Inaccurate speedometer

[bear]

New stock 1958 with 6000 miles. Everybody is passing me! Google and waze indicate I am 4 mph slower than speedometer. I had to raise air pressure to 36psi to keep low pressure alerts off at low temperature. Is this my problem?

 

[Nuke]

Cannot see where the tire pressure would make an appreciable difference at 36 PSI. What was it at prior?

 

[bear]

I don't see it either, grasping at straws. Will lower pressure to test when it warms up.

 

[jbe2289]

Yes, the speedo on my 1958 is off as well, about 3-4 MPH slower than what the speedo says with the stock 245/70. Not sure at this point how off it is with having put 265/70R on, I think it made it even more off by 5-6 MPH slower than what the speedo reads. I imagine the miles are also being significantly underreported on the odometer as well.

 

[Nuke]

I just wish there was a method to calibrate the speedometer/odometer. Not rocket science, just use an accurate GPS-driven reading, and make an adjustment. I do not think even a Carista will do this. And, if I am thinking correctly, if the speedometer/odometer is reading high, it is running out the warranty sooner.

 

[uraniumrich]

I'm running 255/80R17 Falken WildPeak AT4Ws and find that my speedo is nearly dead on when measured by radar and displayed as I pass it on the highway (a lot of construction zones have these setups to remind us to slow down.) At the same time, Waze typically shows me going about 2 mph slower than my speedo. I think the radar is probably more accurate, so I think my speedo is right. If I was on the stock tires, then I'd actually be going slower than the speedo indicates, which means that the LC is overestimating both my speed and mileage (so your warranty runs out faster.) Things that make you go hmmm.