mechanical speedo's off by certain %, so i've heard, true?

[weaselnoze]

or i could make new faces that make my speed waay off. i'll think im doin 160!

[cay]

So you have a bar-mounted GPS on your GS?? care to post a pic of your setup? I hate using the GPS in my backpack.

Heh.  I've never been asked for pics before.  Is this what it feels like to be famous?  

My mount is made by a company called RAM -- they make great modular mounting systems designed around a 1" diameter rubber-sheathed ball.  On my bike I've got the following (links go to the shop where I bought them):

U-Bolt Base



3 inch arm



Cradle for Garmin GPS 60CS



Mount for cradle



And putting it all together...



take care,

C

[cay]

<regarding my post that a 10% overestimated speed should correspond to a 10% overestimated odometer reading>

No, it does not.  Speed is via a magnetic coupling/spring/damping arrangement and the odometer is geared - the DOT types get very angry when the recorded milage is off by any significant amount -

I could've sworn that after a nice long ride my odometer vs. gps was off by a significant amount.  It's a gorgeous day, I think I might have to test this empirically.    

take care,

C

[rizp]

Cay,
Dude, that's awesome. If I mounted my palm pilot on the bars, it'd rattle to pieces!   :lol:

I just tried to do a long tour through Western NY and got a bit..off course. Boy would *that* bar mount have been useful. Especially since I was too aloof to notice I was off course until I was WAAAY off. I ended up changing my trip plans from a loop to an overnight visit to my Parents' ~160 miles away.

Regards
Riz

[starwalt]

I wonder if the speedo is linear?

The speedometer input drives the odometer gearing. The eddy current coupling for the speedo is the same as the tach. With a few of these laying around on my bench, I am beginning to see an experiment involving an electric motor, external rpm sensing, and some required mechanical coupling.  

[Phaedrus]

Ok, I figured after reading through this thread I'd dig it up again 

Back to the original question. It never really seemed to be answered, only debated..unless I missed something.

Does the 15T sprocket swap have any impact on the already inaccurate speedometer? 

And yes weaselnoze has a good point. I think there is a market for some more accurate speed gauges. I used to know of a website of a small business that could make custom gauges. Anyone know a place like that?

[Alphamazing]

Does the 15T sprocket swap have any impact on the already inaccurate speedometer? 

Nope. The speedo is driven off the front wheel, rather than the countersprocket as many modern bikes. No change in gearing will change the speedometer reading.

[Phaedrus]

Thanks 

[PapaFox]

Yeah, I can also confirm that my speedo over-read by 10%, but the odometer recorded perfectly. I've fixed it now by adding a Sigma  BC800 computer. That things works perfectly for the bike, and was a snap to install. This is on a 05f FWIW