guys sorry for the same old question. but still a bit confused on this speedo calibration. i removed the the adapter from tailshaft where speedo cable connects to. looked inside trans tailshaft. counted the threads(gears) on my drive gear? i came up with 6 . what driven gear would i need for a M20/3.31/27inch tire. thanks for any and all help.

The only 6 tooth circle gear was made for a metal driven gear and only for a 4.10 and up gear. I'm betting its a 8 tooth, now all that remains is to know the diameter.

8 tooth would use a 20 tooth driven gear. There are two different diameters, 1.76 and 1.84, the larger is the most common.

the driven gear in it now is a 22. i am afraid that its a 6 tooth drive gear ,thats the way my luck goes. thanks again i will try to get more information and another count on the drive gear

the driven gear in it now is a 22. i am afraid that its a 6 tooth drive gear ,thats the way my luck goes. thanks again i will try to get more information and another count on the drive gear

Well you just answered your own question.

L6T steel: 1.92" OD

Speedometer Pencil Gear
L20T steel

NOTE: this ONE (1) gear used with 1.92" outside diameter circle gear.

So, if you had a 6 tooth circle gear it would eat a plastic driven gear for lunch if you could even make it engage, it would be to big.

So your 22 tooth driven gear is designed for the smaller 1.76 circle gear and that menas to get right for the flight you need to change the circle gear and the driven gear.