Speedo Bounce

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itchyfeet
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Re: Speedo Bounce

Post by itchyfeet »

Took the van for a spin today and tried to get rid of the last bit of wobble.
I found that I could make the VW cable bounce more sub 30mph by adjusting the amount of cable pushed/pulled through grommet behind dash. I could not get it better but could make it worse.
So even with a VW cable needs careful placement.

Somebody sugested clamping behind dash and this may work with a better VW cable but the GEMO I removed was really bad and could not get any position steady

four more things to try :

Pump grease in to cable - no idea how yet
Change the cable route behind dash - I have always used a draw wire, perhaps it was routed badly in the past.
Change the gromet position to be in line with speedo -not sure its possible yet
Buy a new VW cable - Brickwerks are getting some RHD in LHD is no more
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937carrera
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Re: Speedo Bounce

Post by 937carrera »

You do know this has been an issue with cable driven VW speedometers from the Beetle onwards, it's not just a T25 issue. There can also be issues with the "viscous coupling" between the part of the speedo that is connected to the cable and the part that drives the needle. My Autosleeper has this problem I think, while my 412 has the cable bounce. Don't think it's a RHD / LHD issue either, they have the same issues over the pond.

It is certainly true that if you are replacing a cable using the same route, if someone has misaligned it previously, you'll be repeating that mistake. I sense you would have spotted that already though.

But please don't let me stop you in your quest, it'll be interesting to see what you discover along the route :D
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bigbadbob76
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Re: Speedo Bounce

Post by bigbadbob76 »

8" diameter.
I wonder if you could do the old bike chain trick of heating grease in a pan with the cable. Not too hot of course, just enough to get the grease flowing.



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itchyfeet
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Re: Speedo Bounce

Post by itchyfeet »

I refitted the repaired VW speedo cable to the tin top today, took before and after Videos, the GEMO bounced up past 50MPH

ImageTin GEMO Speedo cable by Paul_Barr, on Flickr
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itchyfeet
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Re: Speedo Bounce

Post by itchyfeet »

1988 DG WBX LPG Tin Top
1989 DJ digijet WBX Holdsworth Villa 3 Pop Top
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itchyfeet
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Re: Speedo Bounce

Post by itchyfeet »

A quick update.

Our friends at a well know parts supplier have been onto classic and they are supplying the same GEMO cables as we can buy.

They have also found an old 1980s cable and sent it to GEMO so they can investigate.

my pop top has got a little worse but still better than the GEMO
Tin top still perfect.
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bigherb
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Re: Speedo Bounce

Post by bigherb »

937carrera wrote:There can also be issues with the "viscous coupling" between the part of the speedo that is connected to the cable and the part that drives the needle.
Viscous coupling? The cable turns a magnet which produces eddy currents in a drum which is connected to the needle to pull the needle round.
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937carrera
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Re: Speedo Bounce

Post by 937carrera »

Fair enough, the description was in speech marks, the real point being that there is no physical connection between the part driven by the cable and the part moving the speedo needle
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R0B
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Re: Speedo Bounce

Post by R0B »

Very odd. Just been to pick Tina up and no bounce whatsoever. The only thing that has changed is the weather, but i doubt that has owt to do with it.
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Swebby
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Re: Speedo Bounce

Post by Swebby »

I have found that after it has rained or I have washed the van that the bounce is less and gets progressively worse as it gets hotter when running.

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itchyfeet
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Re: Speedo Bounce

Post by itchyfeet »

My tin top is perfect drove the pop top today and its bad again
pulling what's left of my hair out

looks like I'm going to have to try something else as the oil hasn't lasted. [ rolls eyes like Jeremy]
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R0B
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Re: Speedo Bounce

Post by R0B »

I feel your pain mate.TBH I'm not expecting my non-wobble to last.
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itchyfeet
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Re: Speedo Bounce

Post by itchyfeet »

itchyfeet wrote:
four more things to try :

Pump grease in to cable - no idea how yet
Change the cable route behind dash - I have always used a draw wire, perhaps it was routed badly in the past.
Change the gromet position to be in line with speedo -not sure its possible yet
Buy a new VW cable - Brickwerks are getting some RHD in LHD is no more


3 more things last option is out
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Oldiebut goodie
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Re: Speedo Bounce

Post by Oldiebut goodie »

spray grease? I have one that is a very sticky grease once the solvent has evaporated. It is odd that my Gemo one has been perfect since fitting and others are having bounce.
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adie89
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Re: Speedo Bounce

Post by adie89 »

Oldiebut goodie wrote:spray grease? I have one that is a very sticky grease once the solvent has evaporated. It is odd that my Gemo one has been perfect since fitting and others are having bounce.

I removed my cable from the sheath and liberally coated it with general purpose yellow grease, I can’t give a type the 5kilo tub has lost its label, but the type of stuff you would use to grease suspension joints on old motors with grease nipples. Got rid of the loud whirring noise and bounce on a new cable. I fitted it a while ago so I can’t Remember the brand.
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