ae82 tire size and rpm

[convert]

Hi

I have a 1986 corolla ae82 - 4ac motor with 14" standard wheels and 185/60/14 tires. 95% of my driving is country roads at 100 kph and engine revs at about 3100rpm.

If I put on 185/75/14 tires I calculate revs would be about 2850 rpm at 100 kph. Is there an "ideal" rpm for efficiency?

I'm intereseted in anyones thoughts on any advantages or disadvantages of this, and if it would improve mileage. Realise it would put the speedo out, but it doesn't work anyway.

Any thoughts appreciated.

Convert.

[Vios-GT_07]

*meh* i went from 205/40R17 to 185/60R14 to 205/45R16.. and there's no change in fuel consumption.. revs are more or less the same when cruising too..

it's a bit loud and a bit high, but at 3000 rpms there's very minimal throttle anyway and a lot of response when over-taking..

[Dale]

lol. speedo doesn't work anyway and you have no intention to fix that?

rpm won't directly impact economy anyway, the amount of fuel you use is based on load and how much throttle is being applied

It's possible at lower rpm you'll use more fuel

Not to mention with 75 series rubber the handling will be (even more so) shit house

[TC1600]

My AE82, on the trip to Dubbo at easter got under 8.5l/100km, with 185/60R14's, and that was not being gentle. I thought that was pretty good mileage, and increasing tyre size would be unlikely to improve it much. A taller tyre will have a higher rolling resistance, and at highway speeds I would expect wind resistance to be more of a factor than a couple hundred revs.

Save your money, and get a higher quality tyre in the same size, which can actually help fuel economy.