Speedometer

[Cotmullion]

Is there any sort of cheap, simple speedometer to use on a minibike. I was wondering if a bicycle one would work.

 

[go kart mozart]

ude have to re calibrate it if its the kind that rides on the wheel

 

[Cotmullion]

ude have to re calibrate it if its the kind that rides on the wheel

You mean, on a bicycle wheel, when a contact will come around after every revoloution and hit another contact, or some other sort?

 

[Kenny_McCormic]

Those cheap bike speedo kits use a magnetic pickup you mount the included magnet on the wheel and put the pickup next to it, enter the distance between the axle center and magnet and you have a 99mph speedo.

 

[dpaxson]

you don't input the distance from the center to the magnet. you have to put in either the diameter or circumference of your wheels depending on the brand of bike spedomoter you're using

 

[Kenny_McCormic]

My bad, thinking wrong. If you put a certain number in it becomes a 10K rpm tach.

 

[Cotmullion]

I bought one on ebay and here it is, on my minibike, working and great:

 

[Buick455]

I have one on the way in the mail right now. How did you go about connecting the pickup magnet to the rim without spokes? I'm afraid it will go flyin and be lost forever, lol.

 

[Stumbo]

Do you have an iphone?

 

[spilde24]

i found one for 10 bucks online http://images.google.com/imgres?img...ox-a&rls=org.mozilla:en-US:official&sa=N&um=1
was yours this cheap, would this work on a mini and or a go kart?

 

[hurricane_lane]

I went to Dick's sporting goods, here, in my area and picked up a Sigma 1200 for $20. It was extremely easy to calibrate.

All I had to do was measure the (rolling) circumference of my tire. I just made a mark on my tire with chalk where the valve stem is and then marked the pavement. I then pushed my kart one full revolution and made another mark. Measured from one chalk mark to the other and had my circumference in inches. But bike computers are in metrics, thus making them as accurate as a mm. It's based off of the following formula:

Input your numbers into the formula, multiply into mm and then divide to get your mph reading.

WS(Wheel Size)=RC(rolling circumference in inches) x 25.4(#mm in 1 in.) / 1.61(#of kilometers in 1 mile) = mph

For example:
Tire Rolling Circumference= 36" x 25.4mm=914.4mm
914.4/1.61= 567.95 or 568 <-------------- this is the number you enter into the bike computer. The computers have 4 digit entry, so if its only 3 digits just enter 0 first and then your number it's calibrated.

I hope this helps! Just ignore the Wheel Size chart in the bike computer manual. If you want to see a video of the calibration process you can get it on youtube.

 

[spilde24]

ok i just purchased a bell speedo from target for nine bucks and i welded a fake spoke on the inside of the rim. what i am wondering is if it matters how close the magnet is to the outside because in the manual it says to place the magnet on the spoke and it doesnt specifically say where on the spoke to place it so i am just wondering if it matters where on the wheel the magnet is placed

 

[napalmfire]

It doesn't matter where on the spoke the magnet has to be because one rotation (one pass of the magnet) no matter where it happens to be on the spoke, means that the wheel has traveled however long the tire rolled.

 

[mike75925]

double sided tape, as long as you aren't spinning the wheels too fast. you could try some two ton epoxy as well

 

[Raywelder]

Heres a crazy idea. What if you got a speedo and speedo drive unit from a motorcycle, and Gear the speedo drive so the It will be equivalent to the bikes stock tire size.

 

[spilde24]

i bought a 9 dollar bell speedo for my gokart and to attach the magnet all i did was weld a fake spoke onto my wheel and clamp the magnet to that and it works great