Speedometer/Odometer with Timbersled

n16ht5 · Jan 18, 2015

So not knowing how many miles I have gone bothered me... :noidea: had a bicycle speedometer in the shop and got an idea. Only problem now is how to calculate it?

I have 17/20/17 gearing on a LT. I did a runout measurement on the track and got 23" for one revolution of the sprocket that the speedo pickup is on.

23" X 25.4 = 584MM - which is entered into the ratio on the speedo

I would imagine that would be the same as the circumference of an imaginary wheel that the computer would be trying to clock. Correct?

I am going riding tomorrow, I'll try and check it with GPS and adjust from there. Spinning the track around in the shop it seems to work right.

Took off the inside jackshaft sprocket and drilled it to accept the magnet bolt

the magnet bolt for the speedo pickup

up-high · Jan 18, 2015

If you already have GPS? And how accurate can it be with track spin?

Jon Mutiger · Jan 18, 2015

Your logic is flawed. You aren't measuring track rotation speed at that point. You might be able to calibrate it on the trail vs the gps but it won't be as you described it. I doubt the speedo has enough calibration room to get accurate.

Jon

lacesout · Jan 19, 2015

download the app called "ski tracks"

Wheel House Motorsports · Jan 19, 2015

I use google tracks on my phone to check stuff out. GPS based, exact distance and all sorts of stats along with easy overlay on Google earth or maps.

Butta · Jan 19, 2015

Honestly, I think tracking engine hours is more vital than actual miles driven. Terrain, which gear you are in, etc, all change how many miles your track is actually turning, but engine hours will be consistent. I always put an hour meter on my dirt bikes and performed maintenance accordingly. Worked like a champ for me.

Chadx · Jan 19, 2015

Keep us posted if you are able to get enough adjustment to get it accurate. Always fun to tinker. People have tried different odometers and like Jon mentioned, they seem to not handle the extreme adjustment needed to get accurate.

I just use my gps, but some use the trail tech voyager and like it.
http://www.trailtech.net/digital-gauges/voyager-moto-gps

swedenturbo · Jan 20, 2015

I'm using Koso Stage 6 mulitguage.
Bought it primary for temp guage but it also have more features
Speedometer, odometer, tacometer, revcounter, three shiftlights and dual temp guages.
Is this a must have on your snowbike? Probably not....

You can install two temp probes. I've installed only one at the fan sensor plug.
With a T-piece you can put the second probe on some other coolant hose.

Speedo trigger picks up signal from a magneto installed on one brake disk bolt.
Quite easy to calibrate.
You measure how far the track has moved for one revolution on jackshaft.
Enter the measured distance on the guage menu and you're done. No gear ratio calulation is required.

n16ht5 · Jan 20, 2015

So it worked flawlessly for .69 miles then freaked out and stopped working from the cold temp. Going to check out that koso stage 6. I might just stick to GPS readings

n16ht5 · Jan 20, 2015

I have an hr meter

n16ht5 · Jan 22, 2015

I figured out why it quit working. the small magnet fell out of the through bolt that went through the sprocket. epoxy a new one in and I am good! This mod works!

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Speedometer/Odometer with Timbersled

n16ht5

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up-high

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Jon Mutiger

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lacesout

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Wheel House Motorsports

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Butta

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Chadx

♫ In the pow again. Just can't wait to get in..

swedenturbo

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n16ht5

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n16ht5

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n16ht5

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