BuggyNews Buggy Forum :: View topic - Speedometer Yerf Dog Gx150

Chris -

It is the circumference of the tire that determines the measurement. The height of the tire will determine how much ground you cover per rotation. Varying magnet and sensor placement will still yield the same number of mm per revolution. placing the magnet closer to the outside of the wheel will cause a short duration pulse at the same interval as placing it closer tot the hub and getting a longer pulse.

pghruby wrote:

I understand that...

We're saying the same thing..
Moving the magenet/sensor does have an affect on the speedometer calibration.

Actually you're not. Rim size or location of the magnet makes no difference. The magnet makes 1 revolution with the tire regardless at what radius it's mounted. The only measurement that matters is the circumference of the contact area of the tire. There's a small "fudge factor" involved due to tire inflation & how much "squish" there is at the bottom so it's really best to play with the input number to get the speedo readout to agree with a GPS but you'll get very close with the measured circ. or by calculating it by multiplying the tire height (mm) X 3.1416.

You guys made my head hurt. ](*,)

Just run WOT next to a vehicle and have THEM tell you how fast. Sounds a lot easier!!!!

Author:	jtramseyjr [ Sun Sep 21, 2008 1:14 pm ]
Post subject:	Speedometer Yerf Dog Gx150
Anyone remember how to calibrate the schwinn speedometer that was used on the Yerfs from Yerfer.net.Thanks James

Author:	pghruby [ Sun Sep 21, 2008 11:25 pm ]
Post subject:
In the Schwinn setup there is place to set wheel circumference. Measure the distance required for the front wheel to travel one full revolution in mm and input that number into your speedometer.You should be getting a number close to 1600 mm for a 20" tire.

Author:	TeamHog [ Mon Sep 22, 2008 6:15 pm ]
Post subject:
Remember, it's not the diameter of the tire, it's the circumference that the magnet travels. Most of the time this is the approx. circumference of the rim.

Author:	pghruby [ Mon Sep 22, 2008 6:43 pm ]
Post subject:
Chris - It is the circumference of the tire that determines the measurement. The height of the tire will determine how much ground you cover per rotation. Varying magnet and sensor placement will still yield the same number of mm per revolution. Placing the magnet closer to the outside of the wheel will cause a short duration pulse at the same interval as placing it closer tot the hub and getting a longer pulse.

Author:	TeamHog [ Mon Sep 22, 2008 6:50 pm ]
Post subject:
pghruby wrote: Chris - It is the circumference of the tire that determines the measurement. The height of the tire will determine how much ground you cover per rotation. Varying magnet and sensor placement will still yield the same number of mm per revolution. placing the magnet closer to the outside of the wheel will cause a short duration pulse at the same interval as placing it closer tot the hub and getting a longer pulse. I understand that... We're saying the same thing.. Moving the magenet/sensor does have an affect on the speedometer calibration.

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Speedometer Yerf Dog Gx150 http://buggynews.com/speedometer-yerf-dog-gx150-t15084.html	Page 1 of 2

Author:	guy48065 [ Tue Sep 23, 2008 9:04 pm ]
Post subject:
TeamHog wrote: pghruby wrote: Chris - It is the circumference of the tire that determines the measurement. The height of the tire will determine how much ground you cover per rotation. Varying magnet and sensor placement will still yield the same number of mm per revolution. placing the magnet closer to the outside of the wheel will cause a short duration pulse at the same interval as placing it closer tot the hub and getting a longer pulse. I understand that... We're saying the same thing.. Moving the magenet/sensor does have an affect on the speedometer calibration. Actually you're not. Rim size or location of the magnet makes no difference. The magnet makes 1 revolution with the tire regardless at what radius it's mounted. The only measurement that matters is the circumference of the contact area of the tire. There's a small "fudge factor" involved due to tire inflation & how much "squish" there is at the bottom so it's really best to play with the input number to get the speedo readout to agree with a GPS but you'll get very close with the measured circ. or by calculating it by multiplying the tire height (mm) X 3.1416.

Author:	jtramseyjr [ Tue Sep 23, 2008 10:19 pm ]
Post subject:
Thanks I found the Instructions today.Got to get the magnet and hook it all back up.

Author:	TeamHog [ Tue Sep 23, 2008 10:34 pm ]
Post subject:
guy48065 wrote: Actually you're not. Rim size or location of the magnet makes no difference. The magnet makes 1 revolution with the tire regardless at what radius it's mounted. The only measurement that matters is the circumference of the contact area of the tire. There's a small "fudge factor" involved due to tire inflation & how much "squish" there is at the bottom so it's really best to play with the input number to get the speedo readout to agree with a GPS but you'll get very close with the measured circ. or by calculating it by multiplying the tire height (mm) X 3.1416. You're right, I don't know what I was thinking. Too many sleepness work nights. I was thinking of a particular pulse generation on a turbine/generator set. Similar but different.... Sorry

Author:	MikeK [ Wed Sep 24, 2008 4:06 pm ]
Post subject:
You guys made my head hurt. Just run WOT next to a vehicle and have THEM tell you how fast. Sounds a lot easier!!!!

Author:	TeamHog [ Wed Sep 24, 2008 4:16 pm ]
Post subject:
MikeK wrote: You guys made my head hurt. Just run WOT next to a vehicle and have THEM tell you how fast. Sounds a lot easier!!!! Hey, if they pull you over you're going too fast... Otherwise you still need to mod.

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