morning and had the odd feeling I wasn't going as fast as the speedometer was telling me I was going. Either my perception is wrong or the speedometer needs adjusting. Is this a common problem and is it an expensive fix? Anyone know? Thanks!
What size wheels/tires do you have on her? Supposed to be 205/60x15
Just bought a '93 9000 CDE with only 35K on it. Was driving to work this morning and had the odd feeling I wasn't going as fast as the speedometer was telling me I was going. Either my perception is wrong or the speedometer needs adjusting. Is this a common problem and is it an expensive fix? Anyone know? Thanks!
-nigel, Los Angeles, CA
They appear to be 195/65x89 - does that make sense?
Yes I think it means 195/65/15 since those were originally fitted to my 93' 9000 CSE. However, there may be variations due to wheel/tyre options, but these will have very similar rolling diameters. I don't think that would result in any perceivable change in the speedometer scale. So either the problem is psychological or something else. You could time the distance covered between fixed mileage points.
Actually, there is very little difference.
My '93 9000 CSE has always had 205/60-15's. I see that Tire Rack Web site shows the stock size for a CS is also 205/60, but a CD gets 195/65's. I also do not see a CDE listed, for some reason, but I imagine that there was one, though who knopws what the OEM tire size was.
The diameter of a selected 195/65 is 25" and the same maker's 205/60 is
24.7". That equates to rotations/mile of 831 vs. 841 or a 1.2% difference. So at 60 miles per hour your speedo may be off by slightly more than 1 mph!! yikes...-Fred W
morning and had the odd feeling I wasn't going as fast as the speedometer was telling me I was going. Either my perception is wrong or the speedometer needs adjusting. Is this a common problem and is it an expensive fix? Anyone know? Thanks!
I found myself going about 85 or so in a 70 MPH zone in a 9-5. It may not be your speedometer.
If you can borrow a GPS from someone, it should provide a good speed check, if it has a speed readout.
Harvey
Maybe reading in km/hr. get out your manual and read up on it.
Dick in Falls Church
But but but, how do you know which car show the correct speed?
Thanks! What I'll do is follow my girlfriends Benz on the freeway and sychronize our speeds and see what's up. Its definately at higher speeds when it seems wrong.
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