Mostly unscientific gas mileage observations - YMMV

[pfletcher229648]

If you decide to draft behind a big truck make sure that you can see its mirrors. If you can see its mirror then the driver can see you. Bad sh#+ can happen fast with big trucks.

Always. If I can’t see their mirrors then they can’t see me has been the rule.

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[pfletcher229648]

I don't have ACC in my Jeep, because I've always hated it (and I'm a cheap bastard). My wife has had it for a few years, and I turn it off every time on a long trip. However, I forced myself to use it (and slow down) last summer on an 8 hour trip, and I swear I arrived with blood pressure at least 20 points below normal. It was so much less stressful, and it made me a believer. Now I wish I would have ordered it for mine.

My take is... if you're driving 10+ mph over the speed limit, it's just aggravating. Knock that down to 0-5 over the limit, and it is a game changer.

Massive difference in stress and fatigue levels while driving and I always keep it under 70 in the Rubicon cause it’s a massive difference in gas consumption. I first tried it in the 2018 Honda Accord we bought our daughter and it made a believer out of me.

 

[tomk62]

I am of the lost Gen X generation and have hit my mid-fifties, and have developed a lesser desire for high speeds. Mostly because I now drive a Jeep Wrangler. If I still drove a sports car, I would likely still be driving at much higher speeds. However, the Wrangler was not built for speed, it is a large square chunk of metal that doesn’t appreciate high speeds, especially high speed cornering. So I have slowed down considerably in my daily driving. On the interstates I utilize the Active Cruise Control on the Wrangler and typically just put it around 68 and drive in the right hand lane. I find this to get me optimal gas mileage and interstate driving is much more relaxing as the vehicle speeds up and slows down with traffic without requiring much input from me.

I have had the exact same experience. I am inclined to drive much slower now in my Wrangler than I did in my Audi, and I love my adaptive cruise control on the interstate.

 

[Old Jeeper]

Yep— drafting a big rig improves mpg. Too bad you can’t see what he does that might cause him to panic stop.

paying for the extra gas recommended.This old trucker has seen many of these. The MC riders head was far from his body and I got to watch.

X2
Not worth what little savings you may get!

 

[pfletcher229648]

X2
Not worth what little savings you may get!

I’m not sure what the misdirected scare tactics are for. I’m 57 years old, BS pictures of Lord only knows what the driver was doing don’t bother me or make me clutch my pearls. Go try and be melodramatic on another thread.

I don’t set the ACC and get up and go get coffee or nap. I’m actively driving but the ACC is keeping a consistent SAFE distance between me and the truck. I will bet good money that the ACC does a much better job than your reflexes alone.

My original point, if you read it, is does this scenario benefit from drafting and increase MPG? Please try and stay on topic.

DISCLAIMER:
Let me just state I do not, repeat DO NOT stand behind any of these numbers, simply putting this here for conversation.

GENERAL INFO:
I am of the lost Gen X generation and have hit my mid-fifties, and have developed a lesser desire for high speeds. Mostly because I now drive a Jeep Wrangler. If I still drove a sports car, I would likely still be driving at much higher speeds. However, the Wrangler was not built for speed, it is a large square chunk of metal that doesn’t appreciate high speeds, especially high speed cornering. So I have slowed down considerably in my daily driving. On the interstates I utilize the Active Cruise Control on the Wrangler and typically just put it around 68 and drive in the right hand lane. I find this to get me optimal gas mileage and interstate driving is much more relaxing as the vehicle speeds up and slows down with traffic without requiring much input from me.

HYPOTHESIS:
Drafting behind bigger objects while traveling in a Wrangler can increase MPG.

EXPERIMENT SETUP:
Just got back from picking up our new 2024 Wrangler Rubicon X from an out of state dealer. On the roughly 600 mile trek back home I observed about 18.4 MPG average. The gas mileage estimate on flat roads generally showed about 18 to 19 current MPG. On one particular stretch of I-95 I was traveling in the right hand lane and had the cruise control set on 67 with the follow-behind meter set on two. Don’t like to tailgate people but also don’t like to leave too much room as everybody and their brother cuts in between you and the car in front of you. I find this setting gives me enough room just in case the vehicle in front of me does something drastic or incredibly stupid.

OBSERVATION:
Anyway, after setting the cruise control on 67 and setting a safe distance behind the 18 wheeler in front of me, I noticed the current MPG estimate rose up from it’s normal 18 to 19 MPG to 23 to 24 MPG. As long as we were traveling at a consistent speed and on a flat stretch of road the MPG stayed pretty consistent at or slightly above 23 MPG. After traveling this way for a 10 miles or so I noticed my average trip MPG started climbing from its fairly consistent 18.4. After some distance it went over 19 and eventually hit 19.5.

CONCLUSION:
This Jeep Wrangler is a massive block of machinery that consumes massive amounts of petrol when forcing itself along down the road at highway speeds. When drafting behind a much larger object that is punching a much bigger hole in the atmosphere it’s able to enjoy a somewhat decent increase in MPG. Now, 20 MPG is nothing to get really excited about. However, the prospect of gaining a 20% increase in fuel consumption on a road trip appeals to me on several levels, the least of which is I’m cheap, and due to our current circumstance caused by whatever opinions you may politically subscribe to , we find ourselves in a period of time when gas is not.

Just one man’s observations, YMMV.

I’m not sure what all the misdirected scare tactics are for. I’m 57 years old, BS pictures of Lord only knows what the driver was doing don’t bother me or make me clutch my pearls. Go try and be melodramatic on another thread.

I don’t set the ACC and get up and go get coffee or nap. I’m actively driving but the ACC is keeping a consistent SAFE distance between me and the truck. I will bet good money that the ACC does a much better job than your reflexes alone.

My original point, if you read it, is does this scenario benefit from drafting and increase MPG? Please try and stay on topic.

 

[Ratbert]

Thanks for keeping it rational Ratbert. Like I said folks, I don’t tailgate. I never play footsie with 18 wheelers. I respect the hell out of them and F=MA.

I always keep the setting on two or three bars, depending on conditions and traffic. I always keep my eyes on the road and my foot and hands ready. I do however find ACC to take a lot of the fatigue from long highway drives especially in heavy traffic and less than ideal conditions.

My point and topic is more about does anyone else see gains in this or is it all in my head. My 2022 Rubicon was my first vehicle that I daily drive that has ACC. I just never thought riding at a SAFE distance behind another vehicle would result in a drafting affect and increased MPG. I always thought one had to be way to close for comfort to see benefits of drafting.

Mythbusters did an episode about it (their initial Big Rig Myths episode) and showed that the closer you get the better mileage you get. Apparently 150' was the cut-off for when it began to be effective. Unfortunately it looks like Discovery has taken that video down.

As previously mentioned, I'd feel significantly more comfortable using that technique with ACC than without. And note that you're increasing the chance of getting chips in your windshield, which may or may not be a big concern depending on where you live and how replacing windshields might impact your insurance.

 

[Old Jeeper]

I’m not sure what the misdirected scare tactics are for. I’m 57 years old, BS pictures of Lord only knows what the driver was doing don’t bother me or make me clutch my pearls. Go try and be melodramatic on another thread.

I don’t set the ACC and get up and go get coffee or nap. I’m actively driving but the ACC is keeping a consistent SAFE distance between me and the truck. I will bet good money that the ACC does a much better job than your reflexes alone.

My original point, if you read it, is does this scenario benefit from drafting and increase MPG? Please try and stay on topic.


I’m not sure what all the misdirected scare tactics are for. I’m 57 years old, BS pictures of Lord only knows what the driver was doing don’t bother me or make me clutch my pearls. Go try and be melodramatic on another thread.

I don’t set the ACC and get up and go get coffee or nap. I’m actively driving but the ACC is keeping a consistent SAFE distance between me and the truck. I will bet good money that the ACC does a much better job than your reflexes alone.

My original point, if you read it, is does this scenario benefit from drafting and increase MPG? Please try and stay on topic.

What is this diatribe? Who are you talking to?

You are 57, GREAT, I am knocking on the door of 80!

I don't draft and do not recommend it. ACC does a good job of keeping me off rear bumpers in traffic on my Jeep and my F 450 truck, I love ACC but I do not use it to draft.

Guessing you are all butt hurt because I said this: "Not worth what little savings you may get!" and that is OFF TOPIC? I don't think so!

So don't you knickers in a twist young'un...

 

[pfletcher229648]

Mythbusters did an episode about it (their initial Big Rig Myths episode) and showed that the closer you get the better mileage you get. Apparently 150' was the cut-off for when it began to be effective. Unfortunately it looks like Discovery has taken that video down.

As previously mentioned, I'd feel significantly more comfortable using that technique with ACC than without. And note that you're increasing the chance of getting chips in your windshield, which may or may not be a big concern depending on where you live and how replacing windshields might impact your insurance.

I’ve gotten as many things whipped back at me from cars and trucks as I have 18 wheelers. On a busy interstate you are going to be behind someone. Besides I have guerrilla glass. ?

 

[Ratbert]

Besides I have guerrilla glass. ?

I've got quite a few 1/8" pits in my Gorilla glass. I'm fairly confident that those would have been much more destructive to a traditional windshield.

Note that the first Gorilla glass replacement is covered by Jeep. Don't let your dealer try to convince you otherwise.

 

[pfletcher229648]

What is this diatribe? Who are you talking to?

You are 57, GREAT, I am knocking on the door of 80!

I don't draft and do not recommend it. ACC does a good job of keeping me off rear bumpers in traffic on my Jeep and my F 450 truck, I love ACC but I do not use it to draft.

Guessing you are all butt hurt because I said this: "Not worth what little savings you may get!" and that is OFF TOPIC? I don't think so!

So don't you knickers in a twist young'un...

My knickers aren’t in a twist, I just figured you were too old to stay on topic and needed reminding that dinner was at 4:30.

Now if you don’t mind it’s an intellectual conversation, maybe it’s the big words throwing you off.

 

[2nd 392]

My knickers aren’t in a twist, I just figured you were too old to stay on topic and needed reminding that dinner was at 4:30.

Now if you don’t mind it’s an intellectual conversation, maybe it’s the big words throwing you off.

— this is getting humorous. I do have another fairly big word for you though
,
Can be especially dangerous when thrown at you when following a truck

also avoid tomato trucks and wash the paint eating juice off ASAP

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