I have started driving the car after the long rebuild and I expected some speedo error (205 50 15 tires) but not 10 mph difference at 60 mph (slower indicated than actual). I get the whole rolling diameter versus original and speedo drive gear thing. BUT, the calculators out there say I should be seeing a few percent error, not 17%.
Here's the thing though, parked in the garage the speedo reads half way between zero and 10 mph (~5 mph). I gotta believe this is contributing to the error I am seeing. Has anyone else seen this? Is there any sort of zero set that can be adjusted on the speedo?
On the other hand since I like to drive about 10 over the speed limit (seems to be the range they won't ticket you for) maybe I leave it alone and drive the speed limit knowing I am actually about 9 to 10 mph over.
Jeff Klein, Aiken, SC
1980 FI Spider, Veridian with Tan (sold about a year ago), in the market for another project
1989 Spider, sold
2008 Mercedes SL65
2008 S600 Mercedes V12
When I rebuilt my car, I put in one of 4 good speedos i had. It was fine for a while but started reading higher and higher. It wasn't long before it was reading 70 at 35. I changed out the speedo to one that was more accurate. Haven't had any issues with the one i have in the car.
my speedometer also shows roughly 5 mph when parked. If I tap the speedo hard with fingernail, it goes down to zero.
I did previously disassemble it ; i think it's just related to some friction on post that is connected to spring. I wish I added some lubricant at this point, which I did not. Just not worth disassembly for this
joelittel wrote:Not sure about the pin, but I don't recall there being one. If there were I doubt I would think it odd that the needle rested on it at a stop.
This will go on my " May never get to it" list
While not on my "never get to list" it is certainly on my "when I am really bored" list. I'll try tapping hard as suggested above.
Jeff Klein, Aiken, SC
1980 FI Spider, Veridian with Tan (sold about a year ago), in the market for another project
1989 Spider, sold
2008 Mercedes SL65
2008 S600 Mercedes V12
My speedo has never been very accurate, and it seems to vary with, ...well who knows what? If I'm worried about speed, I have a simple GPS app on my phone that I can turn on to compare to.
Kirk
The speedo on my 77 which is original to the car has a little pin that stops the speedo needle at about 5 mph. The pin is above and inboard a bit from the 0 on the speedo. Tough to see but it's there.
