Speed O off

[Heloavi]

Okay so I checked my speed against the GPS and I am 7 MPH off. I searched the threads but I did not find detailed instructions on how to correct this.

Pretty sure I am searching incorrectly. Any help?

[IndianaVX]

If you have added larger tires than stock, speedo will be off,

[Heloavi]

When I bought it. The guy before me had larger tires but there should be away to set the speed o to correct this.

[Stephen Biko]

You will need an adjustable add-on speedometer. If you could adjust the stock speedometer that would make it trivial to spoof the odometer. There are lots of OBD gauges out there. You can get a bluetooth OBD interace to use your phone as a speedometer or a dedicated OBD gauge. One that was recently mentioned here is the $70 ultra guage but there are others.

[Cobrajet]

Back in the "good old days" you could simply change the gear at the end of the speedometer cable to account for a gear change. However, with todays electronics, it's not so easy. You can't just "flash" to ECM to adjust the speed reading. Most of us have calculated the speed difference, as you have, and take that into consideration. Another option is to use the speed reading from a GPS unit.

[Heloavi]

Anyone replace the dash with a mini IPAD or something like that?

[HeckaTrebeka]

Lots of people change their differential gears to match stock ride and speedo settings.

[LittleBeast]

You can adjust the speedo, but it's tricky. I had my girlfriend at the time put her car on 60mph cruise control and get next to me on the highway. I then matched my speed to hers and put my cruise control on, and then pulled the needle off the VX gauge and carefully placed it exactly at 60mph. While I know it is still not perfect, I know that it is close enough for me. Yes this involves removal of the gauges, but it really is pretty easy.