speedo gear

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I have several different gears advertised in the "Mechanical - For Sale" section. But you need to have the accurate overall height of the rear tires before using a chart to find the correct gear. 727 and 904 use same speedo gears and housings for them.
 
The rear tire outside diameter affects the speedo reading and you didn't include that info. If you have a speedo gear currently in the car and it's just inaccurate, you can do this:
Drive the car with a GPS at a steady speed, say 70 MPH. Note what speed the GPS is actually showing. Take your existing speedo gear out of the trans and either read the number molded into the gear, or count the teeth.
Example: If you were driving at an indicated 70 and the GPS says you were going 62 MPH, your speedo is reading 13% high. (70 divided by 62 = 1.13) Multiply your number of teeth by 1.13 to get the new gear required. So let's say your current gear is 32 teeth, multiply that by 1.13 and you get 36.16. So the new gear needs to be 36 teeth. (you need more teeth to slow the speedo down) I did this with my 68 and it is now dead nuts accurate. I bought the gear off e-bay.
 
I should have one.....just need to know how many teeth you need.
Thanks, Mark
 
get me the number of teeth you need. $12.00 shipped anywhere in the lower 48. Thats $12.00 total shipping included. Steve
 
This may help you....

SPEEDO.jpg
 
Is there anyone left that can calculate the rolling diameter of a G60x15 or a 7.25x15 ? lol It's like a lost language...

Can't you still get these new from the dealer ? I bought a bunch of them about 15 yrs ago and still have some NIB sitting on a shelf .
 
ok very helpful t/a rad 255x60x15 is 27.1 in according to a tire site so i should need a 27 according to chart above
 
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