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TR7 speedo
Posted: 14 Aug 2015 14:21
by Henry
I guess I could ask Steve this but the answer may be of interest to others.
My car (Y reg) has a speedo with 130 mph as the last written digit, the 140 mph mark is a rectangle. While at Malvern I picked up a speedo that has 140 mph as the last written digit, my question is are the two geared differently or is this all done at the gearbox?
I believe the 140 mph one is from an early car, so may have been calibrated for 4 speed 'box.
Thanks in anticipation.
Re: TR7 speedo
Posted: 17 Aug 2015 14:22
by TR Tony
Not aware of any differences in the speedo itself Henry, there were several different "faces" over the years, MPH, KPH, even a USA version that only read up to 85MPH! They are all calibrated the same.
All the gearing of the speedo is done by a combination of an output shaft gear and a pinion gear at the output from the gearbox. There are various gears, identified by colour, which were used to achieve the correct speed reading on the speedo itself, according to the final drive ratio in the car.
Re: TR7 speedo
Posted: 17 Aug 2015 15:45
by FI Spyder
This brought up an interesting question (to me any way). The US speedos have the large outside numbers in mph and small numbers on the inner circle in kph for when they are driving in Canada and Canadian speedos have large outside numbers in kph and small numbers in the inner circle in mph for when they are driving in the US. The question is are the UK/Europe speedos only in kph?
Re: TR7 speedo
Posted: 17 Aug 2015 20:16
by saabfast
European ones are probably in kph, maybe with little MPH numbers as you describe Canadian ones. UK ones are in MPH as the large size with little kph numbers.
Re: TR7 speedo
Posted: 25 Aug 2015 12:37
by Henry
Thanks for the reply's all, apologies for the late reply - been away on hol's for 10 days
I guessed that the speedo's would be the same, just wanted to check, I'm familiar with the gearing variations as I have played about with Land Rovers
There was a brand new KPH speedo head for sale at the TR Register do at Malvern recently so they do indeed exist.