Jump to content

Speedometer


SSBreeze

Recommended Posts

I have a 83 Sunrader that the speedometer reads about 75-80mph when doing 60. Same for around town. Inaccurate. Stock tires 14's. Any ideas please?

Link to comment
Share on other sites

My 1st thought was that someone had swapped rear axle ratios. However, Swapping from the normal 4.10:1 ratio to the common alternative 4.56:1 & 4.88:1 ratios would only change the speedo readings by ~10% & ~15% respectively. Your 60mph/75mph is ~25%.

Is your odometer similarly inaccurate?

Can you confirm if automatic or manual transmission?

Link to comment
Share on other sites

Many times the old speedometer gears can be worn down causing inaccurate readings. What is the diameter of your rear tires? They should be about 26” or 185/195 75R14. Larger tires will also give an inaccurate speedometer reading.

I dont even use my stock speedometer, I use my gps to to tell how fast I’m going.

Edited by fred heath
http://www.tyresizecalculator.com/tyre-wheel-calculators/speedo-error-calculator
Link to comment
Share on other sites

Yes, the odometer is also inaccurate by about 25% as I checked mileage with other vehicle.   The tires are 185 75R14. Great idea about the GPS app for speed. I will try that soon.  

Thank you!

Link to comment
Share on other sites

Also is the 4cyl, 4 speed manual tranny. 

Link to comment
Share on other sites

Pull your speedo drive gear out of the transmission and see how many gear teeth are on it and how its marked.

If in the past some body changed out your transmission it could have the wrong gears in it. Toyota has 4 basic gear setups.

You need a bigger driven gear, a smaller drive gear or a combo of both.

Link to comment
Share on other sites

  • 7 months later...

Found the best solution at a reasonable price. Nearby tranny shop went round and round about all the possibilities of what could be done with no final price, just a guess between $500-700. I walked away from that very quickly. A local speedo and instrument cluster shop has a small attachment to the end of your speedo cable regardless of the teeth. They put in on their dyno machine then calibrate it correctly. Works like a charm for $85 and .5 hour time. Have used it for 2K miles now and is perfect. 

Link to comment
Share on other sites

  • 4 months later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...