Does bigger tyres = more fuel used

[love ke70]

what sort of driving is that?
ive just put 31's on mine to see how they go and at 110 she feels like she is working hard. :( dont think its gonna be good for fuel economy, but around the streets it seems better.
hrmm...

[offroader-rama]

you cant put 35's on a standed gq so to fit 35's you have to lift it. the more you lift the worse the aerodynamics the fatter the tyre the more firction i have 35's with 4.11's and i dont use 5th unless I'm doing 110 plus otherwise it loads the car to much and struggles as for my econamy i get 350ks to a tank with / without trailer, on / off high way, but 4wdring i use much more same with either lpg / petrol

[offroader-rama]

PS thats 25ltr-100ks

[Rogue Patrol]

It all seems rather technical......

If, once you got the car going a taller tyre didn't use any more energy to turn then why do I have to change down for hills?
Or to overtake at anything lower than 100kph?
Different diameter tyres DIRECTLY affect ur gearing.
If ur car has plenty of power it may make little difference.
For most stock engined vehicles it does.
Yes, lots of people suggest that using a taller tyre will decrease ur engine revs which will in effect improve ur fuel comsumption.

Rarely true.

I bolted on a set of 35's to my 60 with a 383 chev in it. That was great.
When fitted 33's to a 2.4D 4runner...... That was bad.
Used plenty of fuel coz the pedal was always to the floor.
Gearing was way to high and the engine couldn't cope.

I won't put 35's on the GQ until I do the diff gears (next month) but with 33's fitted it does about 600k to a std tank of diesel.

Yes, aggresive tyres use more energy than highways.
More so from the added drag on the road than any aerodynamic effect.
Hence the extra noise.

[bogged]

YES a had 33s on my gq deisle and was getting 550 to a tank now with 35 get 420

I think your truck has issues.

[love ke70]

you cant put 35's on a standed gq so to fit 35's you have to lift it. the more you lift the worse the aerodynamics the fatter the tyre the more firction i have 35's with 4.11's and i dont use 5th unless I'm doing 110 plus otherwise it loads the car to much and struggles as for my econamy i get 350ks to a tank with / without trailer, on / off high way, but 4wdring i use much more same with either lpg / petrol

but if you put 31's on, what would you get?
you said your getting 25L/100km with the 35's with standard 31's would you get much better than 20?
not being offensive, ive only ever had my diesel, and by the sounds of it im glad

[offroader-rama]

I have 7 inch of lift rolly polly springs and only had 35's on it it has the aerodynamics of a parrachute and you can feel the drag anything over 100ks you have to keep your foot flat most of the time to keep it motivated at 100ks but once you get to 120ks it picks up as the revs come up and powers to about 150ks then not much else but I have being in plenty GQ's with 31-32 and they get heaps better economy will do 180ks no problem.
throwing the bigger tyre more momentem theroy out the window bigger tyre more drag
having a more torquier engine will make a world of difference hence the 383 coming as it'll have 200hp+ at 2000rpm a tb42 dosent do that at 7000rpm
so at 2000rpm the peddle will be just featherd where it is flat now