OrtonvilleBob Posted February 20, 2023 Share Posted February 20, 2023 Old school meets new school: Using a GPS based smartphone app to check the accuracy of the 70 year old mechanically driven speedometer. The vehicle had been fitted with radials which have a slightly smaller diameter than the original bias ply tires. That caused the speedo to display a higher speed than I was actually traveling. The fix was to install a speedometer adapter with the correct correction ratio to the speedometer cable where it attaches to the transmission. The one I found on eBay needed cleaning and fresh grease but the end result made the effort worthwhile. 3 Link to comment Share on other sites More sharing options...
PhilAndrews Posted February 23, 2023 Share Posted February 23, 2023 Nice, I have the same original, mine over-reads by about 5 mph. I think I'll pull the gauge apart and recalibrate it that way, though. Just because I don't want to source and spend on an adapter... Link to comment Share on other sites More sharing options...
OrtonvilleBob Posted February 25, 2023 Author Share Posted February 25, 2023 Phil, recalibrating a speedo via its spinning magnets and hairspring isn't typically a diy process. But if anyone could have success with the procedure it's you. 1 1 Link to comment Share on other sites More sharing options...
john hess Posted July 19, 2023 Share Posted July 19, 2023 yes, my 53 reads 5 mph over... I'm cheap.. .. I just llive with it, knowing it's 5 over..!! Link to comment Share on other sites More sharing options...
Bloo Posted July 19, 2023 Share Posted July 19, 2023 Check the odometer. The speedometer head only needs recalibration if the odometer is reading correctly while the speedometer isn't. Otherwise, it's gearing. In my opinion, trying to recalibrate a speedometer wrong to compensate for a gearing problem is likely to be highly frustrating. 1 Link to comment Share on other sites More sharing options...
john hess Posted July 20, 2023 Share Posted July 20, 2023 odometer is correct... speedo I can live with... Link to comment Share on other sites More sharing options...
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