Speedometer

[shermro99]

I was on the freeway going about 65 mph (so I thought) but when I got to a part that has the speed checking signs--it said I was going about 56. How can I check/test the speedometer to make sure it is reading correctly?

1970 Chevy C10 P/U

Thank you!

[smn69]

Use the mile markers on the side of the road and use the formula:
Rate (or speed) = Dist/Time

Or find a GPS unit that you can borrow from someone.

Oh, and hello from Orem.

[shermro99]

SMN69
Thank you for the response. I will test it out this weekend. Do you think it would be logical to also have someone drive next to me on the free way and test out the speed? i.e he will go 65 and I will do 65 according to my speedometer?

Oh, and hello from SLC> How goes it down there?

R

[Zeke's Garage]

There's a calculator around here someplace that let's you put in your transmission, rear end ratio and tire size and will tell you what color speedo gear you need in your trans. I'm sure someone with a better organized list of bookmarks will chime in here soon.

Or you can just make it a little game you play by constantly trying to figure out in your head, using a non-linear scale how fast you think you are going when you see a cop. That's what I do on my bike

[mrein3]

A GPS is far more accurate than driving next to somebody or looking at one of those speed checking signs.

If you don't own one see if you can borrow one for a day.