Analog Speedometer

[Molotov256]

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...

 

[fetor56]

Try this:
http://www.motoredbikes.com/showthread.php?t=10156&highlight=mount+speedo

 

[Molotov256]

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...

 

[eltatertoto]

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...

 

[Molotov256]

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?

 

[eltatertoto]

Is it possible that I damaged either the reader or the speedometer by testing it backwards?

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.....

 

[Molotov256]

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?

 

[eltatertoto]

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

 

[Molotov256]

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

 

[Hawaii_Ed]

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.

Ed