Speedo

norseman · Apr 22, 2024

Hi guys

The speedometer of my '87 RRC has thrown a wobbly @ exactly 63k recorded miles. Worked fine up to a short stop in a journey but when it was resumed I became aware of this loud ticking sound, much like a grandfather clock, increasing with road-speed.

Curiously the needle is still recording the speed but is bouncy + or - 5mph at all speeds & neither the odometer or trip mileage are advancing.
The instrument is cable driven on this car, not electronic & as the needle is being driven I assume the cable (2 part) is intact & the fault lies in the instrument itself, though 63k is not exactly a high mileage (?)

Any ideas as to a repairer of speedometers.
I don't think a used unit is a good move, for obvious reasons.

pwood999 · Apr 22, 2024

Sounds like you might have two problems, i.e. stripped gears on the odometer, and the cable needs some lubrication ?

Quixote · Apr 22, 2024

Or, hopefully, just a snapped inner cable

Datatek · Apr 22, 2024

norseman said:
Hi guys

The speedometer of my '87 RRC has thrown a wobbly @ exactly 63k recorded miles. Worked fine up to a short stop in a journey but when it was resumed I became aware of this loud ticking sound, much like a grandfather clock, increasing with road-speed.

Curiously the needle is still recording the speed but is bouncy + or - 5mph at all speeds & neither the odometer or trip mileage are advancing.
The instrument is cable driven on this car, not electronic & as the needle is being driven I assume the cable (2 part) is intact & the fault lies in the instrument itself, though 63k is not exactly a high mileage (?)

Any ideas as to a repairer of speedometers.
I don't think a used unit is a good move, for obvious reasons.

I would bet on the cable.

norseman · Apr 22, 2024

Many thanks for the replies guys, but I don't understand .. if the cable (which was lubed last year to cure a slight needle waver) has failed/snapped why would the speedo continue to give a reading that (if you ignore the 'ticking' & needle bounce) proves accurate when matched to the rev. counter?

Datatek · Apr 23, 2024

norseman said:
Many thanks for the replies guys, but I don't understand .. if the cable (which was lubed last year to cure a slight needle waver) has failed/snapped why would the speedo continue to give a reading that (if you ignore the 'ticking' & needle bounce) proves accurate when matched to the rev. counter?

The needle uses a kind on flywheel effect, the milometer is a direct drive with a kind on ratchet that advances the number wheels. If the cable is flicking back and forth it can stop or slow the advance of the wheels.

aj1954 · Apr 23, 2024

norseman said:
Hi guys

The speedometer of my '87 RRC has thrown a wobbly @ exactly 63k recorded miles. Worked fine up to a short stop in a journey but when it was resumed I became aware of this loud ticking sound, much like a grandfather clock, increasing with road-speed.

Curiously the needle is still recording the speed but is bouncy + or - 5mph at all speeds & neither the odometer or trip mileage are advancing.
The instrument is cable driven on this car, not electronic & as the needle is being driven I assume the cable (2 part) is intact & the fault lies in the instrument itself, though 63k is not exactly a high mileage (?)

Any ideas as to a repairer of speedometers.
I don't think a used unit is a good move, for obvious reasons.

There was a firm called Speedy cables, think they were in London, don't know if they're still going though.

Ratae · Apr 23, 2024

You can't ignore the 'ticking & needle bounce'
You will have the same setup as my '86 EFi.
Suggests an issue with one or both of the cables, the drive gear at the transfer box end, the angle drive gear on the back of the speedo or an internal speedo issue.
Angle drive gear grease can harden & you will get the flickering needle - had it but the odometer still worked.
I don't know if they still do speedo work as it's over 25 years ago but these used to do all the calibration for Leicestershire police cars:
www.irs-gb.com

norseman · Apr 23, 2024

Many thanks again for the recent replies guys, much appreciated.
Poor close work eyesight & arthritis in my hand leaves me 2 choices (1) ignore the problem & drive on the tacho or ask my local mechanic to check out the cable(s) as a starting point .. I'll go with the latter, but it might be a while before I can get the car booked in as the garage is always busy.
Meantime I'll have to endure the speedo sounding like a grandfather clock !

nb: thinking about it I'm pretty sure I have a new 2 part cable .. somewhere

Speedo

norseman

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pwood999

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Quixote

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Datatek

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norseman

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Datatek

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aj1954

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Ratae

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norseman

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