Speedometer for 1999 Caterham

[Scott_]

I've done a search and don't see anything recent.   I've recently acquired a 99 Caterham with a history of failing speedometers.  It appears that various drives and cables have been replaced over the last 25 years even though the car has not been driven that much.  The speedometer has recently failed again and I'm not inclined to fix the problem the same way and am looking to replace it..

 

Is anyone aware of an 80mm GPS speedo that looks similar to the Caterham unit or an 80mm non-GPS one with a sensor I could run to  one of the front wheels?

 

I have found the Speedhut GPS units but those are 85mm and I'm not wanting to modify the dash.   

 

Thanks!

 

Scott

 

 

 

 

[toldfield]

This might work

 

https://mossmotors.com/440-600-t5-smiths-classic-digital-speedometers

 

I went with a Smith's GPS speedo for my car.

 

https://www.nisonger.com/smiths-classic-gauges.htm

 

Tom

[7Westfield]

Racetech has a 80mm unit   I got mine from Burton, surely someone over here has them

 

Mine is wired to the transmission, but I'm sure you can put a GPS sender on it

[MV8]

Mech speedo failures are normally lack of fresh lubrication on the cable (tend to cause a jumpy indicator needle before failure) but can also be caused by poor cable routing. I assume you have a 90 degree drive at the trans.

 

A gps speedo may also have a separate module that should sit in the open for line of sight to the satellite(s) and may still loose indication around buildings and tunnels.

 

The difference in a standard 3-3/8 gauge and the opening in your dash may only be a radius of .059" or less and could be rolled in versus filed away.

[Scott_]

Thank you all, I have my research cut out for me and appreciate the insights.  

 

Scott

[IamScotticus]

+1 for the Racetech.  

RTSC130 and sensors.  

The Racerech speedo has an input that can accept a GPS or a, what I call a proximity or hall effect sensor.  That one is placed near a rotating item like a drive shaft or brake rotor. It senses the rotation.

[IamScotticus]

Regarding Smiths 440-601,

Here:

https://mossmotors.com/440-600-t5-smiths-classic-digital-speedometers

 

 

 

Edited January 22 by IamScotticus

[MV8]

There are very reasonably priced programmable speedos that require a sensor (usually magnetic pickup but there could be hall effect units out there). Depending on the transmission, an oem type electronic speed sensor (such as from a late-80s or newer application) can be installed to replace the cable attachment and 90 degree gear box if equipped. If the programmable speedo input required is a specific waveform or range of rpm and frequency, there are cheap signal conditioners that can be installed. The end result should be about $200 or less in parts.

 

If replacing the original mech speedo with another mech speedo, even if the existing cable fits the speedo, the calibration of the speedo itself varies for Cat depending on the year model as well as the aftermarket units. It just means that a cable drive gear swap may be required. This can be the trans output shaft gear, driven gear, or the gears in the 90 degree box. Speedos are usually between 1000 and 1100 rpm for a 60 mph indication and often have it written on the face.

 

I've lubed cables once the speedo started jumping and they are still in service years later without a relapse (used synthetic wheel bearing grease). If ignored, the cable will fail. Cable cores are available and quils can be made if a replacement cannot be found or the old one repaired.

[Scott_]

I ended up going for Motogadget multifunction gauges for the tach and speedo.   They are 80mm and a bit spendy, but I was aware of these products from my motorcycle hobby.  I 3d printed mounts for them and wiring was fairly straightforward.   So far, apart from tach and speedo, I have only wired in the turn signal blinker. I do like the voltmeter showing.    The Speedometer is triggered by a sensor i ran to the front right wheel.

 

 

 

 

Edited February 14 by Scott_

[IamScotticus]

OH, GOODNESS, THIS IS AN EXCELLENT RECOMMENDATION!

https://www.motogadget.us/products/chronoclassic-2

https://spieglerusa.com/gauges-instruments/analog-gauges/analog-speedo-classic/msc-mounting-clamp-5942.html

 

Does this come as a set? both chrono and speedo for $500?

Let's assume not, do both chrono and speedo have the same digital displays?

 

Could you elaborate on the speedo sensor adaptation? what kind of pick-up?

This?

https://spieglerusa.com/gauges-instruments/analog-gauges/analog-speedo-classic/speedo-sensor-m5-reed-contact-5992.html

Edited February 15 by IamScotticus

[Scott_]

No, sadly that is the cost per unit. However, you get rpm and speedo in both so if you can stand the style mismatch between your original gauge and the Motogadget gauge it would be fine... that was my original plan.... but I couldn't stand the mismatch..

 

Each instrument comes with a speed switch and magnets.  One can be saved as a spare.  On the speedometer the top digital display would be rpm and on the tach the top digital display would be speed.  The lower display on each can show volts, time, oil pressure, and so on as you chose.   My lower display is currently set up with volts on the tach and time on the speedo.  You can set warning lights, for example if the voltage falls below 11.9, or whatever.

 

As you can see from my videos, I do not have the tach signal going to the speedometer yet or the speed signal going to the tach.   That's next on my list of things to do as well as wiring the high beam and the other warning lights to show on one of the instruments.

 

 

 

Here are more details of the installation....

 

The reed speedo sensor is a simple magnet/proximity switch that sends a ground signal to the unit on each rotation of the wheel. A tiny rare earth magnet is glued to the rim.   I made a mount for the switch out of aluminum and a clamp I found on Amazon https://www.amazon.com/dp/B09MLKKW3L?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1 and used the fender stay as the mounting point.  I measured my front wheel and worked out the diameter in mm's and input that into the gauge and got it very close to my GPS speed on the first try.

 

On the tach, at least on my '99 tach plug, pin #3 is the tach signal wire and pin #6 is switched 12v and pin #5 is ground.  Those plus constant 12v from the fuse box are the main taps one needs to make the motogadget tach  work and can also go to the speedo for tach functionality.   The ground signal from the speed/reed switch provides the speed signal to each instrument.

 

I like that I could set the odometer to match the car's mileage.   I haven't set up the shift light or gear indicator or most of the other functions yet.

 

I bought a Motogadget breakout box and apart from speed and tach, that is what the other sensors would go into and then to the instrument through the orange LIN BUS wire.  Rather than cutting wires in the dash I simply tapped the original wiring where needed and ran the constant 12v from the fuse box with a fuse tap.  

 

I added an 80mm o-ring between the bezel and the dash on each gauge to give the installation some depth to help match the larger bezels of the original  instruments.   https://www.amazon.com/dp/B00VFK535G?ref=ppx_yo2ov_dt_b_fed_asin_title

 

Each gauge has three 3mm holes on the back so I cut 3mm threaded rod to length and used my 3d printed mounts and thumb nuts to secure each instrument.    This is the threaded rod: https://www.amazon.com/dp/B0D22QGKHN?ref=ppx_yo2ov_dt_b_fed_asin_title&th=1   I can share the 3d mounts if anyone wants the STL files.  3mm thumb nuts here: https://www.amazon.com/dp/B0DCYK3B98/ref=sspa_dk_detail_1?psc=1&pd_rd_i=B0DCYK3B98&pd_rd_w=Un3M9&content-id=amzn1.sym.8c2f9165-8e93-42a1-8313-73d3809141a2&pf_rd_p=8c2f9165-8e93-42a1-8313-73d3809141a2&pf_rd_r=1QJ58083RXS84TH8TRMZ&pd_rd_wg=cAblT&pd_rd_r=cba31dc4-164b-43ee-9c55-3416a40837e5&s=industrial&sp_csd=d2lkZ2V0TmFtZT1zcF9kZXRhaWw

 

 

I used the hole for the odometer reset for the switch to control the functions on the instruments.   Each instrument comes with a small switch you can install.   I decided to reduce that to one switch to control both.  The hole had to be enlarged slightly.  This is the switch I settled on: https://www.amazon.com/dp/B000HEKULI?ref=ppx_yo2ov_dt_b_fed_asin_title   Clicking left controls the tach and clicking right controls the speedometer.

 

The wiring for either gauge and the breakout box is below.

 

 

Edited February 15 by Scott_

[JohnCh]

In 2006, I replaced a Spa Instruments combined tach/speedo in my Westfield with the original Motogadget Chronoclassic. Other than a reseal required in 2014 (condensation appeared behind the glass) it was still working flawlessly when I sold the car last June. It's a really nice bit of kit, and the newer Chronoclassic 2 you installed looks even better. I wired the yellow button on the steering wheel to control all the functions and programming, the latter of which was shockingly easy given it's a single button to dig through multiple menus. Surprisingly to me, it's much faster and easier to use than the multi-button interface in the AiM MXS I installed in the Caterham.

 

[Scott_]

9 hours ago, JohnCh said:

In 2006, I replaced a Spa Instruments combined tach/speedo in my Westfield with the original Motogadget Chronoclassic. Other than a reseal required in 2014 (condensation appeared behind the glass) it was still working flawlessly when I sold the car last June. It's a really nice bit of kit, and the newer Chronoclassic 2 you installed looks even better. I wired the yellow button on the steering wheel to control all the functions and programming, the latter of which was shockingly easy given it's a single button to dig through multiple menus. Surprisingly to me, it's much faster and easier to use than the multi-button interface in the AiM MXS I installed in the Caterham.

 

 

I'm glad to hear it held up well.    I couldn’t be more please with these gauges.   
 

Scott 

[Slonie]

That Motogadget looks trick (and aesthetically nice as well). And @JohnCh, that's a really good gauge layout you've got there with the Racetech water temp and dual gauge for oil temp/pressure on either side.

[IamScotticus]

Racetech RTSC130 was my first choice for a reed sensor speedo. may still be. But that Motogadget takes up a lot less room behind the dash.  Tempting.

The only nagging issue with Motogadget that would bother me is having 80mph on the dial (120-200) I will never use.

For my car, which I plan to have a single tach in the center, the 8K RPM tach with the MPH in LED display would work nicely.

Edited February 16 by IamScotticus

[Scott_]

 

2 hours ago, IamScotticus said:

Racetech RTSC130 was my first choice for a reed sensor speedo. may still be. But that Motogadget takes up a lot less room behind the dash.  Tempting.

The only nagging issue with Motogadget that would bother me is having 80mph on the dial (120-200) I will never use.

For my car, which I plan to have a single tach in the center, the 8K RPM tach with the MPH in LED display would work nicely.

 

You can switch to kph and the 200 makes perfect sense,.

 

As far as the 200 scale in mph, I think it's hilarious and love the joke.

 

Scott