[Vwdiesel] Speedo drive gear

[dieseltdi at verizon.net]

Well, since it was raining today and I couldn’t do any thing in the way of actual work, I took the Jetta for a 10 mile drive with the GPS.  My goal was not to figure the mph difference, since I already knew that,  but the odometer error. Turns out that they are different of course.  The speedo is off approximately 6% plus or minus but the odometer is off by only 2.2% (high).  It is my intention to install the white drive gear and redo the test.  If Rodger is right, then I should be able to correct the speedometer to an almost exact point but then odometer, assuming there is a direct relationship between the odometer measurement and the speedo measurement, could be understating by about 4 percent (4 miles for every 100 miles driven).  I think I can live with that small error as long as my mph is correct.  I will let you know how things go.  Hayden


> On Dec 14, 2014, at 1:39 AM, lbaird119 at aol.com wrote:
> 
>  As Andrew said, you have to get your odo correct first then adjust the speedo to read correctly.  I'm presuming you're reading 1.16 mile for every mile you drive.  You would need a 13T gear to accomplish this.  Very strange.  The other option (I guess you would have to have a gear custom made by someone to make it a viable first option) would be to find a speedometer with a different calibration number.  Yours is 1540 so you'd need something around 1786.  Not sure what uses what number but I'm pretty sure a 4K Quattro speedo is somewhere close to that.  You might have to hybridize between the odometer and the speedometer to get a viable match.  
> 
>  That's really far off....  I'd say someone maybe put a wrong gear in the speedo, the one that breaks, but you've put in a few different speedometers...  Another option would be a speedometer cable correction box.  Not sure where you get them, if it'd fit, special (for a VW anyway) speedometer cables to connect one...  Can't figure how your odometer is off that far!
> 
> 
>  Other option is like Brian said, measure the circumference of your tire, multiply by 1.16 and try and find what tire is about that circumference.  Then you adjust your speedometer.
>     Loren
> 
> 
> 

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