All-Terrain Tyre MPG

[Dan T]

I've gone from standard summer tyres 255 45 18 to 235 55 18 general grabber At3 . My mpg seems to have taken a fair hit . Struggling to even get 30 mpg even on a longish Run at 70mph. My van is a 150 Dsg
Is this to be expected (normal) when running an over sized heavier all terrain tyre ?

 

[DXX]

No idea what MPG you were getting before but the tyre change has increased the rolling resistance (increase in contact width and tread block type), increase in weight and increase in rolling circumference which will affect the gearing.
It’s going to affect fuel economy.

 

[Dan T]

No idea what MPG you were getting before but the tyre change has increased the rolling resistance (increase in contact width and tread block type), increase in weight and increase in rolling circumference which will affect the gearing.
It’s going to affect fuel economy.

Yes I was average mpg on standard tyres around 33mpg
All terrain Tyres are giving average 27mpg.

 

[bullracing]

Yes its normal, I took a big hit on mpg.... still trying to hide the fact from the Mrs!
I've also lost a huge amount of torque for hill climbs. Before hand I could get up a long hill at 70mph and maintain it. Now I am dropping to 60mph and also ready to drop gears to 4th. I think a remap is now on the cards

 

[bullracing]

17's not 18s on mine

 

[Dan T]

Yes its normal, I took a big hit on mpg.... still trying to hide the fact from the Mrs!
I've also lost a huge amount of torque for hill climbs. Before hand I could get up a long hill at 70mph and maintain it. Now I am dropping to 60mph and also ready to drop gears to 4th. I think a remap is now on the cards

Yes I was thinking a remap may top up the loss in performance as I really like the look and added durability of the At tyres

 

[andys]

Don't worry it's not quite as bad as you think, increasing the overall circumference has meant that the readout for distance, speed and therefore MPG, is incorrect (or rather more incorrect than before) so you're actually getting better fuel economy than the readout says, as you're covering a larger distance per wheel revolution. It needs recalibrating.

 

[bullracing]

I changed my speedo readout using vcds to meet the closest setting but you are spot on Andy, I am doing 70 but it shows as 75 on the speedo so I would be getting better then it shows. I do however only get 310 miles to a tank.

 

[andys]

I changed my speedo readout using vcds to meet the closest setting but you are spot on Andy, I am doing 70 but it shows as 75 on the speedo so I would be getting better then it shows. I do however only get 310 miles to a tank.

Ouch! Even with correction that's horrible. I get 500+ per tankful on my Cross Climates and have been planning on moving to ATs, but that's not good news.

 

[Dan T]

I changed my speedo readout using vcds to meet the closest setting but you are spot on Andy, I am doing 70 but it shows as 75 on the speedo so I would be getting better then it shows. I do however only get 310 miles to a tank.

I'm getting 380 max per tank on the all terrain tyres . was more like 450 + on standard. 310 per tank omg thats thirsty !