roof racks =crappy gas mileage?- Mtbr.com
Results 1 to 72 of 72
  1. #1
    mtbr member
    Reputation:
    Join Date
    May 2010
    Posts
    253

    roof racks =crappy gas mileage?

    So I just put my yakima rack setup up on my camry, and noticed all of a sudden I have less then usual gas mileage. I used to get about 25-27mpg . I just filled up today after having the racks on for a week or so and I only got 23mpg? Can other people chime in if this is true. Im going to be putting a hitch rack on my xb but for now this is going to do I cant believe it effects the mileage this much.

  2. #2
    mtbr member
    Reputation:
    Join Date
    Jan 2005
    Posts
    542
    and those stupid boxes that people love make it even worse.

  3. #3
    mtbr member
    Reputation:
    Join Date
    May 2010
    Posts
    253
    box that people love? do you mean the XB or those carrier boxes.?

  4. #4
    ballbuster
    Reputation: pimpbot's Avatar
    Join Date
    Dec 2003
    Posts
    12,717
    Yep, that's about right.

    My 96 GTi, 2.slow got 31 mpg nekked (with my big 215 pound behind in the left seat and junk in the trunk). With empty roof racks, 28 mpg. With two bikes 23-24 mpg.

    With hitch rack, no mileage hit.

    Over the roof is where the air stream is compressed after the hood and windscreen direct it upwards, so the denser air creates even more drag.

    Heh.... nice thing about those boxes is they come off. Too bad folks are either too lazy to take them off when they aren't using them, or they think that burning 15% more gas is worth looking cool.
    Last edited by pimpbot; 02-10-2011 at 05:11 PM.

  5. #5
    lotto baby
    Reputation: clarkenstein's Avatar
    Join Date
    Mar 2006
    Posts
    553
    its definitely true. my corolla gets just about 30+ mpg with the roof rack on, and it would normally get 35+ (even tho the sticker said 40 mpg when i bought it, i don't think i have ever gotten 40 mpg with it).
    i spurt in the wind, and the wind drug it

  6. #6
    mtbr member
    Reputation:
    Join Date
    May 2010
    Posts
    253
    I put mine up for sale locally. I go riding every weekend for exercise so I do keep it on so I dont have to worry about scratching the car taking it on and off. Im gonna go order a trailer hitch for my XB and pick up a used hitch rack and end this wallet killer.

  7. #7
    since 4/10/2009
    Reputation: Harold's Avatar
    Join Date
    Dec 2003
    Posts
    26,569
    Yep. My Fit takes a few mpg hit with bikes on the roof. Not so much with the bare rack, though. I need the roof rack to carry a canoe around (longer than the car), but I'm working out a way to get a hitch rack to carry bikes. I'll be selling my Thule Sidearm carriers to help fund the purchase. I need a hitch rack for my Fit, also, but it'll be nice to be able to use the hitch rack on the wife's Jeep Liberty, also. I currently carry bikes inside the Fit on a DIY fork mount.

    I really want a Kuat rack, but I'd probably be happy with any solid tray-style hitch rack.

  8. #8
    mtbr member
    Reputation:
    Join Date
    Aug 2010
    Posts
    1,314
    I have a Camry too with a tray-style Thule hitch rack. Very minimal impact on mileage compared to what I've heard about roof racks. Only problem with a hitch rack is your rig taking a lot of road salt slush-n-spray driving around snowbelt states.

  9. #9
    mtbr member
    Reputation:
    Join Date
    May 2010
    Posts
    253
    yeah I have an SE camry and all the hitches I see dont fit because of the ground effects.

  10. #10
    I got the velcros
    Reputation:
    Join Date
    Sep 2010
    Posts
    252
    I think mine drops from 48 to 44ish with a bike on there....

    TDI

  11. #11
    mtbr member
    Reputation:
    Join Date
    Apr 2006
    Posts
    2,738
    Putting a fairing on the roof rack will almost eliminate any lessening of fuel economy.

    And don't rag on roof boxes... I actually get better MPG with my box on my roof. Mind you, I have an '01 Forester which has a worse coefficient of drag than a cement truck, but nonetheless the cargo box does indeed smooth the air out in some magical way.

    PS I am not one of those people who drive around with a cargo box on all the time

  12. #12
    since 4/10/2009
    Reputation: Harold's Avatar
    Join Date
    Dec 2003
    Posts
    26,569
    Quote Originally Posted by XJaredX
    Putting a fairing on the roof rack will almost eliminate any lessening of fuel economy.

    And don't rag on roof boxes... I actually get better MPG with my box on my roof. Mind you, I have an '01 Forester which has a worse coefficient of drag than a cement truck, but nonetheless the cargo box does indeed smooth the air out in some magical way.

    PS I am not one of those people who drive around with a cargo box on all the time
    There is logic to your reasoning. I calculated my fuel economy once with a 16ft canoe on my Fit driving across the Appalachians, and I AVERAGED 35mpg. With a boat bigger than my car on the roof.

    Only time I've come close to that with bikes was when I had a stiff tailwind on a straight highway.

  13. #13
    mtbr member
    Reputation:
    Join Date
    May 2010
    Posts
    253
    I have a fairing on my car, still sucked

  14. #14
    Elitest thrill junkie
    Reputation: Jayem's Avatar
    Join Date
    Jul 2005
    Posts
    31,662
    Quote Originally Posted by XJaredX
    Putting a fairing on the roof rack will almost eliminate any lessening of fuel economy.
    That's way too general of a statement to make any sense. There's still going to be a hit, depending on the car, depending on the rack, depending on the exact location of the rack, and so on. Putting the bikes up there will still cause a rather dramatic loss in milege, not to mention that a fairing may simply delay the speed at which the airflow starts to seperate excessively from the upper surface (but it may also cause that seperation, again depending on the auto).
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  15. #15
    mtbr member
    Reputation: romanl's Avatar
    Join Date
    Jul 2010
    Posts
    77
    yup, w/my GOLF TDI i see about 5-15% drop in MPG's,
    and for my GOLF TDI, going from 40-50 MPG down to 35-42 hurts quite a bit.

  16. #16
    mtbr member
    Reputation:
    Join Date
    Mar 2005
    Posts
    106
    I have an 07 Camry SE. Try playing around with the rack placement on the car. Technically you shouldn't but I haven't had any problems with it so far.

    The key is to place the fairing on the same plane as the windshield. Yakima's specs puts the front at the bend in the A pillar of the side window probably for stability. I just mounted it a few inches closer to the windshield and so far has only reduced MPG by 1MPG or almost none.

    Try at your own risk. hahaha

  17. #17
    ballbuster
    Reputation: pimpbot's Avatar
    Join Date
    Dec 2003
    Posts
    12,717

    It still....

    Quote Originally Posted by XJaredX
    Putting a fairing on the roof rack will almost eliminate any lessening of fuel economy.

    And don't rag on roof boxes... I actually get better MPG with my box on my roof. Mind you, I have an '01 Forester which has a worse coefficient of drag than a cement truck, but nonetheless the cargo box does indeed smooth the air out in some magical way.

    PS I am not one of those people who drive around with a cargo box on all the time
    .... increases frontal surface area... the biggest factor in aerodynamic drag. Heh.... they say you can gain another 3% gas mileage at freeway speed by lowering your car an inch.

    I highly doubt you get better mileage with a roof box (again, the surface area thing, not to mention wake drag), but if that is what you are seeing....

  18. #18
    mtbr member
    Reputation:
    Join Date
    Jul 2008
    Posts
    267
    On my 2000 Nissan Maxima, I would usually average 25-26 mpg in mixed suburban/highway use. When I added Thule feet and square bars, plus a Yakima King Cobra and a Yakima Raptor, my average would usually be closer to 24mpg. I didn't have a ton of mileage with bikes up top, but I think the mileage wasn't much worse. The hit was small enough for me to find it worthwhile. I previously had a trunk rack that I had bad experiences with, and wouldn't go back to one. I would use a hitch rack in the future, but for now I'm happy.

  19. #19
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    219
    It really depends on the vehicle. My '89 Honda Civic wagon RT4WD gets 27-28 with no rack, 27 with rack but no bikes, and 26 with bikes.

    My wife's '06 Jetta 2.5 gets 31 with no rack, and 25 with bikes...

  20. #20
    mtbr member
    Reputation: A1an's Avatar
    Join Date
    Jun 2007
    Posts
    1,927
    MPG on my wife's Rabbit didn't change with the addition of a roof rack with two carriers.
    Signature

  21. #21
    mtbr member
    Reputation:
    Join Date
    Feb 2011
    Posts
    27
    just a roof rack, yes I loose a mpg or two. BUT, I can put a 13.5' tandem kayak on top and stay at the same mileage. Granted kayaks are aerodynamic, but its just amazing That is on my Impreza. The Neon I had was about the same, but I rarely left the rack on it. I plan on getting a fairing before spring so I can leave the roof bars on this year, Sick of taking them on and off, Rail Grab are not as easy as the q-towers I had...

    My old blazer I could leave a bike tray on and even my mountain bike, never lost a single mpg...of course it had a bit of torque, and it was a box (1994 s10 blazer)!

  22. #22
    mtbr member
    Reputation:
    Join Date
    Jul 2009
    Posts
    353
    yeah I took the roof rack off my Liberty because it murdered my gas mileage, especially with bikes on it. going with a hitch mount.

  23. #23
    College Boy
    Reputation: Timeless's Avatar
    Join Date
    Mar 2007
    Posts
    772
    Quote Originally Posted by A1an
    MPG on my wife's Rabbit didn't change with the addition of a roof rack with two carriers.

    Based on that and how my car reacts to a roof rack (Sentra SE-R) it sounds like the once that are hurt the most by a roof rake are cars with engines that are smaller and the car is set up for gas milliage instead of a sporty side.
    I know on my Spec V with the roof rack on it I get the same MPG. Now if I put the bike up there it drops from 28-29 MPG down to about 26-25 but with out the bike up there no real effect.

    Better put my MPG is not effected until I cross about 80 mph. At 70-75 mph I get the same MPG. At about 80 or above there is a bigger drop compared to no rack.

  24. #24
    meow meow
    Reputation: b-kul's Avatar
    Join Date
    Sep 2009
    Posts
    10,622
    definitely goes down. even our pilot with our sleek thule gets like 3 less mpg.

  25. #25
    mtbr member
    Reputation: sasquatch rides a SS's Avatar
    Join Date
    Dec 2010
    Posts
    4,565

    350 + lift + big tires = crappy gas mileage

    9-10mpg on a good day...don't notice any difference with a bike though


  26. #26
    mtbr member
    Reputation:
    Join Date
    Jun 2008
    Posts
    272
    '10 VW TDI Sportwagen with Whispbar rack and 2 Rockymount Tie-rods
    All these are freeway mileages:
    Naked: 43.6 mpg
    Rack w/2 Tie Rods: 42.1 mpg
    w/2 bikes: 38.0

    Whispbars and Tie Rods are super low profile thus the minimal hit to my mileage.

  27. #27
    I Tried Them ALL... SuperModerator
    Reputation: Cayenne_Pepa's Avatar
    Join Date
    Dec 2007
    Posts
    6,450
    Amen to that....roof racks are like dragging a ship's anchor with four flat tires. I'm exaggerating a bit, but you get the idea. Go hitch or trunk mount....
    "This is a male-dominated forum... there will be lots of Testosterone sword-shaming here" ~ Kenfucius

  28. #28
    i call it a kaiser blade
    Reputation:
    Join Date
    May 2008
    Posts
    744
    FZJ80 land cruiser with lift, no roof rack=sub 10mpg.

    FZJ80 land cruiser with lift, roof rack=sub 10 mpg.

    no difference here.
    how durable a bike or component is usually has a lot to do with how heavy and ugly it is.

  29. #29
    mtbr member
    Reputation:
    Join Date
    May 2008
    Posts
    113
    Quote Originally Posted by sasquatch rides a SS
    9-10mpg on a good day...don't notice any difference with a bike though


    I gotta ask...why did you put on the lift and tires? those tires obviously kill your mpgs.....considering that is all for looks i'm just curious since gas isn't cheap.

  30. #30
    mtbr member
    Reputation: sasquatch rides a SS's Avatar
    Join Date
    Dec 2010
    Posts
    4,565
    Quote Originally Posted by wisbike
    I gotta ask...why did you put on the lift and tires? those tires obviously kill your mpgs.....considering that is all for looks i'm just curious since gas isn't cheap.
    The previous owner put the lift on, I bought the truck last February as a junior in high school. I didn't expect gas to go up like it did, but I use it for work way too much to sell it. And with it being my first vehicle of my own, I really just don't want to sell it

  31. #31
    mtbr member
    Reputation:
    Join Date
    Feb 2011
    Posts
    420
    My long armed grand cherokee gets 15mpg hwy(with the 5spd swap) naked and about 12 with the safari rack when I need it.
    At lest theres room inside for a few bikes and the hitch is always there.
    Nothing like driving a brick, even though it's drag coefficient is better than that of an 80's vette...

  32. #32
    XC racer
    Reputation:
    Join Date
    May 2005
    Posts
    281
    I'm surprised anyone here is shocked to find out that putting a sail on their roof lowers their gas mileage...
    To me, it's a tradeoff relative to its utility, and what you consider acceptable gas mileage. My MINI JCW gets close to 30mpg at highway speeds naked, 27ish with rack only, 25-26 with bikes. I don't consider that bad at all. I would never trust my expensive bikes on a trunk mount rack, and have had hitch mounts and just prefer roofracks. Whatever floats your boat.

  33. #33
    Village Dirtbag
    Reputation: @dam's Avatar
    Join Date
    Jan 2004
    Posts
    2,283
    If we measured fuel efficiency like the rest of the world (liters/100km), you'd see a rack with a couple of bike imposes the same amount of drag addition at a given speed, and therefore roughly the same amount of extra fuel burned, regardless of vehicle.

    Lets say I put a rack on my Prius and mpg drops from 50 mpg to 38.

    Then, lets say I put the same rack on my Hummer and the mpg drops from 13 to 12 mpg.

    Most people would say the Prius is more affectd by the rack than the Hummer. After all, it's mpg dropped by 32% and the Hummer only took an 8% hit. This isn't the case- they were affected identically. The Prius went from 4.7 L/100km to 6.2 L/100km- an increase in fuel consumption of 1.5 L/100km. The Hummer went from 18.1 L/100km to 19.6 L/100km- an increas in fuel comumption of 1.5 L/100km

    In other words, it takes about the same amount of gas to push the bike rack down the road regardless of what car it's on- in this example, 1.5 liters of fuel for every 100 km you drive. Obviously, your mileage will vary depending on the thermodynamic efficiency of the engine, what gear you can hold, etc., but this is generally the case. It'll take a certain amount of work to push that rack down the road, and that'll take a certain amount of fuel to do that work. If we stopped using mpg, people would really have a much better idea of the costs and savings different vehicles and different changes represent.

  34. #34
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    We have the best of both worlds -

    I have a roof rack on my BMW 530XIT wagon. Putting a hitch on the BMW's looks horrible since they have to drill a plate onto the outside of the bumper. It's just ugly. So, I have a roof rack that stays on all year - box for skis (we ski 3-4 times per week in the winter), and then change it out for two highrollers in the spring. Don't really carry bikes for a long haul on the roof - just around locally.

    Then for long road trips, 1000 miles or so, we usually use the 1UpUSA on the rear hitch for 4 bikes. No or little fuel impact (however you want to measure it).

    J.

  35. #35
    mtbr member
    Reputation:
    Join Date
    May 2008
    Posts
    113
    Besides the fact that you just made all those numbers up, if one car reduces its fuel efficiency by 32% and the other reduces it by 8%, the 32% car was effected a lot more. that is common sense.

    you don't compare the effect on fuel consumption by total mpgs lost or total increase in consumption, you compare it as a percentage of initial fuel economy. duh.



    Quote Originally Posted by @dam
    If we measured fuel efficiency like the rest of the world (liters/100km), you'd see a rack with a couple of bike imposes the same amount of drag addition at a given speed, and therefore roughly the same amount of extra fuel burned, regardless of vehicle.

    Lets say I put a rack on my Prius and mpg drops from 50 mpg to 38.

    Then, lets say I put the same rack on my Hummer and the mpg drops from 13 to 12 mpg.

    Most people would say the Prius is more affectd by the rack than the Hummer. After all, it's mpg dropped by 32% and the Hummer only took an 8% hit. This isn't the case- they were affected identically. The Prius went from 4.7 L/100km to 6.2 L/100km- an increase in fuel consumption of 1.5 L/100km. The Hummer went from 18.1 L/100km to 19.6 L/100km- an increas in fuel comumption of 1.5 L/100km

    In other words, it takes about the same amount of gas to push the bike rack down the road regardless of what car it's on- in this example, 1.5 liters of fuel for every 100 km you drive. Obviously, your mileage will vary depending on the thermodynamic efficiency of the engine, what gear you can hold, etc., but this is generally the case. It'll take a certain amount of work to push that rack down the road, and that'll take a certain amount of fuel to do that work. If we stopped using mpg, people would really have a much better idea of the costs and savings different vehicles and different changes represent.

  36. #36
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    What he's saying is that it takes so much energy to push a fixed cross section (wind resistance) through the air at a given speed. In other words, it takes so many liters of gas to move your bike down the highway a given distance irrespective of which car it's on. The MPG numbers don't tell the tale. In terms of energy expended for adding the bike it's the same regardless of which car it's on.

    J.

  37. #37
    mtbr member
    Reputation:
    Join Date
    Feb 2011
    Posts
    420
    The effect it will have is also dependent upon what the air charge is doing as it crests the windshield.
    You can't say that a bike will cause identical drag numbers on every vehicle. initial aerodynamics plays a large role in the equation, which would require a super computer to crunch the numbers on such an irregular object.

  38. #38
    Village Dirtbag
    Reputation: @dam's Avatar
    Join Date
    Jan 2004
    Posts
    2,283
    Quote Originally Posted by wisbike
    Besides the fact that you just made all those numbers up, if one car reduces its fuel efficiency by 32% and the other reduces it by 8%, the 32% car was effected a lot more. that is common sense.

    They are made up, but they're in the ballpark of what I've seen reported if you put on a big rack.


    you don't compare the effect on fuel consumption by total mpgs lost or total increase in consumption, you compare it as a percentage of initial fuel economy. duh.
    Unless what you're actually interested in is how much extra gas you'll have to buy when you put the rack on. Which is what you should be interested in. Duh.

    L/100km is just a more useful metric for figuring out fuel costs.

    A car going from 20 L/100km to 19 L/100km will save you just as much gas on a given trip as a car going from 4 L/100km to 3 L. In mpg, those same numbers would look like going from 11.8 to 12.4 mpg vs. 58 to 78 mpg. One is a .6 mpg or 5% improvement in mpg, the other is a 20 mpg or 35% improvement, yet both save the exact same amount of money and gas on any given trip.

    Another way to look at it is this: Intuitively, I think most people would think going from 30 to 45 mpg saves the same amount of gas as going from 15 to 30 mpg...15 mpg. Or, they may say you've doubeled efficiency and say going from 30 to 60 saves as much gas as going from 15 to 30. In fact, to save the same amount of fuel you saved by going from 15 to 30, you'd have to go from 30 to INFINITY miles per gallon. These realities don't reflect well in mpg. Mpg is just a misleading figure.
    Last edited by @dam; 04-20-2011 at 02:23 PM.

  39. #39
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    Quote Originally Posted by wisbike
    Besides the fact that you just made all those numbers up, if one car reduces its fuel efficiency by 32% and the other reduces it by 8%, the 32% car was effected a lot more. that is common sense.

    you don't compare the effect on fuel consumption by total mpgs lost or total increase in consumption, you compare it as a percentage of initial fuel economy. duh.
    You don't understand the math.

    You can have 8% of a large thing being equal to 32% of a smaller thing. If a small car (putting aside aerodynamics for now, which may or may not be better) were able to push a known mass with a known surface area a known distance at a given speed with less additional gas than a larger vehicle, you would essentially have negated the principle of conservation of energy.

    J.

  40. #40
    mtbr member
    Reputation:
    Join Date
    May 2008
    Posts
    113
    Quote Originally Posted by JohnJ80
    You don't understand the math.

    J.

    I understand the math and everything said. you guys just don't know how to accurately compare fuel efficiency between different vehicles. If you are not comparing by percentages of the original mpg, you're doing it wrong.

  41. #41
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    LOL

    You're kidding, right?

    If you put a bike on a car and the incremental fuel used is no different, how do you explain that as a difference in fuel efficiency due to the bike?

    J.

  42. #42
    Village Dirtbag
    Reputation: @dam's Avatar
    Join Date
    Jan 2004
    Posts
    2,283
    Quote Originally Posted by wisbike
    I understand the math and everything said. you guys just don't know how to accurately compare fuel efficiency between different vehicles. If you are not comparing by percentages of the original mpg, you're doing it wrong.
    I don't think you do. The % saved as a proportion of the original fuel economy comes out the same whether you use mpg or L/100km. The difference is that with L/100km, you see how much extra fuel you'll need to buy on a given trip, and can direclty compare across multiple very different vehicles. Using L/100km lets us calculate the affect to the car just as easily as with mpg, but it also lets us more easily compare the affect between cars, and also makes it much more apparant how much the change will affect our bottom line.

    Same goes for air-con use. A 4-cyl family sedan will see a bigger mpg hit with the AC on than the V6 version of the same car, but if you look in L/100km you'll probably find that the AC takes the same amount of extra fuel in either car.

    Lets compare upgrades from inefficient cars to efficient cars. Lets say you start out with a 15mpg truck and upgrade to a 30mpg car. Gas gets expensive and you consider upgrading again another 15 mpg to 45...or maybe even another 100% to 60 mpg. You drive 10,000 miles per year and gas is, say, $4/gal

    15 mpg = 15.7 L/100km = 666.7 gal/year = $2666.7/year
    30 mpg = 7.8 L/100km = 333.3 gal/year = $1333.3/year-

    A $1333.3/year savings. That all looks in order...double mpg, L/100km drops in half...expenses drop in half. Lets do another 15 mpg

    45 mpg = 5.3 L/100km= 222.2 gal/year = $888.8/year

    We saved...uhhh...$445 this time. Huh...this 15 mpg improvement didn't seem as beneficial as the last 15 mpg. It only saved us 1/3 as much money and gas. Of course, if you look at L/100km, it's clear why this is: you're only saving 2.5L every 100km you drive, vs. the 7.8L savings you got before. Well, lets try a 100% improvement in mpg instead of a fixed 15 mpg...

    60 mpg = 3.9 L/100km = 166.7 = $666.6/year

    Huh...a 100% improvement from 15 to 30 saved us $1333/year, but another 100% improvement only saved us half of that amount. Of course, if you look at the L/100km column, it's clear why this is, because you get a much better feel for how much fuel per year two cars will cost you: You're saving 3.9L for every 100km you drive, vs. 7.8L savings for the last 100% improvement you had

    Lets double mpg again to 120 mpg. These are some huge mpg numbers!

    120 mpg = 2L / 100km = 83.3 gal/year = $333.3/year

    Wow- even quadrupeling that 30 mpg doesn't save us as much money per year as going from 15 to 30 mpg. MPG numbers just get really inflated as returns diminish. If you look in L/100km, you can see the linear relationship. It becomes clear that going from 15 to 30 mpg will save you $5.33 every day on your 40 mile commute, but jumping to 60 mpg will only save you an additional $2.66.

    L/100km is the preferably metric because it's a linear relationship with fuel burned, and because people generally have fixed distances they need to drive, rather than a fixed number of gallons they plan to burn after which they'll just stop driving. If that was the case, knowing how many miles you could go on that many gallons might be useful. But, what most people want to know is how much fuel will they need for the driving they plan on doing, and how much a different car, a bike rack, etc. will affect how much fuel they need to buy.

    Electric cars are already transitioning to this. They have their mpge rating, but also a Kwh/100 miles rating.
    Last edited by @dam; 04-21-2011 at 08:42 AM.

  43. #43
    mtbr member
    Reputation: hado_pv's Avatar
    Join Date
    May 2006
    Posts
    696
    My young son at 12 summed this situation up perfectly. In seeing my Saab loaded with 4 roof mounted bikes for a trip to NEMBAfest he said "Dad - your car has the aerodynamics of a rose bush"
    http://facebook.com/CharlemontTrails
    NEMBA Past President...

  44. #44
    mtbr member
    Reputation:
    Join Date
    Feb 2004
    Posts
    555
    Forget about the gas mileage. The big advantage of hitch racks is ease of use. I have a buddy that owns a small Nissan SUV. He's 6' 2" tall and still needs to use a small step ladder to get his bike off the roof. It's a joke as the vehicle came from the factory with a hitch installed! LOL
    Many people just don't have a clue.

  45. #45
    mtbr member
    Reputation:
    Join Date
    Mar 2011
    Posts
    25
    This was the funniest post here, thanks for the laugh.



    Quote Originally Posted by sasquatch rides a SS
    9-10mpg on a good day...don't notice any difference with a bike though


  46. #46
    mtbr member
    Reputation: sasquatch rides a SS's Avatar
    Join Date
    Dec 2010
    Posts
    4,565
    Quote Originally Posted by Iluvmylab
    This was the funniest post here, thanks for the laugh.
    I do aim to please

  47. #47
    mtbr member
    Reputation:
    Join Date
    Aug 2010
    Posts
    1,314
    People are surprised when they see my '98 Camry with a 1.25" hitch and T2 tray rack on there when most guys driving sedans where I live use roof racks. Paid U-Haul $225 with tax for the hitch including installation and its been rock-solid. No major drop in gas mileage, no lifting the bike up on top (I'm only 5'7" and ride a 35 lb. FS AM rig so why lift it if I don't have to?), no worry about low clearance garage issues being stupid forgetful, no bikes whipping back-and-forth wildly on speed humps and rough roads.

    Only major problem I've had is easing through washouts on dirt roads slowly so there's minimal hitch drag.

  48. #48
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    Quote Originally Posted by bigbeck
    Forget about the gas mileage. The big advantage of hitch racks is ease of use. I have a buddy that owns a small Nissan SUV. He's 6' 2" tall and still needs to use a small step ladder to get his bike off the roof. It's a joke as the vehicle came from the factory with a hitch installed! LOL
    Many people just don't have a clue.
    Hitch rack is a better choice than a roof rack in almost all cases. If you have a hitch - it's a no brainer.

    I'm saying this based on the experience of driving a bike into the garage last week. Fortunately it didn't trash the frame, just the back wheel..... It was in a Yak Highroller that I give credit for releasing the bike from the front attachment point so it flipped over and only wrecked the back wheel. Had a had a fork mount, I'd be out a frame right now.

    J.

  49. #49
    mtbr member
    Reputation: Bilirubin's Avatar
    Join Date
    Mar 2010
    Posts
    415
    Thought about a hitch rack, but the bike just fits so well into the payload of my Matrix that I've never bothered with the additional expenses.

  50. #50
    mtbr member
    Reputation:
    Join Date
    Oct 2005
    Posts
    463
    Also, in the Puget Sound area, when riding ferrys, you pay for additional height. Bikes on roof racks definately put you over the limit. Lets not go over the logic of that policy. Also extra fees for length, but platform hitch racks are within standard vehicle lengths.

  51. #51
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,834
    Quote Originally Posted by XJaredX
    Putting a fairing on the roof rack will almost eliminate any lessening of fuel economy.

    And don't rag on roof boxes... I actually get better MPG with my box on my roof. Mind you, I have an '01 Forester which has a worse coefficient of drag than a cement truck, but nonetheless the cargo box does indeed smooth the air out in some magical way.

    PS I am not one of those people who drive around with a cargo box on all the time
    With just a fairing, my mileage actually drops a few mpg.

    With just a box (a big one), my mileage is unaffected as far as I can tell (and I do measure it often). It is also unchanged with the bike carrier up there. With a bike, the mileage does drop , but not as much as when I put the fairing on.

    FWIW, it is a 2003 CR-V.
    15mm is a second-best solution to a problem that was already solved.

  52. #52
    Bicyclochondriac.
    Reputation:
    Join Date
    Jan 2004
    Posts
    13,834
    Quote Originally Posted by @dam
    I don't think you do. The % saved as a proportion of the original fuel economy comes out the same whether you use mpg or L/100km. The difference is that with L/100km, you see how much extra fuel you'll need to buy on a given trip, and can direclty compare across multiple very different vehicles. Using L/100km lets us calculate the affect to the car just as easily as with mpg, but it also lets us more easily compare the affect between cars, and also makes it much more apparant how much the change will affect our bottom line.

    Same goes for air-con use. A 4-cyl family sedan will see a bigger mpg hit with the AC on than the V6 version of the same car, but if you look in L/100km you'll probably find that the AC takes the same amount of extra fuel in either car.

    Lets compare upgrades from inefficient cars to efficient cars. Lets say you start out with a 15mpg truck and upgrade to a 30mpg car. Gas gets expensive and you consider upgrading again another 15 mpg to 45...or maybe even another 100% to 60 mpg. You drive 10,000 miles per year and gas is, say, $4/gal

    15 mpg = 15.7 L/100km = 666.7 gal/year = $2666.7/year
    30 mpg = 7.8 L/100km = 333.3 gal/year = $1333.3/year-

    A $1333.3/year savings. That all looks in order...double mpg, L/100km drops in half...expenses drop in half. Lets do another 15 mpg

    45 mpg = 5.3 L/100km= 222.2 gal/year = $888.8/year

    We saved...uhhh...$445 this time. Huh...this 15 mpg improvement didn't seem as beneficial as the last 15 mpg. It only saved us 1/3 as much money and gas. Of course, if you look at L/100km, it's clear why this is: you're only saving 2.5L every 100km you drive, vs. the 7.8L savings you got before. Well, lets try a 100% improvement in mpg instead of a fixed 15 mpg...

    60 mpg = 3.9 L/100km = 166.7 = $666.6/year

    Huh...a 100% improvement from 15 to 30 saved us $1333/year, but another 100% improvement only saved us half of that amount. Of course, if you look at the L/100km column, it's clear why this is, because you get a much better feel for how much fuel per year two cars will cost you: You're saving 3.9L for every 100km you drive, vs. 7.8L savings for the last 100% improvement you had

    Lets double mpg again to 120 mpg. These are some huge mpg numbers!

    120 mpg = 2L / 100km = 83.3 gal/year = $333.3/year

    Wow- even quadrupeling that 30 mpg doesn't save us as much money per year as going from 15 to 30 mpg. MPG numbers just get really inflated as returns diminish. If you look in L/100km, you can see the linear relationship. It becomes clear that going from 15 to 30 mpg will save you $5.33 every day on your 40 mile commute, but jumping to 60 mpg will only save you an additional $2.66.

    L/100km is the preferably metric because it's a linear relationship with fuel burned, and because people generally have fixed distances they need to drive, rather than a fixed number of gallons they plan to burn after which they'll just stop driving. If that was the case, knowing how many miles you could go on that many gallons might be useful. But, what most people want to know is how much fuel will they need for the driving they plan on doing, and how much a different car, a bike rack, etc. will affect how much fuel they need to buy.

    Electric cars are already transitioning to this. They have their mpge rating, but also a Kwh/100 miles rating.
    Good explanation I would have hoped it would not have been necessary, but it seems too often that the ability to do high-school level applied math problems is quickly lost once out of school (or never gained in the first place).
    15mm is a second-best solution to a problem that was already solved.

  53. #53
    mtbr member
    Reputation:
    Join Date
    Sep 2010
    Posts
    436
    all u gotta do is stick your hand out the window, feel all that resistance. MPG down tubes.
    Aerodynamics is the word, work it baby....
    As long as you not leaving them 24-7 big deal. I would always go for a behind car rack if possible.

  54. #54
    mtbr member
    Reputation:
    Join Date
    Dec 2003
    Posts
    4,739
    Quote Originally Posted by eat_dirt
    FZJ80 land cruiser with lift, no roof rack=sub 10mpg.

    FZJ80 land cruiser with lift, roof rack=sub 10 mpg.

    no difference here.
    Time for a tuneup. You should be getting 11-13 mpg. I get 11.5 in mixed driving with an ARB on the front and 33" tires and about 13.5 on the highway.

    Funny story. Last year the gas mileage on the 80 went up to about 14-15mpg all of a sudden. I was beating my brains out trying to figure out why, as I never got more than 15 on pure highway trips. Finally after a couple of months, my girlfriend starts laughing and tells me she was in a hurry one day and threw in a few gallons of gas between tanks. She saw how exited I was about the mileage and kept doing it.

    Yes, my life if that pathetic.
    Riding slowly since 1977.

  55. #55
    mtbr member
    Reputation:
    Join Date
    Sep 2009
    Posts
    1,150
    ^^ Ha!

  56. #56
    mtbr member
    Reputation: BaeckerX1's Avatar
    Join Date
    Oct 2007
    Posts
    2,267
    Quote Originally Posted by CDMC
    Time for a tuneup. You should be getting 11-13 mpg. I get 11.5 in mixed driving with an ARB on the front and 33" tires and about 13.5 on the highway.

    Funny story. Last year the gas mileage on the 80 went up to about 14-15mpg all of a sudden. I was beating my brains out trying to figure out why, as I never got more than 15 on pure highway trips. Finally after a couple of months, my girlfriend starts laughing and tells me she was in a hurry one day and threw in a few gallons of gas between tanks. She saw how exited I was about the mileage and kept doing it.

    Yes, my life if that pathetic.
    That's hilarious.
    Gotta get up to get down.
    LMB

  57. #57
    mtbr member
    Reputation:
    Join Date
    Apr 2009
    Posts
    930
    Quote Originally Posted by BaeckerX1
    That's hilarious.
    No way, GF buying you gas? that is AWESOME!

  58. #58
    banned
    Reputation:
    Join Date
    Jun 2007
    Posts
    2,320
    Yes, I too find this whole thread hilarious. Bike must be hauled to TH:
    -Bike inside car - interior subjected to stains & tears, passengers go where - on roof?
    -Bike on roof - car uses a little more gas, yet kayaks are happy.
    -Bike on rear - damage to bikes likely if hit.

    If you forget bikes are on the roof and drive into the garage it's entirely your fault, not the person that whacked your car/bikes at the grocery store.

  59. #59
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    Quote Originally Posted by Flyin'W
    Yes, I too find this whole thread hilarious. Bike must be hauled to TH:
    -Bike inside car - interior subjected to stains & tears, passengers go where - on roof?
    -Bike on roof - car uses a little more gas, yet kayaks are happy.
    -Bike on rear - damage to bikes likely if hit.

    If you forget bikes are on the roof and drive into the garage it's entirely your fault, not the person that whacked your car/bikes at the grocery store.
    I'm not sure I understand the difference. Either way you have a whacked bike and it was human error.

    J.

  60. #60
    banned
    Reputation:
    Join Date
    Jun 2007
    Posts
    2,320
    Quote Originally Posted by JohnJ80
    I'm not sure I understand the difference. Either way you have a whacked bike and it was human error.

    J.
    ---
    J,
    Yes, you're correct. Yet the emotions of embarrassment/shame are far from the feelings of anger & rage when someone else does it. We can control our actions - not others.

    FWIW - As a paddler I'm biased towards roof racks, and hang something off the mirror when bikes are atop.
    ---

  61. #61
    banned
    Reputation:
    Join Date
    Sep 2007
    Posts
    7,930
    Quote Originally Posted by mtec
    I think mine drops from 48 to 44ish with a bike on there....

    TDI
    I went L.A, Calif. to Moab and back, about 1700 miles, total trip, on 35.5 gallons of good high aromatic D2 fuel out of Utah , with a trailer hitch bike rack and one fat daddy WFO 29'er on back. About 48 MPG. I have no problems getting 53 MPG with just the rack on the back, with no bikes, all the time, on good, high cetane Utah fuel, Sinclair or Conoco.

    Vehicle:

    2002 Jetta TDI GLS that was an automatic, I converted it to 5 speed when the automatic croaked with 121k miles on it, and Goodyear Assurance TripleTred tires. Tires make a huge difference in rolling resistance and MPG on a VW TDI. Good Michelin's or Goodyear low rolling resistance tires add 5 to 8 % MPG, easily. Keep the airflow clean, keep the tires stock sized, and tick the miles off while sipping diesel, with torque to spare.

  62. #62
    Mountain Man Dan
    Reputation: ProjectDan35's Avatar
    Join Date
    Jul 2010
    Posts
    2,181
    2010 Mustang Gt with the Yakima High Roller racks and 2 bikes brings the mpg down from 22 avg to 19....

    The bike is nothing more then circles turning circles, It's the human motor that makes it elegant.

  63. #63
    mtbr member
    Reputation: stubs179's Avatar
    Join Date
    Oct 2008
    Posts
    122
    I would think the amount of torque the motor in the car has would make the biggest difference in the mpg difference? I could stand a 4'x8' sheet of plywood on the roof of my Dodge w/ diesel and it would hardly make a difference.

  64. #64
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    32
    My Subaru Legacy has been getting 32 w/ cruise control on w/ no rack.

    Added a yakima rack with fairing and a centertube clamping bike carrier w/ a bike on it at the same speed w/ cruise control and now i get 23


  65. #65
    mtbr member
    Reputation:
    Join Date
    Jun 2008
    Posts
    272
    Quote Originally Posted by mhoran89 View Post
    My Subaru Legacy has been getting 32 w/ cruise control on w/ no rack.

    Added a yakima rack with fairing and a centertube clamping bike carrier w/ a bike on it at the same speed w/ cruise control and now i get 23

    Bummer.
    Update on my 2011 Sportwagen TDI- Long trips with racks (Whispbar and rockmount Tie Rods) and no bike I get 42.5mpg. With 2 mtb I get 38.5. With racks, 500lb trailer, 2 250lb dirt bikes and all our gear I avg 36. Note that with bikes on I go 70 but with a trailer I go 60-65. Guess diesel really is the way to go when you tow.

  66. #66
    mtbr member
    Reputation: FZJ80's Avatar
    Join Date
    Sep 2011
    Posts
    11
    Quote Originally Posted by CDMC View Post
    Time for a tuneup. You should be getting 11-13 mpg. I get 11.5 in mixed driving with an ARB on the front and 33" tires and about 13.5 on the highway.

    Funny story. Last year the gas mileage on the 80 went up to about 14-15mpg all of a sudden. I was beating my brains out trying to figure out why, as I never got more than 15 on pure highway trips. Finally after a couple of months, my girlfriend starts laughing and tells me she was in a hurry one day and threw in a few gallons of gas between tanks. She saw how exited I was about the mileage and kept doing it.

    Yes, my life if that pathetic.
    More 80 owners!!

    The LX450 gets roughly 14mpg with or without my baja-rack, which itself weights at least 50lbs. I just gave up chasing MPG, its not even worth tracking as it only leads to depression.
    2012 Trek Marlin

  67. #67
    mtbr member
    Reputation:
    Join Date
    Mar 2005
    Posts
    239
    Quote Originally Posted by ProjectDan35 View Post
    2010 Mustang Gt with the Yakima High Roller racks and 2 bikes brings the mpg down from 22 avg to 19...
    I don't use a roof mounted bike rack, though I do have Yakima bars and a fairing permanently installed. For the past three years, my daily driver has been a 1991 Honda Civic. I've averaged as low as 28 MPG and as high as 33 MPG (all commuting/errands; no road trips). From what I can tell, it's all based on how I drive. In other words, dropping from 22 to 19 may be due to your roof rack, but some of it could also be due to your driving.

  68. #68
    Mountain Man Dan
    Reputation: ProjectDan35's Avatar
    Join Date
    Jul 2010
    Posts
    2,181
    Quote Originally Posted by J_Hopper View Post
    I don't use a roof mounted bike rack, though I do have Yakima bars and a fairing permanently installed. For the past three years, my daily driver has been a 1991 Honda Civic. I've averaged as low as 28 MPG and as high as 33 MPG (all commuting/errands; no road trips). From what I can tell, it's all based on how I drive. In other words, dropping from 22 to 19 may be due to your roof rack, but some of it could also be due to your driving.
    Maybe so. But I can't drive exactly like I did with out bikes. Shift the same. Same roads.

    Sent from your moms house using Tapatalk.
    The bike is nothing more then circles turning circles, It's the human motor that makes it elegant.

  69. #69
    Dirt Huffer
    Reputation: AC/BC's Avatar
    Join Date
    Jun 2006
    Posts
    1,751
    That's why I bought a hatch back. I can lay two bikes down in the back with the rear seats folded down in my Focus ZX3

  70. #70
    mtbr member
    Reputation:
    Join Date
    Oct 2008
    Posts
    2,208
    Great until you get rear ended and all those bikes get tossed around in the car with the passengers and driver.

  71. #71
    rider
    Reputation:
    Join Date
    Jan 2005
    Posts
    2,355
    My Tercel 4wd wagon goes from 29-32mpg highway to the same as I get in town which is 22mpg when I put my XL 29er on the roof. So, for any long haul, the bike has it's wheels off and is in the car. The roof rack is just for short hauls around my riding destinations.

    Interestingly enough is the fact that my Thule rack system does not seem to reduce my highway mileage when it has no bike on it.
    Abandoned the 26" wheel in May '03

  72. #72
    Just Ride
    Reputation: Cormac's Avatar
    Join Date
    Aug 2011
    Posts
    1,738
    I dunno about roof racks, but the rack I had on the back of my car created so much drag I could watch the gas needle drop. Then I figured out if I remove the front wheel it fits just fine in the trunk.
    SS ==> Nut up or Shut up!

Members who have read this thread: 2

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  

THE SITE

ABOUT MTBR

VISIT US AT

© Copyright 2019 VerticalScope Inc. All rights reserved.