Is your car a manual or automatic? 41 in an automatic sounds a bit optimistic!

 

Are you talking US gallons or UK gallons.
I you are talking about US gallon then 35mpg is a no go as a US gallon is smaller than a UK gallon in the UK we can do 35 mpg around the town and 40 + at 56 mph ( Around 44 mpg ) on motorways.

 

My 2008 mtx seems to be geared more for 1/4 mile racing than fuel economy. It's begging for taller tires.

 

Hi SHOZ...Yeah, has anyone put taller tires on to see if the MPG can go up because the rpms are dropped down? A good tall tire is needed & will the wheel wells clear a tall tire? The tall tires only needs to be on thefront wheels, but the Accent could look a bit weird.

 

My 2 cents...

I have a '00 Accent GS 1.5 Hatchback AT, and when I first bought it, it got around 23 MPG (US) highway.

I drive a long way to and from work, so naturally I wanted to fix it.

I installed a new:
--fuel filter
--NGK plugs (.44)
--plug wires
--SRI (Cone filter routed behind battery)
--Oil change
--SeaFoam (a touch in crankcase after oil change, 1/3 can sucked into throttle body vacuum hose, and the rest in gas tank)
--185 tires (1/4" taller and wider than stock - tires are 6lbs below max in front, 8lbs below max in back)

I noticed a good improvement in MPG, but it still wasn't what I thought it should get. So I posted a little and found out that Ethanol *can* reduce MPG by up to 20%, which is the only gas I had put in there!

So, now I'm only going to fill up w/ gas that doesn't have ethanol, and check the MPG again, I might change the PCV and breather if it's still low.

[PS: After doing all that stuff, the car runs awesome! Shifts smooth, has power and everything!]

 

I bumped ny front tires up to 50 lbs, 40 lbs in the rear. This has my mileage up to 36 mpg. But the engine revs too high at highway speeds. 3k rpms at 60 mph. I plan on getting tires and wheels that will be over 1.5" taller. 205/50/16s. This will throw the speedo and odo off by ~5% slow. I wonder if the dealer would reflash the PCM to reflect the different tire size?

The engine only has 1400 miles so I'm assuming it will get a bit better whien more fully broke in. Also I wonder if a 5w20 synthetic wsill yield any better milage over the factory fill of 5w20 whatever it is.

 

50-psiis dangerous and unsafe. Doing that creates a smaller tire patch touching the road. While that does help with fuel economy, it hurts braking and handling. Also, most automotive tires are not rated to handle that pressure. Plus, you will wear out the tire more quickly. So you will be saving money on gas but spending it later to buy new tires sooner. A small increase in tire pressure isn't a problem but a 20-psi increase is not a good idea.

FACTS (Popular Mechanics):
http://www.popularmechanics.com/blogs/automotive_news/4199963.html

While that will help highway mileage, youmay actually be using MORE fuelbecause you are making the engine work harder to accelerate the car. The taller the tire, the more leverage is needed to get the wheel moving.

 

50 psi is not dangerous. The max inflation pressure is based on the load rating. If the load increases tire manufactures will recommend increasing the tire pressure. The tires are rated at 45 psi for 1460 lbs.

Yes it will increase the wear. In the front they will wear on the sides more and in the back they will wear in the middle more. Judicious rotation should get them wore out all at the same time.

I plan on going to a 16" aluminum and larger tire for summer and use the 14" steel rims for winter. Don't really car if the OEM tires wear out.


I doubt if I'll be making the engine work harder. I skip gears the way it is. No need for a stump pulling 1st gear and all the rest of the gears are way to close. Needs a taller 5th too. My Festiva had a 5 speed but it was really a 3 speed with the top two gears both overdrives.

 

50-psi is very dangerous. I'm sure that is over the max inflation pressure for the tire. You could easily cause a blow-out at that pressure not to mention creating a smaller contact patch with the road. Saving fuel is not a good reason to drive in a dangerous manner.


WOW! You really have no clue to what you are talking about. Over-inflating a tire will cause it to wear out in the center more, not the sides.


Yes, you are making the engine work harder. It's like starting out in 2nd or 3rd gear instead of first. Also, overdrive gear ARE gears. Just because they are overdrive doesn't mean the trans is just a 3 speed.

Please stop giving out incorrect information and bad advice.

 

Yes I do know what I'm talking about. I'm quite experienced with tires, wear and traction. On my race tires for one of my other cars when new will be inflated ~10 lbs over the rated max pressure and as they wear you reduce the pressure. This provides maximum traction. Traction with the tires I have are not a problem at all. Wear is not a problem

If you go to the tire rack and look through their tech articles you will see that for high speed driving the tire manufacturesrs will reconmmend increacing pressure beyond the max rating on the tire.