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teotwaki

Excelsior!
Saving gas

I think that I have decided to leave the trailer's suspension as is for now but to help lower the trailer's wind resistance I may bring the tent down closer to the trailer lid.

trailer013.jpg


I'd remove the solar panel slide brackets and store the panel internally or switch to my 65 watt foldable panel. Then I'd either chop the height of the tent support frame legs to bring the tent down lower or possibly bolt the tent directly to the trailer lid.
 

skersfan

Supporting Sponsor
I seriously doubt you will see much improvement. More mileage if you lower the front of the trailer if it is flat as I have seen on this site. The front should be two inches lower than the rear for good towing and it also helps mileage. There is so much turbulance with the box trailers and roof top tents, dropping it will most likely make it worse as you will have a larger blocked area, now there is a funnel for some to pass through. Not a wind tunnel expert by any means. Anything is worth a try at 5 bucks a gallon.
 

cnynrat

Expedition Leader
I am not an aero guy either, but I have been closely following Formula 1 since the late '70's ;).

With that proviso, I think you might find that the biggest issue is the gap between the RTT and the trailer, not the overall height of the trailer. I'm pretty sure your trailer is already much shorter than your 4 Runner. My guess is there is quite a bit of turbulance created by funneling airflow between the tent and the trailer lid. If that is the case, you might think about approaches to closing off that gap rather than actually lowering the tent. That would allow you to still keep the solar panel under the tent, and perhaps even some other similarly flat items.

Think about the kind of thing you are seeing semi-trucks do to close off the gap under the trailer.

While I agree with Bob though that any milegage gains are likely to be small, to cost to acheive them may be small as well.

Just a thought.
 
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teotwaki

Excelsior!
I seriously doubt you will see much improvement. More mileage if you lower the front of the trailer if it is flat as I have seen on this site. The front should be two inches lower than the rear for good towing and it also helps mileage. There is so much turbulance with the box trailers and roof top tents, dropping it will most likely make it worse as you will have a larger blocked area, now there is a funnel for some to pass through. Not a wind tunnel expert by any means. Anything is worth a try at 5 bucks a gallon.

Hi Bob. Thanks for the feedback. The front of the trailer is lower than the back and the top of the tent does stick up higher than the 4Runner. Right now air is forced into the RTT cover and causes it to balloon up higher into the airstream.
trailer036.jpg


Dropping the tent down could also help lower the trailer's center of gravity, right?
 

teotwaki

Excelsior!
I am not an aero guy either, but I have been closely following Formula 1 since the late '70's ;).

With that proviso, I think you might find that the biggest issue is the gap between the RTT and the trailer, not the overall height of the trailer. I'm pretty sure your trailer is already much shorter than your 4 Runner. My guess is there is quite a bit of turbulance created by funneling airflow between the tent and the trailer lid. If that is the case, you might think about approaches to closing off that gap rather than actually lowering the tent. That would allow you to still keep the solar panel under the tent, and perhaps even some other similarly flat items.

Think about the kind of thing you are seeing semi-trucks do to close off the gap under the trailer.

While I agree with Bob though that any milegage gains are likely to be small, to cost to acheive them may be small as well.

Just a thought.

I have thought about closing off the gap a bit by placing an air dam across the front two legs of the tent crossbar. I think that my trailer body is up higher than yours and that your tent's height is a bit lower than mine
837357458_ZKdmy-L.jpg

trailer036.jpg
 

cnynrat

Expedition Leader
I have thought about closing off the gap a bit by placing an air dam across the front two legs of the tent crossbar. I think that my trailer body is up higher than yours and that your tent's height is a bit lower than mine


I wonder if closing off the gap along the sides of the tent would help as well. You'd have to address how you extended the solar panel, but that seems like something that could work.

I guess I didn't realize your tent was up higher than your 4 Runner. Given that, I would expect that lowering the tent a bit would give you some gains as well.
 

skersfan

Supporting Sponsor
I think you are correct on the gravity deal. The lower the better for sure. I do not get great mileage with my box trailer, it weighs a little over 1200 pounds fully loaded. On average about 11. But with the new trailer I am getting right at 12.2, much larger trailer, sets higher and weighs close to 2200 pounds fully loaded. It is solid front but angled up, so aero dynamics has to be playing a part. Possibly a angled cone from the front of the box to the top and angled on the sides to form a nose cone like the semis use would help.

But my guess is it will be so minimal that you will not even be able to keep track of it. But lowering the tent will make the trailer more trail worthy for sure.
 
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teotwaki

Excelsior!
Thanks Dave and Bob! I simply do not know what the exact answer may be because of my minimal experience with this trailer. The trailer tows very well both on and off road so I am hesitant to mess with the suspension or overall dimensions.
 

teotwaki

Excelsior!
I recently had one of the electromagnets in my trailer's brakes go bad. Upon opening up the proverbial can of worms I discovered something much more interesting. Electric brakes are designed to be directional and my axle was rotated 180 degrees.

Yes, the brakes are able to operate in both forward and reverse but the brake shoes are designed to only have the primary (shorter pad) shoe on the forward side. Fortunately the only real difference besides the order of the shoes is the actuating arm that the electromagnet is attached to. Last night I took apart both brake assemblies and when I reassembled them I swapped the left and right actuator arms to the correct side and also placed the brake shoes in the correct spots.

220-2326.jpg

magnet is #1 and the arm is #2
dexter-10x2-25-electric-brk.gif

How else could this have been repaired?: Cut the brake wires, drop the axle off of the shocks and springs, rotate the axle 180 degrees, cut off and re-weld the shock mounts, reattach the leaf springs and brake wires (Way too much work)

How not to repair it?: Don't swap the backing plates from left to right. Unless you cut the wires, unbolt the plates, install all new bearings, shoes and machine the drums and reattach the wires this is not an easy nor quick solution.

The silver lining is that now I am thoroughly familiar with my trailer's brake system!
 

cowboy4x4

Explorer
Jim. I have all my fab equipment back from AZ I'm now in yorba linda CA. garage/shop is set up again. Give me a call if you need some work done my rate is less than what he charged you...... Thomas 805-428-3278
 
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teotwaki

Excelsior!
Jim. I have all my fab equipment back from AZ I'm now in yorba linda CA. garage/shop is set up again. Give me a call if you need some work done my rate is less than what he charged you...... Thomas

Cool! You have great fab skills. I have a few things I want to add pretty soon: mounts for the Scepter gas can holders, maybe some pivot points on the rear bumper for a stabilizer and reinforcement ring around the receiver tube
 
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nwoods

Expedition Leader
Jim. I have all my fab equipment back from AZ I'm now in yorba linda CA. garage/shop is set up again. Give me a call if you need some work done my rate is less than what he charged you...... Thomas

Hey Neighbor! You and I met a long while ago at the TreadTrainer program in Hungry Valley. I had a bone stock LR3 at the time. Now I'm rocking a...... volvo :-(

I'm hopeful by the end of this year to get another 4x4 adventure-mobile.
 

cowboy4x4

Explorer
Hey Nathan, Yes I remember you. I still use that picture we took at hungry valley. Hope you get a vehicle soon..... :)
 

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