Speedo Cable Killer

[Fanfaniracing]

My mini is actually a Speedocable Killer. the Cable he destroyed this Week is the fourth in only 60km

First two cables were chopped on the Speedometer side, the two others were chopped by the gearbox side...

Any suggestions what could the cause?

First cable was in the Car for more than 18 years...

3A333016-9F19-42D2-9E73-D326344150ED.jpeg

[Herbert]

seems like something wrong at the speedo end. Get a new cable and just screw it on the speedo. Then put a drill on the other end, Im not sure which way to rotate the cable and then slowly start the drill. If the speedo works then the prob is at the other end.

[Peter Laidler]

You have only shown us the INNER cable and you haven't told us whether you replaced only the INNER cable or BOTH the inner AND the outer

All the inner cable does at the speedo end is to rotate a round magnetised driver plate that operates the speedo pointer. And a plastic gear wheel that operates against another plastic cog that.... Anyway that serves the plastic odometer part. There is very little in the way of friction - especially the friction forces that would cause the spring steel wire inner cable to chomp itself to death........, 4 times over 60km's

I'd be looking at the outer cable. Not just looking at it, but replacing it

[Fanfaniracing]

Thanks for reply!

The Speedo was overhauled by a professional 3 years go and works fine and was never this accurate before the overhaul.

I replaced every time the entire Cable, GSD101MS from our favorite Supplier.

The Second Cable was the original Cable from my 1965 Countryman.

I have two new Cables left but hesitate to roast another...

[Peter Laidler]

As I thought, it's certainly not a speedo head problem then. From my instrument days I seem to recall that for the speedo to advance, the cable turns anti clockwise. I would lay the new speedo cable assembly flat along a table and put the gearbox end into a battery drill, set to rotate anti-clocklwise. Then test it flat/straight, like that. If that is satisfactory, I'd say that you have kinked the cable while attaching it to the car.

[Herbert]

I must admit, but to change the speedo cable in a mini is by far the worst job to do. I end up with cramp in my hand in trying to thread the cable at the gearbox end. I once took the drive shaft out so I could get in there! Joke !

[TECH396]

Just a thought.... From the looks of that cable, it's broken closest to the speedo head, which says the issue is above that break point.
I'd be carefully testing the speedo head. Also make sure the cable isn't protruding into the head so much that it causes binding when done up tight.
I have several here, and just tested one that i knew had an issue. I used only my fingers and test piece of cable to spin the speedo anticlockwise
(viewed from the back) and every 20th revolution, it would begin to bind. Not a lot, but enough for concern. That resistance will be amplified with faster speeds. Check your speedo head is my thought.

[Fanfaniracing]

If i remember right, the 18 year old cable broke on the upper side 2 cm

The others all broke on the gearbox/ drive side. With the 8 Port it's very easy to replace the cable in 5-10 minutes and there is plenty of space to route it without a kinking it...

[Peter Laidler]

Have you run the cable straight and flat yet? That will eliminate a cable fault. VERY unlikely to be a speedo head problem because due to the very nature of the beast, if the speedo and odometer is working, then by its very nature, there can be hardly any friction (within the head) to cause such a catastrophic failure.

Incidentally, drive cables were one of the exceptions relating to grease. The usual rule of thumb was:
If it rotates, it's LM grease
If it reciprocates, then it's graphite grease
But drive cables - which rotate - the rule was graphite grease for tech reasons that I won't go into

That's only my experience as an apprentice and working in an instrument and calibration workshop. But I could be wrong

[Polarsilver]

My experiences in purchase of new Speedo Cables from out fav supplier .. they are crap with the outer cable end nuts made in material so soft the knurled nut threads were oval and difficult to fit to the gearbox drive & the inner square end that fits into the speedo was oversize with loose stick out wire strands & a fight to get it to fit .. solution bin the new cable and find a " used & scruffy " BMC Speedo Cable that just fitted without any issue .

[Peter Laidler]

Norman could well be on the right lines there regarding the squared ends. In the instrument workshop we had a small manual lever-clamp/cramp that would clamp up a small brass ferrule and then squeeze the end square in the 4x way press bit thinggy. Mind you, we had drive cables that were over 5 feet long.

Thinking on my feet about the brass ferrules we used to use...... but no bress ferrules shown in the photo!

(I wonder where my instrument mates Dennis Aslett and Tony Bowman are now......)

[Fanfaniracing]

Talking about greasing, i used to grease all speedo cables of minis and Vespas till obe day a technician showed me a totally greased inside of a speedometer telling me this was caused by a greased cable.

This time i didn't grease the new cables...

[Peter Laidler]

Difficult to know how the grease gets up there I would say. It's not easy to get it to travel up-hill. The square end of the cable sits into a blind hole! We greased the cable up to 4" from the instrument

[Ronnie]

Difficult to know how the grease gets up there I would say. It's not easy to get it to travel up-hill. The square end of the cable sits into a blind hole! We greased the cable up to 4" from the instrument

"Archimedes' screw" The cable shown appears to be right hand lay and you inferred that it turns anti clockwise

[Fanfaniracing]

Difficult to know how the grease gets up there I would say. It's not easy to get it to travel up-hill. The square end of the cable sits into a blind hole! We greased the cable up to 4" from the instrument

"Archimedes' screw" The cable shown appears to be right hand lay and you inferred that it turns anti clockwise

That's what the guy told me about the grease...