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Faired vs Naked for performance & economy

Discussion in 'Technical and Troubleshooting Torque' started by Spocky, Jan 27, 2012.

  1. Hello all,

    This is a sort of technical question regarding aerodynamics and the potential benefits of bikes with fairings and nakeds of the same bike. I am looking at getting a Kawasaki Ninja 650 and it comes in both Faired and Naked versions of the same bike.

    Now my question is: does the naked version have more performance because it is lighter and therefore maybe would have a significant reduction in fuel use or does the aerodynamic advantage of the fairing offset the additional weight? I am assuming that above a certain speed then a fairing would be more advantageous (hence all Racing bikes are faired) but what is the crossover point for the average road bike?

    It is a question that has bugged me and no-one has been able to give me an answer.

    Cheers Spocky
  2. The difference would be that small your better of just getting the one u like.
    • Like Like x 1
  3. In regards to performance and economy, what z900 said.

    Where fairings can (depending how designed) make a big difference is comfort and some protection from wind particularly during the colder months..

  4. 150km/h is the crossover point. Tahts why on a roadbike, get what you want.
  5. I don't know, if you get a proper touring screen going back to a naked bike feels like your upper body is a windsail :|
    That said, the benefits are pretty minimal, just get what you like best
  6. Twenty years ago Performance Bikes ran some experiments using a CBR600 (IIRC) and various combinations of bodywork including no fairing, stock fairing and a sorta tail fairing thingy made from foam and fibreglass.

    I don't remember the exact figures but the difference in max speed between faired and unfaired was only ~5mph. Given that the top speed of either configuration was in the region of 140mph (timed distance, not speedo figures), such a difference is academic. The tail fairing, blending the rider's back into the bike actually had more effect.

    Another comparison from a few years before was the old Yam FZ750 with all its plastics vs the similarly engined FZX750 power cruiser naked. Faired bike ~142 mph, unfaired bike ~138 mph.

    In short, any real performance difference on the road is negligible. As for economy, you'll see more variation due to riding style and road conditions than you ever will due to the presence or lack of a fairing.

    OTOH, if you regularly do long trips at highish speeds, a well designed fairing can cut fatigue significantly. It can also provide a degree of protection from adverse weather conditions. How effective at either function a fairing is in reality varies widely from bike to bike and is also dependent on rider shape. What works for one rider may, for instance, try to rip the helmet off someone taller or shorter.\

    If, however, most of your riding is twisty bashing or shorter trips in good weather, there is an argument that a naked will feel faster, and therefore more fun. Not a bad thing in these days of diminishing opportunities to give a quick bike a decent handful.

    But yeah. Like the others said, ride both and pick the one you like.
  7. I have already gone for the faired version (looks better IMHO and don't quite understand the appeal of nakeds) but wss wondering as a technical issue whether the fairing added weight that impacted on the bikes performance up until a point where the reduction in turbulent airflow (at speed) makes the benefit of the fairing more. I suppose its like those people that carry their bicycles on the roof of their cars does significantly impact on fuel consumption and was intrigued if the same issue occurred with motorbikes on a day to day basis.

    Cheers Spocky
  8. Bikes on the roof of cars had nothing to do with added weight
  9. If you want economy, don't twist your right wrist so hard. The differences can be massive. On my bike in an aggressive mood I'll get around 190km out of the tank. Same roads, riding gently, I get nearer to 260km out of it. ;)
    • Like Like x 1
  10. No I agree that the way you ride is more important than what you ride to a degree. Just wondering the amount of effect of lightening verses increased aerodynamics.

    Cheers Spocky
  11. True but behind the car (on tailgate) had same weight but less fuel use because of aerodynamic drag reduction.

    That doesn't occur at rocket speeds but normal driving speeds and I was wondering whether the same occurred on bikes at road speeds.

    Cheers Spocky
  12. Well look at it this way. Putting a fairing on is not the same as putting a bike on top of a car. the difference in frontal area is sfa. The difference in drag opportunities along the side is sfa. There is a small difference, but your not putting a sail in the wind. The biggest difference (which will actually make a difference) will come from the engineering which will give better economy to nakeds around town and better to faired out of town, as VC said the crossover is at about 150. But not on the ninja 650 it wont.
  13. On a street ridden bike at legal speeds, the fairing is for protection and looks rather than economy or performance.
    220kmh on an unfaired bike is hard work and you know youre going fast.
    The same speed on a modern bike with full fairing is a lot easier to do and doesnt feel as fast.
    And when you hit a magpie at those speeds, it breaks the screen on the fairing, before bouncing off your head.
  14. Agree with this, having had a blade with a double bubble and then street fightering it you really notice the lack of screen at excess speeds particularly over $1.50 which can be both annoying because of the extra pressure on your body and neck and fun because it 'feels' faster.
  15. There may also be a difference in the insurance premiums which is greater than any fuel difference.
  16. also agree, around $1.50 is about the limmit of comfort.
    i'd say once you get up around $1.80 plus, becomes more dramatic. naked bike requires much effort to change lanes quickly. a sweeping bend requires much more effort. fairing becomes a MASSIVE advantage from this point on. all rider input requires less effort and bike responds much quicker. (not to say it was'nt an advantage sooner)
    performance wise also, seeing as the op queried it. a fairing is just a massive air scoop that channels, or rather rams air through the mechanical internals.

    umm, hypothetically speaking, say you own a litre bike. it's actually not entirely unusual to find yourself at these speeds, albeit very briefly. umm, times and places, you might overtake a slower vehicle, maybe you are on a freeway onramp with lanes merging.
    i mean, a supersport will do $1.80 in first gear, so it's really well within the safe operating range of the machine. a squirt here or there for efficient safe commuting, road positioning. not at all hard to do. these machines can wipe of speed quick too.
    so, you maybe gave a kitten in the vicinity a bit of a fright, but you won't kill it. kittens are really a lot tougher than most people give them credit for.

    of course all of that is entirely theoretical and would never ever happen in Australia. as the motorcycle community here, particularly netriders, never ever speed because it's very very dangerous.
    and myself personally only ever ride a 50cc scooter and i love kittens sooo soo much