Joined: Jun 2018 Posts: 512 Threads: 90
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Stupid question, but.............
When looking down at the output from the gearbox drive for the speedometer cable, does it turn clockwise or widdershins? Logic tells me clockwise, but.........
Mine is buried at the moment, so I cannot check.
Regards,
Jamie.
Joined: May 2018 Posts: 1,909 Threads: 102
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Location: Llandrindod Wells
Car type: 29 Special, 30 RK, 28 C Cab
Hi Jamie
I was testing the speedo (Chummy style PA) on my special yesterday and clockwise rotation on the cable by a cordless drill produced 20mph on the speedo.
That would indicate anti-clockwise viewed down on the gearbox.....I think! Might be different for later speedos?
Cheers
Howard
Joined: Aug 2017 Posts: 920 Threads: 6
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Location: Scottish Borders
I suspect that the PA speedo will indicate speed whichever way it is rotated. It works by a weight swinging out like a Watts type governor.
The mileometer will reverse if turning the wrong way.
Jim
Joined: May 2018 Posts: 1,909 Threads: 102
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Location: Llandrindod Wells
Car type: 29 Special, 30 RK, 28 C Cab
Hi Jim
My speedo didn’t seem to work in reverse. However I was having difficulty screwing the fine thread retaining nut up tight enough (now rectified after a thorough clean).
Cheers
Howard
Joined: Aug 2017 Posts: 1,256 Threads: 32
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Location: Cheshire
Car type: Race Ulster, 1926 Special, 1927 Chummy, 1930 Box
In my youth and before we had cars of our own, a friend had use of his father’s car to travel to school. The understanding being he went that far and no further. The car, a Morris minor had a broken mileometer. We travelled all over Northumberland at lunch times and during free periods in that car. Eventually the car was replaced with an Austin 1100. The milometer worked. The first day I remember driving backwards around a car park for two hours to clock off the miles done during the day. I don’t remember if we got away with it.
Alan Fairless
Joined: Aug 2017 Posts: 3,210 Threads: 100
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Location: Darkest Bedfordshire
Got a 4-speed on my bench now - when turned in normal direction (engine clockwise when viewed from front) the square peg in the speedo drive rotates clockwise (i.e. viewed end on such that you can see it)
Joined: Aug 2017 Posts: 1,528 Threads: 90
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Location: Monmouthshire
Oh Alan, what naughty boys. I am sure that not a single one of us had the faintest idea of which way the odometer spun, good lord no, otherwise we might have put it on the bench and attatched a drill to it for half an hour before recording the mileage for the next year's insurance. No doubt some twenty year old bought up suckling on a computer terminal has found a way of doing that to a modern car, using their smartphone. Then again, maybe insurers just ask the Chinese goverment for a satellite readout of the mileage.
Joined: Jun 2018 Posts: 512 Threads: 90
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Thank you for the replies, which will help. I wish to make a ratio reduction gearbox and want to ensure that I put in the right number of gears to maintain the correct direction of rotation.
Regards,
Jamie.
