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Bicycle speedo in a car??
bitsilly - 12/8/10 at 04:30 PM

Has anyone successfully fitted a bicycle speedo to a car?
Someone mentioned it the other day that it was possible, and as my car has no speedo, it may be a locost solution!
Any suggestions of a good one (easy to fit) appreciated.
Cheers
Ed

matt_claydon - 12/8/10 at 04:32 PM

I know sigma ones have a third digit and can therefore read to 199 mph, mine's working well. Won't meet IVA for various reasons though if that matters.

02GF74 - 12/8/10 at 04:38 PM

I fitted one - cheapo halfords jobbie.

Escort axle drive flanges have two large holes - into one of which I fixed an aluminium disc, drilled to take the magnet, in core plug fashion, held in place by PU. (I mention this since VOSA station have rollers that are driven by rear wheels so fitting to front won't work)

A small bit of steel holds the reed switch sensor.

The display needs to be illuminated when the side lights are on - for this I have two white LEDs glued on with a small plastic hood.

Having said all that, I recall seeing the rules for IVA changed in that the speedo must always show mph, and some bike speedo have a button that changes the display to show other stuff.

I am pretty sure I passed SVA with this but then went to fit a proper Racetech speedo, making my own gearbox sensor.

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[Edited on 12/8/10 by 02GF74]

matt_claydon - 12/8/10 at 04:53 PM

quote:
Originally posted by 02GF74

Having said all that, I recall seeing the rules for IVA changed in that the speedo must always show mph, and some bike speedo have a button that changes the display to show other stuff.


For IVA, bicycle speedos are explicitly not allowed.

bitsilly - 12/8/10 at 05:17 PM

Thats all good! I thought people would just laugh!
Car is already road legal so IVA not an issue.
I did a quick check and noticed some only read up to 99.
Cheers all

cliftyhanger - 12/8/10 at 05:33 PM

I used a pair of bike speedo's for regularity rallies (used for distance) and they were amazingly accurate, could be set up to give zero error on a 1 mile stretch. They ran of a magnet glued with JB weld to the wheel rim, sensors on a small bit of steel attached to the brake disc shield. All very satisfactory in terms of accuracy, but a bit of fuss to reset, so coughed up for a Brantz.
Mine were fleabay cheapies, 3 cost a tenner delivered. (2 in the car, one spare) and measured speed up to 199 mph or kph

bitsilly - 12/8/10 at 06:13 PM

Have just bought a wireless one as I was worried about the length of the wire otherwise.
I'll let y'all know how it works once I have an engine!

skydivepaul - 12/8/10 at 06:17 PM

quote:
Originally posted by bitsilly
Have just bought a wireless one as I was worried about the length of the wire otherwise.
I'll let y'all know how it works once I have an engine!


the wireless ones do not work over about 1 metre. they are designed for the wheel sensor to be underneath the head unit which will be on the handlebars.
i have tried a few that will not work from the back wheel of my bike to the head unit on the handlebars

Dingz - 12/8/10 at 07:51 PM

I have used one for a long time, I have sierra diff with push in shafts, magnet is mounted on one of the tin can bits going into the diff, sensor hangs on a bracket. The gap has to be minimal, I extended the cable with thin screened wire, and just set it up knowing the size of the wheel. Works fine but impossible to read in the dark, I keep meaning to fit a small light but haven't done it yet.