Piran2 Posted July 18, 2022 Share Posted July 18, 2022 So, I was quite sure that the speedo wasn't reading correctly, I got one of the Eling GPS speedometers to see how they compared (I don't know how acurate the GPS speedo is at this point) but comparing the two and the Herald is reading about 0.75 of the GPS one through out the speed range. Quote Link to comment Share on other sites More sharing options...
Howard Posted July 18, 2022 Share Posted July 18, 2022 A easy way to check is to borrow a GPS Satnav and compare the speeds. Some GPS speedos are adjustable so you have to calibrate them against something else. Cheers Howard Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted July 18, 2022 Share Posted July 18, 2022 1 hour ago, Piran2 said: So, I was quite sure that the speedo wasn't reading correctly, I got one of the Eling GPS speedometers to see how they compared (I don't know how acurate the GPS speedo is at this point) but comparing the two and the Herald is reading about 0.75 of the GPS one through out the speed range. Don`t forget to take the whee land tyre sizes into consideration along with which diff you have. Quote Link to comment Share on other sites More sharing options...
Tim Hunt Posted July 19, 2022 Share Posted July 19, 2022 15 hours ago, Velocita Rosso said: Don`t forget to take the whee land tyre sizes into consideration along with which diff you have. According to Sue's satnav my 4A speedo is spot on at all speeds up to the Motorway and dual carriageway NSL (don't know how accurate the Garmin is though). I took a recent opportunity to check the odometer against kilometre posts on a decent stretch of the M4 and found it to be under-reading by just 0.3%. Speedograph Richfield did an excellent job when they overhauled the intrument some 40 years ago! Tim Quote Link to comment Share on other sites More sharing options...
Velocita Rosso Posted July 19, 2022 Share Posted July 19, 2022 3 hours ago, Tim Hunt said: According to Sue's satnav my 4A speedo is spot on at all speeds up to the Motorway and dual carriageway NSL (don't know how accurate the Garmin is though). I took a recent opportunity to check the odometer against kilometre posts on a decent stretch of the M4 and found it to be under-reading by just 0.3%. Speedograph Richfield did an excellent job when they overhauled the intrument some 40 years ago! Tim After finding I had speedo problems(not working) I bought a digital speedometer, which gives speed in mph/kph, one hour wake up bleep, max speed setting eg when going through mway speeds re road works, and is really good. Then when doing routine maintenance found the angle drive dangling on the silencer. Refitted and with new cable.....and now speedo works ,spot on to electronic speedometer. 1 Quote Link to comment Share on other sites More sharing options...
Piran2 Posted July 20, 2022 Author Share Posted July 20, 2022 On 18/07/2022 at 20:41, Velocita Rosso said: Don`t forget to take the whee land tyre sizes into consideration along with which diff you have. Wheels are 155s so that should give about a 3% difference, don't know about the diff. Quote Link to comment Share on other sites More sharing options...
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