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Mechanical or Electronic Speedo?
albertz - 16/11/04 at 05:59 PM

I am about to order a speedo and rev counter, but i would appreciate some advice/guidance. Should i buy a mechanical or electronic speedo?

I have a type 9 gearbox coupled to a Toyota 4AGE engine. I have a dash made already with 80mm dia cutouts for the speedo and rev counter.

Will a standard mechanical speedo be the same drive as the type 9? what about calibration?

Also, is there any preference when it comes to SVA time in terms of accuracy?

Any help gratefully appreciated, i dont want to spend my hard earned cash on something which is no use.

Thanks


scoobyis2cool - 16/11/04 at 06:17 PM

I used an electrical one that takes readings from magnets on the prop shaft. It's pretty good but I think if I was doing it again I would look into a different type of sender - you can get ones that plug into the gearbox and take readings directly from there, like a mechanical one would, but they then convert that to an electrical signal.

This sounds like it would combine the accuracy of a mechanical speedo with the flexibility (in case you change wheel diameter etc) of an electrical one.

Pete


theconrodkid - 16/11/04 at 08:29 PM

the cable would need to go round a pretty tight corner and would probly break,electronic ones look sexier


wilkingj - 16/11/04 at 10:31 PM

I got an Electronic one from Half-Fords.
Expensive though!...

£4.99 in a Clearance bin, Its a bike speedo. Does up to 120Mph, miles, trip, and times. I will use this as the calibrated speedo.. Until I can find something nicer..


pmc_3 - 22/1/05 at 07:35 PM

I've heard of people using bike speedos before. Where do you mount the sensor and how do you calibrate for the different wheel size?


Peteff - 22/1/05 at 07:48 PM

Most use the circumference of the tyre to calibrate them and read out in MPH or KPH. Mount a magnet on a wheelrim or brakedrum and a sensor on a bracket.


britishtrident - 22/1/05 at 08:19 PM

Fitting a mechanical speedo to type 9 is fairly easy, but is has to match the final drive ratio, tyre size and speedo drive gear. Also in the Locost a right angled adaptor is needed or the cable will have to turn a very tight bend.

My car has a Smiths 1000 turn per mile speedo I think from a Trumph which was bought as new old stock from an autojumble for a tenner this worked out an exact match for my type 9 box and 3.89 english axle.


Rorty - 23/1/05 at 04:27 AM

I've used one of the bike speedos with a pickup mounted just above the six CV screw heads.
This article on fitting a bicycle speedo may be of interest.

or this article.


Trev Borg - 23/1/05 at 02:40 PM

What kind of money are you talking about for a decent looking electronis one.

I'm starting to put my loom together and have started loking at clocks. (although the have to be cheap..

Any one know of any good cheap white faced clocks.

There are a few on e-bay, Autogauge, progauge seem to be cheap and the need to be electronic. I don't want to mess around with pipes, files and alike


jollygreengiant - 25/1/05 at 07:12 PM

Granada's have the same gearbox type (engine relative) as Sierra's, BUT, Granada's have an electronic speedo and electronic gearbox output as standard with NO drive cable.




Enjoy.


James - 27/1/05 at 12:16 PM

Anybody know what sort of speed you need an electronic speedo to go up to?

I'm rather disappointed to find the really sexy Topeak one I wanted only does 99mph which I suspect won't be enough.

Cheers,
James


JAG - 27/1/05 at 12:28 PM

The SVA inspector will insist that it should read beyond the cars max' speed.

I have a Sigma Targa bike computer on my car. The instructions say that will read upto 300km/h or 183mph - that should be enough for my beast

The only downside to bike computers is that they don't have a backlight - another SVA requirement. I have made a bracket to mount mine on the dash and this also holds a spare bulb/bulb holder like the ones found in the back of all my other instruments. Hence when the lights are on the bike speedo' is illuminated.


James - 27/1/05 at 12:52 PM

quote:
Originally posted by JAG

The only downside to bike computers is that they don't have a backlight


Now you say that but... the Topeak one I want does have a backlight. In fact it's perfect (it even has service interval programming if you so desire) apart from the top speed!

Cheers,
James

[Edited on 27/1/05 by James]


JAG - 27/1/05 at 01:40 PM

Really - wow!

Not seen that one - pity about the top speed then.

All the Sigma computers (I have a 1200 unit on my mountain bike) read upto 300km/h.