Simple Speedometer Correction
Posted: Fri Dec 06, 2013 10:15 pm
I figured I would share this since I know allot of us have issues with our speedometer reading the incorrect MPH.
Several months back I replaced the tires on my 68 Toronado. I assumed that since the owner’s manual indicated a radial tire size of 235 R15 then that is what I needed. Therefore, I went with a set of Hankook 235/75R15's w/ whitewalls. Well apparently, the world today does not measure tires the same way that they did in 1968, or Hankook just sizes their tires differently. They simply do not have the same height and obviously not having the same; height is going to cause the speedometer to read incorrectly… Well over the last few months, I have been trying to understand this complicated speedometer gear teeth thing. Well I learned that the first and second generation Toronado’s (Also assuming any vehicle with a THM425 transmission) have 32 teeth, which cannot simply just be changed out…
Well then, I started reading about these Speedometer Ratio Adapters, which turned out to be a very simple solution to my problem. Therefore, I simply downloaded a GPS speedometer app on the old Android and took the old girl out to see how off she was…
Therefore, I determined when the speedometer set solid at 70 mph my speedometer app indicated that I was actually going 63 mph… So 70 mph – 63 mph = 7 mph… So 7 mph of 70 mph would mean that it is 10% off… Therefore, I went ahead and ordered a Speedometer Gear Ratio Adapter that indicated that it would reduce my speedometer reading by 10%...
BTW, here is the site I worked from. They charged me $62.00 + $12.66 S/H, but you can probably can find them cheaper somewhere else online…
http://www.transmissioncenter.net/sp...n_______va.htm
Well I received it in the mail today and I think it took about two minutes to hook up. Took the old girl out for a drive and now when she sets at 70 mph my speedometer app indicated that I am actually going 70 mph…
Several months back I replaced the tires on my 68 Toronado. I assumed that since the owner’s manual indicated a radial tire size of 235 R15 then that is what I needed. Therefore, I went with a set of Hankook 235/75R15's w/ whitewalls. Well apparently, the world today does not measure tires the same way that they did in 1968, or Hankook just sizes their tires differently. They simply do not have the same height and obviously not having the same; height is going to cause the speedometer to read incorrectly… Well over the last few months, I have been trying to understand this complicated speedometer gear teeth thing. Well I learned that the first and second generation Toronado’s (Also assuming any vehicle with a THM425 transmission) have 32 teeth, which cannot simply just be changed out…
Well then, I started reading about these Speedometer Ratio Adapters, which turned out to be a very simple solution to my problem. Therefore, I simply downloaded a GPS speedometer app on the old Android and took the old girl out to see how off she was…
Therefore, I determined when the speedometer set solid at 70 mph my speedometer app indicated that I was actually going 63 mph… So 70 mph – 63 mph = 7 mph… So 7 mph of 70 mph would mean that it is 10% off… Therefore, I went ahead and ordered a Speedometer Gear Ratio Adapter that indicated that it would reduce my speedometer reading by 10%...
BTW, here is the site I worked from. They charged me $62.00 + $12.66 S/H, but you can probably can find them cheaper somewhere else online…
http://www.transmissioncenter.net/sp...n_______va.htm
Well I received it in the mail today and I think it took about two minutes to hook up. Took the old girl out for a drive and now when she sets at 70 mph my speedometer app indicated that I am actually going 70 mph…