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Hello! I have 3.08 gears with 29 inch tires (2.994 1st gear helps.) It’s got a 17 tooth purple pencil gear, but my speedo still reads 45 at GPS AND RPM measured 55. Are there smaller gears than 17? Did i do something wrong with the gear installation? Any advice would be great!
Try this site and charts. Drive or driven gears, rear ratio, etc. Charts for tooth count and color.
I dunno…I always used the freeway mile markers to see if the odometer is high or low reading. Then it’s a simple ratio to answer more or less teeth required on the driven gear. If you are way off, then you may need to re-gear the drive gear. Keep it simple….
Thanks for reaching out Steve O, looks like that calculator also points me to the ballpark of a 17 tooth! All muncies used an 8 tooth DRIVE gear correct? I have an M23 from AutoGear, I’m sure they’d have 8 tooth DRIVE as well?
If i geared it to match, it’d be 3.73s. My cam would LOVE IT, but my highway cruising WONT. I’d love to keep my 3.08s if possible!
Not sure about your purple 17 tooth as it's not listed in the GM speedo drive gear options. Your issue is arising at least in part because your tires are about 1.5" larger in diameter than the original 27.5" tires.
Hello! I have 3.08 gears with 29 inch tires (2.994 1st gear helps.) It’s got a 17 tooth purple pencil gear, but my speedo still reads 45 at GPS AND RPM measured 55. Are there smaller gears than 17? Did i do something wrong with the gear installation? Any advice would be great!
You either have a typo or have left something important out concerning your transmission. NO Munice ever came with a 2.994 1st gear. Where did you find a 17 tooth driven gear, not listed by GM?
Not sure about your purple 17 tooth as it's not listed in the GM speedo drive gear options. Your issue is arising at least in part because your tires are about 1.5" larger in diameter than the original 27.5" tires.
If your speedo is reading too slow to actual, you need more teeth on the gear.
i thought that you have to go SMALLER to make the speedo FASTER? Because a smaller DRIVEN would make it turn faster, right?
You either have a typo or have left something important out concerning your transmission. NO Munice ever came with a 2.994 1st gear. Where did you find a 17 tooth driven gear, not listed by GM?
I got an M23 from AutoGear. Its a super duty, and has customizable ratios! I went with a 2.99 first, and a bigger gear spread, so i can get away with a lower (numerically) rear end! I got the 17 tooth from classicindustries.com , but maybe its too small to catch the drive gear constantly, resulting in a low reading? This makes sense if it was never listed as a GM product!
i thought that you have to go SMALLER to make the speedo FASTER? Because a smaller DRIVEN would make it turn faster, right?
Drat, apparently I had it backwards; further reading agrees with you that more teeth = lower reading, fewer teeth = higher reading. Because you are already at a very low tooth count in your driven gear, you may need to explore changing the drive gear.
I got an M23 from AutoGear. Its a super duty, and has customizable ratios! I went with a 2.99 first, and a bigger gear spread, so i can get away with a lower (numerically) rear end! I got the 17 tooth from classicindustries.com , but maybe its too small to catch the drive gear constantly, resulting in a low reading? This makes sense if it was never listed as a GM product!
I reached out to verify that they installed the larger drive gear (1.84”) and am awaiting response. I think an issue is that not many people run such a low (numerical) gear with larger tires.
Just confirmed it IS a 1.84” drive gear. Brown 18 tooth is being shipped. I’ll see where my speedo is with that! If its a tad slow, i also bought a 1:1.0574 multiplier. Ill keep y’all posted
LOW speedo reading.
.) It’s got a 17 tooth purple pencil gear, but my speedo still reads 45 at GPS AND RPM measured 55. Are there smaller gears than 17? Did i do something wrong with the gear installation? Any advice would be great!
