Does anyone know the part number and color for a 16 tooth driven gear for a world class T5 tranny?
Thanks in advance,
Alan T.

 

I've never seen or heard of a 16-tooth. Least I know of is 18. But I'm an idiot, so I could easily be .... just stupid.

Cable or electric?

What are you really doing?

 

probably gonna need to get a ratio adapter + gearing of it.

 

It is an electric speedo. Using the Hanlon motorsports speedometer calibration utility and the stock size tires for my 91 Formula (245 50 16) and 3.42 gearing it comes up with 16 tooth driven and a 6 tooth drive. I already have what I believe I need which is the 7 tooth purple and 19 tooth white. I just got the car on the road after the engine rebuild and don't feel like pulling and tearing apart the tranny to change the drive gear yet. When I remove the VSS the drive gear I see is red in color and with the angle I'am at it looks to have 6 teeth. I should have checked it before I put the tranny in but I didn't think of it. The driven gear that came with the used tranny is a 21 tooth. I changed that out and put the 19 tooth one in there and still get the same results basically. She's about 5 mph off until you get between 40 and 50 mph and then it starts to increase to 10 mph but above 70 mph I'am not sure since I haven't pushed the car yet since the motor is still being broken in. Thats why I figure fewer teeth on the driven gear should slow the revolutions. But after I first posted I went back to the Hanlon site and ran the calc again and its showing that my size tires should be 25.65" tall and when I measure the ones I have (Firestone Firehawks) they are roughy 24.5" tall. I'am sure an inch diameter change would register a mph change. Well thats about it if someone has heard of a 16 tooth please let me know. RB83L69, my local GM parts dealer agrees with you, we searched yesterday for a 16 tooth and he couldn't find one. Either for a f-body equipped with 16 inch tires or 15 inch tires with the 3.42 gears. Oh yeah every time I try calling Hanlon to see if they have one I get a busy signal.

 

• It's wrong. Every single online speedometer gear calculation site I have ever seen is wrong. Close, but wrong. Avoid them like the plague and go for what the factory used.
  
• I've heard of 7 & 9 tooth drive gears but not 6. Mark it with a marker, rotate until you get an accurate tooth count.
  

 

Never heard of a 6-tooth drive gear for one of these either. 7 is the fewest I know of.

7 & 20 or 7 & 21 are the closest for 3.42s, depending on your exact tire radius. I have 7 & 19 in mine and it's real close for 3.73s.

Do a search on my userID and the phrase "SMUC"; it tells you how speedometers work and how to calculate the gears. And of course, keep in mind you're never going to be able to get the "perfect" gear, any more than the factory did; you can only get teeth in whole-number counts, and not all possible tooth counts are still available. But yours should be no problem to get to within 2.5%, which is 1.5 mph at 60, since that's half of teh approximate 5% step between driven gears.

Screw a bunch of quoting what "size" tires you have and pretending to "calculate" their diameter. That's a good bit of your problem right there. It'll be wrong every time, guaranteed. Go measure your wheels with the correct air pressure in the tires and the car sitting on the ground, from the center of the wheel to the ground. That's the only number that matters. Use that in the "SMUC" formula.