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Question for those who have recalibrated their Speedometers with a Tazer and/or the like.

How do you measure tire size?


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XraytecH

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Successfully upgraded firmware and installed my new Tazer JL Mini.

Question for those who have recalibrated their Speedometers with a Tazer and/or the like.
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Planerdude

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I bought the “ECRI”, it will calculate the tire size while driving using GPS. No guessing. Very easy to use,
 

gerky18

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I measured the actual tire and that got me close. Then I would take it out for a drive with a GPS app for the speed and adjust from there. I used an app and also Google maps to have multiple references. Also if you have the static speed signs helps to verify.

I used the jscan if it makes a difference.
 

Gobi Wan K

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I have the Tazer. I have BFG Ko2 315/70 17. They are listed as 34.5 but mine measure about 33.6 ish from the ground to the top of the tire. According to tazer I use this measurement but I actually ended up setting it around 34.6 for the speed to be on.
 

CerOf

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I started at 1/2” less than the actual unmounted height as per the specs I read on tire rack. I used a local static speed sign in my neighborhood and a speedometer app on my phone. I ended up pretty much spot on.

Couldn’t find my tape measure. My wife is rearranging furniture, decorations on walls, etc.
 

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CrazyCooter

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Mark the tire, roll one revolution, measure the distance traveled, the divide by pi. You get the average loaded diameter this way.
 

johnparjr

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Went to the manufacturers website and looked at what they put and bingo your done. Did that yesterday with my new Patagonia’s
 

TrainMan

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Measure center of hub to edge of tire ACROSS, then times by 2. Got 34". Then reduced half an inch for compression on pavement.
 

firehog

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Successfully upgraded firmware and installed my new Tazer JL Mini.

Question for those who have recalibrated their Speedometers with a Tazer and/or the like.
I entered the number from the manufacturer spec. Its a 35” tire and measures 34.4”.
 

brianinca

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Stuck a long spirit level across the tire tread, measured 34.4 vs 32.6 for the stock Falken. I think there was only 34.46 or something in the Tazer, close enough. 2MPH low at 84 MPH according to GPS (speedo reads 82 MPH).
 

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Gren71

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I bought the “ECRI”, it will calculate the tire size while driving using GPS. No guessing. Very easy to use,
Did you have to pay for the full version?
 

KurtP

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None of the above. Measure the circumference of the tire you run, down the center of the tire, on your rim, at your street pressure, then calculate diameter from that. Install that number as your tire size.

use the spare or jack up the truck if you didnt do your spare. Its the most accurate measurement, and accounts for the fact that the diameter of the tire parked is not the diameter of the tire at highway speed. Youll find this method extremely accurate. I have a 0mph variance between my speedo and my (unplugged) gps at 80mph.
 

jtimbrook

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I did mine based on how AEV used to determine calibration, measure wheel height from road surface. Get it drive it with my GPS running to give me current speed to make sure calibration is correct, if not set it for either a little higher or a little lower depending on the speed. Viola, calibrated! Keep in mind unlike AEV the Tazer's tire size settings have weird increments so it's not going to be dead-on perfect
 

Lo Tek

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Set to tire manufacturer’s specs then checked with a GPS app; was within .2 mph at 75 which IMHO is “close enough”.
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