just read this how true is it

kbekl · 25-10-2010, 19:06

A tire sized P265/75R15 112S inflated at the 30 psi front and rear recommended for your suv has a load carrying capacity of 2,319 lbs.

A LT31x10.50R15 109S sized tire at 30 psi has a load carrying capacity of just 1,595 lbs - dangerously low as it reduces total load capacity for your truck by a staggering 2,900 pounds! Even at the maximum inflation pressure of 50 psi a tire of this size can only carry 2,270 lbs which is barely adequate - equivalent roughly to driving with the stock tires under-inflated by 2 psi. If you do buy the 31's you absolutely need to increase your inflation pressure to 50 psi or you could have a safety issue. Under-inflation not only causes premature tire wear but it can also cause the tire to overheat and fail.

Adz · 25-10-2010, 19:16

On road i run my KL71's 33x12.50R15 at between 40 to 50 psi

Off road i have dropped as low as 10 psi

Let common sense pre-vale

MudLifeCrisis · 25-10-2010, 23:12

Quote:

Originally Posted by kbekl

A tire sized P265/75R15 112S inflated at the 30 psi front and rear recommended for your suv has a load carrying capacity of 2,319 lbs.

A LT31x10.50R15 109S sized tire at 30 psi has a load carrying capacity of just 1,595 lbs - dangerously low as it reduces total load capacity for your truck by a staggering 2,900 pounds! Even at the maximum inflation pressure of 50 psi a tire of this size can only carry 2,270 lbs which is barely adequate - equivalent roughly to driving with the stock tires under-inflated by 2 psi. If you do buy the 31's you absolutely need to increase your inflation pressure to 50 psi or you could have a safety issue. Under-inflation not only causes premature tire wear but it can also cause the tire to overheat and fail.

1,595 lbs =723.5 kg per tyre

4 tyres = 2894 kg

car weight (LWB) 1850 kg approx

Looks ok to me or am I missing something?

Brian

briggie · 25-10-2010, 23:15

Quote:

Originally Posted by MudLifeCrisis

1,595 lbs =723.5 kg per tyre

4 tyres = 2894 kg

car weight (LWB) 1850 kg approx

Looks ok to me or am I missing something?

Brian

http://www.nissanpress.co.uk/press_s...sions_2003.pdf

MudLifeCrisis · 25-10-2010, 23:32

Even gross weight is well under at 2580kg

kbekl · 26-10-2010, 09:14

these tyre things are confusing me lol

235 is width yes
75 is height from wheel or hub?
15 is rim size

so how can a 255 70 15 be taller than my 75 ??

briggie · 26-10-2010, 09:17

Quote:

Originally Posted by kbekl

these tyre things are confusing me lol

235 is width yes
75 is height from wheel or hub?
15 is rim size

so how can a 255 70 15 be taller than my 75 ??

usefull tool for you mate here .

http://www.kouki.co.uk/utilities/vis...ize-calculator

kbekl · 26-10-2010, 09:19

Quote:

Originally Posted by briggie

usefull tool for you mate here .

http://www.kouki.co.uk/utilities/vis...ize-calculator

thats where i found out the 255 was taller lol

briggie · 26-10-2010, 09:31

Quote:

Originally Posted by kbekl

thats where i found out the 255 was taller lol

http://www.jettyres.co.uk/tyre-tips/tyre-markings/

kbekl · 26-10-2010, 09:37

Quote:

Originally Posted by briggie

http://www.jettyres.co.uk/tyre-tips/tyre-markings/

ah so 80 is a percentage of 255 and 75 is a percentage of 235

Muckypup · 26-10-2010, 09:56

Quote:

Originally Posted by MudLifeCrisis

1,595 lbs =723.5 kg per tyre

4 tyres = 2894 kg

car weight (LWB) 1850 kg approx

Looks ok to me or am I missing something?

Brian

Yes I was thinking the same

Karl - the load is shared between 4 wheels...

kbekl · 26-10-2010, 10:11

Quote:

Originally Posted by Muckypup

Yes I was thinking the same

Karl - the load is shared between 4 wheels...

i didnt write it some yank did lol just read it and thought thats odd as i would have thought they were the same

i is new to all this 4x4 tyre malarky lol

thinking about the same as that technic on the rear of mine but in a bigger size

Muckypup · 26-10-2010, 12:40

bonny tread that for an A/T

The Patrolman · 26-10-2010, 18:37

Quote:

Originally Posted by kbekl

ah so 80 is a percentage of 255 and 75 is a percentage of 235

255 is the width of the tyre

75 relates to the height of the sidewall as a percentage of the width
ie. 75% of 255 = 191.25mm

so a 255 75 r15 is 191.25 + (15x25.4) + 191.25= 763.5mm tall or 30.05 inches

rustic · 26-10-2010, 21:38

Quote:

Originally Posted by Muckypup

Yes I was thinking the same

Karl - the load is shared between 4 wheels...

You also need to check the maximum axle loading as stamped on the plate under the bonnet.
Both added together may exceed the Gross vehicle weight, so keep the GVW as the total weight and don't exceed each axle load.

25-10-2010, 19:06	#1
kbekl Senior Member Join Date: Aug 2010 Location: Manchester Vehicle: Ford Maverick 2.7 LWB GLX Posts: 1,519	just read this how true is it A tire sized P265/75R15 112S inflated at the 30 psi front and rear recommended for your suv has a load carrying capacity of 2,319 lbs. A LT31x10.50R15 109S sized tire at 30 psi has a load carrying capacity of just 1,595 lbs - dangerously low as it reduces total load capacity for your truck by a staggering 2,900 pounds! Even at the maximum inflation pressure of 50 psi a tire of this size can only carry 2,270 lbs which is barely adequate - equivalent roughly to driving with the stock tires under-inflated by 2 psi. If you do buy the 31's you absolutely need to increase your inflation pressure to 50 psi or you could have a safety issue. Under-inflation not only causes premature tire wear but it can also cause the tire to overheat and fail.

25-10-2010, 19:16	#2
Adz Senior Member Join Date: May 2009 Location: Roaming Nomad Vehicle: 1995 SWB Terrano Posts: 5,370	On road i run my KL71's 33x12.50R15 at between 40 to 50 psi Off road i have dropped as low as 10 psi Let common sense pre-vale

25-10-2010, 23:32	#5
MudLifeCrisis Senior Member Join Date: Sep 2006 Location: St Albans Herts Vehicle: 1997 Mav 2.7tdi lwb Posts: 1,377	Even gross weight is well under at 2580kg

26-10-2010, 09:14	#6
kbekl Senior Member Join Date: Aug 2010 Location: Manchester Vehicle: Ford Maverick 2.7 LWB GLX Posts: 1,519	these tyre things are confusing me lol 235 is width yes 75 is height from wheel or hub? 15 is rim size so how can a 255 70 15 be taller than my 75 ??

26-10-2010, 12:40	#13
Muckypup Senior Member Join Date: Dec 2009 Location: Lancs Vehicle: Jeep Grand Cherokee 4.0 Posts: 485	bonny tread that for an A/T