Increasing fuel economy with bigger tyres

[Sutton]

Anyone ever up'ed their trucks with larger wheels/tyres?

 

My Cabstar is on 205s and I can comfortably go with bigger diameter tyres for not much more than the normal cost of a new set even allowing for suspension movement and mudguard clearance etc

 

Just an idea given that bigger wheels means increasing mpg

[Tree Man Tom]

Bigger wheels on my landy decreased MPG, but they were mud terrains.

[Samuel]

i would of thought that it would decrease mpg because they would be heavier than normal tires

[Graham]

Bigger diameter means longer rolling radius = higher gearing. In theory it should increase mpg as long as engine can cope easily with the higher gearing and you don't have to run it in a lower gear all the time.

[armchairarborist]

taller tyres would give better mpg unless they are wider aswell, mines worse on fuel now with muds, wider and taller with lugs churning the air, i havn't got stuck since i changed over though:thumbup:

[dent]

205 by what

stick with 205 but find tyres where the second number is bigger

 

for anyone thats confused on tyre sizes heres an explantion i stole

 

235 70 R16 109 H

 

235 mm across the tread

 

70% of 235 is the wall height

 

R16 is the wheel diameter in inches

 

109 is the weight restriction

 

H is the top rated speed

[b101uk]

205 by what

stick with 205 but find tyres where the second number is bigger

 

for anyone thats confused on tyre sizes heres an explantion i stole

 

235 70 R16 109 H

 

235 mm across the tread

 

70% of 235 is the wall height

 

R16 is the wheel diameter in inches

 

109 is the weight restriction

 

H is the top rated speed

 

235 70 R16 109 H

 

235 mm across the tread

 

70% of 235 is the wall height

 

R = radial type ply construction ("B" = bias ply i.e. cross-ply or it can be missing which also denotes bias ply as in "235 70 B16 109 H" or "235 70 16 109 H")

 

16 is the wheel diameter in inches

 

109 is the weight restriction

 

H is the top rated speed

[treefeller]

bigger/larger tyres will make your speedo reading incorrect!normally on a landrover this is about 10% slower ....so watch the speed cameras!

[gensetsteve]

bigger/larger tyres will make your speedo reading incorrect!normally on a landrover this is about 10% slower ....so watch the speed cameras!

 

And factor in the speedo inaccuracy when calculating your new mpg

[Danny Boy]

smaller diameter tyres give quicker acceleration & a lower top speed.

bigger diameter tyres give slower acceleration & a higher top speed.

 

assuming you get the same type tyres (say road tyres) as the ones you have now, you may end up pushing the engine harder to get the same rate of acceleration you're used to which will reduce your mpg.

 

also if your new tyres are wider it means you'll have a larger surface area in contact with the road which means better grip but also more fiction, hence less mpg.