Tazer JL Mini Tire Size Adjustment + Shift Points/MPG

LLRubylady

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@LLRubylady

The discussion here regarding automatic transmission, shift points being off, pertains only, to those with automatic transmissions.

Your speedometer will be off, though. You will need to go to the dealer and get your JL programmed in regard to tire size. Once you do this your speedometer will be correct.

SO, do keep in mind that your speedometer is presently not telling you the correct speed you are traveling.

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So in a manual my shifting isn’t off?
I’ve only driven one day do hard for me to tell but it seemed like it takes more effort at lower Rpm which I guess makes sense.





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So in a manual my shifting isn’t off?
I’ve only driven one day do hard for me to tell but it seemed like it takes more effort at lower Rpm which I guess makes sense.
I can't speak for a manual tranny from experience but in that situation, the driver is in-charge of shifting. You might have to relearn when to shift but that's more under your control. The issue we're trying to work out is with an automatic transmission because (unless we're using the autostick or whatever it is called in a Jeep) we don't have much control over when the engine shifts gears. I can see my RPMs running higher than normal and I know the transmission should shift in to the next gear but it doesn't do it the way it should (did before tire change). The Tazer reset the speedometer to be accurate but the shift points aren't right. They're close but not the way I want them. I think this is having both a performance and MPG hit. My original ask was whether or not the Tazer made any adjustments to the computer so that it would shift gears properly given the new tire size.
 

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So in a manual my shifting isn’t off?
I’ve only driven one day do hard for me to tell but it seemed like it takes more effort at lower Rpm which I guess makes sense.
@LLRubylady

Suffice it to say, you will get used to it.

Unless, you just never get used to it an truly regret moving up to bigger tires. Some do regret moving to bigger tires..

After a couple of months, a road trip or two, your figuring out how much gas you are going through, etc., and you may just regret it.

Sure the 35's look great, but do change the vehicle's character, in many many ways. And some of the ways it changes are negative ways.

Anyway, what you are feeling... seat of the pants feel so to speak, is normal. Get used to it... relearn your shift points (you don't have an automatic tranny that remembers for you)

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LLRubylady

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@LLRubylady

Suffice it to say, you will get used to it.

Unless, you just never get used to it an truly regret moving up to bigger tires. Some do regret moving to bigger tires..

After a couple of months, a road trip or two, your figuring out how much gas you are going through, etc., and you may just regret it.

Sure the 35's look great, but do change the vehicle's character, in many many ways. And some of the ways it changes are negative ways.

Anyway, what you are feeling... seat of the pants feel so to speak, is normal. Get used to it... relearn your shift points (you don't have an automatic tranny that remembers for you)

.
Thanks. I’ll live with it a few months and see how it goes. I’ll go back to 33s if need be.
I can’t remember what the stock mph was at 2000 rpm. Now it’s about 48 mph.
 

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I have zero regrets running larger tires and adding my steel bumper and winch, I currently sport BFG 315 KO2’s and a Roam bumper with stubby bull bar and RC winch, did my MPG’s dropyou bet they did as I went from 21-22 down to 17-18 doing hand calculations based on miles driven and gals used and I lost about 4 MPG and rarely see 8th on my AT and have no plans on rehearing as I would never recoupe the investment and the gearing is so close it’s not determental other than lost mlleage
 

LLRubylady

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I have zero regrets running larger tires and adding my steel bumper and winch, I currently sport BFG 315 KO2’s and a Roam bumper with stubby bull bar and RC winch, did my MPG’s dropyou bet they did as I went from 21-22 down to 17-18 doing hand calculations based on miles driven and gals used and I lost about 4 MPG and rarely see 8th on my AT and have no plans on rehearing as I would never recoupe the investment and the gearing is so close it’s not determental other than lost mlleage
I’m curious to see what I lose with mpg. Too soon to tell only day 2 of the bigger tires. They look awesome. Will snap more pics tomorrow as I’ll have the day off and can do it in the daylight.
My acceleration is ok. I only notice a slight difference. It does bounce more over bumps and the view from the backup camer shows the inside of the rim but it is ok to see behind me.
I wasn’t really thinking about the view out the back window. Kinda no view at all now.
 

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I’m curious to see what I lose with mpg. Too soon to tell only day 2 of the bigger tires. They look awesome. Will snap more pics tomorrow as I’ll have the day off and can do it in the daylight.
My acceleration is ok. I only notice a slight difference. It does bounce more over bumps and the view from the backup camer shows the inside of the rim but it is ok to see behind me.
I wasn’t really thinking about the view out the back window. Kinda no view at all now.
You are correct as far as view goes as there is pretty much none with a 35 hanging on the back, the loss of MPG’s is not as bad as I thought and I honestly don’t even miss 8th gear

Be mindful of tire pressure as over inflating causes more bounce so my suggestion is start at 32 and get a piece of chalk and do one front and the opposite rear, you can do all four but doing just two is fine, you are looking for even wear on the tire, you can do this test in a flat parking lot and it only takes about a 50ft drive forward and back and my guess is at 32 the chalk will be worn in the middle but the edges won’t be touched so you lower a pound and test again but my bet is somewhere between 27-30 is gonna be the sweet spot
 

LLRubylady

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You are correct as far as view goes as there is pretty much none with a 35 hanging on the back, the loss of MPG’s is not as bad as I thought and I honestly don’t even miss 8th gear

Be mindful of tire pressure as over inflating causes more bounce so my suggestion is start at 32 and get a piece of chalk and do one front and the opposite rear, you can do all four but doing just two is fine, you are looking for even wear on the tire, you can do this test in a flat parking lot and it only takes about a 50ft drive forward and back and my guess is at 32 the chalk will be worn in the middle but the edges won’t be touched so you lower a pound and test again but my bet is somewhere between 27-30 is gonna be the sweet spot
Yeah, they are inflated to 37 because the installer said he didn't want to make my sensors go nuts. I will air them down and see how that feels. I guess I'll live with the sensors goin off until i can have it programmed.
 

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Yeah, they are inflated to 37 because the installer said he didn't want to make my sensors go nuts. I will air them down and see how that feels. I guess I'll live with the sensors goin off until i can have it programmed.
37 is way to much, I believe that’s the door plaque pressure for stock tires on a Rubicon, you can go down to 32 and be good but if you have a Rubicon below 32 will trip the tpms sensors and you will have to go back up to 38 to clear, the only way to go under the 32 is either remove all the sensors or get a Tazer or Flashcal to reset the limits, also be mindful that running bigger tires your speedo will be off so that will have to be reset but I believe stock Rubicon tires are 33’s so going to a 35 may not have a huge impact on the speedo so DL a speed GPS app like Speedbox and check you speed at 70-50-30 mph
 

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