 Speedo recalibration, I'm really not going that fast. |
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| Cevan |
 Aug 20 2007, 08:38 AM
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#1
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Senior Member  Group: Members Posts: 1,079 Joined: 11-December 06 From: Western Massachusetts Member No.: 7,351  |
I just bought a '75 1.8 last week, 54K miles (please insert "This post is worthless without pictures" here). I've put about 300 miles on the car in the last 6 days. (IMG:style_emoticons/default/driving.gif)
My speedometer and odometer both work in my car. However, on the highway, I noticed that the odometer would record a mile in roughly .9 miles. I used the mile markers on the Mass Pike. The speedometer also appears to read a little fast. The tires are 195/60-15 Yokohamas. I'm assuming the tire diameter is less than the stock tire that the speedo was calibrated for. The question: Can the speedo be recalibrated? If so, how? |
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| derekdenman |
Aug 20 2007, 09:30 AM
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Newbie Group: Members Posts: 33 Joined: 29-June 07 From: Mckinney, Tx Member No.: 7,852 |
Mine does the same thing. I am going to a place today to does speedo repairs and I will let you know what I find out.
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| Cap'n Krusty |
Aug 20 2007, 09:41 AM
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#3
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Cap'n Krusty Group: Members Posts: 10,794 Joined: 24-June 04 From: Santa Maria, CA Member No.: 2,246 Region Association: Central California |
Rather than going to "a place that does speedo repairs", send it to North Hollywood Speedometer or Palo Alto Speedometer and have it done by experts in VDO instruments. Odds are it'll cost about the same, but it'll be done right the first time. The Cap'n
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| rhodyguy |
Aug 20 2007, 09:52 AM
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#4
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Chimp Sanctuary NW. Check it out. Group: Members Posts: 22,240 Joined: 2-March 03 From: Orion's Bell. The BELL! Member No.: 378 Region Association: Galt's Gulch |
this is common. have someone pace you with a car that has a correct reading speedometer and do the mental math. figure it reads roughly 10% higher than your acutal speed. your actual fuel fuel milage is lower by the same %.
k |
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| swl |
Aug 20 2007, 05:23 PM
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#5
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Senior Member Group: Members Posts: 1,409 Joined: 7-August 05 From: Kingston,On,Canada Member No.: 4,550 Region Association: Canada |
According to the tire size calculator your 195/60 should indicate 4.7% too fast. http://www.914world.com/specs/tirecalc.php
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| Cevan |
Aug 20 2007, 07:32 PM
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#6
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Senior Member Group: Members Posts: 1,079 Joined: 11-December 06 From: Western Massachusetts Member No.: 7,351 |
It seems closer to 10%. Here are a few pictures of the car.
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| swl |
Aug 20 2007, 08:00 PM
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#7
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Senior Member Group: Members Posts: 1,409 Joined: 7-August 05 From: Kingston,On,Canada Member No.: 4,550 Region Association: Canada |
Nice looking car! Looks to be in great shape.
I'm not an expert with the speedo but I would imagine the speedometer could indeed fall out of spec. From what I have read the odometer is just a bunch of gears. It should never go out of whack. If you can get a stretch of maybe 10 miles with mile posts try that to get your calibration. The extra distance will add to the accuracy. If the odo is that same 10 % as the speedo then I'm lost in my understanding of how this stuff works. Assuming of course the tire size calculator doesn't have a bug in it. Does any one know what the ratio was for the 165sr15? I've never seen it expressed with the sidewall ratio. |
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