Lotus Elan and Lotus Elan Plus 2 Forums

Carefully modifying the speedo on an Elan so that the face remains as is but is replaced by an electronic mechanism rather than cable drive?

Or is this something that Speedograph Richfield (or similar) have done for anyone?

I am tired of inaccurate speedos - especially with so many cameras out there nowadays and want a completely reliable speedo.

My alternative is to run a second electronic speedo but it does seem a little over the top (albeit it does preserve the original speedo)

Thanks
Gavin

I have this connected to my original mechanical Smith?s speedometer:

https://www.classicautoinnovations.com/classic

Gives an accurate reading regardless of gearing and tire size.

Hi Gavin,
If your speedo is working OK for normal driving purposes, then what about putting three white dots on the glass at 30, 50, and 70mph for camera use. I have done this on the tachometer, accurate when in top gear. Calibrated by G.P.S. and costs nothing and no changes to the car.
Just another option.
Eric in Burnley
1967 S3SE

Gavin,

I bought one of these devices from classicautoinnovations, and yes it seems to work. I say seems to work as my restoration is incomplete. I am installing an MT75 five speed gearbox into my Elan ( much more work than anticipated) and this gearbox has an electronic output to the speedometer. I am unable to convert the electronic signal to a mechanical drive, nor was I able to find anyone who can. I bought this device from classicautoinnovations and although not fitted to my car it seems to work whilst I hold the device when I am being driven by a friend. I could not resist the temptation to take the cover off and have a look inside, it is an electric motor the speed of which is being controlled by a GPS signal.

Richard Hawkins

Classic Speed GPS speedometer drive install:




Quite inobtrusive. Motor and antenna hidden.

This is an interesting post.

Gavin, you could also note that Caerbont (Smiths) produce original style speedometers with a digital feed (a sensor is placed on say the drive shafts).

However, the down side is that the upgraded mileage/km counter is digital, which is not very pretty. I have one of these for my Elan GTS car but it has yet to be installed and a fair amount of head scratching will be needed.

The classic auto innovations device sounds a more interesting idea. Perhaps Richard could give an idea of the dimensions / weight of the black box ?

Andrew

Here?s the spec sheet on the Classic Speed:

https://docs.wixstatic.com/ugd/bb633d_1 ... bda937.pdf

I particularly like that I didn?t have to calibrate for my 185/60 r13 tires. Installation was trivial. The Elan being fiberglass is nice because the antenna can be hidden completely.

I also ordered from them a speedometer cable of the correct length for where I placed the motor unit under the bonnet support. Slips perfectly into the space underneath.

gav wrote:My alternative is to run a second electronic speedo but it does seem a little over the top (albeit it does preserve the original speedo)

Thanks
Gavin

The classic speed device does look like the way to go if money and yet more devices to find space for in the engine bay are no problem. My cheapskate solution has been to use cycle speedometers - the sort that clamp to bicycle handlebars and work by having a magnetic sensor somewhere on the wheel hub. Over the last 20yrs or so I've used quite a few of them on motorcycles with useless speedometers and used one on the Elan for a while about 10yrs ago.

You can buy them now for about ?5 or less and from memory the Elan one took around 3hrs + glue drying time to fit. With a bit of calibration care they're accurate to 1mph or better.

I think we've discussed this awhile back and I remembered it was brilliant, eliminating all the speedo 'fixes' for
those to change to whatever 5 speed they choose. But just to reiterate: Nothing is needed to exit the
gearbox for this thing, right?

OR.....you could have your speedo. rebuilt and accurately calibrated by Speedy Cables. Mine is spot on.
Jim

Hi Gents
I have a similar speedo drive problem with a type 9 5 speed in an early Spyder space frame , can?t get a speedo drive on gearbox without serious space frame modifications.
For the last 2 years I?ve been using a Talex Lite safety camera alert unit , that uses gps signal to alert position of fixed safety cameras and a very accurate real time speed display, as a short term solution whist looking into alternatives- similar to the motor driven gps units, there is/was several different suppliers and being careful with expenditure was hoping to find a cheaper solution, whilst retaining classic smiths speedo look
Cheers
Mark

The T9 I have, has a cable driven speedometer drive. I turned up an adapter similar to the one used on the 2000E where the angle drive connects. The big difference was where the adapter is secured to the tailshaft housing. The flange needs to be much thinner, as the original for the T9 has a simple washer, secured by a circlip and not a forked piece.

To reiterate, no cable or right angle drive on the gearbox is needed or used with the Classic Speed unit. Just a normal speedo cable (of appropriate length) from the Classic Speed unit to the original Smiths speedometer. I have a plug for the gearbox speedo opening once the drive is removed from the gearbox though I haven?t done this yet. I have just put a protective cap on the right angle drive for now while it is still fitted to the gearbox and not being used.


As mentioned, it also eliminates the speedo connection problems sometimes encountered fitting alternative gearboxes.

I should further add, you don?t have to put the GPS motor unit in the engine bay. Since the speedo cable is flexible you could also put the unit somewhere inside the car, under the dash, or passenger footwell, or?
The website shows the unit installed in a variety of positions for various cars.

Frogelan wrote:This is an interesting post.

Gavin, you could also note that Caerbont (Smiths) produce original style speedometers with a digital feed (a sensor is placed on say the drive shafts).

However, the down side is that the upgraded mileage/km counter is digital, which is not very pretty. I have one of these for my Elan GTS car but it has yet to be installed and a fair amount of head scratching will be needed.

<Snip>

Andrew

I've fitted the Caerbont electronic speedo, and I'm very happy with it. No speedo cable, no inaccessible angle drive, no swinging needle. Perfect calibration. The digital mileage/tripmeter may not be quite original, but it works perfectly. I have the pick-up mounted on the diff to count the output shaft bolt lugs, pic attached.