nosajwp
NAXJA Forum User
- Location
- Winston-Salem, NC
I've always thought my 2001 XJ's speedo was a little off. This weekend, I drove by one of those speed trailers cops put out, and it said I was doing 51, and my speedo said 55 dead on.
I also figured I would check my speedo based on rpm's. The numbers are as follows:
speedo reading/expected rpm/actual rpm
40/1680/1750
50/1575/1580
55/1733/1750
60/1890/1920
65/2048/2080
70/2205/2250
75/2363/2375
I got the expected rpm numbers from the calculator on Randy's R&P website, for a 3.55 R&P ratio, 28.4" tire diameter, and 0.75 transmission ratio (1.00 for 40 mph). Do you guys think my speedo is really that far off, or could it be something else?
I also figured I would check my speedo based on rpm's. The numbers are as follows:
speedo reading/expected rpm/actual rpm
40/1680/1750
50/1575/1580
55/1733/1750
60/1890/1920
65/2048/2080
70/2205/2250
75/2363/2375
I got the expected rpm numbers from the calculator on Randy's R&P website, for a 3.55 R&P ratio, 28.4" tire diameter, and 0.75 transmission ratio (1.00 for 40 mph). Do you guys think my speedo is really that far off, or could it be something else?