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What amount weight reduction is noticeable?


SD01TJ

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Joined
Aug 8, 2019
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22
Location
San Diego
I'll also re-iterate that a li-ion battery will save 36 lbs over the OEM sized battery...for a couple hundred bux, that is a lot less $$$ than a CF or fiberglass hood and the associated paint work. Downside is lower reserve capacity if you like to sit with the engine off and run accessories. I'd like to do one as I have in many of my other cars, but will prob wait until it is battery replacement time vs. buying one right now as the 36 lbs isn't going to make/break me. =)
 
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LittleTankTJ

LittleTankTJ

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May 9, 2019
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198
Location
Bay Area, CA
I'll add some from myself into the mix.

With the back seat and spare off(had to do a home depot pickup and the spare would block out the back) I couldn't tell if the weight reduction was helpful or not. The steering became very squirrelly, likely from the rear not having any of the weight it was aligned with.

But back seat+hard top off was enough to make my daily hill climb a little easier.

I plan to change my rear bumper with something lighter. Maybe replicate my front in aluminum. Switch to a lighter+synthetic winch and learn tub fabbing by replicating my cargo cage in aluminum.

That should be a lot of steel being dropped
 

eastbloc

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Oct 9, 2018
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270
Location
FL
Interesting topic, and i think it will be different for everyone.

Lets take 31.5" tires and two gear sets, 3.07 and 4.56
The one with 3.07 gears is coming from the perspective of struggle, and every -50lb is a noticeable difference.
In contrary, one with 4.56 is considered sightly overgeared, you can add +100lb to their Jeep and they will swear on their life that there is no difference.

That breaking point will be different for everyone.

Gross weight of my Jeep with soft top is 4120 lb. Other than 60lb tire carrier, it is stripped off all "creature comfort".
When i was on 3.07, i switched from 33" MT tires that came with Jeep, to 31.5" AT, the difference was unarguably there. And only way to make it better was to go down to even smaller tires.
I went up and down lift heights 3 times, tried lighter oils, had days without passenger seat.. Everything was a moot point, a sort of placebo effect. Yes, unarguably every weight reduction is a gain in performance, but i never noticed that 1% or 3% difference in driving characteristics, or on the gas receipt.
I was burning more gas in 1 hour trip against the wind, than i did in a month of driving with all seats in.
The engine was struggling with those gears, period. Less struggle, more struggle - don't matter, struggle is struggle.

Eventually i have regeared... Bruhhhh.....
Stop to go - effortless.
Highway 70mph 3000rpm 6th gear, head on wind, rain, hills, trunk full of tools and camping gear - effortless.
Right now i am at the point where other than mounting larger and heavier tires, or hooking up a heavy trailer, not that much will have an effect. I am not at that breaking point where + or - 200lb in my cargo will be noticeable.

I saw rooftop tent mentioned somewhere, that is different, it is a combination of weight and resistance that only get stronger with added velocity.
 
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Skylinessuck

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Mar 28, 2020
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169
Location
Warrenton, VA
Every vehicle is different tuned vs untuned. Some factory tunes leave a lot on the table, some don't. I am fairly confident saying those kind of gains would be a stretch from a canned tune on a lightly modified Jeep 4.0. You might see that on a custom tune for a highly modded stroker. Maybe. And it certainly *could* hurt depending on the tune, but probably not. Hopefully you'll pick something up.

And what I was getting at before and has been mentioned since is different vehicles are going to get different gains at different speeds mpg and hp wise. 200lb off a Jeep that spends most of it's time on the highway isn't going to matter much. Aerodynamics is going to matter a lot more, and a Jeep ain't got that. A heavy ass rig that gets tooled around town though, yeah.
 
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Mobusaki

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Jul 20, 2018
Messages
21
Location
Pennsylvania
Interesting topic, and i think it will be different for everyone.

Lets take 31.5" tires and two gear sets, 3.07 and 4.56
The one with 3.07 gears is coming from the perspective of struggle, and every -50lb is a noticeable difference.
In contrary, one with 4.56 is considered sightly overgeared, you can add +100lb to their Jeep and they will swear on their life that there is no difference.

That breaking point will be different for everyone.

Gross weight of my Jeep with soft top is 4120 lb. Other than 60lb tire carrier, it is stripped off all "creature comfort".
When i was on 3.07, i switched from 33" MT tires that came with Jeep, to 31.5" AT, the difference was unarguably there. And only way to make it better was to go down to even smaller tires.
I went up and down lift heights 3 times, tried lighter oils, had days without passenger seat.. Everything was a moot point, a sort of placebo effect. Yes, unarguably every weight reduction is a gain in performance, but i never noticed that 1% or 3% difference in driving characteristics, or on the gas receipt.
I was burning more gas in 1 hour trip against the wind, than i did in a month of driving with all seats in.
The engine was struggling with those gears, period. Less struggle, more struggle - don't matter, struggle is struggle.

Eventually i have regeared... Bruhhhh.....
Stop to go - effortless.
Highway 70mph 3000rpm 6th gear, head on wind, rain, hills, trunk full of tools and camping gear - effortless.
Right now i am at the point where other than mounting larger and heavier tires, or hooking up a heavy trailer, not that much will have an effect. I am not at that breaking point where + or - 200lb in my cargo will be noticeable.

I saw rooftop tent mentioned somewhere, that is different, it is a combination of weight and resistance that only get stronger with added velocity.

I think you hit the nail on the head. I have ~31.7 (265/75r16) tires and 4.56 gears (5 speed, 6 cyl) and 200 lb is definitely not noticeable to me. I can see the Jeep sit a little lower, so I know offroad performance must be affected a bit not just by the added weight itself but also the slightly reduced ground clearance. But actually noticing a difference behind the wheel ("Gee golly my rig is so sluggish now that you're in it, dear wife!") is another story.

And just to be clear, I'm not saying I think it is not worthwhile to try to reduce weight. Braking, acceleration, handling, and offroad performance will all improve with each pound of weight you reduce. Physics works. The difference is there. You just may not notice it, and the extra money therefore may not have been worth it, and that's a decision between each of us and our wallets. But it all adds up, and after a few years of adding steel or aluminum you will someday realize your Jeep has become either a pig or a mountain goat.

None of my aftermarket upgrades were aimed at saving weight. There's no aluminum. Tummy tuck, engine skid, rock sliders, front and rear bumpers, and winch line. All steel. I take that back: my wheels are Moabs from a Rubi so I guess that counts. I spent all the money on steel already because not only did I not know any better but I also couldn't afford aluminum anyway. If I want to save weight now I have to buy the same part twice. Ouch.

When I wheel I could remove the rear seat, doors when I can, and reduce my tool weight (I carry almost every tool I've ever had to use on my Jeep with me when I wheel...). I will replace the steel winch cable with synthetic when the time comes, and replace the rollers with a light aluminum fairlead. I may put my stock front bumper back on since I lost approach angle with my aftermarket one.

I think that gets me close but not quite to 300 lbs. Will I notice it? Only when I'm looking at the Jeep, probably not when I'm driving it. But it's (mosly) free and it has to help, so why not?
 
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Mobusaki

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Joined
Jul 20, 2018
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21
Location
Pennsylvania
Last week I used my 5 spd, 4.56 gear, 32" tire TJ to pick up a utility trailer which weighs 550 lbs empty. I could not feel it back there.

Yesterday I needed to pick up a piece of furniture, but I've been having trouble installing a trailer harness on my 5 speed (instructions don't match reality...), so I put my wife's TJ to work (3.73 gears, auto, 31" tires, factory tow harness). I could feel the trailer back there. Braking and acceleration were noticeably affected.

It is weird that her braking seemed affected while my TJ's did not. My TJ is significantly heavier (way more steel mods and armor, more tools inside, rear seat still inside). I do have rear disc brakes, but I doubt they are making that much of a difference. Perhaps it's the engine braking w/the manual, or the extra weight of my TJ helps control the trailer, while the extra power of the gearing helps accelerate it. I don't know for sure.

Hopefully this doesn't muddy the waters but it's a recent experience that I thought may be useful to the "how much weight?" question. And it is odd considering previously I said that I could definitely notice a difference with ~600 lbs extra cargo in my TJ, but recently with that much trailer weight I could not notice it. :unsure:

However, the 600 lb cargo comparison was when wheeling, and the 550 lb trailer weight is on the road. So I believe I've discovered something we probably all knew already: X added pounds will be more noticeable offroad than it will be on road.
 
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SD01TJ

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Aug 8, 2019
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Location
San Diego
Some great advice above, so thanks to everyone. I'll refresh that for now (summer and doors off contributing to 400lbs total weight removed) that the Jeep is feeling better. 4th gear at 65 indicated (70 GPS) is 2600 and pulls fine. I have the used Superchips FlashPaq F5 hooked up and on the 87 tune while I burn out the 87 gas remaining in the tank. The 87 tune already seems more willing to rev out with some noticeable power gain, but haven't hit the freeway with it yet. I took advantage of the Memorial day sale and ordered myself a Magnaflow muffler to replace the OEM unit...hopefully that will only help altho I don't expect a whole lot. That mod is two fold in purpose. My son is pretty fresh at driving stick and it would be nice for him to be able to hear what the engine is doing to reduce potential stalling on take-off. Plus, it will sound better (although I got one that closely resembles the size of the OEM muffler body Magnaflow Part # 11255 so it shouldn't be much louder than stock). Jeep already has a K&N intake and hot air shield. And as someone who is deeply interested in aero and drag, I understand that we have pretty much the worst vehicle for higher speeds money can buy. As others stated that the problem at 70 is largely the wind resistance, not the weight.

But, as many here have attested to, gearing is where the magic happens and I'm sure I'll get there. So, be patient with me. Haha. =)
 

eastbloc

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Joined
Oct 9, 2018
Messages
270
Location
FL
Because of wind, weather, your mood or fuel quality your Jeep may feel different every day of the week.

If you say it works - it works, as long as you not forcing yourself to believe that it works. I just know that if i stare at the moon long and hard enough, i will swear that i see someone waking on it.

It is your Jeep and you are the man, do as you wish and believe. I simply hate and hate to see people waste money on imaginary unicorns.
 

Captain Phoenix

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Feb 2, 2020
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217
Location
Wilmington, NC
For those with a lot of experience with recovery hooks: if you need extra winch power can you run your winch line to a tree, around a snatch block, then back to a recovery hook? I've never liked the thought of having hooks instead of heavy duty pad eyes but no aluminum front bumpers have pad eyes.
 

BuildBreakRepeat

Check your bumpstops
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Jan 21, 2019
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Corvallis, Oregon
For those with a lot of experience with recovery hooks: if you need extra winch power can you run your winch line to a tree, around a snatch block, then back to a recovery hook? I've never liked the thought of having hooks instead of heavy duty pad eyes but no aluminum front bumpers have pad eyes.
Yeah that’s perfectly fine if you snatch is set up right.