My speedometer is 5 mph more than it should be. I realized this when I was going 40 and one of the street radars showed 35. I have stock size wheels. Is there anything I can do about this or is it just what happens over time?

 

Whoever calibrated the street radar could if set it just a hair off, I wouldn't worry about it, your speedo is prob right.....

 

i agree,i think it just averages your speed.

 

If you have a smartphone download a GPS speedometer app and see what result you get on highway with the cruise control set.

 

those street radars are never right. the only way your speedo can be off is if you have the wrong tire size.

 

Those street radars aren't reliable. Your speedo should be good.

 

The only way to find out is to blast by it at top speed and see if it's off again, if it is, then the sign is probably wrong, but on the bright side you had fun testing it out.