how right you feel, you have no idea who's going to die! You don't know who's children are going to scream and burn. How many hearts will be broken. How many lives shattered. How much blood will spill, until everybody does what they were always going to have to do from the very beginning: SIT DOWN AND TALK!"
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| 7th Nov 2022 8:54 pm |
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