Km to mph speedo conversion

[AngeloEvs]

I have a km per hour speedo with trip odometer, I have calibrated for mph and fitted a spare mph facial but the mileage increment's in km covered not miles. I think that to increment in miles, the gear and pinion that drives and rotate the numeral wheels assembly need to be replaced.

I have compared it to my UK mph speedo and the only difference I can see is that the UK gear and pinion have more teeth.

Has anyone done this conversion?

[bigherb]

I have compared it to my UK mph speedo and the only difference I can see is that the UK gear and pinion have more teeth.

Has anyone done this conversion?

Yes, the worm and pinion need to be changed for MPH gearing, unfortunately, they are hard to find except in the States.

[AngeloEvs]

Thanks, can well imagine the wormgear and pinion are hard to get.......

[Cobra88]

Hi angelo

I have a mph speedo with a broken needle
Its from an Aircooled and has no trip counter

Not sure if it would be suitable for you to use gears out of it.

Regards
Rick

[AngeloEvs]

Not sure Cobra, I could take a photo of what I need and may be you could compare to yours. Thanks for the offer.....

[bigherb]

Hi angelo

I have a mph speedo with a broken needle
Its from an Aircooled and has no trip counter

Not sure if it would be suitable for you to use gears out of it.

Regards
Rick

There are different gears, the metal speedos used the old bay window 11 teeth gears, later speedos used 15 teeth gears.

[Cobra88]

Hi angelo

Yes that would be fine

If yours has a trip counter i think well n
Be missing the gears to turn it
Thats a guess though

The speedo i have works fine but needs a needle either from another speedo or one making from toothpick etc
The needle base is ok, just actual needle missing.

You can collect it from ipswich for free
Or i can post it to you if you pay post
Possibly i might drop it off as we visit north norfolk coast salthouse often

Rick

[AngeloEvs]

Many thanks for your kind offer Cobra, this is the gear and worm assy on the later MPH UK speedo, based on what I have seen and Bigherbs input, I think the earlier UK speedo has a different gear set.

I have found a worm drive, just need the15 tooth gear...........

Speedogears by Angelo Evans, on Flickr

[Cobra88]

Hi Angelo

Sadly the one i have is metal backed and looks like 11 or 12 tooth so wont work

I have a couple of kmh plastic back speedos with trip but no mph ones

Sorry
Rick

[bigherb]

Was discussing with CJH of this parish of 3D printing some gears, he did do some prototypes, he has been busy of late might be worth sending a PM to him.

[colinthefox]

Many thanks for your kind offer Cobra, this is the gear and worm assy on the later MPH UK speedo, based on what I have seen and Bigherbs input, I think the earlier UK speedo has a different gear set.

I have found a worm drive, just need the15 tooth gear...........

Speedogears by Angelo Evans, on Flickr

Here is a 15 tooth gear for a VDO speedo, third one down the page. https://www.speedometergears.com/volvo- ... eter-gears" onclick="window.open(this.href);return false;. They may have used common components so it might be the same.

When mine failed (Volvo 850) I made one from a bigger gear wheel out of a timer and filed the teeth with a watchmakers file. I don't recommend that as a way forward, although it has done 150K miles since and still working.

[Aidan]

the one in Angelos picture is 16 teeth

[tobydog]

Was discussing with CJH of this parish of 3D printing some gears, he did do some prototypes, he has been busy of late might be worth sending a PM to him.

We have a new resin for the Formlabs printer at work, really stable and accurate. Just need a model or spec. for the gears to print some..... Couple of hours print time plus UV hardening. Can always slip a few homers in...

[AngeloEvs]

What file format would you need Tobydog? I could get the measurements of the gear, I no longer have AutoCAD but I do have some other 3D software.

The drive gear teeth have a slight helix to interface with a worm drive but I think straight cut drive gear teeth would work.

[tobydog]

Inventor reads most cad system files. Step, iges, x_t(b) etc.