SSBreeze Posted January 28, 2018 Share Posted January 28, 2018 I have a 83 Sunrader that the speedometer reads about 75-80mph when doing 60. Same for around town. Inaccurate. Stock tires 14's. Any ideas please? Quote Link to comment Share on other sites More sharing options...
Derek up North Posted January 28, 2018 Share Posted January 28, 2018 My 1st thought was that someone had swapped rear axle ratios. However, Swapping from the normal 4.10:1 ratio to the common alternative 4.56:1 & 4.88:1 ratios would only change the speedo readings by ~10% & ~15% respectively. Your 60mph/75mph is ~25%. Is your odometer similarly inaccurate? Can you confirm if automatic or manual transmission? Quote Link to comment Share on other sites More sharing options...
fred heath Posted January 28, 2018 Share Posted January 28, 2018 (edited) Many times the old speedometer gears can be worn down causing inaccurate readings. What is the diameter of your rear tires? They should be about 26” or 185/195 75R14. Larger tires will also give an inaccurate speedometer reading. I dont even use my stock speedometer, I use my gps to to tell how fast I’m going. Edited January 28, 2018 by fred heath http://www.tyresizecalculator.com/tyre-wheel-calculators/speedo-error-calculator Quote Link to comment Share on other sites More sharing options...
SSBreeze Posted January 28, 2018 Author Share Posted January 28, 2018 Yes, the odometer is also inaccurate by about 25% as I checked mileage with other vehicle. The tires are 185 75R14. Great idea about the GPS app for speed. I will try that soon. Thank you! Quote Link to comment Share on other sites More sharing options...
SSBreeze Posted January 28, 2018 Author Share Posted January 28, 2018 Also is the 4cyl, 4 speed manual tranny. Quote Link to comment Share on other sites More sharing options...
WME Posted January 28, 2018 Share Posted January 28, 2018 Pull your speedo drive gear out of the transmission and see how many gear teeth are on it and how its marked. If in the past some body changed out your transmission it could have the wrong gears in it. Toyota has 4 basic gear setups. You need a bigger driven gear, a smaller drive gear or a combo of both. Quote Link to comment Share on other sites More sharing options...
SSBreeze Posted September 1, 2018 Author Share Posted September 1, 2018 Found the best solution at a reasonable price. Nearby tranny shop went round and round about all the possibilities of what could be done with no final price, just a guess between $500-700. I walked away from that very quickly. A local speedo and instrument cluster shop has a small attachment to the end of your speedo cable regardless of the teeth. They put in on their dyno machine then calibrate it correctly. Works like a charm for $85 and .5 hour time. Have used it for 2K miles now and is perfect. Quote Link to comment Share on other sites More sharing options...
DanAatTheCape Posted January 29, 2019 Share Posted January 29, 2019 another option is a gps or even an app on your phone. My android has an app called US Topo Free - you can select the tracking icon and it gives a readout, even if there is no cell service. Sure there are others. Quote Link to comment Share on other sites More sharing options...
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