Analog Speedometer

Discussion in 'Electrical' started by Molotov256, Mar 14, 2009.

  1. Molotov256

    Molotov256 Member

    Hey everybody -

    I'm trying to figure out a way to get a speedometer on my bike (mostly to satisfy my curiosity regarding how fast I'm going when it feels like I'm going really fast). I ordered an analog speedometer off ebay for pretty cheap, but it didn't come with any directions, so I just tried to figure it out on my own. It wasn't a very complicated unit - it's got a piece that mounts on the front axle and has a metal rod that sticks into the spokes to turn the reader, and cable turns with the reader and attaches to the speedometer itself to turn the needle over the gauge face. I think I hooked it all up right, but I'm getting obviously inaccurate readings. Here's some pics:


    The speedometer seems to think I'm going about twice as fast as I actually, am, but that's just an eyeballed estimate. Then, once the needle approaches 25mph, it jumps around all over the place and quickly pegs itself all the way around to the underside of 0, as if I'm going 70mph or something. When I stop the bike, the needle slowly works its way back down to zero, but it still indicates that I'm moving after I've stopped.

    I'm wondering if I have the reader piece that sits on the front axle clamped too tight between the forks... my front axle isn't very long, so it doesn't leave much room for the reader. Would I be better off with the reader outside of the forks? If that's the case, it would be problematic, because I wouldn't have enough thread left on the axle to put the nut on to hold the wheel in place.

    Has anybody else dealt with this kind of cable driven analog speedometer setup? Any insight would be much appreciated...

  2. fetor56

    fetor56 Guest

  3. Molotov256

    Molotov256 Member

    Thanks for the link - I've got the same speedometer as he does, but his seems to work right. I read through the thread, and it sounds like he had some issues fitting the reader in between the fork, too, but that didn't cause any issues in his application. I'm still not sure what's messing mine up...
  4. eltatertoto

    eltatertoto Guest

    sounds to me, like one of two things. the 1st thing is you might have installed the reader on the wrong side (see pics in other thread) the side without the cap says r, meaning it goes on the right. if you mounted it on the wrong side that could be the problem. the other possibility, is they sent you a head unit made for a 16" wheel rather than a 26" resulting in the "double speed" like you said. these were originally manufactured for stingray bikes in the 70's wich had 16 inch wheels. the 26 inch ones were an afterthought.

    my guess is the latter. id return it and have them send you a new one made for a 26" wheel...
  5. Molotov256

    Molotov256 Member

    Thanks for the feedback - this forum rules!

    I'm hoping mountainman is right - I'll give it a shot tomorrow. Sometimes the simplest fixes work best...

    As for Eltater's suggestion, I've contacted the ebay seller (bikeworldusa) about the possibility of exchanging readers, so we'll see where that goes. Regarding the left and right side installation, I learned the hard way; the first time I installed it, I got no reading off it whatsoever, so I figured I'd try taking the wheel back off and reinstalling it on the other side. That's when I noticed the L and R. Is it possible that I damaged either the reader or the speedometer by testing it backwards?
    Last edited: Mar 15, 2009
  6. eltatertoto

    eltatertoto Guest

    its possible, but not likely unless you were going full speed or somthing... because it has to go backwards or you would ruin it every time you pushed the bike backwards.....
  7. Molotov256

    Molotov256 Member

    I tried mountainman's microsoft style solution (take it apart and put it back together/turn it off and turn it back on), and it still doesn't work right. My ebay vendor got back with me and basically instructed me to make sure that I've got the reader on the correct side of the wheel, which I'm pretty sure I do since it didn't work at all on the other side.

    All in all, I'm not 100% committed to this particular speedometer, and after reading other posts about it, it doesn't sound like it will hold up too long even if I do get it to work. I've been looking on ebay for true moped/scooter speedometers, but most of them don't come with the cables and readers to operate the dial, and the ones that do seem to be driven by the axle of the specific model they're designed for instead of being spoke-driven. Can anybody out there recommend a more reliable setup than the one I'm pursuing right now with this ACME genero-brand unit?
  8. eltatertoto

    eltatertoto Guest

    im pretty sure most analog speedos use the same cable and fitting, so you might be able to use the existing cable....
  9. Molotov256

    Molotov256 Member

    Good news about the cable, Mr. Tater... how about the reader? It sounds like that's the weak link in this setup...
  10. Hawaii_Ed

    Hawaii_Ed Member

    Try disconnecting the cable from the sender, spin it with a drill. If the needle moves, the gauge and cable are ok. Also, attach the cable to the sender, disconnect it from the speedo, if the cable is spinning inside, the sender and cable are OK, and it is the gauge at fault.

    These are pretty cheap little units. I run one. The reviews say quite a high number arrive DOA.

  11. eltatertoto

    eltatertoto Guest

    well, ive never had a problem with mine, but the reader on mine looks oddly similar to the ones on my dad's harleys. and his are all metal. id go to your local harley dealership and ask to see some readers. just remember when shopping for a speedo, its not the reader or the cable that determines the readout, its what size wheel the speedo is designed for.

    you could always get a digital one, just make sure to route far away from the c.d.i, and the sparkplug/wire or you will get very odd readings.
  12. Molotov256

    Molotov256 Member

    I've been in contact with the seller, and she's agreed to send a replacement for the whole setup. The new one is on its way, and she's even sending a postage-paid envelope so I can return the seemingly defective unit. This is turning out to be one of the best ebay sellers I've ever dealt with, so we'll see how it goes from here.

    Thanks for all your help, everybody - hopefully this replacement works.
  13. eltatertoto

    eltatertoto Guest

    yeah the lady at bike world is cool. i ordered a lot of stuff from her last year.
  14. tony7281

    tony7281 New Member

    I have the exact same analog speedometer as Molotov.

    I'm trying to put it on a go-kart. Does anyone need to know where I can find a longer cable. I need one that is about 4'.
  15. bideronit13

    bideronit13 Member

  16. loquin

    loquin Active Member

    The speedo's are essentially identical for 26 inch and 20 inch, with one exception - the gearing in the axle unit.
  17. Big Red

    Big Red Active Member


    I have one, but only cause it looks cool. If you want accurate readings get a digital. Also, As you can see if you look close enough, it's not holding up very well. The needle is stuck at 5mph. It goes up, then comes back down to 5mph. The small 16" wheel I'm using makes it read 30mph when I'm only doing 15mph. I know, we clocked it with a car. But I allow for that and realize I'm not REALLY doing 60. :jester:

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