Auxiliary Fuel Tanks - Pro/Cons?

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Aux tanks are for suckers. They totally hide your cool Jerry can/rotopax street cred. ;-)

actually I just went with the rotopax because $100 vs $1500+ and I don’t regularly need it. Also I have to stop for fuel every few hours anyway or else my legs and back ache. Also I have concerns about emissions changes which can end up throwing occasional codes…

An aux tank would be spiffy when doing a really long trip where fuel is sparse and space is a premium (eg The Maze where I might want 15gal of water on the roof and 24gal of fuel underneath). But in most cases I personally wouldn’t need it. Ymmv of course.
 
thirdparty said:
I had to remove my spare, but have not had any problems there either. I do now have onboard air and am an expert tire plugger. Barring total delamination or blowout, I should be okay there. I do carry a spare on certain trips and tows.
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Where/how do you carry the spare? And do you just ignore the TPMS light/warning on the dash when you're not carrying it?

My biggest concern is having to resort to a swingout tire carrier for the spare. That thing would just plain suck for me. I have the swingout for my bumper sitting in the basement, I've never installed it. I asked this before but didn't get any responses: does the swingout hit the trailer when you're towing? Am considering adding a teardrop trailer, but there's no way to test it out.
 
I have the LRA 40 ga and love it. Only issue I've had was the pump got crushed by a control arm when it bottomed out. Replaced and no issues. I do plan to go to heavier springs to compensate for the extra weight.
 
linuxgod said:
Aux tanks are for suckers. They totally hide your cool Jerry can/rotopax street cred. ;)

actually I just went with the rotopax because $100 vs $1500+ and I don’t regularly need it. Also I have to stop for fuel every few hours anyway or else my legs and back ache. Also I have concerns about emissions changes which can end up throwing occasional codes…

An aux tank would be spiffy when doing a really long trip where fuel is sparse and space is a premium (eg The Maze where I might want 15gal of water on the roof and 24gal of fuel underneath). But in most cases I personally wouldn’t need it. Ymmv of course.
Click to expand...

As you travel with a large camper, I would think you may be able to benefit from an aux tank more than most. Range without a trailer is okay, but range under tow is what drove me to seek an aux tank in the first place. I was getting about 190-220 miles range when towing conservatively and that can be frustrating at times for longer tow days. I think you're only getting 160-190 miles? It's the slogs through wind and grade, and trying to makeup for a late start, that really start eating range. Having 300 miles range towing, and not being captive to every tourist trap gas station (and prices), has been a huge game changer.

Of course you know all this. Just trying to help you justify your next mod :)
 
Madtiger said:
I am itching to add 12.5 but i am also fearful of crash safety. In a rear end (or any other type of collision or rollovers), are these aux tanks safe?? I hate to add something that actually adds risk to me and my family in an accident.
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In the rest of the world there is a factory Aux tank is the same location these aftermarket tanks mount in. I think we will be fine.
 
LivEviL said:
I have the LRA 40 ga and love it. Only issue I've had was the pump got crushed by a control arm when it bottomed out. Replaced and no issues. I do plan to go to heavier springs to compensate for the extra weight.
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Curious where your pump is mounted?
 
LivEviL said:
Not sure where it is now. Close to where it originally was, over by a few inches
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I'm a tad curious if you're referring to the pump or the OEM evap filter (not the charcoal canister). I only ask because my evap filter was originally relocated to a spot where it also was smashed by suspension componentry. Now the evap filter is in the wheel well and the pump is mounted to the frame rail, I think.
 
indycole said:
I'm a tad curious if you're referring to the pump or the OEM evap filter (not the charcoal canister). I only ask because my evap filter was originally relocated to a spot where it also was smashed by suspension componentry. Now the evap filter is in the wheel well and the pump is mounted to the frame rail, I think.
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The LRA fuel pump
 
The original location.
20210223_164209.webp


20210223_164209.webp
 
KLF said:
My biggest concern is having to resort to a swingout tire carrier for the spare. That thing would just plain suck for me. I have the swingout for my bumper sitting in the basement, I've never installed it. I asked this before but didn't get any responses: does the swingout hit the trailer when you're towing? Am considering adding a teardrop trailer, but there's no way to test it out.
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SO, with your trailer, especially if you are going to go off road with it where you may find yourself in tight situations, you need to watch out for how far you can jack knife your trailer. When backing up in tight quarters you will not be able to make as tight of a turn with a spare on the back - especially if it is offset to one side or the other. I suppose having your trailer hit your spare is preferable to hitting the rear quarter of your vehicle, but it will limit your turning radius backing up on tight trails. Having said that, many tow with two spares on the bumper so you can do it, you just have less room to work with when backing up versus not having the spare on the back.
 
TeCKis300 said:
As you travel with a large camper, I would think you may be able to benefit from an aux tank more than most. Range without a trailer is okay, but range under tow is what drove me to seek an aux tank in the first place. I was getting about 190-220 miles range when towing conservatively and that can be frustrating at times for longer tow days. I think you're only getting 160-190 miles? It's the slogs through wind and grade, and trying to makeup for a late start, that really start eating range. Having 300 miles range towing, and not being captive to every tourist trap gas station (and prices), has been a huge game changer.

Of course you know all this. Just trying to help you justify your next mod :)
Click to expand...
Oh the extra mileage would be wonderful when on the long stretches out west where gas is not plentiful, for sure. But I've also found I really need to at least stop and stretch my legs after ~2 hours in the truck, otherwise my legs and lower back start to ache. I get maybe 150 miles, sometimes less (Nebraska, for whatever reason, my gas mileage always seems to suck). So aside from actually being unable to find a gas station, it would be less helpful than I'd like.

Part of me wants the 24 so I can do stuff like the Maze and not worry about fuel though
 
linuxgod said:
Oh the extra mileage would be wonderful when on the long stretches out west where gas is not plentiful, for sure. But I've also found I really need to at least stop and stretch my legs after ~2 hours in the truck, otherwise my legs and lower back start to ache. I get maybe 150 miles, sometimes less (Nebraska, for whatever reason, my gas mileage always seems to suck). So aside from actually being unable to find a gas station, it would be less helpful than I'd like.

Part of me wants the 24 so I can do stuff like the Maze and not worry about fuel though
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Ooof! 150 miles is rough.

Yeah, I hear you on regular stops. I'll do that to degree as my wife still doesn't care to drive with the trailer in tow. Regular stops keep me fresh if only to visit the fridge in the trailer to top off a favorite beverage. I find the opportunity is to stop at nicer places, overlooks, and points of interest rather than gas stations. I'm pretty comfortable in and out of stations but it's not my favorite thing with 50' of rig, particularly at busier stations, so the range helps to have more choices.
 
TeCKis300 said:
I find the opportunity is to stop at nicer places, overlooks, and points of interest rather than gas stations. I'm pretty comfortable in and out of stations but it's not my favorite thing with 50' of rig, particularly at busier stations, so the range helps to have more choices.
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100% this.
 
TeCKis300 said:
Ooof! 150 miles is rough.

Yeah, I hear you on regular stops. I'll do that to degree as my wife still doesn't care to drive with the trailer in tow. Regular stops keep me fresh if only to visit the fridge in the trailer to top off a favorite beverage. I find the opportunity is to stop at nicer places, overlooks, and points of interest rather than gas stations. I'm pretty comfortable in and out of stations but it's not my favorite thing with 50' of rig, particularly at busier stations, so the range helps to have more choices.
Click to expand...

Yeah. Worst I've seen is about 6 MPG (adjusted) which is ~120 miles. I'll see 6 to 6.5MPG like that when we go through Nebraska, for some reason. Doesn't matter if I'm running 87 or 91, ethanol or ethanol-free. Actually I feel like higher ambient temps (95F+) seem to hurt MPG though maybe it's open plains and lots of winds? It was similar for me in North Dakota this year too, IIRC. In general that area of the country just seems to suck for mileage.

More typically I will see ~7 to 7.5MPG adjusted, driving ~72-74 most of the way. So 150 miles on a tank in that case

I can get better, but I can't bring myself to drive ~60 mph. 15 mph difference on a 17 hour trip adds multiple hours. Even accounting for additional fuel stops it's nowhere near worth it time-wise. Locally I drove ~60 miles back from my parents at the end of our trip and averaged 9.9 mpg adjusted with a mix of suburban, light highway (~60 mph), and some city streets (but little traffic). 45-50mph is probably the perfect speed with 4.88 gears and 34" tires but relatively speaking gas is cheap and I like to get places before my vacation ends.

Speaking of relatively cheap, and pretty OT, here are the stats from my recent trip:
  • Fuel: $3436.29
  • MPG: 8.4 (computer) -> 8.82 MPG (adjusted 1.05x for tire size)
  • Miles: 7354 (odometer) -> 7721 (adjusted)
  • Avg speed: 33.7 MPH (computer) -> 35.4 (adjusted)
  • Gallons of fuel consumed: 875.4
  • Average cost per gallon: $3.93
  • # hours of ass-in-seat time: 218.1
  • time away from home: 39 days, 38 nights (if I'd extended this another 36 hours I could've said this trip was biblical at 40 days and 40 nights)
Just got back from the dealer and the maintenance bill at 121k miles was $1592.48. Oof. Probably should've done it myself but my 100 year old garage is about to be torn down and replaced so I couldn't risk starting on this and ending up with a truck I couldn't move when they're ready if something goes wrong or I run out of time. So I ponied up. That covered:
  • LOF, grease driveshafts, air filters, 5 tire rotation
  • spark plugs
  • coolant, transfer case and full A/T fluid flush
  • two new TPMS sensors
  • 5 tire rebalancing (JustTires did an awful job... anything about 70 sucked this trip)
  • General inspection (no leaks, everything was tight as expected)
Sure it'd be great to cut my fuel bill by 20-25%, but no friggin way I want to add on to 218 hours in the front seat to do it. A hypothetical $700 (20%) is a luxury tax I'll pay in a heartbeat to save 40 more hours in the truck (as much as I love driving).
 
linuxgod said:
Yeah. Worst I've seen is about 6 MPG (adjusted) which is ~120 miles. I'll see 6 to 6.5MPG like that when we go through Nebraska, for some reason. Doesn't matter if I'm running 87 or 91, ethanol or ethanol-free. Actually I feel like higher ambient temps (95F+) seem to hurt MPG though maybe it's open plains and lots of winds? It was similar for me in North Dakota this year too, IIRC. In general that area of the country just seems to suck for mileage.

More typically I will see ~7 to 7.5MPG adjusted, driving ~72-74 most of the way. So 150 miles on a tank in that case

I can get better, but I can't bring myself to drive ~60 mph. 15 mph difference on a 17 hour trip adds multiple hours. Even accounting for additional fuel stops it's nowhere near worth it time-wise. Locally I drove ~60 miles back from my parents at the end of our trip and averaged 9.9 mpg adjusted with a mix of suburban, light highway (~60 mph), and some city streets (but little traffic). 45-50mph is probably the perfect speed with 4.88 gears and 34" tires but relatively speaking gas is cheap and I like to get places before my vacation ends.

Speaking of relatively cheap, and pretty OT, here are the stats from my recent trip:
  • Fuel: $3436.29
  • MPG: 8.4 (computer) -> 8.82 MPG (adjusted 1.05x for tire size)
  • Miles: 7354 (odometer) -> 7721 (adjusted)
  • Avg speed: 33.7 MPH (computer) -> 35.4 (adjusted)
  • Gallons of fuel consumed: 875.4
  • Average cost per gallon: $3.93
  • # hours of ass-in-seat time: 218.1
  • time away from home: 39 days, 38 nights (if I'd extended this another 36 hours I could've said this trip was biblical at 40 days and 40 nights)
Just got back from the dealer and the maintenance bill at 121k miles was $1592.48. Oof. Probably should've done it myself but my 100 year old garage is about to be torn down and replaced so I couldn't risk starting on this and ending up with a truck I couldn't move when they're ready if something goes wrong or I run out of time. So I ponied up. That covered:
  • LOF, grease driveshafts, air filters, 5 tire rotation
  • spark plugs
  • coolant, transfer case and full A/T fluid flush
  • two new TPMS sensors
  • 5 tire rebalancing (JustTires did an awful job... anything about 70 sucked this trip)
  • General inspection (no leaks, everything was tight as expected)
Sure it'd be great to cut my fuel bill by 20-25%, but no friggin way I want to add on to 218 hours in the front seat to do it. A hypothetical $700 (20%) is a luxury tax I'll pay in a heartbeat to save 40 more hours in the truck (as much as I love driving).
Click to expand...
Wow, and I thought my 13.7 mpg on 34's was bad. I've pulled a 3000lb trailer 650 miles and averaged 11.
 
Madtiger said:
I am itching to add 12.5 but i am also fearful of crash safety. In a rear end (or any other type of collision or rollovers), are these aux tanks safe?? I hate to add something that actually adds risk to me and my family in an accident.
Click to expand...
This is one of the primary reasons I used the factory sub tank.
 
WCDAVE said:
SO, with your trailer, especially if you are going to go off road with it where you may find yourself in tight situations, you need to watch out for how far you can jack knife your trailer. When backing up in tight quarters you will not be able to make as tight of a turn with a spare on the back - especially if it is offset to one side or the other. I suppose having your trailer hit your spare is preferable to hitting the rear quarter of your vehicle, but it will limit your turning radius backing up on tight trails. Having said that, many tow with two spares on the bumper so you can do it, you just have less room to work with when backing up versus not having the spare on the back.
Click to expand...
I'm really more just wondering about if the swingout can be opened at all, with the trailer hooked up, even on level ground. I know this is very dependent on the brand of bumper and trailer, but I'm wondering if this is even possible. Seems like the tongues on these teardrops are kinda short. It would really suck to not be able to get the rear hatch open any time the trailer is hitched up. But there are none around here on any of the lots for me to try before buying.

Really liking the Bean trailers, but no dealers and no delivery. Would have to plunk down a deposit, then drive all the way out to UT to fetch it.
 
KLF said:
I'm really more just wondering about if the swingout can be opened at all, with the trailer hooked up, even on level ground. I know this is very dependent on the brand of bumper and trailer, but I'm wondering if this is even possible. Seems like the tongues on these teardrops are kinda short. It would really suck to not be able to get the rear hatch open any time the trailer is hitched up. But there are none around here on any of the lots for me to try before buying.

Really liking the Bean trailers, but no dealers and no delivery. Would have to plunk down a deposit, then drive all the way out to UT to fetch it.
Click to expand...
Yeah I have the same question. You could measure and sketch it up, or even try some cardboard to simulate. If the swing outs are equal length I *suspect* in most cases so long as your tongue is at least 6” or so from the jack it’ll work when backed up evenly. And you can probably add length with a longer shank for your hitch. But I do think it’s both bumper/swing out and trailer dependent.

maybe find someone local who has a swingout that’s similar and try hitching up your trailer to their rig? I don’t have a swing out but pretty sure even if I did that whatever bumper I chose combined with my trailer would yield at least slightly different results than the setup you want :-/
 
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