Speedometer and Odometer

[SCRunner12]

So I just got back from a long road trip in my 95 and noticed that my speedometer is off. I have had a hunch for a little while, but just driving around town I could never confirm it. I drove 65 the whole way down and was keeping up with traffic consistently. I conveniently drove alongside a prius and saw that my speedometer is about 5 mph slow at 65 mph compared to the prius (they have the digital speedometer in the middle of the dash, which was easy to see and compare). I have 31's and 4.56 gears and an automatic, but I thought with that tire size and gear ratio the speedometer should be correct. Also with 4.56 gears the 4runner should have came out of the factory with 31's and the speedometer should be correct. Is there any way to figure out my exact speed (besides driving next to someone)?

Also will the difference in my speedometer effect my odometer reading? I averaged about 17.5 mpg, which seems a little low, but I am running AT's and the 3.0.

 

[T?@\7]

take it to your local dyno... or a speedo place, i know there is one or two around here.

or drive around town and look where the sherrif has posted up a "your speed is" digital sign, cheapest route!

 

[cometobanks]

Speed = Distance/Time.

Stop watch. Mile marker on the highway.

Travel mile marker to mile marker, note time on the stop watch,

divide distance by time= speed in approx. MPH.

Or ask a cop real nice to ladar or radar you

 

[illzoni]

Speed: Use a GPC. They're accurate at steady speed.

Odo: Run several miles on the freeway and compare your odo to the mileposts.

 

[T?@\7]

lol good stuff. we're all fvcking nuts

 

[SCRunner12]

Thanks. Yeah I usually only drive on the highway for 2 or 3 miles at a time and feel I wouldn't get the best results with such few miles. I will try some of those techniques soon. It's not that bad and with my previous 87 4runner and 33's I was running about 12 mph slower on the speedometer. I never really knew exactly what speed I was going.

 

[T?@\7]

im running 33s and am only 3 or 4 mph off, according to previously mentioned digital speed signs from johnny lawson.

 

[SCRunner12]

Yeah my old 87 was a piece of work and I think the gears had been changed prior to me owning it. So I never really knew what I was running. It was my highschool car and I basically beat the hell out of it. I miss her though.

 

[T?@\7]

lol, this one is a piece of work aswell, something special
Its become my new college car after i wrapped the 05, but I like this one better :-D more my style