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Speedo query???
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Jim_Gruber
Yoda
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Or you cvan ignore it and go to a SIGMA Digital Speedo for your Spridget like I did for Bugsy. An interesting engineering challenge you can do for $35-$40 and always have a right on Speedo. That does not jump and is always accurate.
Pythias
Jedi Knight
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Is it the speedo or a loose drive gear from the tranny?
Have you tried another speedo?
An easy check is to pull the cable off the back and hold the end in your fingers as you drive. If you feel the cable pulsing, (and you've already greased the it in the housing) it's most likey the tranny, not the speedo. ..
Have you tried another speedo?
An easy check is to pull the cable off the back and hold the end in your fingers as you drive. If you feel the cable pulsing, (and you've already greased the it in the housing) it's most likey the tranny, not the speedo. ..
I swapped a crappy old speedo from my parts stash and it works fine so I am ruling out the cable or drive. I'd like to refit the original cause the blue jewel still glows blue, the odometer says 35K, and the bezel is'nt rust pitted. Suppose I could start swapping piece'es but my time has a little value.
I'm wondering if sitting for almost 40 years could have magnetized something that is'nt supposed to be. Any one run into similiar problems?
Kurt.
I'm wondering if sitting for almost 40 years could have magnetized something that is'nt supposed to be. Any one run into similiar problems?
Kurt.
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Jim, tell us more about the SIGMA speedo.
Thanks,
Charlie
Thanks,
Charlie
dklawson
Yoda
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Until Jim gets back...
Sigma is a bicycle speedometer. They use magnetic pickups so you bond a magnet onto a rotating component, extend the switch wires (the original bicycle wires will likely be too short), then mount the pickup so it can detect the magnet going by. The Sigma bicycle speedos are programmable based on the tire diameter. You can get them "close" by calculation and then determine an exact setting based on either comparing the display with a GPS... or driving a measured distance. They are wonderfully accurate and easy to mount.
I have used both the Sigma BC800 and the BC1600L. The 1600L has an EEPROM that will save your calibration and odometer settings so that when the battery dies you don't loose anything.
EDIT:
The picture in the link below shows my 1600L mounted on the dash of our Mini. The wire above it is a small LED to illuminate it at night.
https://home.mindspring.com/~purlawson/pictures/gauges/Dash03.jpg
Sigma is a bicycle speedometer. They use magnetic pickups so you bond a magnet onto a rotating component, extend the switch wires (the original bicycle wires will likely be too short), then mount the pickup so it can detect the magnet going by. The Sigma bicycle speedos are programmable based on the tire diameter. You can get them "close" by calculation and then determine an exact setting based on either comparing the display with a GPS... or driving a measured distance. They are wonderfully accurate and easy to mount.
I have used both the Sigma BC800 and the BC1600L. The 1600L has an EEPROM that will save your calibration and odometer settings so that when the battery dies you don't loose anything.
EDIT:
The picture in the link below shows my 1600L mounted on the dash of our Mini. The wire above it is a small LED to illuminate it at night.
https://home.mindspring.com/~purlawson/pictures/gauges/Dash03.jpg
dklawson
Yoda
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On a bike... wireless is easy since you are talking about the signal going from the forks to the handlebars. Wireless may not be an option on a car. The signal would have to travel through sheet metal to get from the switch to the display.
Sigma has a tech support office in the U.S. They know that a lot of people use the bike computers for other purposes and do a decent job of answering non-bicycle questions about their product. For example, I learned through them that the fastest pulses their products can handle are about 30 Hz. That means on a Spridget you need to count wheel revolutions, not driveshaft revolutions.
Sigma has a tech support office in the U.S. They know that a lot of people use the bike computers for other purposes and do a decent job of answering non-bicycle questions about their product. For example, I learned through them that the fastest pulses their products can handle are about 30 Hz. That means on a Spridget you need to count wheel revolutions, not driveshaft revolutions.
Jim_Gruber
Yoda
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I took a new pic hopefully attached below that shows how I mounted the Digtal Speedo in Bugsy. Need to go wired as wireless distance ratings are < 4'.A couple of things I used for Bugsy.
1) Sigma Bicycle Speedo - Wired - Can read up to 180 MPH
2) Magnetic Reed Switch - I replaced the standard switch from Sigma with a commercial rated magnetic reed switch $2.50 at any industrial; parts place, Grainger. Easier mounting flat package
3) Round Button Magnet - cone 10-15 per package - Hardware store $3.00
4) Aluminum bar stock, 1": wide x 6"-or so - Drilled to fit spacing of rear spring U bolt, bar extends and holds magnetic reed switch pickup next to rear drum. $1.59; 2 nuts and lock washer to fit lower spring U bolt
5) J-B Weld - used to glue button magnet to rear drum and hold reed switch to pickup Bar Stock Arm.
6) Telephone mounting cord - flexible, bends, can handle flexing needed as rear axle moves up and down.
1) Sigma Bicycle Speedo - Wired - Can read up to 180 MPH
2) Magnetic Reed Switch - I replaced the standard switch from Sigma with a commercial rated magnetic reed switch $2.50 at any industrial; parts place, Grainger. Easier mounting flat package
3) Round Button Magnet - cone 10-15 per package - Hardware store $3.00
4) Aluminum bar stock, 1": wide x 6"-or so - Drilled to fit spacing of rear spring U bolt, bar extends and holds magnetic reed switch pickup next to rear drum. $1.59; 2 nuts and lock washer to fit lower spring U bolt
5) J-B Weld - used to glue button magnet to rear drum and hold reed switch to pickup Bar Stock Arm.
6) Telephone mounting cord - flexible, bends, can handle flexing needed as rear axle moves up and down.
Attachments
Jim_Gruber
Yoda
Offline
Speedo Readout is mounted to a piece of scrap sheetmetal with one side drilled to fit mirror mount and the other side going to a right angle tab that sticks up and rubber bungy bands that come with speedo wrap around.
Round 3/4" button magnet is glued to outside of drum using JB Weld. Prep drum by using a sanding disk and cleaning off some of the rust on spot where magnet will be glued on.
Pickup arm mounts to one of the Spring U bolt shackles, I used a piece of angle iron bolted to the pickup arm to provide a 90 degree angle flat surface for mounting the reed swich.
Round 3/4" button magnet is glued to outside of drum using JB Weld. Prep drum by using a sanding disk and cleaning off some of the rust on spot where magnet will be glued on.
Pickup arm mounts to one of the Spring U bolt shackles, I used a piece of angle iron bolted to the pickup arm to provide a 90 degree angle flat surface for mounting the reed swich.
Attachments
Jim_Gruber
Yoda
Offline
I can provide more details for anyone interested. This setup has worked well for me for the past 6 years. Total investment $35-$40 plus some spare bits of wire in the shop. Speedo is absolutely accurate as readings are calibrated to circumference of tires.
I found a reference to using bicycle speedo in a Lotis 7 Kit Car but I cannot locate the link any more. Anyway an interesting engineering challenge and a fun project.
I found a reference to using bicycle speedo in a Lotis 7 Kit Car but I cannot locate the link any more. Anyway an interesting engineering challenge and a fun project.