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Thread: Does carbon fiber really make a difference?

  1. #21
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    Quote Originally Posted by rider2371 View Post
    I think it would be quite an expensive exercise to try to achieve a 20kg weight difference using carbon fiber.
    It would vary from bike to bike, but basically I think you could save weight like this (note that these numbers are pure guesses):

    Lithium battery: 3-5kg
    Titanium full exhaust: 5kg
    Carbon fiber wheels: 5-8kg
    Carbon fiber bodywork: 3-6kg
    Titanium bolts, etc: 2-3kg
    Stripping off unnecessary parts (pillion seat, etc.): 3-5kg

    So there's definitely potential to save weight out there... but eventually it becomes a matter of cost.
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  2. #22
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    Default Does carbon fiber really make a difference?

    Quote Originally Posted by Guy Jinbaiquerre View Post
    It would vary from bike to bike, but basically I think you could save weight like this (note that these numbers are pure guesses):

    Lithium battery: 3-5kg
    Titanium full exhaust: 5kg
    Carbon fiber wheels: 5-8kg
    Carbon fiber bodywork: 3-6kg
    Titanium bolts, etc: 2-3kg
    Stripping off unnecessary parts (pillion seat, etc.): 3-5kg

    So there's definitely potential to save weight out there... but eventually it becomes a matter of cost.
    I think your estimates are over optimistic. About half your numbers would be appropriate for the majority of bikes...

  3. #23

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    Using just one example for a 2007 GSX-R 1000 Akrapovic claim their full race system will save 9.05kg.

    http://shop.jamparts.com/pdf/GSXR%20...ingle%2007.pdf

    There's a myriad of other places to save weight, most weight reduction comes from lots of 100g to 500g gains put together.
    Another point is things you might change for other reasons are often lighter than the stock parts, for example I fitted a Ohlins steering damper as the stock one was freaking me out, that saved 200g right there.

  4. #24
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    Quote Originally Posted by Doug68 View Post
    There's a myriad of other places to save weight, most weight reduction comes from lots of 100g to 500g gains put together.
    Yep. Just for fun, here's an X4 owner I used to ride with (he dropped out of sight a few years ago after getting married ) who first was bolting on whatever extra parts he could find, but then got the weight-saving bug and started stripping stuff off and lightening what he could -- sometimes in big chunks, sometimes gram by precious gram. He ended up getting it down to 64kg below the stock weight:

    http://www.geocities.jp/x_4_custom/


    That's almost one-fourth of the stock bike, gone! He carefully measured the weight of every part he removed versus the replacement, if any. Sometimes he went back and replaced a particular part again when he found something lighter. He even had custom one-off parts molded out of dry carbon fiber, because ordinary carbon fiber has extra weight from whatever plastic sealant they put on it to make it shiny. Probably the most extreme change he made was modifying the frame and swingarm, including changing the bike from twin rear shocks to a monoshock. Insane.

    NOTE: He poured ridiculous amounts of money into this project. I don't recommend it unless the Internet company you founded just went public.
    IBA #42657
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  5. #25
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    Default Does carbon fiber really make a difference?

    Yep, this obviously depends on what components the stock bike comes with. If it comes standard with lightweight component reducing a significant amount of weight is going to be a lot harder and more expensive...

  6. #26
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    Quote Originally Posted by Guy Jinbaiquerre View Post
    He ended up getting it down to 64kg below the stock weight
    Impressive! That's almost as much as a trials bike weighs!

    Did he ever tell you how the bike handled after achieving that?
    ----------------
    2008 R1200GS | 2009 NSF100 | 2009 CRF250X | 2011 Address V125S


  7. #27
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    Quote Originally Posted by rider2371 View Post
    Did he ever tell you how the bike handled after achieving that?
    Much better, as you might expect. I sat on it and the sensation of lightness compared to my X4 was astonishing. But part of the improvement in handling was probably also due to his modifying the frame to decrease the rake angle. Yes, he actually had somebody cut and weld the frame itself.
    IBA #42657
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    09 BMW R1200GS Adventure ・ 09 KTM 990 SMT (sold) ・ 97 Honda X4 ・ 95 Kawasaki ZZR400 (sold)

  8. #28
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    My solution: Eat less! The weight of the rider makes a huge difference.

  9. #29

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    Quote Originally Posted by JapanRob View Post
    My solution: Eat less! The weight of the rider makes a huge difference.
    Read earlier in the thread, we already established that not to be the case
    Apexmoto Inc - Dyno tuning, engine/chassis/suspension upgrades, repairs, shaken, tires & changing with balancing, graphics printing, stickers, media blasting, painting & powder coating.

  10. #30
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    Quote Originally Posted by JapanRob View Post
    My solution: Eat less!
    Or to quote a long distance rider I work with, "take a big dump".
    ----------------
    2008 R1200GS | 2009 NSF100 | 2009 CRF250X | 2011 Address V125S


  11. #31
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    Wink Weight Training

    Vamping the thread I know!!!

    You can spend lots of money getting a heavy bike to be not quite so heavy, or you can just start off with a light bike--like a Replica Racer. But I really suggest that you don't do this--you'll find your RSV posted for sale, and you'll start riding modified fifties (don't ask me how I know this). And then when you can find the carbon fiber for your Racing Replica you'll get that as well. ;)

    Carbon fiber is much lighter than stock body parts. Fiberglass is also lighter than stock body parts. Think of it like this:

    carbon fiber < fiberglass < stock plastics

    A light bike is very intoxicating. Two hundred pounds seems to be like a magic number. Bike I have that are around that are just way more fun to ride. I also have a Cagiva Mito with a bunch of the SP (sports performance) parts on it. I would guess it's probably around 250lbs. It's a really fun bike--but the slightly smaller Racer Replicas are just way more fun to ride, and it's probably because they are just a bit lighter to make it past that 200lbs threshold. There is also the sense of speed. On a lighter bike you feel the speed more intensely than you do on the heavier bikes. Which is to say you wont feel as comfortable going the higer speeds on the lighter bike.


    With regards to being fat, and GP riders and such. If you are overweight getting down to a healthy level will improve your riding quite a bit. Not so much because of less mass for the bike to haul around, but because you'll be in better condition. The GP riders are in top physical condition. Super lean dudes. When you are overweight it will drag on you. You'll have less energy, be tired more frequently, and your reaction times will frequently be slower than they would if you were in lean mode.

    With regards to wheels, and unsprung weight. Lighter wheels will improve acceleration--both going forwards, and directional changes. There are some caveats however. When you go to a lighter wheel you will loose some of the gyroscopic effect that keeps the bike upright. Also, if it is a street bike carbon fiber and magnesium wheels have some huge disadvantages with regards to reliability. Track bikes don't have to deal with pot holes, and crapy roads. These hazards will wreak havoc on those wheels. But a lighter aluminum wheel is a nice compromise for the street.

    Unsprung weight are things that aren't suspended. Things like your front fender on a sport bike. Going to fiber there is an advantage. Going to an aluminum swing arm can be an advantage too, as would a fiber hugger. There are also a bunch of steal parts on a bike that could be swapped out for aluminum. Like the subframe for instance (although that would be an example of something sprung).

    But as has been noted is previous posts you do tend to give up things like convenience when dropping weight from your bike. Ultimately it should be judged on the kind of riding you want to do.

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