Speed Not Calibrated

utopia

Member
:
Mazda3
Guys noticed on those "current speed" signs you're always a little slower then what the speedometer says?
 
utopia said:
Guys noticed on those "current speed" signs you're always a little slower then what the speedometer says?
My speedo is dead on, calibrated with GPS. This is surprising, every other car and motorcycle I have owned has the speedo reading high by about 5% stock.
 
utopia said:
Guys noticed on those "current speed" signs you're always a little slower then what the speedometer says?
those things are never accurate.
 
the speedometer or the sign? i hope the speedometer is fast so when i throw rims on my car it should be just about accurate then
 
Yeah, I've noticed that too. I'm curious about the accuracy of those, and how it actually measures speed.
 
SeanMSIII said:
This is bad news. I've been counting on mine to be fast and keep me just under 10 mph over when I want to be.(five-0)
It will start reading fast as your tires wear down. (naughty)
 
Keep in mind, when your speedo is off, so is your odometer and any gas mileage computed from your trip meter.
 
chuyler1 said:
Keep in mind, when your speedo is off, so is your odometer and any gas mileage computed from your trip meter.
That is not necessarily true.
A mechanical speedometer (like other mechanical devices) has tolerances.
It's possible for the odometer to be accurate even if the speedometer is not.

It would be a big no-no (for obvious reasons) if a speedo read low.
 
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mine works fine..cops have been behind me and i do the speed limit then they pass me and look for other victims
 
Cops usually only pull people over for 10+ over the limit. Inaccurate speedos and radar guns are part of the reason...they want someone who is definitely guilty.
 
all of the "current speed" signs in my area run off of older X band radar technology (what brand/make I couldnt tell you).

keep in mind radar guns have to be calibrated for accuracy, so theres a higher possibility that the SIGN is wrong and not your car.

IIRC the MS3 uses a mechanical speedo gear, which would be really hard to be set innacurately (assuming stock tire hieght...)

chuyler is right though - most cops arent going to pull for more than 10+ mph. Its a waste of time as it could be anything from your car being off to their radar gun being off... unless they are extremely bored/have a clear reading on you. in my state up to 9mph over, its a slap on the wrist.

more than 10mph over the speed limit and its clear to both the officer and yourself that you are speeding. you may not realize a few miles over, etc.
 
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