Jeep Garage  - Jeep Forum

Jeep Garage - Jeep Forum (http://www.jeepgarage.org/forums.php)
-   Audio/Visual/Navigation (http://www.jeepgarage.org/f155/)
-   -   speedometer accuracy / calibration? (http://www.jeepgarage.org/f155/speedometer-accuracy-calibration-43673.html)

ChuckinMA 06-21-2012 11:38 AM

speedometer accuracy / calibration?
 
Anyone know how accurate the WK2 speedometer is with stock 20 inch wheels? In other words, when I set the highway cruising speed, how concerned do I need to be if it's a few mph over the posted limit (assuming zero tolerance by the police)?

kmitch80 06-21-2012 12:04 PM

Re: speedometer accuracy / calibration?
 
with stock wheels it should be +/- 1 MPH. when you start increasing tire height, it will go up slighty.

Yadkin 06-21-2012 12:51 PM

Re: speedometer accuracy / calibration?
 
Why are you worried about the police. Oh, never mind, I see where you're from.

http://www.youtube.com/watch?v=xBdpINm9UBU

ColdCase 06-21-2012 01:26 PM

Re: speedometer accuracy / calibration?
 
All the OEM tires have nearly identical diameters, regardless of wheel size. My EVIC speed display for both 20 and 18 OEM tire sizes is pretty much right on my GPS. Its harder for me to read the dial accurately, however. The speedo dial seems to indicate a mph or two high.

You will be rolling the same % faster than indicated as your tire diameter increases. A 2% increase in tire diameter means you are traveling 61.2 mph when your speedo indicates 60.

dave2002ti 06-21-2012 07:44 PM

Re: speedometer accuracy / calibration?
 
I am lucky I live in state where the state police give you 12mph he posted speed limit and so do my local LE. Only exception is Interstates posted with a 70mph speed limit since 80mph or above is considered Reckless in VA. Now this also doesnt apply in school zones and some work zones.

Yadkin 06-21-2012 07:51 PM

Re: speedometer accuracy / calibration?
 
VA troopers are pretty fair. One time I lost track of my speed on a 55 divided four lane east of Danville, headed for the beach. I came over a rise and saw him waiting in the median, and I looked down at my speedometer and saw 72. :eek:

Knowing that 15 over is a serious fine I asked him as politely as I could how fast he clocked me. He said "69" and I said "thank you". :thumbsup:

OjeeperO 09-27-2012 04:10 AM

Re: speedometer accuracy / calibration?
 
been a little while i know, but if it helps anyone i just found tire-size-conversion.com has a speedo calibrator...type in the stock tire size and a new tire size along with a sampl speed and it tells you how fast you are actually going compared to the speedometer reading.


All times are GMT -5. The time now is 04:57 AM.

Powered by vBulletin® Version 3.8.8 Beta 4
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2012 - JeepGarage.Org
The Jeep Grand Cherokee Owners Community