Plastic Bicycle Chains?

Discussion in 'Cycling Equipment' started by jbennett1987, Oct 4, 2009.

  1. jbennett1987

    jbennett1987 New Member

    Joined:
    Sep 29, 2009
    Messages:
    2
    Likes Received:
    0
    Hey all!
    Quick question, do plastic bicycles chains exist? If so, where can I go to find them? and if not, what are the main reasons for this being so?
    Cheers
    Joe
     
    Tags:


  2. dhk2

    dhk2 Active Member

    Joined:
    Aug 8, 2006
    Messages:
    2,214
    Likes Received:
    39
    Plastic isn't strong enough, or wear-resistant enough. Your drivetrain gears multiply the force on the pedals by as much as 5-to-1, so a 200 lb load on the pedal could become 1000 lbs of tension in the chain. Also, plastic rollers and bushings would wear quickly compared to the hardened steel in our chains.

    There are toothed-belt bikes though; the new Trek (Urban) is one example. It uses a wider belt with an 8-speed internal hub. Neat and clean. Looks perfect for all-weather commuting, with a belt splash guard, fenders, and rear rack.
     
  3. cwdzoot

    cwdzoot New Member

    Joined:
    Sep 30, 2003
    Messages:
    59
    Likes Received:
    0
    I have to ask, what makes you long for a plastic chain?
     
  4. Emp

    Emp New Member

    Joined:
    Mar 14, 2008
    Messages:
    82
    Likes Received:
    0
    Imagine what gonna happen when you go for sprinting at 50km/h+ using those plastics?:rolleyes:
     
  5. stevegreer

    stevegreer Member

    Joined:
    Sep 4, 2008
    Messages:
    166
    Likes Received:
    9
    Never heard of a plastic chain before. And I agree with the previous posts about how a plastic chain just could not stand up to the stresses placed on it. I think maybe you are thinking about the belt drive. I read an article about it in Mountain Bike Action magazine. The cog is carbon fiber and the belt is (I believe) the same material as the fan belt on automobiles.
    Think I'll just stick with the good old fashioned steel chain.
     
  6. meehs

    meehs New Member

    Joined:
    Nov 7, 2003
    Messages:
    1,868
    Likes Received:
    0
    Actually there are now automobile engine parts made from advanced plastics. I wouldn't doubt that the technology exists to make a bike chain out of some type of high-tech plastic and I suppose it would have the advantage of being impervious to rust. Even if it is possible, it's probably cost prohibitive for anyone to puruse such a venture. Especially when one can buy a steel chain that works perfectly fine for a very reasonable price.
     
  7. steve cross

    steve cross New Member

    Joined:
    Sep 9, 2013
    Messages:
    1
    Likes Received:
    0
    Plastic bicycle chains was around in the 50s/60s, they were not for bicycles, they were a fashion icon, which were worn around the neck.
     
  8. oldbobcat

    oldbobcat Well-Known Member

    Joined:
    Aug 31, 2003
    Messages:
    3,233
    Likes Received:
    95
    Quote: Originally Posted by meehs .

    Actually there are now automobile engine parts made from advanced plastics.
    Cam timing chains are still made from steel. Some manufacturers use steel-reinforced rubber belts, which are lighter and less expensive, but they need to be replaced after 50K miles or so.
     
  9. dabac

    dabac Well-Known Member

    Joined:
    Sep 16, 2003
    Messages:
    2,289
    Likes Received:
    139
    I think the venue of research/engineering is Tribology, the science and engineering of interacting surfaces in relative motion, where metal still has the upper hand WRT plastics and composites. Basically as soon as you've made a non-metal chain that has a survivable load at the contact surfaces and sufficient overall strength, the only remaining "advantage" left is that you can say "hey, it's not metal". Belt drive bikes are available but are more along the lines of "different" rather than "better". Sure, the potential life of a belt can be longer than the potential life of a chain. But honestly how many people actually see chain life as a limiting factor on a SS/IGH bike? And yes, the belts don't need lube, so if you need to bring your bike on trains, buses, or have to carry it inside your car often you have removed a potential contamination problem. Assuming you had it in the first place. And that you just can't see yourself using a chainguard. A belt would still be able to snag a floppy trouser leg, so that risk is still there. So they address some rather specific problems, and since there aren't any belts that can be opened and closed yet they require special frames. And should your belt fail, or be vandalized, you'll have to get hold of an exact replacement. No cutting to length here. (well, there's probably some leeway depending on dropout/bb design, but nowhere near as generic as the traditional chain.)
     
  10. Mr645

    Mr645 New Member

    Joined:
    Jun 22, 2013
    Messages:
    65
    Likes Received:
    4
    Drive belts can last a long time, look at Harley Davidson motorcycles, those belts last 100,000 miles and require very little maintenance , no grease to get clothing dirty.
     
  11. CAMPYBOB

    CAMPYBOB Well-Known Member

    Joined:
    Sep 12, 2005
    Messages:
    11,945
    Likes Received:
    1,038
    The original 'rubber band' primary and secondary chains on Harleys were pretty fragile. They did not handle heat and aggressive riding at all. High output engines and banging gears and hole shots destroyed them easily. Rocks and stones also caused damage or failure. Over the years, going to wider belts/pulleys, different polymer compounds, revising the tooth form and reinforcing materials have resolved those problems. You can find drag bikes using belt drives and those motors put out huge HP and torque numbers.

    Given that we are riding plastic frames propelled by plastic pedals, plastic crank arms, etc. I wonder how much longer it will be until Campy or shimaNO introduce a polymer chain/gear or belt/gear set.
     
  12. Kakashi

    Kakashi Active Member

    Joined:
    Feb 3, 2018
    Messages:
    634
    Likes Received:
    39
  13. Froze

    Froze Well-Known Member

    Joined:
    Jul 13, 2004
    Messages:
    4,680
    Likes Received:
    377
    Funny, but my garage door opener uses a belt that's made of polyurethane with steel fibers infused into the belt, and that belt has lasted 10 plus years, and I know another person who belt drive door opener is 30 years old and the belt has never been replace, I would think a garage door opener with 1 1/4 horsepower pulling on a heavy double car garage door made of wood several times a day would be more stress than a bike would ever see. What I don't understand is why bicycle belts are only made of pure polyurethane with no steel infusion, wouldn't the steel infusion make the belt last forever? If weight is the issue I don't think so, I helped a friend put a belt drive garage door opener on his door and the belt was stupidly light and a lot longer than a bike belt, in fact that belt is lighter than the chains on my bike! So unless someone has a good reason why they don't infuse steel into a bicycle belt to make it stronger the only reason I can come up with is that the belt manufacture wants you to replace that belt due to economic reasons.
     
  14. CAMPYBOB

    CAMPYBOB Well-Known Member

    Joined:
    Sep 12, 2005
    Messages:
    11,945
    Likes Received:
    1,038
    "What I don't understand is why bicycle belts are only made of pure polyurethane with no steel infusion"

    It's simply not needed. Gates is manufacturing belts with fabric, polymer and carbon: https://www.gatescarbondrive.com/products/overview

    Santana is one of the premier Tandem builders and the Gates drive system is regularly optioned on Santana tandems in place of the timing chain. It will handle the power of two strong riders. Like the motorcycle drive belts, they've come a long way over the last 25 years or so.
     
  15. Froze

    Froze Well-Known Member

    Joined:
    Jul 13, 2004
    Messages:
    4,680
    Likes Received:
    377
     
Loading...
Loading...