Too much power loss?

NevadaJohnny

Active Member
I recently put on 33's and 17x9 aluminum wheels, plus a 2.5 inch lift, and I feel like my engine (3.6L) is working alot harder than it should be. I don't think I've added too much weight, but maybe I'm wrong? I didn't go with 35s since the little bit of research I've done suggests re-gearing at that size. Could the steel bumpers and steel line winch be affecting it as well? I understand the jeep will drive a bit different after the adds but I just feel like its struggling more than it should.
 

wayoflife

Administrator
Staff member
Did you make sure to calibrate your speedometer after installing your new tires?

Either way, some power loss is always something you should expect to see after installing bigger tires and without re-gearing.
 
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NevadaJohnny

Active Member
Did you make sure to calibrate your speedometer after installing your new tires?

Either way, some power loss is always something you should expect to see after installing bigger tires and without re-gearing.
I did not. Something I'll need to do this week. Would re-gearing be something to consider?
 
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kevman65

Hooked
You don't need to regear, even for 35's, but you do need to reprogram for tire size.
Your transmission shift points are off and that is what you're feeling.
 
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NevadaJohnny

Active Member
You don't need to regear, even for 35's, but you do need to reprogram for tire size.
Your transmission shift points are off and that is what you're feeling.
That makes sense to me. I took an hour trip and my RPMs were running high for the vast majority of the time.
 
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cozdude

Guy with a Red 2-Door
As mentioned just make sure you reprogram for the new tire size. That will play a part in the shift points and help make it feel better. Obviously you can’t do much about the added weight as that has slowed you down a bit as well
 
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wayoflife

Administrator
Staff member
LOL - stepped out into the garage to do some work and it looks like everyone else came on and answered things nicely :)
 
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kevman65

Hooked
It would help a bit knowing what Jeep you have…
LOL, I was thinking that too. With me having a Rubicon I don't think about the other trim levels and what gearing they come with.
So my advice may be off on the 35's with the other gear sets they come with.
 
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cozdude

Guy with a Red 2-Door
Oops! Maybe now many of the previous answers are not correct! 😂
Nope I stand by my answer as well as everyone else’s. A “jump” to 33” tires isn’t a large one even for the 3.73 gears in the jk. It’s very manageable especially once the shift points are changed. I ran 35’s on my jk for almost 2 years before regearing and only did cause of goin 37’s. What the op is experiencing is the added weight from the armor, the tires, and it not staying in the proper power ban due to not being calibrated properly
 
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tweeve

Member
according to GPS, on my jk rubi, when I went to 33's my speedometer went from 3-4 miles an hour slow to dead on. Should I look into calibrating as well? I don't plan on doing any regearing till I move up to 37's.
 
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Bierpower

Hooked
Nope I stand by my answer as well as everyone else’s. A “jump” to 33” tires isn’t a large one even for the 3.73 gears in the jk. It’s very manageable especially once the shift points are changed. I ran 35’s on my jk for almost 2 years before regearing and only did cause of goin 37’s. What the op is experiencing is the added weight from the armor, the tires, and it not staying in the proper power ban due to not being calibrated properly
Don't forget that a lot of sport JK's had 3.21 gears not 3.73.
 
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