looking for ski/bike roof rack help

Discussion in 'Mountain Bikes' started by Monique Y. Herm, Mar 13, 2004.

  1. G.T.

    G.T. Guest

    Chris Phillipo wrote:
    > In article <[email protected]>,
    > [email protected] says...
    >
    >>On Sat, 13 Mar 2004 21:27:40 -0000, "Doki"
    >><[email protected]> wrote:
    >>
    >>
    >>>Why not just take the wheels off and chuck the bikes in
    >>>the boot (trunk)? Bike racks do very bad things to your
    >>>cars aerodynamics,
    >>
    >>That is really dependent upon the aerodynamics of the
    >>vehicle.
    >>
    >>Roof racks don't have to have that great an impact, let
    >>alone do "very bad things" to a vehicle's aerodynamics.
    >>
    >>
    >>
    >
    >
    > I think you are spoiled by Mercedes and Porche
    > horsepower Pete. On a base model Civic hatchback with a
    > roof rack fitted, you are constantly checking your rear
    > view mirror to see if someone has attached a larget kite
    > to your bumper.

    Power aside I'm still having difficulty believing Pete's
    assertion that roof racks don't have that great an impact
    on a vehicle's aerodynamics. Especially when the bikes
    are mounted.

    Greg
     


  2. G.T.

    G.T. Guest

    Monique Y. Herman wrote:
    > On 2004-03-18, Adam penned:
    >
    >>Further, at (any) speed a car will push a shock wave
    >>in front of it; the faster the vehicle, the larger
    >>and further forward the shock wave. This will change
    >>the surface aerodynamics and I would have thought
    >>would go some way to reducing the drag of the racks,
    >>if not the bikes
    >>- in effect the racks get partly drafted by the leading
    >> surface of either the roof/windscreen or the bonnet
    >> (hood) depending on how fast the vehicle is and its
    >> shape. With more aerodynamic cars, this effect will be
    >> less, as the air flow over the bonnet (hood), windscreen
    >> and roof would be more laminar (without the racks in
    >> place).
    >>
    >
    >
    > So you're saying that the less aerodynamic the car, the
    > less the bikes will impact mpg?
    >

    That's the way I see it.

    Greg
     
  3. "G.T." <[email protected]> wrote in message
    news:[email protected]...
    > Power aside I'm still having difficulty believing Pete's
    > assertion that roof racks don't have that great an impact
    > on a vehicle's aerodynamics. Especially when the bikes are
    > mounted.

    "Roof racks don't have to have that great an impact, let
    alone do "very bad things" to a vehicle's aerodynamics."

    "My comments relate to driving at high speeds where the
    additional wind resistance doesn't make that great a
    difference, for some vehicles, based upon my experience."

    Experience #1:

    9.5-10 mpg with 6 bikes/front wheels up top driving 90-110.

    12 mpg sans racks and bikes.

    Experience #2:

    17 mpg with two bikes/front wheels driving 90-110ish

    20 mpg sans rack and bikes.

    Hardly "very bad" is the mpg department and not even close
    to being "very bad" as far as vehicle dynamics.
     
  4. G.T.

    G.T. Guest

    p e t e f a g e r l i n wrote:
    > "G.T." <[email protected]> wrote in message
    > news:[email protected]...
    >
    >>Power aside I'm still having difficulty believing Pete's
    >>assertion that roof racks don't have that great an impact
    >>on a vehicle's aerodynamics. Especially when the bikes are
    >>mounted.
    >
    >
    > "Roof racks don't have to have that great an impact, let
    > alone do "very bad things" to a vehicle's aerodynamics."
    >
    > "My comments relate to driving at high speeds where the
    > additional wind resistance doesn't make that great a
    > difference, for some vehicles, based upon my experience."
    >
    > Experience #1:
    >
    > 9.5-10 mpg with 6 bikes/front wheels up top driving
    > 90-110.
    >
    > 12 mpg sans racks and bikes.
    >
    > Experience #2:
    >
    > 17 mpg with two bikes/front wheels driving 90-110ish
    >
    > 20 mpg sans rack and bikes.
    >
    > Hardly "very bad" is the mpg department and not even close
    > to being "very bad" as far as vehicle dynamics.
    >

    Well, 15% for me means having to stop much sooner than I
    wanted to to. It's only a big deal when I'm going to a place
    I know I can make on one tank if I throw my bike inside,
    i.e. Laughlin or Vegas.

    Greg
     
  5. Adam

    Adam Guest

    "Monique Y. Herman" <[email protected]> wrote in message news:<[email protected]>...
    > On 2004-03-18, Adam penned:
    > >
    > > Further, at (any) speed a car will push a shock wave
    > > in front of it; the faster the vehicle, the larger
    > > and further forward the shock wave. This will change
    > > the surface aerodynamics and I would have thought
    > > would go some way to reducing the drag of the racks,
    > > if not the bikes
    > > - in effect the racks get partly drafted by the leading
    > > surface of either the roof/windscreen or the bonnet
    > > (hood) depending on how fast the vehicle is and its
    > > shape. With more aerodynamic cars, this effect will be
    > > less, as the air flow over the bonnet (hood),
    > > windscreen and roof would be more laminar (without the
    > > racks in place).
    >
    > So you're saying that the less aerodynamic the car, the
    > less the bikes will impact mpg?

    Broadly, yes, but I think the size of the car will have a
    much more dramatic effect and even then we're talking about
    a small number of percentage points.

    My old mini was a 'classic'. As you probably know, they
    weren't built with aerodynamics in mind - in fact they were
    modelled more on a brick. My new mini is a BMW and its shape
    tips much more of a nod to aerodynamic efficiency, although
    it's huge in comparison. At motorway speeds with the bikes
    on top, the old mini saw a greater loss of fuel efficiency
    simply because the bikes represented a much larger
    proportion of the overall frontal area.

    Of course, apart from aerodynamics and fuel efficiency, roof
    mounted racks represent one major advantage. Last year we
    were driving down to the Lakes when I stopped at a 'Stop'
    sign. The car behind me wasn't about to make such a silly,
    schoolboy error and decided a much better course was to
    plough into the back of us (that's why my partner insisted
    we get a new car - classic minis are *very* vulnerable to
    rear impacts). Had we had any other type of rack on, the
    bikes would have been toast. As it was, despite the fact
    that the car was very nearly written off, we got the bikes
    into the back of a hire car thoughtfully provided by the
    insurance company and still rode one of the best trails I've
    ever been on.

    HTH - Adam...
     
  6. Adam

    Adam Guest

    "Monique Y. Herman" <[email protected]> wrote in message news:<[email protected]>...

    > So you're saying that the less aerodynamic the car, the
    > less the bikes will impact mpg?

    Forgive the second post on the same topic, but I thought of
    something else I wanted to add: I would guess that the
    torque characteristics of the engine would have a much
    greater effect than aerodynamics. A torquey engine will
    handle the additional load represented by the bikes without
    having to burn more fuel to maintain the same revs - at
    least, that's my guess.

    Cheers - Adam...
     
  7. In article
    <[email protected]>,
    [email protected] says...
    >
    > "G.T." <[email protected]> wrote in message
    > news:[email protected]...
    > > Power aside I'm still having difficulty believing Pete's
    > > assertion that roof racks don't have that great an
    > > impact on a vehicle's aerodynamics. Especially when the
    > > bikes are mounted.
    >
    > "Roof racks don't have to have that great an impact, let
    > alone do "very bad things" to a vehicle's aerodynamics."
    >
    > "My comments relate to driving at high speeds where the
    > additional wind resistance doesn't make that great a
    > difference, for some vehicles, based upon my experience."
    >
    > Experience #1:
    >
    > 9.5-10 mpg with 6 bikes/front wheels up top driving
    > 90-110.
    >
    > 12 mpg sans racks and bikes.
    >
    > Experience #2:
    >
    > 17 mpg with two bikes/front wheels driving 90-110ish
    >
    > 20 mpg sans rack and bikes.
    >
    > Hardly "very bad" is the mpg department and not even close
    > to being "very bad" as far as vehicle dynamics.
    >
    >
    >
    >

    I think 12 MPG is pretty bad regardless considering I can at
    least expect my underpowered 4 Runner with 32x11.5" mud
    terrain tires to get between 14 and 16 on the highway doing
    about 85/90. Even racing I can expect 10-12 going much
    slower, although the odometer is no that acurate when you
    are looking out your side view window at the apex of the
    turn 50% of the time :) So what is that first vehical you
    mentioned, the ML320?
    --
    _________________________
    Chris Phillipo - Cape Breton, Nova Scotia http://www.ramsays-
    online.com
     
  8. "Monique Y. Herman" <[email protected]> wrote
    >
    > So you're saying that the less aerodynamic the car, the
    > less the bikes will impact mpg?

    Well, sure. If you're dumb enough to be driving some
    overpowered, cube-shape shitbox that only gets 12 mpg to
    begin with, you could probably put a half a dozen bikes on
    top and still get 9.5 or 10 mpg.

    CC
     
  9. "Corvus Corvax" <[email protected]> wrote in message
    news:[email protected]...
    > "Monique Y. Herman" <[email protected]> wrote
    > >
    > > So you're saying that the less aerodynamic the car, the
    > > less the bikes will impact mpg?
    >
    > Well, sure. If you're dumb enough to be driving some
    > overpowered, cube-shape shitbox that only gets 12 mpg to
    > begin with, you could probably put a half a dozen bikes on
    > top and still get 9.5 or 10 mpg.

    ROTFLMAO.

    The great unwashed masses are heard from...
     
  10. Geedubb

    Geedubb Guest

    Penny S wrote: .
    >
    > Anyone remember the "wasting energy" speeding tickets
    > in Nevada?
    >
    >
    > Penny

    Here in AZ is was 'misuse of a finite resource' and I was
    the proud recipient of such a ticket.

    Gary
     
  11. Geedubb

    Geedubb Guest

    Doki wrote:
    > Penny S wrote:
    >> Doki ran this through spell check:
    >>> I was under the impression that the max speed limit on
    >>> lots of roads is 55. I had heard of some experiments
    >>> with removal of speed limits though.
    >>
    >> You are behind the times and misinformed.
    >
    > I do live in the UK, and have never driven in the US. The
    > only info I get on US speed limits is from seeing signs
    > and people getting pulled over in films.
    >
    >> While for many years the Federal limit was 55 ( like
    >> anyone paid attention to that once you are out in the
    >> boonies) it was raised to 65 and then 70 on the
    >> interstates several years ago. Montana does not have a
    >> speed limit per se, but how fast you can go before you
    >> are ticketed it totally up to the local law enforment.
    >
    > I see.
    >
    >> Anyone remember the "wasting energy" speeding tickets in
    >> Nevada?
    >
    > That's how they introduced speed limits here. During the
    > fuel crisis of the 70s, speed limits were introduced on
    > motorways and country roads, on the grounds of saving fuel
    > then were never removed. The Isle of Man is an exception,
    > and still has no speed limit outside of town.

    I just got back from England and nobody, NOBODY, drives less
    than 70 except for the lorries. I had people up my butt and
    I was doing 90 trying to get out of the way. But the drivers
    are much more curtious than drivers here.

    And your steering wheel is on the wrong side of the car! <g>

    Gary
     
  12. Doki

    Doki Guest

    GeeDubb wrote:
    > Doki wrote:
    >
    >> That's how they introduced speed limits here. During the
    >> fuel crisis of the 70s, speed limits were introduced on
    >> motorways and country roads, on the grounds of saving
    >> fuel then were never removed. The Isle of Man is an
    >> exception, and still has no speed limit outside of town.
    >
    > I just got back from England and nobody, NOBODY, drives
    > less than 70 except for the lorries. I had people up my
    > butt and I was doing 90 trying to get out of the way. But
    > the drivers are much more curtious than drivers here.

    The lorries are on 90kph (roughly 56mph) limiters ;).
     
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