Bigger tires vs. re gearing?

[NC_Overland]

What I don’t understand is people saying I got a taser and got 8th gear back. I have stock 3.73 gears and 285s vs my stock 255s. They are almost 2” larger than my stock 255s and considerably heavier because bigger and E load. I only have 8th gear on flat ground at interstate speed. If I manually put it in 8th to try to hold it, it doesn’t accelerate or I lose speed. Even on a very slight incline.

I saw a post earlier where someone said the difference I power isn’t noticeable, and they only lost 1 mpg when going from the stock 33s to 37s. It was a Mojave so I know it wasn’t a diesel. Granted 4.10s vs my 3.73s, but that like saying I didn’t notice a difference going to 35s and only lost 1 mpg. I’m on the bleeding edge of losing mpg (I haven’t significantly) with a 33.7” tire and I can definitely feel a difference in power. It’s not bad, but you can tell a difference. It takes a bit more momentum to get it moving and only 8th gear in the right conditions.

Sponsored

 

[Gvsukids]

What I don’t understand is people saying I got a taser and got 8th gear back. I have stock 3.73 gears and 285s vs my stock 255s.

The computer needs to be told of the taller tire size, otherwise it will think it's pushing more weight and we'll therefore have to work harder.

 

[USMC-SSGT]

What I don’t understand is people saying I got a taser and got 8th gear back. I have stock 3.73 gears and 285s vs my stock 255s. They are almost 2” larger than my stock 255s and considerably heavier because bigger and E load. I only have 8th gear on flat ground at interstate speed. If I manually put it in 8th to try to hold it, it doesn’t accelerate or I lose speed. Even on a very slight incline.

I saw a post earlier where someone said the difference I power isn’t noticeable, and they only lost 1 mpg when going from the stock 33s to 37s. It was a Mojave so I know it wasn’t a diesel. Granted 4.10s vs my 3.73s, but that like saying I didn’t notice a difference going to 35s and only lost 1 mpg. I’m on the bleeding edge of losing mpg (I haven’t significantly) with a 33.7” tire and I can definitely feel a difference in power. It’s not bad, but you can tell a difference. It takes a bit more momentum to get it moving and only 8th gear in the right conditions.

People on forums are full of it and in denial. The variables on a 3.73 with a 2” lift and 35” tires are nearly identical, yet they still continue to make up stories to justify it.

You have a Sport on 35” tires and a 2” lift with 3.73 gears? Oh, AND you still average 18.6 mpg on the highway and always see 8th gear and notice zero change? No, no you don’t. There are 400 members on this site with that same jeep, same rims and tires, and exact same lift. Your truck pulls like shit and is way undergeared like the rest.

The GREAT news however- that’s fine. It’s not hurting a damn thing and if it doesn’t bother you then great. You do you. Just don’t don’t try to convince others that your jeep is somehow special and has seen 0% of the known issues of being undergeared.

 

[NC_Overland]

The computer needs to be told of the taller tire size, otherwise it will think it's pushing more weight and we'll therefore have to work harder.

Right but it’s not witchcraft. Why do I have no power to accelerate in 8th manually when I try? It’s not like it’s a tuner adding more power.

 

[LostWoods]

What I don’t understand is people saying I got a taser and got 8th gear back.

That has to be the 4.10 crew because that was exactly my experience. The computer hesitated hard out of 7th like I was towing 2-3k but as soon as I flashed the new tire size it was all the same on the freeway. You don't get power back but the computer will actually use 8th gear like its supposed to instead of hesitating going in and kicking out at the slightest sign of load.

I test drove a Sport with 35s initially and I just don't know how someone could live with that. Felt just as bad as 37s on an otherwise stock Rubicon.

 

[WILDHOBO]

Right but it’s not witchcraft. Why do I have no power to accelerate in 8th manually when I try? It’s not like it’s a tuner adding more power.

The taser won’t help with getting gears back, nor will a tire size change with a programmer. The programmer sets the correct tire size to make the speedometer and odometer accurate. Regearing gets your gears back, but you still need to use a programmer to set the new gear ratio as well.

 

[LostWoods]

This gear ratio chart is your friend. Going from 32.7” tires to 35“ tires drops your effective gear ratio to 3.83, which is below 4.10, so you will notice a difference in performance. The new ratio needed to get back the feeling of the original stock ratio (4.10) is 4.39.

https://tiresize.com/gear-ratio-calculator/

Good for the mathematical calculation but there's a ton more that goes into it. Larger tires are significantly heavier and all that weight is as far out as can be so while this chart is good for getting your RPMs where they need to be, it's not going to translate into feel and you'll often need to go an additional step up.

 

[NC_Overland]

The taser won’t help with getting gears back, nor will a tire size change with a programmer. The programmer sets the correct tire size to make the speedometer and odometer accurate. Regearing gets your gears back, but you still need to use a programmer to set the new gear ratio as well.

I want a taser for a lot of things, but I’m not expecting magic.

 

[WILDHOBO]

I want a taser for a lot of things, but I’m not expecting magic.

You won’t get magic. My opinion is they’re more trouble than they’re worth. Several live settings were malfunctioning. Live settings only work with it plugged in. The vehicle settings, such as tire diameter, gear ratios, and TPMS PSI setting, stay set if you remove it. That’s what I did. It’s in the glove box. If I need to change something, I pull it out.

 

[NewGladdyOWNR]

Good for the mathematical calculation but there's a ton more that goes into it. Larger tires are significantly heavier and all that weight is as far out as can be so while this chart is good for getting your RPMs where they need to be, it's not going to translate into feel and you'll often need to go an additional step up.

Yea, sure. But it’s a good starting point for people who want to understand the fundamentals of regearing when it comes to tire size.

 

[jeremy342]

Good for the mathematical calculation but there's a ton more that goes into it. Larger tires are significantly heavier and all that weight is as far out as can be so while this chart is good for getting your RPMs where they need to be, it's not going to translate into feel and you'll often need to go an additional step up.

the stock falken mt's weigh 63. bfg ko2's in 315/70r17 or 35/12.5r17 weigh 62 - 65 lbs. so i wouldnt say they are significantly heavier depending on your choice. the ko2 c 37s are less then the falkens as well. i think its more about the circumference for the gearing. weight, while it can be a factor if picking huge new rims + heavy E tires, but if you do it wisely you can come in at or very close to stock weights.

 

[LostWoods]

the stock falken mt's weigh 63. bfg ko2's in 315/70r17 or 35/12.5r17 weigh 62 - 65 lbs. so i wouldnt say they are significantly heavier depending on your choice. the ko2 c 37s are less then the falkens as well. i think its more about the circumference for the gearing. weight, while it can be a factor if picking huge new rims + heavy E tires, but if you do it wisely you can come in at or very close to stock weights.

It's not just the weight but where the weight is located. All else held equal (including ratio), a lighter weight tire can feel heavier depending on the size of the two because an increase in diameter has a greater impact than a proportional increase in weight. Where larger tires get in trouble is that they not only require more energy to move because of the above, but the reduced mechanical ratio is also generating less force than it was previously. Gearing can fix all but using the calculator/chart like above will only fix the second issue.

There's so many variables there really can't be an absolute statement here but I've done a lot of tires and a lot of gears and the only people who were happy targeting a similar ratio were the ones who wanted fuel economy... everyone else wasn't thrilled with how the truck felt off the line.

 

[JD101]

People on forums are full of it and in denial. The variables on a 3.73 with a 2” lift and 35” tires are nearly identical, yet they still continue to make up stories to justify it.

You have a Sport on 35” tires and a 2” lift with 3.73 gears? Oh, AND you still average 18.6 mpg on the highway and always see 8th gear and notice zero change? No, no you don’t. There are 400 members on this site with that same jeep, same rims and tires, and exact same lift. Your truck pulls like shit and is way undergeared like the rest.

The GREAT news however- that’s fine. It’s not hurting a damn thing and if it doesn’t bother you then great. You do you. Just don’t don’t try to convince others that your jeep is somehow special and has seen 0% of the known issues of being undergeared.

100% ! The only reasonable circumstances would be folks who do vs those that do not live at elevation . How much crap do you have pushing wind on the truck and what is your highway speed . But ya alot ignorant feedback running around . And none of the above will excuse a poor gearing scenario.

 

[Ricky]

To piggy back on this thread, what are the thoughts on the 24 gladiator if it’s a hybrid which if it’s like the wrangler it will have more horsepower and more torque. I wonder if the extra amount of torque and horsepower would defeat the need to regear?

Sponsored