In March 2017 A Speedo cable was purchased for type-9 gearbox to Jaeger clock from Speedy cables .
The speedo is naturally out of calibration due to the gearbox change.
Speed in mph is roughly half indicated speed in kph.
Several options are available to adjust this.
I feel keeping the instrument original is a good idea, so..
The speedo is naturally out of calibration due to the gearbox change.
Speed in mph is roughly half indicated speed in kph.
Several options are available to adjust this.
- speedy cables can calibrate the existing speedo. from £80
- www.speedograph-richfield.com can also calibrate the speedo but they also make mini gearboxes. from £90
- make my own gearbox with ratio 3/4.
I feel keeping the instrument original is a good idea, so..
I started with option 3 and made a cumbersome belt driven gearbox, connecting the input and output to the cables was the tricky part.
Then noticed that the speedo graph also do a type 9 right angle drive changer but also incorporate ratio changes. So this would help fix two issues at once as the speedo cable aims directly at the exhaust pipe.
The original speedo cable will also fit the new gadget.
I've contacted speedograph for details to ensure the ratio is correct.
Its possible the standard RGB1030-08A 1:1.33 NR ¾ x 26 / 3mm Square will be just right but nice to get it spot on.
Speedograph need the tyre size and number of turns per 6 wheel revs.
I measured the speedo cable rotation at the office car park as it has a gentle slope to aid pushing the 6 turns of the driven wheel. I measured 8-1/8 turns.
With tyre size 185/55/R15 this should have a radius of 72.3" and 877 revs per mile.
some Alpine speedos types
S/N 6117/01 - ??? - 1000 revs per mile
S/N 5324/18 - Series 3 o/d - 1408 revs per mile
S/N 5324/23 - Series 4
Anyway - it seems I need a 1:1.19 ratio mini gearbox
After a short wait I fitted the new box today - its not quite right as They recomended 1:1.19 and I thought I needed 1:1.33 - I think I was closer. Maybe my speedo isnt standard 😒
Oil leak is making a mess!
It turns out my speedo had already been modified for the Automatic box.
So Speedograph Richfield modified my speedo and it is now reading correctly and doesn't need the gearbox. The speedo is indicating a few mph lower than the GPS which is probably a good thing 😁
The speedo failed on the way to Le Mans 😞 - turns out it was the cable that broke.
I measured the speedo cable rotation at the office car park as it has a gentle slope to aid pushing the 6 turns of the driven wheel. I measured 8-1/8 turns.
With tyre size 185/55/R15 this should have a radius of 72.3" and 877 revs per mile.
some Alpine speedos types
S/N 6117/01 - ??? - 1000 revs per mile
S/N 6117/02 - Up to B9105974 - 980 revs per mile
S/N 6117/11 - From B9105975 up to Series 3 - 1000 revs per mileS/N 5324/18 - Series 3 o/d - 1408 revs per mile
S/N 5324/23 - Series 4
Anyway - it seems I need a 1:1.19 ratio mini gearbox
After a short wait I fitted the new box today - its not quite right as They recomended 1:1.19 and I thought I needed 1:1.33 - I think I was closer. Maybe my speedo isnt standard 😒
Oil leak is making a mess!
It turns out my speedo had already been modified for the Automatic box.
So Speedograph Richfield modified my speedo and it is now reading correctly and doesn't need the gearbox. The speedo is indicating a few mph lower than the GPS which is probably a good thing 😁
The speedo failed on the way to Le Mans 😞 - turns out it was the cable that broke.
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