MPG increasing with driving technique alone (no mods yet)... so happy!

[newhavenpatriot]

Originally Posted by Old Mechanic

Top up the tank it will make a difference.

regards
Mech

You're right... I just did another half-tank mileage check, and my mpg actually dropped. This was with cold weather, and my tires were down at 30 psi. Same driving style as before, but as I don't have a ScanGauge, I haven't been really "watching" my mpg. We'll see how the 40 psi tire pressure affects my mileage when I use another half-tank.

[Seraph]

The 10 PSI makes a big difference, lower rolling resistance, higher amounts of grip to turn at speed which also means you can carry a higher speed (plus less body roll if you turn hard), easier to accelerate to target speed. I remember when my dad 'pumped' my tires to 32 PSI when they were previously at 50. The car would vibrate and take longer to get to the speed i wanted, not to mention my glides were horribly short. When i pumped it back up, the vibration went away and my glides went back to normal.

Tire pressure makes a big difference especially if you pulse and glide.

[newhavenpatriot]

Well, I don't P&G because I have an automatic, but I'm hoping the extra 10 psi will make for noticeable gains in mileage anyway.

[dwtaylorpdx]

Just remember that if you raise the pressure too far, you'll wear the tires out faster and undo the energy savings. Its a balance of compromises...

Dave

[Seraph]

Since he's below the max sidewall he should be fine

[newhavenpatriot]

Why is the factory/manufacturer recommendation for tire pressure so low, anyway? The recommendation for my Yaris is 32 psi, front and rear. Is it because they are trying to strike a balance between ride/handling and fuel economy? One would think that since Americans usually have their tires somewhat underinflated, they should suggest a pressure closer to what's on the sidewall.

[Seraph]

Yeah i heard its for the ride quality, it seems most people want that. Can't say i agree with that though, ride quality is one of the lowest things on my mind when i drive. Tire traction, LRR and generally durable are the best qualities for picking out a tire.

[user removed]

When I replaced the original Bridgestones on my Insight with the same tires, they were inflated to 44 PSI (sidewall max).

It took almost 800 miles for the little nubs to wear off the center of the tread, longer than it took for them to wear off the edges.

Remember when you inflate a tire to higher pressures the forces on the sidewalls increase just as much as on the center of the tread.

So far I can find no reason to think the tires will wear any faster than manufacturers recommended pressures. In fact the opposite is true, lower rolling resistance means less heat generation so it should equal longer life.

When my VX went on the road in April, 08 (now sold) the tires were made in March of 1993. I rebuilt the car with 27,492 miles on the odometer (actual). The tires were dated from March of that same year.

I ran them at 39 PSI and drove the car another 15k miles with the original tires that were 15 years old when I got the car. I replaced them when the sidewalls had cracked to the point where I just didn't feel like risking having a blowout at some place where I would not be able to find the proper size to replace them.

The Michelins I put on the car (X model on special at $235 total with warranty) cost me 7 MPG compared to the 15 year old Bridgestones.

regards
Mech

[newhavenpatriot]

Woohoo! With tires increased to 40 psi, and my highway speed lowered to 55 fairly consistently, I just achieved 42.4 mpg! In an automatic!! I heart hypermiling.

[Chalupa102]

Originally Posted by newhavenpatriot

Woohoo! With tires increased to 40 psi, and my highway speed lowered to 55 fairly consistently, I just achieved 42.4 mpg! In an automatic!! I heart hypermiling.

That's awesome man . Once i dropped my highway speeds to about 55-60, i started to see nice gains as well.