Theoretically determining possibility of backing into tight turns

[doughpat]

Hi all -

I have a potential storage scenario involving a "side entry" garage (i.e. enter the driveway from the street, then garage is at a 90 degree angle to the street rather than the typical parallel arrangement). I'd like to know if there's a way to know if backing into this space is possible without actually trying it (long story, but if it doesn't work out, it's a waste of a full day).

If I were to make careful measurements of the dimensions of the driveway, length/width of the airstream/TV, etc., is there a way to know if it would be possible?

There is also the possibility of using a reasonably large ATV/Quad to back it in, as it is obviously much shorter than my Tundra. I'd even consider using one of those motorized hitch devices.

[BayouBiker]

Yes it is possible to calculate backing trajectory theoretically but the geometry and trigonometry and calculus is not simple. Perhaps I can find something to make this easier....

[Bill M.]

You could get some cones or a couple of hoses and lay it out in a empty mall parking lot and give it a try. Wasting a day might be better than hitting something or getting jammed up. Some things take more time than we wish to devote to them. A trip to Jackson Center to repair a dent is time consuming also. With the truck you have to be sure the truck does not hit the trailer when it is jack knifed. Mine does not. I have a space in Fl that requires almost a 270 turn and I can do it in about the length of the trailer with my 32'. But the truck makes a pretty wide sweep. It would take a lot further in a garage because you need to limit the swing from side to side. Maybe use a tractor of some sort. Or the atv. I sorta like that option. I assume you are good on height?

[skyguyscott]

Well, I’ll take a crack at it.

I am guessing that you will need to take into account the following variables:

1. Length of trailer
2. Measurement of center of wheels to rear bumper
3. Distance from center of wheels to center of ball
4. Wheel base of tv
5. Steering range of tv
6. Width of trailer and tv I.e. at what point does the rear of tv crush into trailer in a tight turn
7. Width of alley or street and if there are any trees, bushes, fences or other obstacles to obstruct either trailer or tv in the turn I. E. Ripping off bumper at some point
8. Slope or angle of alley and drive I.e. point at which you bottom out and scrape bottom of trailer or hitch
9. Width of opening you are trying to fit
10. How much space you have beyond and to sides of opening

Those are the essential variables I can identify off the top of my head. There may be more I have overlooked.

You could go to the time and trouble of building a toy model and play with that or you could see if there is any 3D software available to model the turn but it would likely be faster just to try.

[brick1]

It will vary, based on the tow vehicle and hitch setup. If the area is tight, consider using a powered tow dolly.

[Iansk]

A front hitch will likely overcome this challenge. I have one on my tundra and regularly put trailers in impossible to back in spots.

Ian

[telcoman]

Yes you would be surprised at how much easier it is with a front hitch. Your only issue may be hitch weight. A Tundra is a pretty light truck. Depends on the trailer.

[BayouBiker]

So I did find some instructions on figuring turn radius for your situation. How are you at math?

[Iansk]

Originally Posted by telcoman

Yes you would be surprised at how much easier it is with a front hitch. Your only issue may be hitch weight. A Tundra is a pretty light truck. Depends on the trailer.

If I’m concerned about the weight I’ll remove the LP tanks and shift stuff around inside. My Avion tongue weight is around 675lbs and I’ve moved it around just fine with the tanks off. I do connect a pair of empty 20lb tanks whenever my 40’s are off for filling or whatever.

Ian

[GeeSag]

A computer program like Visio makes modelling fairly easy.
It allows drawing a rectangle of the trailer and driveway to scale.
then move the rectangle and measure the clearances at each move.

It is not as accurate as all the Trig using equations, but Sooo much easier.

[BayouBiker]

If the driveway and garage have a simple 90 degree configuration with no twists or turns the numbers are not too hard to determine. You will need to know the max outside and min inside radius to clear all objects, the turning angle of your vehicles front tires, wheelbase, mid trailer axle to ball, vehicle overhang, axle to ball and front axle to front bumper. Vehicle and trailer width, trailer rear overhang mid axle to bumper.

[Trowbridge]

Here's how to do it. Get the trailer into the garage using a shorter vehicle....a caddy...a tractor or bobcat...even hitching and unhitching your regular tow vehicle to change angles. Then, with the trailer in the garage, hitch up your regular tow vehicle and see if you can drive the trailer out to the street smoothly [but while you're doing that have another person follow with a paint can or some type of chalk powder next to the inner set of wheels (switch sides anytime the turn direction changes). You will now have a 'path' to back the trailer in the next time wherein you know the towing vehicle won't hit anything.

[oldenavy]

Skyguyscott seems to have outlined most of the variables but the calculations would be rather complex (and I'm an over-educated engineer). Lots of geometry, but no calculus or differential equations involved. However, if any of your measurements and/or assumptions are wrong, you may calculate an answer that doesn't work out in real life. It may be faster & easier to simply take your trailer to the location and give it a try even if it does shoot a whole day.

FYI, we have a side load garage & built our pole barn opposite to that for the trailer (HOA rules don't allow front-facing garage doors). So, we have to do a 90 degree turn to get from street into the single lane driveway, then another opposite 90 degree turn to line up with the pole barn where we keep our 30' AS. It works for us. I take it slow and have a superb spotter.

Obviously, the key for you is all of the dimensions involved with your situation.

[wrhnco68]

Originally Posted by telcoman

Yes you would be surprised at how much easier it is with a front hitch. Your only issue may be hitch weight. A Tundra is a pretty light truck. Depends on the trailer.

This indeed a good suggestion and even more pronounced with an ATV.

One thing to consider when trying something like this is the weight distribution of the whole setup. The tongue weight of a travel trailer of any kind is substantial. Normal hitch setups put the weight aft of the rear wheels causing squat. The length of most TV's makes this an annoyance but generally not a problem. Other setups might be different.

(yes I have a story...)

My neighbor had just bought a new Other Brand TT. He wanted to park it across the yard into a tight space. He had a 50hp tractor with a fork attachment. Said fork attachment had a hole for a ball. We live on a hill. Yup, as he was starting down the hill, everything bounced a bit, the big rear wheels of the tractor came off the ground and the whole shebang headed down the driveway. He wisely (or accidentally) managed to ram the spare tire into a large pine at the bottom of my driveway rather than running it all into the rather deep ditch.

A bit off topic aside but the impact buckled in the aft end of the NEW TT, exposing the wooden wall framework. I noted the live mold already growing on the lower ends of the 2x2's and decided that I would go with the Airstream. There is still the plywood subfloor but its one less place for nasty stuff to grow.

[elstunr]

We also have a 90 degree turn from our alley into our parking area. We had a 19' Bambi that was easy to back into the parking area, but we upgraded to a 23FB. I was able to make the turn into the parking area, but it was very tight. We purchased a Parkit 360 battery-powered dolly and it has made the parking so much easier. Here is a link to Parkit 360: https://parkit360.ca/collections/trailer-dollies

[tbashin]

Make a diagram with all the dimensions and post it here; that'll help.

[uncle_bob]

Hi

As long as there are no hills or major slopes involved, a motorized "under the hitch" gizmo (with adequate weight rating) will do a pretty good job. The only question is: will the "outline" of the trailer fit?

So: Build a trailer sized rectangle out of some scrap lumber and see if it can be dragged over the course you intend to take. If it will go down the route, so will the trailer on one of those under the hitch gizmos.

Yes there is some common sense involved. You need to watch where the tires will go and where the hitch goes. If they head off the road, that's not a good thing.

Bob

[guskmg]

Try "U" turning at various intersections to get an eye for the amount of real estate you need to turn, then do some measuring at both places and it will become obvious what will fit. What looks good on the drawing board will not be easily duplicated in the real world. You might borrow a powered tongue dollie to see If that is doable at all.
guskmg

[BayouBiker]

Sorry for all the rigamarole, but for a simple rough guess one could assume no obstacles and no pavement limitations giving you the minimum absolute turning radius which will be equal to the minimum of the tow vehicle itself. That is the wheelbase divided by the sine of the max wheel angle. This is why a front hitch is so helpful because the effective minimum radius uses the distance between the ball and the live steering axle.

Anyway, no need to go out and build a mock up. If your tow vehicle can make it in without having to reverse and jockey, then it can be used to get the trailer in also. If you have to jockey to get the tow vehicle in, then it won't be possible to use that vehicle to back the trailer in.

[Hermes]

Originally Posted by elstunr

We also have a 90 degree turn from our alley into our parking area. We had a 19' Bambi that was easy to back into the parking area, but we upgraded to a 23FB. I was able to make the turn into the parking area, but it was very tight. We purchased a Parkit 360 battery-powered dolly and it has made the parking so much easier. Here is a link to Parkit 360: https://parkit360.ca/collections/trailer-dollies

You can plug the Parkit 360 into your Airstream batteries (with the supplied plug by Parkit) and swivel the dolly 90 degrees without any problem.