How do I adjust the speedometer on an older car?

I have an 88 Accord and I plan to buy aftermarket wheels. The wheels will probably end up a different diameter, so I was curious if it's possible to adjust the speedometer on an older car. Many people have told me that only the newer cars are adjustable, which I do not agree with.How do I adjust the speedometer on an older car?I have worked on cars for years and the only way on your model would be to change the speedo drive gears inside the transmission, you will need to know the outside circumference of the new tire and wheels you are going to put on ,and your differential ratio. Or you can get a new wheel and tire that have the same outside circumference of your old tires and it should be the same.How do I adjust the speedometer on an older car?They sell the gears that go inside the tailshaft on the transmission with different number of teeth on them.How do I adjust the speedometer on an older car?you cannot adjustHow do I adjust the speedometer on an older car?You may be able to get a different drive gear for the speedometer. Ask the dealer.How do I adjust the speedometer on an older car?Go to miata tire charts to see what size combinations work,also a speedo shop that is good can put an adapter on your speed sensor that is adjustable. There are also different size pinnion gears that you put on your car to make adjustments. You increase or decrease the amount of teeth on pinnion gear to achieve the correct combination to have an accurate speedo. Speedo shops are more rare and hard to find. You can use the miata charts to effectively change your rims and tires and keep your speedo accurate.