installed 4.56s and i needin speedo help

[Streetgliderx]

i pulled a search but i can't find an easy to understand calculator the tci one is down i guess.. i have a 350/700r4/np208/35"/4.56 setup my speedo says 75 when runnin 65 on my tom tom... whats the gears needed to correct this?

thanks

 

[user]

http://www.bgsoflex.com/speedo1.html

http://www.transmissioncenter.net/speedometer_calibration_______va.htm#700r4

http://www.transmissioncenter.net/highperflist.htm

 

[dcubb]

I've got the same combination. Running a 15 tooth drive and a 43 tooth driven. My speedo is on the money now according to my GPS

 

[Streetgliderx]

thanks is the 15 tooth drive the one that is factory installed?

 

[dcubb]

Every one I've dealt with had the gray 15 tooth gear.

 

[badmix]

how hard is it to install these? I actually picked them up along time ago, but was under the impression it wasnt worth the trouble or effort to change.

my speedo is 20mph off at 65mph and a lil less at slower speeds.

 

[dcubb]

Changing the drive gear requires removing the d/s and tailshaft housing. The driven is super easy. Most times, you can "calibrate" just by changing just the driven gear. I usually get them at the local dealership for around $4.

IIRC, there's only three or so different tooth counts for the drive gear available. Also, if you have to make a drastic change in the driven gear tooth count, you may have to change to a different speedo drive housing.

 

[pauly383]

thanks is the 15 tooth drive the one that is factory installed?

I've seen some blue installed , but most were grey . Mine was so far out with the 35's and 4.56 , they made no gear for my tooth count requirement .

I have to run a adapter box , THEN go get a new gear

 

[Streetgliderx]

i installed a 43 tooth and i still about 7 mph fast.. dealer said he can get me a 44 and i can swap with no charge. so we gonna try it