Diameter for 180 degree turn

We have a 3585RL 39'+. Vehicle is F350 with Reese hitch in shorter truck bed - so can't turn as tightly as others. Want to bring it home but exit would require using the circle at the end of the cul-de-sac.

Assuming no vehicles parked in the cul-de-sac does anyone know the diameter the circle must be to successfully turn around?

Thanks in advance!
Jeff

JeffG1947 said:

We have a 3585RL 39'+. Vehicle is F350 with Reese hitch in shorter truck bed - so can't turn as tightly as others. Want to bring it home but exit would require using the circle at the end of the cul-de-sac.

Assuming no vehicles parked in the cul-de-sac does anyone know the diameter the circle must be to successfully turn around?

Thanks in advance!
Jeff

Click to expand...

I understand your concern. However, if the cul-de-sac is that tight perhaps take it to a Wal Mart parking lot and mark off your radius. To many variables to give you solid advice. Enjoy your unit.

<p>
I have a 42 foot LandMark with a longbed dually and live in a cul-da-sac and have done it once. No cars in the circle and I had to make one stop in the middle to adjust so I did not take out anyones mailbox with the back of the camper. This is in a circle that was built in 2001 as we have been there since 2002. Hope this helps</p>

Just remember that when making a very tight turn, the inside tires may skid/slide rather than turn. Plus the wheels will be somewhat cockeyed till you straighten out. We live on cul-de-sac and I will use the whole thing (very large circle---probly don't have to, but I do). Keep in mind as well the proximity of RV corner in relation to back of cab.

Good idea to inspect your rear spring hangers anytime you make a tight corner on asphalt, such as cul-de-sacs, parking lots, etc.

I Have a 22 foot long, dually long bed truck, with a 41 foot long fiver. Different brand trucks I would think have different turning radius's. But that situation your decribing makes my RV alarms go off big time. Once you go into that culdesac, your committed no matter what. I know my RAM 3500 with camper take alot of room to negotiate a full lock turn...a lot! I could see me taking out the front lawns of the neighbors, and their mailboxes.

I doubt the culdesac is that big.

Flick said:

I understand your concern. However, if the cul-de-sac is that tight perhaps take it to a Wal Mart parking lot and mark off your radius. To many variables to give you solid advice. Enjoy your unit.

Click to expand...

I like that idea - now to find the right parking lot. I did just find the following calculation for the turn (the diameter of the cul-de-sac is 90+ feet so I think it's doable). His example indicates a 53' trailer with a 45 degree cab angle requires a 94 foot diameter. Since both my truck and trailer are smaller I shouldn't have a problem. If I had any real ability to backup that would be an alternative - but we're on a curve and if I was somehow able to backup to the corner then I'd need to turn the trailer 90 degrees to exit the area.


[h=1]How to Calculate the Turning Radius of a Truck With a Trailer[/h]BY RICHARD ROWE
Tractor-trailers are complex beasts; every aspect of the unit's performance depends on dozens of factors within not only the truck but the trailer also. A truck's purpose is to tow a trailer, which is why the trailer makes up most of the unit's size and mass. So, you don't need to ask what the tractor's turning radius is, since the unit's overall turning radius and diameter usually depends more upon the trailer than the tractor. Either way, all you need is to apply a bit of simple trigonometry to calculate the truck's steering and Ackerman angle.

[h=4]Step 1[/h]Measure your truck's wheelbase in inches from the center of the rear axle hub to the center of the front axle hub. If you have tandem drive axles, as most tractor trailers do, then measure from the center of the empty space between the tires on the two rear axles. For the example Freightliner Classic XL and 53-foot trailer combo, say the tractor's wheelbase comes out to 250 inches.


[h=4]Step 2[/h]Check your manufacturer's info for the maximum steer angle of the inside turning tire, the left tire turning left and right tire turning right. If you can't find this info you can measure it pretty easily with a store-bought protractor. For the Freightliner, the inside tire's steer angle comes out to exactly 55 degrees at full lock.



[h=4]Step 3[/h]Break out your trig calculator, enter the degrees of steer angle and hit the "sin" key. In the example, we wind up with 0.819. Now, divide the wheelbase of the truck by your sin figure; for the example, the result is a turning radius of 305.25 inches, or about 25.43 feet. Multiply that by two to get the truck's total turning diameter, or turning circle, which is 50.87 feet for our example. If you're measuring that in traffic lanes, that's five 10-foot-wide country roads or a little more than four 12-foot-wide state roads to do a U-turn.


Perform this same calculation with the trailer, but this time measure from the center of the tandem trailer tires to the center of the drive axles and use the angle of the truck relative to the trailer as your steering angle. With the 53-footer's tandems set all the way forward, the wheelbase measures 400 inches. With a 10-degree angle of truck to trailer the turning radius is 2,312 inches, or 192 feet. Increase the turning angle to 45 degrees, and turn radius decreases to 565 inches or 47 feet. Jackknife the truck at 90 degrees or more and the trailer rotates on its tandems with a turn radius of 400 inches or less.

Did you ever think about backing down the cul-de-sack? I have done it in the past and then some. Rear view camera did help some, but rear view mirrors were best. Could use a spotter as well.