Welcome to Netrider ... Connecting Riders!

Interested in talking motorbikes with a terrific community of riders?
Signup (it's quick and free) to join the discussions and access the full suite of tools and information that Netrider has to offer.

Digital Speedo

Discussion in 'Modifications and Projects' started by conspiracytheorist, Feb 15, 2007.

  1. Hey just got my digital speedo attached and working. Its a sigma1200, designed for a push bike but still alot more accurate than stock speedos after you tune it right. Unfortunately at the moment, just based on a clumsy wheelbase measurement, it reads 63 when stock says 60. I'm pretty sure it should be close to the other way around so need to tune it.

    I've heard the best way to do this is to find a measured length of road about 15-20kms. Then using the digital speedo vs. actual distance you can correct it. I know there are some places that have 'x km starts/ends here' signs, but I can't think of any. Can anyone recall some measured distances around 10-20km in sydney? Thanks!
  2. Newcastle Freeway, perhaps?

    I know there's one between Wollongong and Albion Park, but that's a bit far if all you want to do is to tune the speedo :LOL:.

  3. WTF! Is it worth it? How accurate can that be anyway with so many varibles?
    I'd go here:
    and scroll down to the part that shows you how to calculate the wheel setting.
  4. Not much point in doing it other than getting a more accurate speed since stock kawa speed is 4% wrong (like all speedos) and I've heard reports of up to 10% in extreme cases. So wanted to be more confident of the exact speed I'm going so I don't get done. Also I like the cool computer functions, clock, average speed, stockwatch ( :twisted: :cool: ), trip timer, extra odo, top speed ( :twisted: ). Like adding things to bikes as lets me learn a bit, and I have lots of free time at the moment.

    I don't need links for how to tune it, I have dozens of different installation guide sites and have already tuned it using it by measuring wheel base length, however it is not the most accurate way - doesn't take into account for when tyres are heated, road surfaces, full weight of me on bike, and other random things. Not to mention that a small error over 20km will make a significantly smaller than error from rolling it for a few wheel lengths.

    Thanks for trying to help though! :) Just need some measured 20kmish stretches, the more specific the better.

    edit: as to the sigmas accuracy, when tuned properly it will have about a 0.3% error at speeds less than 120km/h compared to 3-5% of stock speedos and up to 10% for kawas.

    *by error I'm referring to bike manufacturers showing you going that % faster (eg. indicated speed 60, vs. real speed 57) so that variances in your particular speedo will almost never mean that you're caught speeding because of speedo error.
  5. Best way is to borrow a sat nav, find a straight and quiet road, pick a dry day and calibrate away.
  6. My sigma was dead accurate when dialled in with gps.

    The only thing I didn't like about it was that it wasn't backlit, but you could rig something up pretty easily.
  7. Whenever I've installed and calibrated my Sigma Sports speedos, using the manufacturer's method of measuring the wheel's size and then entering in the figure never seemed to be totally spot on when checked against a GPS.

    I would find the flat and quiet piece of road about 3-5km in length. Then reset the speedo and the GPS's trip computer. Then do a couple of runs, compare figures, adjust the cycle speedo/computer til both indicated speed and trip meter were reading the same as the GPS.

    I've tried the 5km marker bit on highways but it's difficult to get it exactly right as I've had to watch for traffic. In any case, how do you know if the markers are correctly positioned?
  8. Yeh you need the 'x km starts/ends here' signs, as they are correct.

    As for gps, anyone care to lend me one? :cool:
  9. Pretty sure there isn't one on the F3 anymore. The only one I can thing of is on the slab down to Canberra...
  10. I think there's one near the Newcastle link road exit.

    Regards, Andrew.
  11. Much easier way. Find a nice flat bit of ground. Draw a chalk mark across the tyre. Roll the bike fowards till the wheel does a few turns -you might have to reapply the chalk a couple of times. Measure the distance with a tape. Divide by the number of turns of the wheel & enter this into the digital speedo. Should be spot on now as you have used the actual rolling diameter of your tyre.
  12. Yes, I already have done this twice. The most accurate way is real distance vs odo distance, but I need a signed measured length of road for that. And thats what I'm asking for.

    Sorry for the tone but I have researched sigma installation at length and don't need people telling me what to do, just where a signed distance is.. / use of someones gps.
  13. Do you have any speed check displays in Sydney?

    I find they are very accurate (when they work!). I calibrated my sigma off this first, it was only out 2km/h (according to gps) at 100km/h.
  14. find a nice fixed speed camera and testout your 60km/h, better yet ask a nice plod doing speed check to help you out. Bonza. :p
  15. As far as I know police cars use stock speedos, and thus would still be inaccurate. Need Romus to borrow a radar :LOL:

    Friend with prius is coming over today, think I'll try figuring something out with that.
  16. I did this with the Sigmasport. Unfortunately I couldn't get it calibrated accurately. I used a GPS later on to check it. Ended up finding a flat bit of road and compared GPS to Sigmasport readouts and adjusted settings til they matched.
  17. How strange!

    I re-measured wheel length with 10 rotations. Turned out to be 2mm off when I had measured with 2 rotations (200mm makes 10mph difference), so didn't even bother adjusting it. Went for a ride anyway and suddenly I'm doing an indicated 60 and digital speedo claims I'm doing 56. What the!

    Any ideas to explain this difference? would sensor moving slightly away/closer to magnet make a difference? Only thing i could think of was if the sensor was on the edge between not working and working so on some rotations it wasn't picking up the magnet, thus lowering the speed. But I'm pretty sure thats 100 to 1 shot.

  18. The difference between speedo and digital speedo may well be correct. Bike speedos are notoriously inaccurate and in the optimistic direction.

    The placement of the sensor and magnet may or may not make a difference. I dunno. I experimented by placing one (rare earth magnet) on the rim and one on the disc and mounted the sensor accordingly. Neither seemed to make any difference as to accuracy or otherwise.

    The sensor's placement in relation to the magnet does make a difference. I think that it has to be as close as possible to the magnet without the magnet hitting it, of course. I had problems with an Echowell F7 cycle computer. It would go spastic, indicating 120 km/h when doing 40 to 60 kays. And the max. speed reading would sometimes spike to around 350 km/h, even though the speedo is only good for 200 km/h...

    I ended up repositioning the sensor by rotating it around the fork leg. Seems to have fixed it. I think though, that I'll get another Sigma Sport. That brand seems to be more reliable, albeit more difficult to fit to a motorbike than the Echowell. I've had 3 Sigmas now, and all of them worked faultlessly (til they either failed or I upgraded or whatever).
  19. Thanks for that.

    I found one of those 'your current speed is x' signs on the way back from wisemans today and did a few laps. Seemed pretty dead on.

    Which is good as I'm going 3-4kms faster around town and up to 10kms faster at speed.