Tazer - Increasing Tire Size Not Changing Speedometer

[Punkindave]

Then I would suggest that the tazer has done what it was designed to do: your speedometer reads just like it did before the tire change.

If your goal is to match the gps programs, you could try lying to the program about the size of your tires - experiment with it - until you match the gps.

He is stating that there is no change in gps after using the Tazer. Adjusting tire size should absolutely change the speedo. I used the closest setting to the BFG diameter listed in their specs and its spot on with the gos.
And to the OP, try to unmarry and start from scratch paying particular attention to the full rest process. It does work but the method and the buttons aren't 100% clear.

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[Jason Oliver]

He is stating that there is no change in gps after using the Tazer. Adjusting tire size should absolutely change the speedo. I used the closest setting to the BFG diameter listed in their specs and its spot on with the gos.
And to the OP, try to unmarry and start from scratch paying particular attention to the full rest process. It does work but the method and the buttons aren't 100% clear.

Then I was not specific enough. My question is this: before physically changing tires, did the speedometer match the gps programs? Trying to establish a baseline.

 

[BLACKMOAB]

My apologies if the OP already knows this but the value you put into the Tazer needs to match the true diameter of the loaded tyre on the vehicle. Firstly because tyres aren’t necessarily manufactured accurately to the size the makers state and secondly because the height of the tyre is reduced under load. To get an accurate figure for the Tazer measure the radius from the centre of the wheel to the ground and multiply by two to give the true rolling diameter. Set the Tazer to this size.

I measured them using a level an a yardstick and all four tires are within 1/8” of being the exact same size, which is the size I originally set them at using the Tazer.

 

[Rudolph Hart]

I measured them using a level an a yardstick and all four tires are within 1/8” of being the exact same size, which is the size I originally set them at using the Tazer.

OK, so when you’ve changed the size and it’s still displayed on the screen are you saving that by pressing the left button and the cruise control button before you move on to the reboot procedure?

 

[BLACKMOAB]

Then I was not specific enough. My question is this: before physically changing tires, did the speedometer match the gps programs? Trying to establish a baseline.

The answer to this is yes. With my stock tires, the speedometer and GPS were spot on exactly the same. I ran for over a month with my new, larger tires and was in no hurry to buy the Tazer. After comparing the speedo with the GPS almost daily at highway speeds and the the GPS indicating 72 vs speedo 70 (slower speeds indicated less of a variance and higher speeds indicated more), I decided to bite the bullet and buy the Tazer as I wanted to also have the ability to lower the TPMS warning when I aired down.

 

[BLACKMOAB]

OK, so when you’ve changed the size and it’s still displayed on the screen are you saving that by pressing the left button and the cruise control button before you move on to the reboot procedure?

Yes as that is confirmed when I go back in to increase the tire size, the last size that I entered is indicated.

 

[Rudolph Hart]

Yes as that is confirmed when I go back in to increase the tire size, the last size that I entered is indicated.

Well that’s me out of suggestions sorry, I hope Z Automotive are more successful sorting it out for you.

 

[BLACKMOAB]

He is stating that there is no change in gps after using the Tazer. Adjusting tire size should absolutely change the speedo. I used the closest setting to the BFG diameter listed in their specs and its spot on with the gos.
And to the OP, try to unmarry and start from scratch paying particular attention to the full rest process. It does work but the method and the buttons aren't 100% clear.

I’m going to try this today, hoping that taking it all back to factory settings and starting over from scratch may do the trick. I’ve also considered going back a few versions in Firmware and trying that, however I will wait until I hear from @joe@zauto or Ian before doing that. (I sure wish they offered tech support on the weekends when the majority of DIY’ers are messing with this stuff).

 

[BLACKMOAB]

Well that’s me out of suggestions sorry, I hope Z Automotive are more successful sorting it out for you.

Thanks for your input @Rudolph Hart I appreciate it.

 

[Jason Oliver]

The answer to this is yes. With my stock tires, the speedometer and GPS were spot on exactly the same. I ran for over a month with my new, larger tires and was in no hurry to buy the Tazer. After comparing the speedo with the GPS almost daily at highway speeds and the the GPS indicating 72 vs speedo 70 (slower speeds indicated less of a variance and higher speeds indicated more), I decided to bite the bullet and buy the Tazer as I wanted to also have the ability to lower the TPMS warning when I aired down.

I gotcha now. The only other thing that you might try would be to lie to the tazer, and tell it your tires are larger (say, in 1 inch increments) until you get a match to the gps.

 

[WranglerMan]

Just for a test try plugging in a way larger number than what your tires are and do a few complete reboots of the Tazer after verifying the higher number was accepted then take it for a drive on the highway and see what happens

 

[BLACKMOAB]

I wanted to thank everyone for their suggestions and replies. I determined that the key to obtaining programming success with the Tazer is that when you hit a roadblock where it isn't responding to your commands, the key is to un-marry it, do a couple of sleep cycles (turning the ignition off, opening and shutting the door and waiting until the dash lights go out then starting the engine, shutting it down and repeating this process again). That get's everything back to stock and allows you to start with a totally clean slate. Then, you re-marry it and start over from scratch. I did that once and obtained immediate success.
My second takeaway and hint for those that want to get their speedometer set perfectly with the GPS, is that you may need to try two or three tire size settings as the Tazer choices (which are in .09 inch increments) may or may not correspond with your manual measurements of your tire heights or what your tire manufacturer specifies as the tire height.
So, in the end, I got mine programmed perfectly and everything set exactly the way I wanted it. I'd say the main key is, be patient and prepared to do some experimenting with the tire size/speedometer setting (test runs to get to highway speeds to check your success took some time), but it works as it should and I am happy (however I have yet to hear back from @joe@zauto or Ian who I emailed at tech support).

 

[WranglerMan]

@BLACKMOAB you have to realize that zauto motive is not a huge company and until Ian it was just Joe, not saying that not hearing from them is acceptable but patience is a virtue but like you when I have issues with a particular item I want to go to the front of the line for service.

Glad you got it figured out and it’s working well now.

 

[roll]

I got taller tires by 2”. I’ve increased (and successfully saved) an increased size 6 times in increments and according to GPS it’s not changing the speed on my speedometer - GPS shows 72 mph when speedometer shows 70 mph. I increased the tire size to over 2” taller than what they are with no change to speedometer. The size changes are saving and I’m doing a full reboot after every increase and then making a highway run to check. What could be wrong? I’ve emailed Z Automotive but they probably won’t answer me until Monday.

Same exact problem. no matter what tire size I put in it's 2 mpg off. The conclusion I've came up with is the Jeep software picks up on the tire size that you put on automatically. The Tazer won't override it.

 

[Arrowhead]

Same exact problem. no matter what tire size I put in it's 2 mpg off. The conclusion I've came up with is the Jeep software picks up on the tire size that you put on automatically. The Tazer won't override it.

Did you read ANY of the posts in this thread other than the first one?

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