Tall tire test (taller gearing advantage offset by wider, heavier wheels/tires?)

[mcrews]

I usually say you need to be at 5% or better to honestly see a decent improvement so you are close.
The weight will make only the smallest improvement BUT it will provide 4 times X less moving weight. SO you are headed in the right direction. Again nothing really measurea ble but a known improvement.
Since it is not a 'sports car' I personally dont think you will notice any difference in handling.
On my KIA Sportage I actually like the feel of the 70s but they were a 7% jump in diameter and feel safer.
YOu might consider going w/ poly sway bar bushing to tighter up the handleing.

[campisi]

Thanks - I may opt to pick up a 1mm thicker sway bar to compensate a little but it's really not a big deal to me. $94 for the bar so it's not too too exoensive.

[aardvarcus]

Well, I am going to be another guinea pig of the theory. I just ordered Michelin Energy Saver A/S 205/65 R16 tires to replace my Fusion 205/50R16 tires on my Toyota Celica. That is going from a height of 24.1” to 26.5”, and a slight reduction in width 8.6” to 8.2”. Another motivation for this particular size was how cheap this size of tire is compared to the other sizes, as I probably would have used 205/60/16’s (25.7) except for the cost difference. From my measurements they should fit without rubbing at full lock, just need to trim the plastic wheel well liner a bit. Not at full lock, there is plenty of room. This will change my 2900 RPM at 65MPH to 2610 RPM. I am sure there will also be a significant difference due to the change in rolling resistance.

[mcrews]

changing the world......4 tires at at time!!!

suggestion.
initially run the same psi as you currently run to get a fair test.
also, if you have created a test run on a freeway, do that with the old tires.

[justme1969]

Biggest change for my car was the tires. I kept the stockers on rear so it caused front height issues too. I just swapped the design of the air dam into a spoiler and immediatly noticed my coast down improved alot. Please remember that higher tire also = higher overall car roof line. My stock shorties on the back ever so slightly raked the windshied perhaps off setting this factor. My work was all done for hiway travel and it would not be much fun operating it in town traffic with such tall final drive. It would stall alot or burn up a clutch fast.
For townie use rotate the tires easy peeasy.

[litesong]

An old thread, but I'll belatedly add my experience. My 2008 front drive Hyundai Accent rpms were a too high 3000 at 60MPH. Using used tires, changed our standard 175x65x14 wheels/tires to 195x65x15 inch wheels/tires on the front, & 195x60x15 on the back. The tires now fill the wheel wells, gaining the Accent its first compliments ever. The Accent ride handles bumps better with the larger diameter tires, & handling & cornering is surer (try NOT to take advantage by stressing the suspension more than in the past). With the reduced rpms, the MPG ALSO went up. This past spring, summer, & fall, 18 tanks in a row were 40+MPG, with highs of 45, 47+ & 48+. Expect the 140,000 mile Accent will nicely go another 100,000 miles(more?).

[SentraSE-R]

It's been ages since I visited/posted Ecomodder and this thread. For those of you who started reading this thread, and got bored or lost interest, or those of you wondering what the fuss is about, the meat of the testing is on page 6, post #56. That's where the benefits of tall tires really came on display for my short-geared Scion xB. Toyota really handicapped it with gearing that buzzed something like 3000 rpm to go 55 mph in top gear (manual transmission).

I gave that car to my daughter, and now drive a Prius Two Eco, averaging >62 mpg over 29k miles. I averaged >49 mpg in the boxy Scion xB over 65k miles (hypermiling, ~100k total miles), and it was still on the original clutch, starter, and brake pads/shoes.

[MetroMPG]

Thanks for the updates, guys.