Different Speedo Gear

[rangerin]

How do I find out what speedo gear I need to put in the tranny? I just went from a 195/75/14 tire to a 215/70/15 tires. Speedo is reading apprx 10mph fast.

 

[swynx]

Go to the tech library do the conversions to see what your "new" gear ratio is then find the page there that lists the ddifferent plastic speedo gears. Mine was yellow 28? Spline for 3.73

 

[iiqjohnwick]

How do I find out what speedo gear I need to put in the tranny????

 

[Earl43P]

http://www.therangerstation.com/tech_library/Speedogear.shtml

Might need to do a little math...

 

[hank857]

go to ford parts counter and ask them they will have what is needed. I changed mine and it was worse, so just just a correction factor for the odometer of +4 miles/100 driven. DId a rodway cal and really with the original gear it was only off a little not enought to worry about. ALso you can just cal with a gps unit on dash and figure the correction.

BTW I put the original gear back in the trans.

 

[Captain Ledd]

you sure it's not reading slow? going to a bigger tire than what was originally there will mean more distance traveled per revolution and an increase in speed (per tire revolution).

195/75R14 = ~25.5"
215/70R15 = ~26.8"

If that's the change that took place you should be driving faster than what's indicated on the speedo.