I'm hoping somebody out there understands the math involved well enough.....!
I understand it well enough to have found great value in building 2d scale models. Just cut objects out of paper, truck, 5er, house, street, driveway... everything. I also did this to place objects in the truck bed. Not perfect, but pretty darn helpful.
* This post was
edited 01/19/12 04:44pm by 2oldman *
As I understand it, turning radius is affected by both the length of the rig and the placement of its wheels.
I'm hoping somebody out there understands the math involved well enough to tell me how the formula would differ for a rig with the wheels (pivot points) situated differently than those on the rig in the picture.
When trip planning, the widths of ingress/egress roads and sharpness of campground curves is readily available...
It's be nice to be able to make a real determination of accessibility before deciding on destinations!
I thought I answered it, but my Engineering math hasn't been used for a bit...The semi trailer with it's wheels at the very back will have a wider turning radius than a 5er with the wheels situated in the middle of the 5er . The wheels on the 5er act as the pivot point more so than the tow vehicle..
As far as planning ahead on where your going to tow a 40' 5er, I'd plan on staying on Interstates and secondary roads as much as possible, but I've had my 5er on some really curvy, "just barely" secondary roads in WV and all was well...(watch out more for overhead obstacles than not enough road..
Best tool one has for what your talking about is there mirrors, and possibly someone spotting for them when backing up or making a close, sharp turn..
As far as a formula, there are some, but doing a little research on roads you might travel and knowing how your 5er tracks behind your truck and using your mirrors is how most of us approach this...least it's been my experience towing my 5er for about 6 yrs. on some very scary roads at times.....
As stated above, and as I stated in my first post, you would be surprised at just how sharp of a curve you could make if you had too....my truck is a long bed crew cab dually, and again, my 5er is 3" shy of being 40' and I turn it around in my cul-de-sac.....
If you have a 5er with wheels at the very end, and I've never seen one like that, your going to need more room than I'm talking about.. but now that I think about it, I may be wrong about that scenario also...may not take as much...a trucker could answer than one for us.
Jim & Kathy
2013 Dodge 3500DRW Longhorn 4X4/CC/LB/Aisin tranny/4:10/Cummins: 385HP/850TQ
06 HR Presidential Suite 37RLQ/ 4 slide/ dual pane windows/Winegard SK3005 Satellite/Splendide XC2100 W/D
Boxers;Buddy& Sheba II
USAF 71-75 Nam Vet
You are over-thinking what is not really a big problem. Some practice and a little experience will tell you what you can and cannot do.
Most camping areas were, by the way, not laid out by a surveyor and don't have "standard" curves.
When we used to check engineering drawings for access by school buses, semi trucks and/or fire equipment, we used clear plastic templates that were laid over the drawings to check curbs and obstructions. I don't think there were formulae. The templates were drawn from field measurements using a real fire truck, etc.
Formerly posting as "littleblackdog"
Martha, Allen, & Blackjack
2006 Chevy 3500 D/A LB SRW, RVND 7710
2008 Titanium 30E35SA; EZ-Lube axles; wet bolts; spring hanger gussetts; BFG Commercial TAs
"Real Trucks Don't Have Sparkplugs"
Every trailer's inside wheels will track inside the inside rear wheels of the TV. So the turning radius of the Trailer has no real effect on the turning radius of the pair other than clearance of the 5th wheel with a short bed truck.
On edit: I should clarify. The outside turning radius of a combo TV and trailer/5th wheel is determined by the TV not the trailer/5th wheel.
The inside is different. The inside will track inside the inside rear wheels of the TV. The inside radius will be dependent on the TV, type of trailer/5th wheel for hitch location and distance from the hitch pin (TT or 5th in bed) to the inside wheels on the trailer.
There wont be 1 number that fits all but there is likely a formula that could provide this information.
* This post was
edited 01/20/12 05:52am by wittmeba *
I was born in Great Falls, Mt. My parents moved when I was 5. I found them when I was 10 - they were in California.
As far as planning ahead on where your going to tow a 40' 5er, I'd plan on staying on Interstates and secondary roads as much as possible, but I've had my 5er on some really curvy, "just barely" secondary roads in WV and all was well...(watch out more for overhead obstacles than not enough road...
I decided to take HWY 50 out of Clarksburg, WV instead of staying I-79 to I-68 and I got caught in some terrible hills and hairpin turns. I was in 1st gear a while climbing the side of the mountain because the road turned into a billy goat path and I was too far in to turn around and go back and there was no place to turn around. I got on one hwy and drove into the clouds and as I was exiting the other side it was a storm. I told my wife it wasn't fog that we were in the clouds and when hit the strom before coming out of it she couldn't believe it.
Anyhow my 5er can turn much tighter than my previous 32' TT. So I have to really watch the inside of the turn that I don't drag the 5er over something the truck cleared. The TT pretty much followed the truck so if the truck cleared it so would the TT but not so with the 5er.
Skip and Allworth offer some good points.
I have a chevy and a Dodge truck. Both are 140" wheelbase 4 door trucks. The Dodge has a much shorter turning radius and can make about any turn I start. Not so the chevy that requires making a 2-3 point turn to get around the same curve/cornor with the same trailer.
Even the tractor in the pic may have a wide or very short turning radius depending on the trucks steering geometry.
It takes practice and experience with your particular vehicle combo to know what the turning radius and swing will be.
"good judgment comes from experience, and a lot of that comes from bad judgment" ............ Will Rogers
'03 2500 QC Dodge/Cummins HO 3.73 6 speed manual Jacobs Westach
'97 Park Avanue 28' 5er 11200 gvwr two slides