Turning radius for truck and tow-behind with (almost) hairpin turns?

[james000222]

Good day RV forum!

We have recently purchased a new home...on the side of a small mountain. The driveway has two hairpin turns in it. We are planning on putting a shop where the red box is in the image. I am trying to find a guide or expert advice on how long of a trailer I can maneuver up that driveway - past both hairpins, then back into the shop past the second hairpin.

Right now I have an F150 crew-cab/short bed that is 19.5 feet. Current TT is a 21' trailer, with standard 4' hitch, so 25' total. It is dual axle. So basically: 20' truck, 25' trailer. The image below is scaled correctly - off google maps but scaled to the actual plot of the property. Building a trauck/trailer model to scale (fairly primitive - using powerpoint) ***looks like*** I can do it...but a contractor we have coming says that may not be right.

Any advice from veteran trailer towers? I do think a fifth wheel would improve the outcome but would still need to be kind of short...

Thanks in advance.

(Edit) - lol - my forum avatar is my old Tundra and 29' trailer - both have been updated.

 

[RRR]

Company I worked for used this Idaho Transportation Department For entertainment one extremely slow day we used the calculator and it was fairly accurate.

I would think the measurements of the standard log truck picture would work in your situation, as your trailer is stinger steered, meaning the coupling device is behind the center of the rear axle.

 

[Kirk]

There isn't nearly enough information for us to give more than a guess. How wide is the road and how close to the edges of that road are the trees, rocks, and other obstacles? Will you be pulling directly into the shop, or must you back into it?

 

[james000222]

Very good points Kirk. Haven't moved in yet, but from memory and map measurements, the driveway is 12 feet wide with about 2 feet ditches. The corners widen out some, to about 16 feet, so 20 feet(?) clearance including ditches (which are shallow). There is a fairly steep grade up, so it's cut into the side of the hill, so that's a hard stop as there is an embankment on the upside of the first curve.

The angle of the first turn looks like 35 degrees, so 145 degrees turn, and the second one 55 degrees so 125 degrees turn.

I plan to make the second turn and back the trailer in --- there will be more area on that uphill side as that will be the entrance to the shop.

@RRR - thank you - with all that effort you think they would have made one for a standard truck and travel trailer! The truck and two trailers does not work as the trailer wheels are far apart.

I dont see how the log truck would work? IDK...

 

[Kirk]

While you should keep a close eye on the uphill side, I doubt that you will have a problem getting through the turns, by keeping the track toward the downhill side. Where the catch could be is if you need to back out, after you get past the turns. I'd make darn sure that you can turn around once you get there. There is one more factor that you should give very harsh consideration. That is the driver skill set. I believe that most of us either over rate or under rate our level of driving skill.

 

[Derby6]

I really don’t think anyone can really help with this.
My advice is take your current rig up and see how much extra room you have and guesstimate from there.
Worst case when you have the equip there to clear area for shop have them widen the turns.
I am sure pic is deceiving but those don’t look like tight hairpin turns. More sweeping. But again pic likely deceiving.

 

[Derby6]

There is one more factor that you should give very harsh consideration. That is the driver skill set. I believe that most of us either over rate or under rate our level of driving skill.

Yea really good point. Impossible for some can be done in one shot by others.

 

[Tulecreeper]

A better/clearer sat picture would help. One from straight down instead of at an angle I can't really even tell where the road is because of the shadowing.

 

[RRR]

Very good points Kirk. Haven't moved in yet, but from memory and map measurements, the driveway is 12 feet wide with about 2 feet ditches. The corners widen out some, to about 16 feet, so 20 feet(?) clearance including ditches (which are shallow). There is a fairly steep grade up, so it's cut into the side of the hill, so that's a hard stop as there is an embankment on the upside of the first curve.

The angle of the first turn looks like 35 degrees, so 145 degrees turn, and the second one 55 degrees so 125 degrees turn.

I plan to make the second turn and back the trailer in --- there will be more area on that uphill side as that will be the entrance to the shop.

@RRR - thank you - with all that effort you think they would have made one for a standard truck and travel trailer! The truck and two trailers does not work as the trailer wheels are far apart.

I dont see how the log truck would work? IDK...

Think about it. Replace the log truck picture with your pickup. The fact that you have a single rear axle has no bearing you measure to centerline of axle for measurement A. For C1 it is self explanatory. For B it is the center point between the axle, (trunion or trunnion), unless you have a single axle trailer then to the CL of the axle.

A side note that some loggers, especially pole haulers, have a one or two pullout reach on the truck that extends the hitch further to the rear. The log trailer will only offtrack a minor amount from the truck.

I doubt if IDOT was/is too concerned with the RV segment, even though they allow double trailer towing for RV's. In the commercial end for long combination towing you have to use the calculator to get your permits, then you might be restricted from certain routes or interchanges.

 

[james000222]

I really don’t think anyone can really help with this.
My advice is take your current rig up and see how much extra room you have and guesstimate from there.
Worst case when you have the equip there to clear area for shop have them widen the turns.
I am sure pic is deceiving but those don’t look like tight hairpin turns. More sweeping. But again pic likely deceiving.

WELLLL....if I am wrong, then that would be a heck of a problem getting it out...

Thank you all. Yes I do agree on the experience. I have enough to be leery and ask lots of questions especially when the outcome could be rough to deal with if I'm wrong!

 

[Onyrlef]

Is it a one time move? If so rent or hire an all terrain forklift, rig up a ball on the fork and you're good to go. A lot cheaper than getting hung up and the small fortune it would cost to salvage the operation.
An alternative is skid plates, which you can make from 2x10's or 2x12's, place the greased skid plate perpendicular to the tangent of the road, pull the trailer wheels onto the plate and either jack or using a come-a-long move the ass end of the trailer toward the inside of the curve. Repeat if necessary. ( that's how they get those 16x80 mobile homes up the winding mtn. rds. in WV).

 

[james000222]

Think about it. Replace the log truck picture with your pickup. The fact that you have a single rear axle has no bearing you measure to centerline of axle for measurement A. For C1 it is self explanatory. For B it is the center point between the axle, (trunion or trunnion), unless you have a single axle trailer then to the CL of the axle.

A side note that some loggers, especially pole haulers, have a one or two pullout reach on the truck that extends the hitch further to the rear. The log trailer will only offtrack a minor amount from the truck.

I doubt if IDOT was/is too concerned with the RV segment, even though they allow double trailer towing for RV's. In the commercial end for long combination towing you have to use the calculator to get your permits, then you might be restricted from certain routes or interchanges.

Hmm.

A: Center front wheel to back wheel (aka wheel-base) 147"
C1: Center rear wheel to hitch pivot 45"
B: Hitch pivot to the center point between the axles 195"

This results in an off-track of 1.23
I had no idea what that meant,but this old document explains turning radius vs off-track and has a couple of tables.

https://onlinepubs.trb.org/Onlinepubs/hrr/1967/159/159-001.pdf

1.23 off track equates to a 45 foot turning radius

AND --- I found this. Its UK but still.

Offtrack trailer turn calculator

I do think I can get it round there.

Is it a one time move? If so rent or hire an all terrain forklift, rig up a ball on the fork and you're good to go. A lot cheaper than getting hung up and the small fortune it would cost to salvage the operation.
An alternative is skid plates, which you can make from 2x10's or 2x12's, place the greased skid plate perpendicular to the tangent of the road, pull the trailer wheels onto the plate and either jack or using a come-a-long move the ass end of the trailer toward the inside of the curve. Repeat if necessary. ( that's how they get those 16x80 mobile homes up the winding mtn. rds. in WV).

Thanks for that - a greased skid plate - whodathunkit. If my experiment fails that will provide a solution.

 

[Kirk]

Is the road already established? What would it take to widen the road? If you are going to build that shop building then you probably need to have the site leveled and prepared so the same equipment can be used widen the road?