does anyone know the process of how to recalibrate a speedometer? I was wondering for two reasons, i have a different set of rims that are slightly larger than stock with tire and also i have a gauge cluster set in kmh and i'd like it to be "reasonably" accurate if not dead on :D

i remember having a conversation with a "law enforcement specialist" who mentioned they have cards certifying the accuracy of their vehicle's speedometer in the event they are challenged in court regarding their method in determining the speed at which a suspect was traveling. for example, (not exactly sure of the distance) say the "law enforcement specialist" was following a suspect for an 1/8 mile. While doing this he notices the suspect is travling at an average speed of 85 in a 55 zone (this is in hawaii :p :rofl: ) if questioned in court as to how the speed was determined (not using a gun obviously) he can whip out his handy dandy certification card stating that his vehicle (squad car or bike) is calibrated to exactly what the speedometer reads (which was performed at a certified shop...this is the part i'm not sure of, what they're called, the shops, or what type of shops the equipment for speedo calibration are typically located in)


thank you!

p.s my apologies if this topic has been explored before, but i searched "speedo* cal*" and "speedo* recal*" but i didn't find any threads which looked promising. ;)

Not sure if the head can be redone within cost reasonability - seems to me you'd have to recalibrate the magnetic pickup (?). At the gearbox it's called changing teeth and I've never heard of different ratios for the primary and secondary wheels there for the Nissans, unlike we used to have it on old American boxes - like the Warners and Muncies - given we were always changing the ring and pinion on the differentials of our old iron, there were dozens of ratios to be able to get the speedo to match whatever we'd done at the differential or tires.

i still have a cable driven speedo, does the cable itself make a difference? for example, those who do the NX1600 gauge swap into a se-r, do/can they use the 1.6 speedo cable to make the speedo more accurate?

due to lack of response, i'm going to redirect. is there ANYONE who's calibrated their speedo?

hopefully someone responds soon, my speedo has been 8mph off for nearly 2 months now. I gave up on trying to learn how.

good luck man

you have to change the plastic gear on the spedo sensor. nissanmotorsports sells a whole heap of different gears that you choose to give you the correct mph. like more teeth or less teeth. the gear is really easy to change. just pull out the sensor out of the tranny, and use a punch to remove the pin( if i remeber correctly) and then put on the new gear.

well first you need to get a motorsports catalog form the dealer. i think its the 2002 catalog. and then figure out which gera it is that you need.

good luck.

what size tires you running....maybe i can sell you a new set that fits!!

I, too, am looking for how to get my speedo recalibrated (since my cable broke and I'll be working on fixing that anyways :tongue:). In my searching I found the speedometer pinions (http://www.courtesyparts.com/nms/b13/b13_2.html) for cable-driven speedos at Courtesy Nissan. They've got pinions with 33, 34, 35, and 36 teeth on them, with the statement that "Increasing the tooth count on the pinion will decrease the MPH readout." So the $1M question seems to be how do I know which pinion to get? My speedo (when it was working) is off by about 4-5mph. Does anyone know how many mph one tooth will decrease/increase your speedo reading?

you have to change the plastic gear on the spedo sensor. nissanmotorsports sells a whole heap of different gears that you choose to give you the correct mph. like more teeth or less teeth. the gear is really easy to change. just pull out the sensor out of the tranny, and use a punch to remove the pin( if i remeber correctly) and then put on the new gear.

well first you need to get a motorsports catalog form the dealer. i think its the 2002 catalog. and then figure out which gera it is that you need.

good luck.


wow! thank you so much! answered my question on how to do it and my next question of where to look!


I, too, am looking for how to get my speedo recalibrated (since my cable broke and I'll be working on fixing that anyways :tongue:). In my searching I found the speedometer pinions (http://www.courtesyparts.com/nms/b13/b13_2.html) for cable-driven speedos at Courtesy Nissan. They've got pinions with 33, 34, 35, and 36 teeth on them, with the statement that "Increasing the tooth count on the pinion will decrease the MPH readout." So the $1M question seems to be how do I know which pinion to get? My speedo (when it was working) is off by about 4-5mph. Does anyone know how many mph one tooth will decrease/increase your speedo reading?

AU-RYTE! another option! thanks again people! gotta love this fourm!

once i get my ass around to doing this, i'll report with my findings :p

hopefully someone responds soon, my speedo has been 8mph off for nearly 2 months now. I gave up on trying to learn how.
good luck man

Are you 8 MPH off throughout the speedo range (well, I mean up to legal speeds...?)
If you are off in that manner, then the problem is not with your sending unit but with your speedo calibration. There are 2 ways to fix this:
The first is the Tom Paule Monkey Method (tm) that takes advantage of the fact that in 4th gear with tires of stock circumference, the angle of your speedo needle equals the angle of the tach needle. It also assumes that your tachometer reads correctly, but you can double check that with an automotive multimeter. So, you remove your gauge surround, take out the gauge cluster and remove the clear plastic front and take off the speedo needle. You may want to temporarily reinstall the gauge cluster at this point to make the next step a bit easier. (It will be a necessity if you have a cable driven speedo.) Put the front of the car up on jack stands with the parking brake on and the rear wheels chocked (or up on jack stands) get in, start the car and "drive it" until you get to 4th gear. At this point, turn enough RPMs to have the tach needle either horizontal at 9:00 or vertical at 12:00 (using cruise control might help) and reinstall the speedo needle at the same angle.
The next method is to use some cool technology like a NissanDataScan, etc. in conjunction with a Blatz or PLMS cable that allows you to put in the stock tire size and the tire size you are using and the readout shows you the true speed your car is going as you "drive" the car on the jack stands and reinstall the needle. If you are a mathematical genius, you can figure all of this out as well.... This method can also be useful if you have access to the hardware and software but are too cheap to get a speedo drive gear and just want to calibrate your speedo for one particular speed (lets say you drive at 75 MPH most of the time and only care that the speedo is correct at that speed to keep Johnny Law off your back....

Using the NissanDataScan is how I know that my speedo reads 2 MPH slow at any speed.

well thought this was gonna be more towards the digital stuff! but great write up

I used a GPS on my laptop to tell when I was going 55 and put the needle back on.