First Prius highway trip, horrible MPG

Discussion in 'Fuel Economy' started by swineone, May 16, 2015.

  1. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    I concur regarding raised tire pressures. I've done the last tank with pressures ALMOST per Toyota spec.: dropped from around 38 to 34 psi. We have the low profile optional tire size, 215/45R17. They're harder ride at any pressure. Tanks have been coming in at 4.6~4.7 (liters per 100 km, calculated). The drop in tire pressure: I went from 4.6 to 4.7, which could be vagaries of the driving conditions, as much as anything.

    I'm concerned too: the tires, in absorbing some shocks, are lessening the stress on the car's suspension.
  2. ALS

    ALS Super Moderator Staff Member

    Something I thought about this morning that hasn't been brought up yet. Check your brake calipers and see if any of them are sticking. At a little over 40K I had to replace the rear pads on my car due to one side sticking. A quick guess was the problem was costing me around five mpg. It seems to be a regular on going issue with the Prius.
  3. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    A quick way to check for brake drag is by just feeling all the wheels after an extended drive. Now, we don't have wheel covers, so maybe that facilitates this method; the wheel covers on 15" might insulate a bit, not sure.

    With the rears, you can chock the front, jack up the whole back, release the parking brake and see how free spinning they are. A very slight amount of drag is normal: the parking brake is self adjusting, tends to stay right on the cusp of grabbing.

    The rears are trouble prone: the inner rear pads have a pin on the back, that's supposed to be locked in between the raised spokes on the face of the caliper piston's face. If not installed in the correct orientation, AND carefully seated (by repeated brake pedal depressions, to pressure up the system): the piston may rotate when the parking brake is applied, the pin rides up on the piston's spoke, the pad skews instead of sitting flat, drags like heck. It just gets better and better, lol.

    Another issue is caliper pins, front and back: they should be pulled out at the more in-depth brake inspection intervals: relubed with the proper stuff. Toyota specs "lithium soap base glycol grease", which I believe the parts department can sell you. Sil-Glyde is one more universally alternative, what I've used.
  4. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    Mendel , the wheel covers on my 15" wheels only cover a portion of the (painted) alloy wheel. You can touch part of the wheel.
  5. phoebeisis

    phoebeisis Well-Known Member

    Once you are at recommened pressure-or perhaps 2-3 psi over-there isn't much gain in FE
    We run the Prius about 37-42 psi(I think 35 or 36 is recommended)
    The Suburban runs about 42 PSI-chevy calls for a peculiar 32 ft 41 rear??

    Our 2006 Prius tolerates 42 psi -ride wise-but it has the stock 185/65 15 fairly tall sidewall tires

    Main thing on tires-is never run less than recommended-so pump them to 4-5 psi over-and they will be at recommended or above for a month or so

    Dropping to 25 psi-which is very common since most folks NEVER check pressure-and gas stations don't have air at the gas pumps- and they charge for the air-and you have to move and park again to get air

    Yeah putting the air hose-with a gauge-at the pumps-
    would probably improve USA car FE by a couple of percent
    Oh-and air HAS to be FREE of course!!
    I have several bicycle pumps-and an old sears heavy tank compressor-you know the kinda noisy ones with the belt and shroud.
  6. ALS

    ALS Super Moderator Staff Member

    Harbor Freight is your friend 12V high volume air pump for less than $25. No need for seventy five cents to use a public air pump which is limited to five minutes. Mine paid for itself within a year with two cars.
  7. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    Chevron has good old fashioned free air, at least in Canada. Guess where I fill up. :)
  8. 08EscapeHybrid

    08EscapeHybrid Moderator

    There's a couple stations I know about with free air. Its a rare, dying breed though...

    Many times the coin operated air pumps have a button hidden on the side that activates it for free, so patrons of the station can get air for free. If you looked closely at the air pumps at stations in your area you might find one or two of these.
  9. phoebeisis

    phoebeisis Well-Known Member

    I don't know of any "free air" stations in the
    NOLA area.
    When I had a chronic leak-on the Prius-losing 15 psi every 3 days
    I got a heck of a workout with my bicycle floor pump.
    Pretty sure it took about 7 -8 strokes per PSI-the suburban with just 235/75 15 takes about 15 per psi in the usual range(imagine the bigger tires on current ones)

    (this was before I set the old compressor up for easy use-we have 3.5 cats who spend a lot of time in the room where the compressor is-so I have to be careful with the hose thru the door(they will escape)-and carefully cover it cat hair and cat "other stuff"

    Anyway-free convenient air with a gauge would probably add 1-2 % to the car fleet FE- easily paying for itself
    Heck the green folks should push that-maybe give gas stations some sort of tax break to encourage it-
    drop CO2 production
    drop oil consumption
    drop $$ to various states who export oil-all of which-except you canucks- are enemies
    extend tire life-making then safer too(everyone here must remember the low tire pressure EXPLODER(Explorer/Firestone) problem-sunk Firestone-
    Ford called for 26 psi(or so) recommended pressure in the 4500 lb explorer to improve ride quality-

    08 free secret button?? I do remember one shell station gave you a code when you actually bought gas

    I had a cheapo 12v harbor freight type pump-worked ok-but it croaked after a few years-
    but for $20 can't complain much-it was kinda slow-
    almost as slow as bike pumping-lot easier of course-
  10. ALS

    ALS Super Moderator Staff Member

    Hi Charlie,

    This is the unit I have and it is $30. It will take a 185/65/15 tire from 32 - 44 psi in around three to four minutes. :). 12v-100-psi-high-volume-air-compressor

    I had one of their older cheaper units and it was slow as molasses at filling an automobile tire.

  11. 08EscapeHybrid

    08EscapeHybrid Moderator

    The stations I've seen with the "free button" were mostly equipped with this type of unit. There is sometimes a small button on the left side of the coin box, push it and get free air.

  12. phoebeisis

    phoebeisis Well-Known Member

    08 Escape

    Should have figured the "frugal folks" on this forum would have the free air deal scoped out.
    I am cheap-but I gave up on even looking for free gas station air 15 years ago

    Amazing how things changed from when I was a kid-50's-60's
    Back then the station attendant asked"fill it up-check water/radiator oil tires do windshield"

    And my dad would say "yes"

    Vehicles used PLENTY of oil back then-1 qt per 500-750 miles would have been average I guess.

    Al-thanks for the tip-I will get one-see if they have them at my local HF- just one mile away
    Been meaning to get a 1.5 aluminum "racing jack" I have a $59.95 coupon-
    I have to use a jack to change the prius oil-waaaay to stout to get under there-despite being small 170 5 5" by USA standards-
    I can wiggle under the suburban OK-but it is impossible to get under the prius

    Huge aside-just saw the end of Dirty Harry-love that speech" …most powerful handgun in the world… well do you punk" hah,hah I should grow up but…

    Huger aside-noticed S&W makes a 25 ounce 44 mag-scandium/aluminum alloy frame-titanium cylinder $870 on sale
    Yeah kinda pointless handgun-horrendous recoil- but I still like the idea-still like revolvers

    Speaking of revlovers-Starsky just shot the gangsters- with his python-on magnum force

    Thanks for the tip-I'll get one for the prius
  13. ALS

    ALS Super Moderator Staff Member

    Hi Charlie,

    My buddy has a 3 inch model 29 in 44 magnum. Accurate, but a real handful to shoot if you know what I mean. I call it the laughing gun because all you can do is laugh yourself silly when your shooting it. :D

  14. RedylC94

    RedylC94 Well-Known Member

    Or you can do about the same with a decent muscle-powered pump, without abusing your battery or wasting time and gasoline traveling to a "free" station pump.
  15. EdwinTheMagnificent

    EdwinTheMagnificent Legend In His Mind

    I went a different route and bought a small 110 VAC compressor at Lowe's , for about $150. I use it for cars and bicycles. My hand pump was failing and my patience was low.
  16. phoebeisis

    phoebeisis Well-Known Member

    I have 2 muscle powered floor pumps
    For the bicycles-but I used them quite a bit on the cars
    as I mentioned 7-8 pumps per psi on the prius tires in the 25-45 psi range

    Al- 3" hmmm the muzzle blast on short barreled revolvers-gets your attention-
    I see S&W and Ruger pushing 2.75 and 3" 44's as "bear protection"
    Yeah like bears kill many people-probably several 1000's time more likely to get killed by a 2 legged predator
  17. 08EscapeHybrid

    08EscapeHybrid Moderator

  18. fuzzy

    fuzzy Mild hypermiler

    My usual muscle-powered bicycle floor pump will do it in slightly less than half the time of that 12V unit.
  19. Mendel Leisk

    Mendel Leisk 2010 Prius (CAN Touring) Staff Member

    I use a hand pump on our car tires on occasion. I've even used it to bring a tire up to pressure all the way, after a plug repair. But, I'm not a complete luddite, would be interested in a half-decent 110 volt compressor, with hose and tire valve interface.

    I've looked up compressors, but the descriptions seem to focus on everything BUT tire inflation. Any suggestions?

    Please don't mention Lowes or Harbour Freight. Canadian Tire and Princess Auto ok, though. :)
  20. phoebeisis

    phoebeisis Well-Known Member

    $42-figure maybe $20 or so for hose and SCHRADER valve "hand piece"-maybe
    a couple of other fittings
    $65 OR SO- would probbaly last forever if all it had to do was top up your tires once a month.
    Mendel-any 110 would/should last forever if it is just topping up tires-

    Any 110 would work much faster than the 12 v ones
    but you couldn't toss it in the back seat-take it on road trips
    A decent floor pump-bike pump -is maybe $30 $40

    One thing to keep in mind-
    some of you/us- probably run well over door pressure
    The 12v ones really get SLOW SLOW-over 40 psi-
    kinda doubt they could get over 50 psi

    So if any of you folks want much over 45psi-the 12 v might not be up to it-no matter what they claim

    A floor pump-bike pump-good ones-can exceed 100 psi easily enough(takes a lot of strokes of course)
    and a 110 v one will get 110-130 psi-no problem

    So if you run 50 psi-the 12 V might have some problem reaching 50 psi
    My cheapo wal mart 12 v would top out about 40 psi

    So keep in mind the 12v might not be so great over 40 psi
    and it could take maybe 5 minutes to get from 20 psi to 40 psi
    Roughly the same as the floor pump (depending on your fitness level)

    Cost for the three-
    $65 for 110+ hose hand piece-
    $30-$40 floor pump
    $30 for 12v

    Mendel- LUDDITE??-
    Never would have guessed you Canadians went in for that!!

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