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Changing sproket

Discussion in 'Technical and Troubleshooting Torque' at netrider.net.au started by Janosh, Aug 3, 2007.

  1. I'm looking for a 600 sports (zx6, gixxer, etc) at the moment and I love doing mono's.... So i think I'm either going to go +2 at the back, or -1 at the front when I get it.

    Any advantage of changing one over the other??

    I've also read about the speedo not reading correctly after a swap - why?
  2. I prefer to go down in sprocket size at the front, as you can usually get away with a standard length chain.

    It's not always the best though if the standard sprocket is on the small side, the tighter turn can wear the chain out prematurely.

    The speedo will only be out if it's read from the gearbox, some hondas do this, dunno about the bikes you mention. You can always just whack a $20 pushbike speedo on, it'll stay accurate with all gearing changes then.
  3. Assume your doing stunting on private property :wink:

    Droping one tooth from the front is enought to get a considerable change in take of torque.

    You speedo is based on engine RPM depending on what gear your in the electronic device translates that RPM into a speed.
    By changing the teeth, you change the speed of the bike at a given RPM and gear. Hence your speedo will be out!

    If you drop (or shorten) the gearing, eg. remove a front tooth. The bike will rev higher at the same throttle position than before the change. Your bike will think that it is going faster than it actually is. So your speedo might say 60 Kph, but your doing 55.
  4. I thought that was the case, so roughly what year did the digital speedo readings come in? I'm looking at 2000 ish bikes.. So would the ones with analogue speedo's be affected??
  5. Oh, and how small is too small on the front??
  6. bikes already have too small front sprockets. In industrial chain design the rule of thumb is preferably keep it above 21 teeth and don't go below 19 teeth.

    bike usually have between 13 and 17 teeth on the front, so they are really pushing shit up hill. The difference is exponential too. So expect it to be considerably worse.

    I'd be going up 2 on the rear myself.
  7. It doesn't make a difference whether its electronic or mechanical.

    If the speedo pickup uses the front wheel, gearing changes won't affect the speedo. If the pickup is off the gearbox, all of these speedos will be affected.
  8. 14T runs fine, I wouldn't go below that.

    A 520 conversion will also keep the chain and sprockets lasting longer if you go for a smaller front sprocket, just make sure you get the good stuff.
  9. Yea, have been looking at a 520 chain conversion - looks like good value and perfect for what I want :twisted:
  10. +1.

    It should be fairly easy to spot the speedo cable on a bike if it is on the front wheel (or back wheel, like the Tuono). If you can't find one, it's probably gear-driven. I think most jap bikes' speedos run from the gearbox though, so if that's what you're after, it will be out.

    There are devices to correct them, however.