I bought a 2004 Civic Hybrid about a year and a half ago, and have been VERY
happy with it. At this point, my average mileage, according to the panel
display is 42 mpg. I use it mostly in town and avoid freeways whenever
possible. Highway mileage is a bit better if I keep my speed at 65, but
drops pretty precipitately at speeds over 70.
I'm just wondering how this compares with the experience of other Civic
not true, certainly not anywhere near true enough to be used as a
blanket statement. In many cases, its as much straight time as cycles,
and in other battery types, its mainly dependant on the type of cycle.
I just upped my tire pressure all around from 28 psi to 40psi, and saw an
IMMEDIATE improvement of 5.5 mpg in town driving--from 42 to 46.5 mpg. I
expect to see an even greater improvement at 60 mpg. Max pressure for OEM
tires is 55 psi.
Low air pressure could account for your poor gas mileage.
Have you checked around to see if such a high pressure (to
me) is safe?
Maybe it is, but I'd at least google.
Off the top of my head, I would expect the tires to heat up
while driving, and so raise the pressure, perhaps
dangerously close to the design limit.
As I said in my previous post, the maximum air pressure shown on the tire is
55 psi. I'd feel completely safe going to 45 psi. So far, I can't feel any
bad effects in the ride--just a tad stiffer. I'd say it actually rides very
Incidentally, running the tires on my Grand Caravan at 38psi makes for a
better ride than the recommended 30.
What does it say on the sticker inside the driver's door jamb?
On my '93 Accord, the recommended pressure specified by Honda on the
sticker is 29psi, and my current all season tires specify a maximum
pressure of 44psi. I usually put 30-32psi in them. But one time I tried
it at about 35psi, and it felt too jittery for my liking. I didn't keep
it like that long enough to see how it affected my gas mileage.
yeah, it kind of amazes me that there are so many "but it says 45 on the
tire" people out there. do they also drive 120 because that's what is
says on their speedo? logic dictates they should.
fact is, honda, who know far more about the dynamics of their vehicles
than i suspect do /any/ of us. not following their advice is going to
have negative results. and /i/ can attest to that from recent
experience. i have an 89 civic dx hatch, and have a set of si tires on
it. what i didn't know, not /owning/ an si or the owners manual, is
that the si tire pressures are lower than the dx's skinnier tires. so,
having now applied the correct pressures i am pleased to report that i
can happily drive a certain freeway on-ramp much faster than before
because i'm not skipping and bumping as much on it's rutted broken
hairpin surface! truly, correct pressures are a good thing.
This has been quite an issue in the Toyota Prius group in Yahoo. The tires
(at least on the first generation) are max inflation of 50 psi but Toyota
recommends pressures of 33 psi front and rear. At those pressures the tires
show serious underinflation wear. The gurus have pretty much settled on 42
front, 40 rear. The tires still show signs of underinflation wear, but it
isn't as bad.
Dunno about the Civic hybrid, but the Prius is an unusually heavy car for
the tire size, which means it has to have XL (IIRC) load range tires. Those
load ratings are only valid at maximum inflation; there is some arcane
derating system as the tire pressures decrease.
The Prius uses every trick in the book to increase fuel economy ratings,
including many which have nothing to do with hybrid technology. Few
people realize that narrow, tall tires give better fuel economy than
wide, squat tires. The effect isn't huge, but it is there.
Tire technology has developed amazingly in recent years. The rolling
resistance of today's tires is way less than it was. I don't know, but I
suspect Honda has done enough homework to have tires with low rolling
resistance as OEM on its cars. I think it's more than the larger contact
patch that affects mileage when tires are under-inflated--a low tire has
MUCH more rolling resistance than a correctly or reasonably over inflated
At 40-45 psi, the LAST thing I'd worry about is heat buildup: most of the
heat buildup arises from internal resistance in the tire. IIRC, that's
called hysteresis loss
Oddly, the OEM Low Rolling Resistance tires operated at the recommended
pressure give almost 5% poorer fuel economy than more standard tires at
proper inflation. The most popular aftermarket tires for the current
generation Prius are the Michelin Hydroedge, with maximum rated inflation (I
forget the numbers) in the front and 2 psi less in the rear.
The "bleeding edge" in fuel economy is a marketing issue, not a design
issue. The Prius was originally designed to be a 21st century car from the
ground up, and the revolutionary passenger capsule and suspension designs
were the first considerations. The original design outline (in November
1993) only called for 50% better fuel economy than the equivalent Corolla
and there was no thought to use a hybrid power train. It was only when the
fuel economy spec was increased another 50% a year later that the team
turned to what was then very experimental hybrid technology. See
http://www.vfaq.net/docs/Prius_that_shook_world.pdf (note: more than 1 MB
You don't make any sense here.
The proper inflation for ANY tire is what's recommended by the
manufacturer. There is no different inflation value for a replacement
tire than there is for the tires that came on the car.
You must be thinking that the "max inflation pressure" listed on the
side of the tire is some kind of "proper" inflation amount. It's not.
No - the proper inflation is both application dependent and tire dependent.
The load rating on the tire is only applicable at the maximum rated
pressure, regardless of the vehicle. Car manufacturers state an inflation
with the OEM tires that produces the ride they want with adequate inflation
for safety with the tires they provide, but the tire manufacturers are not
bound to the car manufacturer's recommendations when they offer a tire for
that car. The good news is that people usually want wider tires, which
increase the margin of safety between the car manufacturer's recommendations
and the minimum inflation.
My partner worked at a Discount Tire when he was young and absolutely rails
about the folly of putting tire pressures in the owner's manual. Tire
retailers have charts that tell them the proper pressure for the tire in a
given operating load range, and he got no end of grief from people who said
that didn't match the owner's manual... as though the manual had any
foreknowledge of the tires that were to be used.
The real test of inflation (as long as it is at least the required inflation
for the load and no more than the max inflation) is tread wear. I don't
bother with the tape test for inflation wear because I'm lazy that way - I
choose an inflation and wait until they wear out, then look at the wear
pattern. I've never seen a tire show overinflation wear.
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