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Proportioning Clearance Between Smart to Drom Box and Smart to Trailer


Jim Gell

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I am laying out chock positions on my bed to accommodate the 2016 smart. I pushed on my car a bit and it seems to only move a couple inches sideways. My drom is attached to the same deck the car sits on, so it should not bounce back toward the car much. Right?

 

The best use of the space seems to be to minimize the folded mirror of car to drom box clearance to just enough to be comfortable, and maximize the distance from trailer to the other side of car.

 

My current thinking is to have 3 inches clearance while loading the car. This is between the folded mirror and hand grip bars on vertical fairing as the car comes onto the truck. There will then be about 4 inches clearance between folded mirror and the drom box when car tires are lashed down. Is that enough?

 

Using that clearance from drom box, leaves 9 inches, plus or minus an inch of clearance, from side of car to the front corners of the trailer in a 45 degree turn on level ground. Before you say that is plenty, keep in mind I am singled short with the pin 6 feet behind my rear axle. One thing I don't know, and maybe someone can help me with, is estimating how much closer the trailer may come to the car when turning on real world unlevel ground. The rear axle is 17' 3" from front axle. The impact point would be about 40 inches above the pin. Any engineering types care to chime in on how much closer I can expect my car to come to the trailer in a 45 degree turn while rear axle is in a significant dip? Is 9 inches plenty, or will I need to be careful to avoid turning like that in dips?

 

Thanks for your assistance.

 

Jim

 

 

 

 

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2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift

Passenger assist elevator to enter cab - for when we need it, or sell it?

'05 Travel Supreme Select 40 RLQSO 5th wheel

2016 smart car

 

We started full timing on December 1st 2014

Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain
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Jim, which way are you loading the car? It's a pain in the rear to fold in that passenger side mirror to gain very little.

Although I just read the rest of your post...ok, maybe you are that tight??

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The drom box door panels come out near even with fairings. The drom door hinges and fairing mounted grab bar stick out another inch.

 

I would prefer to leave a little more room for the mirror to clear drom, and not need to fold it, but I don't want it to result in cutting the car to trailer clearance too tight. That is why I am asking for help. I don't trust my own math skills.

 

I thought of another factor that may or may not come into play. Maybe in the right circumstance it will even alert me if I am getting close to bumping the car into the trailer. Our rear truck bumper is roughly 10 inches off the ground. (I have rope lights around the truck, including wrapped around my engine, so I did not air it up to measure.) The bumper extends 88 inches from the center of the rear axle. Maybe the bumper will drag the ground well before the smart can hit the trailer. Another question for a Trig whiz!

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2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift

Passenger assist elevator to enter cab - for when we need it, or sell it?

'05 Travel Supreme Select 40 RLQSO 5th wheel

2016 smart car

 

We started full timing on December 1st 2014

Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain
Not all that wander are lost - J. R. R. Tolkien

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The fairings curve forward as they go up. The drom box measurements compared to fairing in previous post are at deck level.

Volvo+and+Travel+Supreme+400+x+103.jpg

 

2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift

Passenger assist elevator to enter cab - for when we need it, or sell it?

'05 Travel Supreme Select 40 RLQSO 5th wheel

2016 smart car

 

We started full timing on December 1st 2014

Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain
Not all that wander are lost - J. R. R. Tolkien

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OK, I just went out with my tape, so here goes. I know how much I miss the deck hatch by and it's not much 2 " or so. After all the figuring is done that leaves 7" to reach in between the fairings and the tire to get the tire cages on. You are reaching up and over the tires to get them on the tire cages on. Clip them on the deck tie down points first.

 

If you are less than 6' and don't weigh more than 200 lbs you will be reaching in to the shoulder. Possibly more if the tiredowns are tucked in behind the tires and you have to drive over them. Any closer to the drom or fairings and there may not be enuf room to reach in..

 

The body sticks out a little beyond the wheels but no that close to interfere with reaching in. The fattest part of the car is the middle of the door and the mirror, neither of which interfere with putting on the wheel cages.

 

Getting the cages onto the tiedown then up and over the tire can be a challenge sometimes. Body parts where you can't see them sometimes catch the webb and you can't force it or things can break..

 

The front of your car is narrower than the rear, so the rear will probably be more of an issue.

 

Also pack along a couple of chunks of 2x6 a foot long or so. If the car goes on crooked and one of the front chocks won't go in far enuf to be able to get the bolts into the dek holes. Roll the car fwd just onto the ramp and put a the chunk of 2x6 on the deck behind where the chock goes and drive the car back on the deck.

 

In my case lifting the car by 1.5" was enough to be able to get the chock to line up with the bolt holes.

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Using that clearance from drom box, leaves 9 inches, plus or minus an inch of clearance, from side of car to the front corners of the trailer in a 45 degree turn on level ground.

That's scary close even for making a normal 90 degree right turn. My opinion is you will HAVE TO lengthen the frame and set the hitch back further.

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Roger,

 

I don't anticipate any problem attaching the wheel cages. It won't be that much different than my 2011 smart. I think the difference that makes mine easier is that my drom box was built narrower than I wanted. I had them convert my vertical stacks to a weed burner to make room for a full width drom box. Apparently they had one design for a drom box and that is what they built and put on. I have 15-16 inches from side of drom box out to the fairing on each side. My 34 inch sleeve length arm reaches around through that opening to attach inside ends of the wheel cages for my 2011 smart fine. Looking at the new car, I don't see it being much harder even if it's a little closer to the drom box.

 

I appreciate the heads up though. It would be a real bummer to set it all up just to find out I can't reach afterwards.

 

Jim

Volvo+and+Travel+Supreme+400+x+103.jpg

 

2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift

Passenger assist elevator to enter cab - for when we need it, or sell it?

'05 Travel Supreme Select 40 RLQSO 5th wheel

2016 smart car

 

We started full timing on December 1st 2014

Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain
Not all that wander are lost - J. R. R. Tolkien

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I think I would mount a temp camera and watch it during a turn over smooth and rough terrain and I would go further then just 45 degrees. I have been in some tight places and have been way past the 45 degree angle a few times.

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I am laying out chock positions on my bed to accommodate the 2016 smart. I pushed on my car a bit and it seems to only move a couple inches sideways. My drom is attached to the same deck the car sits on, so it should not bounce back toward the car much. Right?

 

The best use of the space seems to be to minimize the folded mirror of car to drom box clearance to just enough to be comfortable, and maximize the distance from trailer to the other side of car.

 

My current thinking is to have 3 inches clearance while loading the car. This is between the folded mirror and hand grip bars on vertical fairing as the car comes onto the truck. There will then be about 4 inches clearance between folded mirror and the drom box when car tires are lashed down. Is that enough?

 

Using that clearance from drom box, leaves 9 inches, plus or minus an inch of clearance, from side of car to the front corners of the trailer in a 45 degree turn on level ground. Before you say that is plenty, keep in mind I am singled short with the pin 6 feet behind my rear axle. One thing I don't know, and maybe someone can help me with, is estimating how much closer the trailer may come to the car when turning on real world unlevel ground. The rear axle is 17' 3" from front axle. The impact point would be about 40 inches above the pin. Any engineering types care to chime in on how much closer I can expect my car to come to the trailer in a 45 degree turn while rear axle is in a significant dip? Is 9 inches plenty, or will I need to be careful to avoid turning like that in dips?

 

Thanks for your assistance.

 

Jim

 

 

 

 

Jim , what would the distance be from the smart door to the center of the fifth wheel hitch.

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Jim ?, (On The Road)

 

The center of my pin will be 58.75" from the closest point on car, the folded mirror. I measured to mirror since the closest the trailer will come will be when it is turned to 90 degrees or more, making the mirror the likely first casualty. The door will be a bit further away, 1.5 to 2 inches, if I remember right.

 

Today, I got up on the truck and set the bottom of a broomstick at 59 inches from the pin. Then I tilted it back the 8-9 inches toward where the car would be. Without any complicated trig computations, it looked obvious to me, from the angle of the broomstick, that the truck would need to be at a severe angle for there to be a collision. Just like jackknifing, I will need to use a bit of common sense while maneuvering. At this point, I am going to assume I will be fine in all but the most unusual circumstances. If anyone thinks I am wrong, I would like to hear from you.

 

I don't want to extend my hitch again. As I recall, the engineer who designed my bed extension, with the width of the 2016 smart cars in mind, said he gave me a little extra room. Then when the job was passed off to the welder, he said he also added a bit more room just to be safe. I am glad they did, because I don't feel we have too much extra room.

 

Jim

Volvo+and+Travel+Supreme+400+x+103.jpg

 

2001 Volvo 770, Detroit 60 Series, Gen 2 Autoshift

Passenger assist elevator to enter cab - for when we need it, or sell it?

'05 Travel Supreme Select 40 RLQSO 5th wheel

2016 smart car

 

We started full timing on December 1st 2014

Travel is fatal to prejudice, bigotry, and narrow-mindedness - Mark Twain
Not all that wander are lost - J. R. R. Tolkien

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I don't think you will have an issue Jim. The 4" to the box from the folded mirror should be fine. It really should be no more difficult to attach things that your last smart.

 

Total width should work too, but you will want to check it all out after you load for the first time. I had less than that on my grey truck and tried some really tight/dipping turns and never got closer than 1.5" to the car. That is tight, but still clearing. And you have more room. You can do the math all you want, but in the end you just have to put it on and try it.

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