U7136---Tire Size Adjust no effect!

[xkm121]

My stock tire size is 225/60-R18. I changed to 235/55-R18 tire and I tried to use Predator U7136 to adjust my tire size accordingly. The quick adjust shows that adjustment is done. However, when I was using GPS to log my speed I found that the speedo is still off! My speedo displays 65mph while my gps only detect 63.97mph. I even asked a LEO friend to use a laser gun to help me log the correct speed and it turns out the same.

So what is wrong with this? How come the predator unable to adjust the tire size? Please help me!


My Predator is U7136 using 9r07 firmware. My car is an 08 Dodge Charger SXT.

Thank you!

[Mike_Levy]

Because seemingly same size tires aren't the same size. Besides different manufacturers being different, tires expand when they're spinning. Use the actual measurement of the tire and it'll be accurate

[mikel]

My stock tire size is 225/60-R18. I changed to 235/55-R18 tire and I tried to use Predator U7136 to adjust my tire size accordingly. The quick adjust shows that adjustment is done. However, when I was using GPS to log my speed I found that the speedo is still off! My speedo displays 65mph while my gps only detect 63.97mph. I even asked a LEO friend to use a laser gun to help me log the correct speed and it turns out the same.

So what is wrong with this? How come the predator unable to adjust the tire size? Please help me!


My Predator is U7136 using 9r07 firmware. My car is an 08 Dodge Charger SXT.

Thank you!

did you ever check to see how far off it was when the stock tires were there???

[xkm121]

My stock tire size is 225/60-R18. I changed to 235/55-R18 tire and I tried to use Predator U7136 to adjust my tire size accordingly. The quick adjust shows that adjustment is done. However, when I was using GPS to log my speed I found that the speedo is still off! My speedo displays 65mph while my gps only detect 63.97mph. I even asked a LEO friend to use a laser gun to help me log the correct speed and it turns out the same.

So what is wrong with this? How come the predator unable to adjust the tire size? Please help me!


My Predator is U7136 using 9r07 firmware. My car is an 08 Dodge Charger SXT.

Thank you!

did you ever check to see how far off it was when the stock tires were there???

Yes. It was right on the spot with stock 225/60-R18 tires.

I dont know why but this function is not working for me.

[xkm121]

And it seems nothing can affect it. I went as far as changing it to 255/40R18

[mikel]

And it seems nothing can affect it. I went as far as changing it to 255/40R18

and clicked apply, and did the key cycle?

[xkm121]

I did everything the tool showed me to do. It says tire size updated successfully.

I also tried input direct tire height. My tire measures 28.1in so I input 28. No effect. I tried 29 and 27, still the same

[mikel]

4 speed auto?

[xkm121]

Yes. My car is 2008 Dodge Charger SXT. 3.5 engine with 42RLE trans.

[xkm121]

So no more tech support? Is it because u7136 cant program the tcm part of the 42rle? Come on guys, show some love to the 7136 crowd!

[BatmanPPC]

I just went from stock to 255/55/18 on my '08 Magnum SXT (v6 3.5L) and entered the size using the predator. Said it accepted. Will need to test tomorrow or over the weekend.

[BatmanPPC]

I just went from stock to 255/55/18 on my '08 Magnum SXT (v6 3.5L) and entered the size using the predator. Said it accepted. Will need to test tomorrow or over the weekend.

OK. This is in no way absolutely accurate as I used my iPhone 4S to determine speed from GPS. The sample rates from apps aren't really high enough to give you instant speed readings but it should give an idea.

I compared to 40 MPH constant for about 1/4 mile on my cluster to GPS and it was pretty much spot on.

[BatmanPPC]

Question for Mike: When adjusting tire size when tweaking a canned tune, is it supposed to write the tire size adjust right away or wait until I finish tweaking and commit to writing the adjusted tune? As it is now, it writes the tire size to the car right away.

[typan]

mikel, when I do my wheel size change with tool u7135 & v.9r28, after applying the change I want & then if I go back to check so if the change did take the tool tells my tyre size is not set, WTF?