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Speedometer calibration VTR250

Discussion in 'Technical and Troubleshooting Torque' started by Jozlyn, Jan 25, 2015.

  1. I'm not sure if this is the right place to ask, I've tried searching but I'm just not getting an appropriate answer. I have a 2000 model VTR250. The speedo is out by heaps and we know why, it has the wrong size tyres on it. Please don't judge us harshly. We bought the bike for me 2 years ago, unregistered. Fully knowing we had to get a RWC and reg' for it once I got my licence. We knew when we bought it that it needed new tyres, so when we ordered the tyres we got the same as what was already on it, without checking whether they were the right ones or not, with 20/20 hindsight, we now know that was a mistake.

    So my question is, is it possible to recalibrate the speedo? At 100kmph it reads 80 - 85kmph. Or do we have to do the GPS and a marker pen to mark out each of the "normal" speeds (40, 60, 80 & 100). Not only do I live in Victoria, but I also live in the most speed policed area of Victoria and I'm very conscious of not helping to fill the governments coffers any more than necessary. I'm also on my L's, so a speeding fine is not a good idea!

    Any help would be greatly appreciated.

    Thanks :)

  2. hey joz I would get the correct tyres on it im not sure how the speedo works on your bike but I would assume it works from the front wheel
    oh you left out the 50,70,90 and 110 limits all common as well
    • Like Like x 1
  3. Can you not just mount a smart phone with GPS app on the bike? Or just a GPS - the speedo readings in those are more accurate than some manufacturers stock speedometers.
    • Like Like x 1
  4. Unfortunately we just can't afford another set of tyres at the moment, we're almost out of "bike" money.

    lol, yes, I did leave them out, my bad ;)
  5. No, unfortunately I'm not allowed to have ANY sort of electronic gizmo's while I'm on my L's :(
  6. if the speedo drive is on the front tyre, you only need to change the front to get the speedo back to spec...
    front tyres are cheaper than rear or pair..

    speedos usually red maybe 0-5% fast.. so to get it to read 15-20% slow is a huge change in tyre?
    stock is 110/70-17.. how small did you put on?

    a speedo drive correction thingy is likely more expensive than correct size tyre (~$100?).. and you'll only use it for 1 tyre :)
  7. I would say it is larger to read lower dear sir
  8. true :p sell the tyre, buy correct one

    got a bicycle computer lying around? one of those with a large screen would be easy enough to see, and they are easy to calibrate
    • Like Like x 1
  9. good idea
  10. The front tyre is 120/70/17.
  11. does it adversely affect the handling?
  12. You can sell a used tyre? Who would buy that?

    I can't have any sort of screen display, GPS, iPhone (if I had one), iPod, nothing. I'm not even supposed to carry my mobile on my person, I do, but I leave it switched off in a bum bag.
  13. No, not at all. But given that I don't know any different, I guess I don't really know lol
  14. ok go to a pushy shop and check out the options old mate suggested
  15. There's a shop on Maroondah Hwy Mitcham, just up from Ringwood that specialises in speedo corrections. They might have an adapter or be able to supply a cog with a different number of teeth that will fix the issue, or at least give you some safety margin.
    Ringwood Speedometer Service
  16. 120/70-17 vs 110/70-17
    the larger tyre is only 2.3% larger circumference... (yeah it's a car tyre site but..)
    if anything, given that speedos almost always read fast, it should make the speedo read correctly.

    methinks to get a 20% change, there is something else screwy... but 120/70/17 should be ok
    • Agree Agree x 1
  17. I'd be double checking that the speedo drive in the front wheel is the correct one (compare number of teeth) and checking that the speedo is actually from a VTR250 of that vintage....
    • Agree Agree x 2
  18. Thanks, I'll look up their number and give them a call on Tuesday. I would never have known it was out, except that I asked my husband why he was going so slow for me and that I felt fine doing 80k's, I was quite shocked when told me we were doing 100! Not being able to use any electronic devices while on my L's, in this situation is VERY frustrating, especially given how strict speed enforcement is here.