Economy, a different POV?

[moorey]

I had been thinking that I was losing about 10-15% economy while running 35's on the highway, reading the RACV rag last night it reminded me that my Odomoter will be misreading, as the 35 tyres have a much greater rolling circumference...at least 10-15% more (so travelling much further than i thought, or the odo was saying), I'd reckon than the stock 235/58's that are low on tread (more like 31.5's)
Do you guys consider that when calculating?

[Ace]

I had been thinking that I was losing about 10-15% economy while running 35's on the highway, reading the RACV rag last night it reminded me that my Odomoter will be misreading, as the 35 tyres have a much greater rolling circumference...at least 10-15% more (so travelling much further than i thought, or the odo was saying), I'd reckon than the stock 235/58's that are low on tread (more like 31.5's)
Do you guys consider that when calculating?

I do consider it when i have mine on but its diffucult to work it out withouth getting right into it. The best you could do is drive between two fixed points with your normal tyres on measure the distance recorded on your odometer then put the larger tyres on and record the distance recorded on the odometer between the same two points then you can work out how many kilometres per 100 it is reading over or under and use that to work out the real figures to see if it is any more economical to use the smaller tyres. Matt

[moorey]

I think you is right moite...
Funny thing, these fenders. With the same tyres, I get virtually identical economy around town, in the bush and on the highway. Being so 'non-aerodynamic', highway cruising doesn't seem to help, as opposed to idling around the bush...