Your classic car classifieds & community
Login to MyOldRide Account
Close Search Box
OldRide Answers Home
Using OldRide Answers
Ask a Question
Browse Questions In:
Classic Car News
Site Suggestions & Comments
What plastic speedometer driven gear is right for me?
I have a turbo 350 transmission and my rear differental gear ratio is 3.55 with 15 inch tires on the car, what size or color speedo gear do I need? My speedometer is way off and I want to change the plastic speedometer driven gear in the tail of the transmission housing, but not sure on what size to get to make my speedometer read the correct speed the car is going. Any help would be greatly appreciated!
July 11, 2010
Each tooth is equal 5 mph See how far you are off and reduce or expand to equal the correct speed. e.g. if you are off by 10mph to slow go up two teeth on your existing gear. For the situation you describe I believe that 22 teeth will get you very close.
July 14, 2010
Sorry if it is too slow you go down in gears and if too fast go up Jeez now I am confused Have fun.
July 14, 2010
I have seen a lot of speedo gear sets etc on ebay. Some of the chevy trucks and cars had a reduction adapter that threaded on the tranny then the cable threaded on. It that was a item used if the rig had oversized tires. there are some still out there. we parted out several gm cars that had them. My kid put a 48 buick speedo in his 23 chevy coupe and figured out the gearing was way off in the speedo. the adapter got him a lot closer. good luck
July 16, 2010