i think my speedo is off

[jeremy judge]

I passed a radar box on the side of the high way last week and it said I was going 4 miles per hour faster than my speedo. I just did a search and I think it is off because at 70 on the speedo I am at 2100 rpm and most other people are claiming right at 2000.



it is a 2004. 5 qc swb 3. 73 6 speed wanted to see if any body thought there might be a problem

 

[milehigh.o.]

Find a friend or someone that has a GPS and that will tell you right away.



I have one and I was off by 1-2 mph at 75mph. That was close enough for me though.

 

[John - K5AWO]

ditto the GPS suggestion. Only reliable method for instantaneous readings.



The radar boxes are shooting at an angle causing a slight discrepancy.

 

[RNash]

Jeremy, time yourself over 1 mile ( using mileposts) & divide 3600 by your time in seconds. This is your MPH.