Got Dueler D697LT - what pressure do you run?

[jammers]

Just swapped over from pirelli scorpion ATR (two for sale in the markets ) to the Bridgestone D697LT 265/60R18. Never had LT tyres before so wondering what pressures people run?

I ran the pirellis at ~38psi around town which seemed fine.

[Tombie]

I found they work well at the Placard recommended pressures....

Except offroad... Then down they go

[Redback]

I have 36psi in the front but kept the placard pressure of 38psi for the rear, works well for me.

Baz.

[go-disco4]

Just swapped over from pirelli scorpion ATR (two for sale in the markets ) to the Bridgestone D697LT 265/60R18. Never had LT tyres before so wondering what pressures people run?

I ran the pirellis at ~38psi around town which seemed fine.

When absolutely fully loaded to GVM I ran 38 and 44 (cold) on highways

works well

Only a little bit bouncy when empty, but I have left it there for the roads

ran around 26 - 28 (cold) in the Vic high country

around 20 (cold) in the Simpson, and adjust when it got hot, even a bit lower with very soft sand

seems to work

GD-4

[SimmAus]

I run at 40 around town (which was tyre installer suggestion).

Recent Vic High Country - run at 30-33 and no problems.

Cheers

[jimc]

dunno if its the right advice or not, but I was told many years ago to significantly up the pressure when on highway as the manufacturer specs a lower pressure so the tyre can provide some cushioning.

I run d697's and to test I recently ran 52psi on a trip to Flinders Ranges and fuel economy seemed better for it! The ride was little harsher, but the weight of the camper seemed to iron out most of that.

I even did skytreck with those pressures, but I reckon I could get a stock commodore around those tracks.

[Tombie]

The std is the bigger the rubber the lower the pressure.

Running at 52psi is going to result in:

Centre tread wear exceeding outer edge wear.
Reduced road grip in wet conditions.
Decreased ride comfort
Increased chance of puncture
Tread block damage offroad

[jon3950]

dunno if its the right advice or not, but I was told many years ago to significantly up the pressure when on highway as the manufacturer specs a lower pressure so the tyre can provide some cushioning.

I run d697's and to test I recently ran 52psi on a trip to Flinders Ranges and fuel economy seemed better for it! The ride was little harsher, but the weight of the camper seemed to iron out most of that.

I even did skytreck with those pressures, but I reckon I could get a stock commodore around those tracks.

Manufacturers will specify a pressure that gives what they consider the best compromise between ride and handling. In simple terms, increasing tyre pressures on bitumen will improve handling, while reducing pressure will improve the ride. On dirt, reducing pressure will improve handling while still improving the ride. For normal on-road driving, both on bitumen and dirt, this shouldn't be more than a couple of psi either way in my experience.

To take this a little further, tyres have an optimum pressure at which the grip level is highest. Reducing or increasing the pressure from this point will reduce the level of grip. This will vary according to road conditions and load - eg, it will be higher on bitumen than on dirt. Running at this pressure is what you aim for when racing or rallying as grip is everything, however manufacturers tend to specify pressures a little lower than this as they are also trying to provide a decent ride.

Increasing the pressures significantly (ie over the optimum) will improve fuel economy, as it reduces the rolling resistance of the tyres by reducing the amount they flex. This comes at the cost of not only a harsher ride, but more significantly less grip and greater suspension wear as higher loads are transmitted through the suspension components.

The tyres form an important part of the suspension system. The flex in the sidewall absorbs the low amplitude vibrations from the imperfections in the road surface, leaving the springs to absorb the high amplitude vibrations such as bumps and potholes. This reduces the amount of vibration transmitted through the suspension components to the body, reducing levels of NVH and also reducing wear in suspension bushes. It also allows the tread of the tyre to remain in contact with the road surface. This reduction in grip level can become dangerous, particularly in the wet.

Increasing the load on a tyre (ie vehicle weight) will require an increase in pressure. This is needed to maintain the amount of sidewall flex at an acceptable level. As you load a Disco the load on the rear tyres increases more significantly than the load on the front, because most of the weight will be added near to or behind the rear wheels, moving the cog towards the rear. Note the placard on the D4 recommends increasing pressures in the rear more than the front as you load it for this reason.

Given all the above, I would suggest that 52psi in any tyre on a D3/4 is overinflated. This is particularly so on the front, where you will be experiencing considerably reduced levels of grip.

Cheers,
Jon

[discojools]

The std is the bigger the rubber the lower the pressure.

Running at 52psi is going to result in:

Centre tread wear exceeding outer edge wear.
Reduced road grip in wet conditions.
Decreased ride comfort
Increased chance of puncture
Tread block damage offroad

And much less grip...therefore more dangerous...especially in the wet. I have had 2 very scary occasions when unknown to me service people had upped the pressure to mid 40s!
I run mostly + 2psi on manufactures recommended due to extra weight of bull bar and long range tank.

Jon below puts it all in a nutshell

[Graeme]

Increasing the load on a tyre (ie vehicle weight) will require an increase in pressure. This is needed to maintain the amount of sidewall flex at an acceptable level.

I suggest its the contact patch area that has to be maintained, achieved by flexing the sidewall appropriately, although with more weight the contact patch needs to be bigger to get the same grip.