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Speedo Bounce

Posted: 11 Jun 2018, 09:42
by itchyfeet
This is realy annoying me now

fitted new Gemo cables to both vans and while they have run stable for a while I can no longer get them stable.
http://forum.club8090.co.uk/viewtopic.php?f=37&t=159513" onclick="window.open(this.href);return false;

I have checked the runs are smooth is it just me or are these Gemo cables just bad quality?

What am I missing?
could it be the speedo needs lubrication I have heard some noise from the speedo on occasion?

I have tried twisting the cable outer at the speedo and this has an enormous affect, I have tried varying the amount of cable pushed into the cab from the grill area too.

Re: Speedo Bounce

Posted: 11 Jun 2018, 10:58
by 937carrera
"They all do that Sir"

I've got the same issue on my WBX to a minor extent and on my 412. I was going to suggest checking that the hole in the hub is in fact square, but you posted that it was in the other thread.

The hole isn't properly square in my WBX and it has so far resisted my attempts to effect a repair rather than replacing the hub cap.

Re: Speedo Bounce

Posted: 11 Jun 2018, 11:05
by R0B
I replaced my cable and cap last year.hurrah no bounce.Until a couple of months ago. :-( I have decided i will have to live with it.

Re: Speedo Bounce

Posted: 11 Jun 2018, 11:29
by CovKid
A hell of a lot of grease seems to help

Re: Speedo Bounce

Posted: 11 Jun 2018, 12:17
by itchyfeet
CovKid wrote:A hell of a lot of grease seems to help

Where do you put the grease please?
afaik you can't slide the inner out of the outer and grease the cable so I.assume you mean in the hub?

Re: Speedo Bounce

Posted: 11 Jun 2018, 12:19
by itchyfeet
937carrera wrote:"They all do that Sir"
.

Not true
I fitted a Gemo 10 years ago to the tin top and it bounced so I put my broken VW cable back and had 10 years bounce free intil I fitted the gemo again recently.

I stil have the broken VW cable.

I wonder if you can still get VW?

Re: Speedo Bounce

Posted: 11 Jun 2018, 13:20
by DoubleOSeven
I think they bounce because the inner wire catches on the out sleeve. I’ll go and have a look but wondering if putting some 3 in 1 oil down at the
Binnacle end would fix?

Re: Speedo Bounce

Posted: 11 Jun 2018, 14:25
by RogerT
I once spent an hour slowly dribbling oil into the Speedo cable, I think it was a thin oil. There was a temporary improvement. If I remove the speedo cable completely any time I’d think about a thick Teflon oil. Or just live with it. That’s hard tho cos at its worst the needle would bounce repeatedly off the stop, such that my better half would ask what was going wrong with the van this time! But lube does help...

Re: Speedo Bounce

Posted: 11 Jun 2018, 15:37
by itchyfeet
DoubleOSeven wrote:I think they bounce because the inner wire catches on the out sleeve. I’ll go and have a look but wondering if putting some 3 in 1 oil down at the
Binnacle end would fix?

you need to remove it and pour oil in the other end,
just can't do it fro the speedo end, maybe a bit of tube and a funnel and let it drip through overnight.

Should not have to do this, they should be good to fit out of the packet.


Why when I make small movements to the cable at speedo end does it make such a difference?

Re: Speedo Bounce

Posted: 11 Jun 2018, 16:15
by 937carrera
itchyfeet wrote:
937carrera wrote:"They all do that Sir"
.

Not true
I fitted a Gemo 10 years ago to the tin top and it bounced so I put my broken VW cable back and had 10 years bounce free intil I fitted the gemo again recently.

I stil have the broken VW cable.

I wonder if you can still get VW?

Actually that was just a tongue in cheek "service reception" comment.

You're right, thinking a bit more as I haven't been out in mine yet this year, mine doesn't bounce, it smoothly under reads, I can be doing an indicated 40 and then with no change in road speed it will accelerate up to 50, maintain that speed and then drop down to 45 or 40 again. I suspect that's to do with the speedo head but haven't investigated yet.

I think what may be happening is that there is some friction between the cable and the outer lining. That friction causes the spiral wound cable to twist a bit like a torsion bar until it gets to a certain amount of tension and then the spring uncoils. Maybe what you are doing at the speedo head end is exaggerating the tighten / release process ??

Good life out of your broken VW cable :)

Speedo Bounce

Posted: 11 Jun 2018, 16:33
by DoubleOSeven
Image
Image
Mine was snapped, maybe my issue but that was a blessing for getting the oil down there. Didn’t make any difference, mind. It’s worse at low speed.

https://drive.google.com/open?id=10IAbb ... wVjN-VAJ6x" onclick="window.open(this.href);return false;

Re: Speedo Bounce

Posted: 11 Jun 2018, 18:24
by itchyfeet
mine was broken in the same place Martin, this is the splint bodge that kept it going for 10 years, I'm tempted to put it back but I feel there must be a solutuon we are all missing.

ImageP1020543 by Paul_Barr, on Flickr

Re: Speedo Bounce

Posted: 12 Jun 2018, 11:44
by diabolov
When I needed to oil the clutch cable on the bike I used to make a plasticine cup around one end of the cable and hang it up fill the cup and let gravity
do the job. Or you can buy cable oiler and there is a cheaper non-hydraulic type to.

Try baby oil as a lubricant

Regards

M

Re: Speedo Bounce

Posted: 12 Jun 2018, 12:25
by 937carrera
The problem with oiling as a solution, apart from getting the stuff in is it depends what the liner is made of and will it swell in some way, defeating the object ?

I've been reading around, looking at other models as I know the problem does occur on many VW's even going back to the Beetle. Consensus seems to be a kink in the cable is the cause, oil, powdered graphite, vaseline all have been suggested as fixes. I suppose laying the whole cable in an oil bath may allow lubrication along the full length. I think I found the answer to my own speedo problem along the way, I'll have to see if the t25 has the same two brass cups inside the speed head https://www.aircooledvwsa.co.za/viewtopic.php?t=18617 .

Paul, if you fancy an experiment, why not rig up one of your Gemo cables with an electric drill and a spare speedo (assuming you have access to one). Keep one end fixed start with the cable straight and move the other end around / introduce bends and kinks, see if you can induce the problem. Also see if squeezing the cable has an effect ???

I suppose the kink could even occur when installing, and not be there when installed ?

My timer for the "how long did it take you" thread can perhaps be started now. :)

Re: Speedo Bounce

Posted: 12 Jun 2018, 14:56
by itchyfeet
I'm wondering if the kink is caused by the plastic sleeve that Gemo supply at the speedo end, it might not allow a nice curve and may put too much stress on the connector, who knows what route it takes behinf the dash its hard to see.
The VW cables didn't habe this and presumably why they snap
might try removing it or shortening it first, I'm not convinced a need cable needs lube.