Windshield mpg

Discussion in 'General Harley Davidson Topic' started by jamesearl, Apr 19, 2014.

  1. jamesearl

    jamesearl Junior Member Contributor

    Whenever I take the windshield off,it feels like I'm coasting further,even going a little faster.Which makes me think it's really like a giant speed brake.I wonder if there is a difference in mileage with it off?
  2. Jack Klarich

    Jack Klarich Expert Member

    One sure way of telling for sure, run a tank of gas both ways same mileage same roads then you should be close to final answer:D
  3. fin_676

    fin_676 Experienced Member Staff Member Moderator Contributor

    Depending on the size and shape of the windshield it will create a wee bit of resistance to pushing past the air
    Also at higher speeds a vacuum will be created at the rear of the windshield as the air rushes into the vacuum it will cause buffeting it also causes drag the drag will reduce the efficiency of the bike to move through the air
    Most vehicles these days are wind tunnel tested to help improve the drag co-efficiency of the vehicle the shape at the rear of anything moving through the air is as important as the front

  4. Bodeen

    Bodeen Well-Known Member Staff Member Moderator Contributor

    I ran with mine off for about an hour once. It went right back on and I have never even thought of taking it off unless to clean it. We have so much sand on the road here that it makes it very uncomfortable for my liking. Probably would make a slight difference in mileage though.....
  5. Harttoo

    Harttoo Senior Member

    I took Mine off once on Road King I owned,got a June bug right in the forehead.Reinstalled and won't ride without one.On 2012 Limited had a piece of shingle fly up from highway and hit My fairing.Happy to have the "protection" of a windshield.JMO
  6. Davidw2415

    Davidw2415 Senior Member

    I'm sure it has to degrease MPG's put makes for a more comfortable and somewhat safer ride so it is worth the trade off.
  7. gator508

    gator508 Senior Member

    Follow Jack's experiment above, I don't think you will see any real difference in mpg, although the ride will feel different.
  8. jamesearl

    jamesearl Junior Member Contributor

    Thanks for replies.I have to agree,it's a nicer ride.I initially liked a windshield just to keep warmer at lower temps.And the wind buffeting,lack of wind noise in the ears were just a bonus.One thought about braking and a windshield I got was from when I was a plane Capt. in an F 14 fighter squadron,we would do walk arounds,and on a plane, a thing called a speed brake,is just a flap of metal about 12 in. across,2 of them pop up,on the back of the plane.And greatly reduce the speed.I don't have a batwing or small curved back windscreen.I have the reg. RK,with a wind. up to my eyes.I just thought that someone may have done a test with or without.Something more accurate than I could do.I mean the wind alone could make such a difference.
  9. plow boy

    plow boy Member

    Without the windshield the wind will hit me , and the windshield being a smooth surface , I think that there wouldn't be very much if any difference . I have never tried it but it looks like we are in for some nice weather , and I have been wanting to ride some anyway . Thanks for the excuse. I'll have to get my barkeepers friend and clean the bathroom fixtures first . Everyone have a good ride .
  10. ciscokid

    ciscokid Member

    there will be a difference for sure. i take mine off for riding around town and back on when long ride's are in order. i notice that with it off i go faster quicker and with it on there is a lot of drag. so its got to hurt the mileage but prob not a whole lot at the normal riding speeds ie around here 55-65 i have a tall wind screen. with it off i get longer ride's on a tank with it on anything above 65mph and i get really bad mileage .