Civic VX - which tires is better to use for MPG - Page 3

IndyFetch · 10-16-2009, 07:09 AM

I have Michelin Harmony tires size 175/70R13. They are quiet, smooth, have excellent grip in rain, snow, and dry conditions (outstanding performance in the snow due to open tread blocks on the outside of the tires, one of my prerequisites to buying a tire). After being on the car for nearly 20,000 miles, they show almost ZERO wear.

IndyFetch · 10-16-2009, 08:53 AM

My bad... they're Michelin Destiny tires, not Michelin Harmony.

I paid $225 or so for them at Discount Tire. I have seen mileage soar into the high 50s to mid 60s with sensible driving with these tires.

theholycow · 10-16-2009, 03:58 PM

Quote:

Originally Posted by CA ExhaustCoatings

http://www.physicsforums.com/archive.../t-330790.html

so it seams we were both half right.

my conclusion is two tires of the same OD and two different widths will basically have the same contact patch. As I had stated earlier, a larger OD will increase the contact patch. So to have the smallest contact patch a tire would have to be wide with a small OD. But according to the white paper posted and as most know aerodynamics reduces mpg the most at 50 mph and over, whereas wide would be bad.
It seams a balancing act is needed for the use of the vehicle and weather conditions one expects to see for the best mpg size tire to use.
Using a larger dia wheel so that the tire side wall is smaller will help reduce tread movement thereby increasing mpg.

Ah! I must have missed the part about diameter; I had assumed we were talking about the same diameter, where we only change the width.

I totally agree that a balance is the best idea.

As for low-profile tires...Common knowledge has been that upsizing (same OD, larger wheel, smaller sidewall) results in increased RR (and decreased MPG), but I'm not sure that I've seen any data. I think I also haven't seen any logic to explain it in either direction, so I can't really say if one way or the other is better.

GasSavers_Bobert · 10-16-2009, 05:07 PM

Larger wheels almost always reduce mpg even if the total OD of the tires is the same as the old wheel/tire combo. Often it's the city mileage that takes the worst hit because it requires more effort for the engine to get larger wheels moving compared to smaller wheels. There might be some exceptions though where the larger wheels are significantly lighter (eg. made of magnesium) than the older smaller wheels made from a heavier material.

CA ExhaustCoatings · 10-20-2009, 06:03 AM

Quote:

Originally Posted by Bobert

Larger wheels almost always reduce mpg even if the total OD of the tires is the same as the old wheel/tire combo. Often it's the city mileage that takes the worst hit because it requires more effort for the engine to get larger wheels moving compared to smaller wheels. There might be some exceptions though where the larger wheels are significantly lighter (eg. made of magnesium) than the older smaller wheels made from a heavier material.

not true. look at the white paper I posted. Any thing that can reduce tread movement helps mpg. a shorter stiffer sidewall works. Too big and wide of a wheel whereas the unsprung weight goes up too much, then I would agree.
I biggest pet peeve is these hwy depts that groove the hwys, this increases tread movement lowers mpg but increases the states fuel tax revenue as a result.

theholycow · 10-20-2009, 02:33 PM

Which highway department grooves a highway? The only grooving I've ever seen was during construction and was temporary (as well as dangerous for motorcycles).

hondaguy72 · 10-20-2009, 02:45 PM

Quote:

Originally Posted by Fetch

My bad... they're Michelin Destiny tires, not Michelin Harmony.

I paid $225 or so for them at Discount Tire. I have seen mileage soar into the high 50s to mid 60s with sensible driving with these tires.

Hoping these will do the same for me. I was lucky enough to get the $70 rebate, so $225 was the net total mounted and balanced. They do look like an awesome tire, especially for the $$$.

CA ExhaustCoatings · 10-21-2009, 06:29 AM

Quote:

Originally Posted by theholycow

Which highway department grooves a highway? The only grooving I've ever seen was during construction and was temporary (as well as dangerous for motorcycles).

should have been more clear, the rain grooves some hwys have esp calf., u can feel the vehicle moving side to side. I guess some clown thinks because tires have tread grooves that the hwy should also, IMO it just holds the rain on the hwy.