Aussieveedubbers 路 Tech Talk

What does this Speedo marking mean

https://forums.aussieveedubbers.com/threads/102013/what-does-this-speedo-marking-mean

psimitar 路

So got an old mph speedo to play with and wondering what the W0.8 stamped on the back means?

There is nothing to state how many revolutions per mile the speedo goes like an old Smiths gauge would so I'm wondering if this is the worm drive ratio?

Fancy playing with making it a KPH speedo as it's easy enough to screen print the dial from MPH to KPH but the odometer is the trickier part.

Ta 馃檪

matberry 路

Your onto it, it;s the internal preset ratio

All VDO are like that so I'm sure google will tell more details

Joel 路

Its the code for what size tyres the speedo is meant to be fitted with.

There was a list on Thesamba about what tyres for what code, but I'm sure from memory the late Beetle 25.3" tyres was W0.51

psimitar 路

Yea, I've been playing around with it and doing some calcs and for std Beetle tyre diameter your looking at 800 revolutions and as speedos are given in respect to every 1000 revs then the 0.8 is this ratio. Basically the last worm and cog of the odometer sets the ratio so for kilometers I need the drive ratio to be 0.5.

As for the speedo itself I could mess around with strengthening or weakenin the permenant magnet in the drag cup but trying to reprint to kph seems the easier option 馃檪

bajachris88 路

psimitar wrote:Yea, I've been playing around with it and doing some calcs and for std Beetle tyre diameter your looking at 800 revolutions and as speedos are given in respect to every 1000 revs then the 0.8 is this ratio. Basically the last worm and cog of the odometer sets the ratio so for kilometers I need the drive ratio to be 0.5.

As for the speedo itself I could mess around with strengthening or weakenin the permenant magnet in the drag cup but trying to reprint to kph seems the easier option 馃檪
G'day mate, if you find a mob that does the reprinting please let me know. I'm going to be changing tyre diameters soon and it will put the whole scale out of whack 馃檨

DylanTheDubber 路

I Can Re-Calibrate VW Speedos.

Im on the Gold Coast Now.

Let me know what wheels and tyres your running i can do the rest.

From Dylan

psimitar 路

DylanTheDubber wrote:I Can Re-Calibrate VW Speedos.

Im on the Gold Coast Now.

Let me know what wheels and tyres your running i can do the rest.

From Dylan
So does this mean you reduce the magnetism to allow the drag drum to turn slower so that the MPH scale now works as a KPH scale?
And then you change the gears for the Odometer to work in kilometers too?
If so then how much does a re-cal cost roughly?

Ta,
Mike

psimitar 路

bajachris88 wrote:G'day mate, if you find a mob that does the reprinting please let me know. I'm going to be changing tyre diameters soon and it will put the whole scale out of whack 馃檨
Will do 馃檪 Looking into how hard it is to either screen print it meself or get a stencil sticker made to re-spray the face.

For yours tho the Odometer will be out by the percentage increase in the tyres rolling radius but having the magnet within the drag drum strengthened by a gauge recalibrators would mean the dial wouldn't need repainting 馃檪

So gives you the option if you wish to recalibrate instead of re-painting the dial.

matberry 路

To change calibration, it's more usual to fit a gearbox into the cable, that way speedo and odometer stay in sync. Flex-drive Agencies used to do it, I think they are still around.

Joel 路

bajachris88 wrote:G'day mate, if you find a mob that does the reprinting please let me know. I'm going to be changing tyre diameters soon and it will put the whole scale out of whack 馃檨
I'm not sure if Brent at Castlehill Gauges still does it but he made my new faces up.



They are plastic with opaque number like modern cars have so light up much better at night and he can alter the design,
I wanted that ring around the center gone on my new one and the odometer cut out as one not individual.
I'm sure changing the scale wouldn't be too hard.

cb john 路

I have plenty of those in different colours and for different gauges...all the other stickers as well...

psimitar 路

matberry wrote:To change calibration, it's more usual to fit a gearbox into the cable, that way speedo and odometer stay in sync. Flex-drive Agencies used to do it, I think they are still around.
Now that's an intriguing idea 馃檪

if not then the stickers may work but at the same time I like the early style of speedo as it has 5 lines between each number whereas the later speedos are just a plain black background with the numbers on it.

68AutoBug 路

psimitar wrote:So got an old mph speedo to play with and wondering what the W0.8 stamped on the back means?

There is nothing to state how many revolutions per mile the speedo goes like an old Smiths gauge would so I'm wondering if this is the worm drive ratio?

Fancy playing with making it a KPH speedo as it's easy enough to screen print the dial from MPH to KPH but the odometer is the trickier part.

Ta 馃檪
always wondered what that was... lol

easier to have a new sticker/face made...

Lee