How far should tow mirrors stick out?

[Bill]

In response to the recent thread on tow mirrors - here is an interesting experiment for everyone. Install your outboard mirrors (whatever kind), lower both of your tow vehicle's front windows, and pass a measuring tape through from one mirror to the other. Measure the distance from the center of the left mirror to the center of the right mirror. This measurement should be well in excess of 91", which is the width of the TM body (not including awning, etc).

On my Explorer, the stock mirrors are 77" apart, center-to-center. Not NEARLY enough to see back past the sides of the TM. When I mounted the McKesh mirrors right out of the box, they were 103" apart. In other words, each McKesh sticks out 6" beyond the side of the trailer. This lets me see down the sides of the TM, of course, but it is BARELY enough so that my left and right sight lines converge somewhere behind the TM. If the sight lines don't converge, you have no idea whether anyone is behind you, and to me, that is a requirement. A bit more spread is in order, and fortunately McKesh makes it easy to do.

I'd like to know other folks' experience. What are your measurements? Do you think they are adequate? Let's collect some data here.

Bill

 

[BobRederick]

Bill
I cheat on this a little. Just cause the TV to turn a little: left for looking at the left mirror & right for looking at the right mirror. That extends the view out the rear a whole lot and you can see if there is a car behind the TM. It doesn't take much of a turn to see and definitely does not result in leaving the well traveled part of the road on either side. Hold the turn for only a few seconds. That really helps with the longer McKesh mirrors and is mandatory but not sufficient for shorter OEM mirrors.

 

[rockerga]

I am at 86-1/2" on my slip-ons center to center on my tow mirrors. (96 Grand Cherokee) In my towing experience I have done as Bob describes with a little "wave left or right motion" to get a clearer view when required as to what is behind me.

Taking the TM out for its maiden voyage this weekend and I will be on every imaginable type of road including southern appalachian mountains so "we'll see" (No pun intended).

 

[PopBeavers]

I haven't measured mine, but here is some info I pulled from California DMV code.

A left* and right* hand outside mirror is required on the towing vehicle
if the RV or trailer obstructs the driver's rear vision. Make sure the
mirrors are large enough and that they are positioned for vision at least
200 feet to the rear of the vehicle. You need the mirrors to do more than
back the vehicle. Check your mirrors frequently for traffic conditions
behind you so you can avoid last minute maneuvers and surprises. Side mirrors
should be as large as practical, with a separate convex mirror mounted below.
Mount the mirrors as wide apart as possible for maximum rear vision and easy
backing. Trailer towing mirrors should be adjusted so that the inside edge of
the mirror is further out than the outside edge of the trailer. The RV or
trailer's rear wheels should be visible in the convex mirrors to check for
correct tracking.

Lights, mirrors, or devices which are required to be mounted upon a vehicle
under this code may extend beyond the permissible width of the vehicle to a
distance not exceeding 10 inches on each side of the vehicle.

The total outside width of any vehicle or its load shall not exceed 102 inches

It seems to me that if you have your mirrors sticking out the maximum amount of 10 inches on each side and you still can not see behind you then you need a wider tow vehicle. But I am guessing. I am not a lawyer

 

[Bill]

Info pulled from California DMV code

Lights, mirrorsand devices ... may extend beyond the permissible width of the vehicle to a distance not exceeding 10 inches on each side of the vehicle.

The total outside width of any vehicle or its load shall not exceed 102 inches

It seems to me that if you have your mirrors sticking out the maximum amount of 10 inches on each side and you still can not see behind you then you need a wider tow vehicle.

PopBeavers -

I think I am reading the last paragraphs a little different. But I'm not real sure that I am reading it as intended.

First, the permissable width of a vehicle is apparently 110". (Middle para.)

Then it says that lights and mirrors may extend beyond the permissible width of the vehicle by 10" on each side. (First para.)

I'm not a lawyer either, and I agree that the language is pretty ambiguous.

Perhaps the real point is that mirrors should be far enough apart that you can see the wheels on the trailer, and that the sight lines converge no further than 200 feet behind the trailer.

Bill

 

[Jim-NY]

Again, not a lawyer, but I read this to say you must have no more than 10 inch extensions on EACH side ...therefore not exceeding the width of vehicle plus 20 inches between outside edges of mirrors AND if this takes you beyond the 102 inch maximum vehicle width, that is OK.

As a State Park Manager my concern was always with campers who did not remove extended mirrors after they unhook the trailer. It is too common for pedestrians or bicyclists to get clipped by a mirror because the driver forgets they are there and passes to close on a narrow road such as those in often found in parks. It's been a while since I managed a camping park, but I think it was either NYS Motor Vehicle or NYS Parks Law that mandated such removal.

If I understand the previous comments, it sounds like some of you swerve a little so you can see what is following you. Maybe it's because I drive too fast to begin with, but it has never occurred to me to worry that much about what is behind me. I try to be real careful changing lanes though, and I could see where someone might come up quickly behind me then go into a lane I was about to move into. I am leaving this weekend for FL, I will have to try the small swerve technique. If nothing else it might scare folks behind me into submission.

Jim
:new_newbi

 

[rockerga]

Jim-NY: We drive too much alike! I am not advocating it as safe; but usually I am not worried who is behind me either as they are no more than the last ones I passed. "A properly executed controlled move" to one side of the lane or the other is adequate with properly adjusted mirrors to get the complete birds-eye view of what is behind you in order to then complete whatever maneuver you plan on. This is for everyone’s safety as there are idiots out there that think it is either Daytona or Lemans and not just the ones on motorcycles either that will come-up on you in less than a millionth of a heartbeat. The famous quote after it was too late: "I never saw them..." well you actually didn't look! Bill is correct in collecting this data; that however we drive and hopefully within our own individual skill sets we need to use all the tools we have at our disposal for safeties sake because however you do it; if you can’t see what is behind you that is a serious safety issue.

 

[Jim-NY]

rockerga,

I agree with what you are saying. It's a good topic and we each need to take responsibility for everyone's safety. I have never tried making "a properly executed controlled move" to one side of the lane or the other, unless I did it instinctively and don't remember. (It's been 4 months since I towed the trailer and that's a long time for this memory.) I will try a controlled swerve ..er... I mean controlled move on my upcoming trip.

I should probably add that I do have McKesh extension mirrors, with the fisheye add ons, that I extend out to the max. - more than California's 10 inch limit. I have never taken the time to measure how far behind the trailer my right and left hand mirror views converge. I just might do that sometime on this trip too.

Jim
:new_newbi
(And one of those @#&@ *&@ aggressive NY drivers :new_evil: )

 

[Bill & Lisa]

Went camping this weekend and before removing my mirrors took the measurements you asked for. OEM mirrors = 76" (center to center)
Towing Mirrors = 99 inches (again, center to center)
Bill

 

[Bill]

Thanks for the input, Bill. Based on that measurement, I imnagine that you can see down both sides of the TM, and your sight lines converge less than 200 feet behind the trailer. That's a good thing, in my opinion.

I have to admit I am less than thrilled with the "controlled swerve" maneuver, although I too have used it on the rare occasion when I have to know if there is anything close behind me. Two problems with the maneuver. First, it annoys the **** out of other drivers - how many times have you mumbled under your breath about "that SOB is wandering all over the road!" Once you have started a swerve, it is not clear to the other guy if you are going to actually change lanes or not - or if you even see him.

More important, though, if you choose to rely on the swerve to see into the blind spot beside your TM, it means you have intentionally given up the ability to flick a quick glance at the mirror and see what the situation is. In normal driving (no trailer), most drivers flick a glance at the inside and outside rear view mirrors every few seconds. It is quick, automatic, and you may not even realize you are doing it - but it keeps you cognizant of the world around your vehicle. The military guys call this "situation awareness". When you hook up a trailer, it seems to me that you need situation awareness even more. This is NOT the time, in my opinion, to intentionally give it up, and resort to a somewhat clumsy, time-consuming, and irritating alternate procedure.

Just my opinion, of course.

Bill

 

[Bill & Lisa]

I don't like the swerve either. I prefer to maintain my SA (situational awareness) diligently and glancing in the mirrors often remind me the trailer is back there. I try not to forget that since the time I found myself in a starbucks drive through with a 180 degree turn with an 8 foot radius with the trailer attached. (search on starbucks if you missed it and want a laugh). I have the mirrors that clip on with 3 little adjustable legs with pads that keep falling off and they take awhile to get adjusted properly but I don't feel safe driving without them and they do accomplish the intended goal. More things in life to worry about than inconvient mirrors.

I would agree with your assesment on my site picture. I have yet had anyone "disappear" behind me and they like to follow close in this area :new_Eyecr

 

[grampa]

My 2 cents worth. In Florida the DMV code says mirrors must be sufficiently far apart to see a point 200 feet behind the towed vehicle. this applies to 18 wheelers,RV's, etc.
Hope this helps.

 

[BrucePerens]

Besides being able to see behind the trailer, towing mirrors give the driver a visual cue about the side clearance necessary to accommodate the width of the trailer. My 3023 is 7 inches wider than my Grand Cherokee on each side. The mirrors help me to maintain the side clearance. Without them, it might be too easy to shear off the side of the trailer.

 

[Padgett]

My main mirrors are 76" center to center, strap ons 87" (usually pointed at TM wheels) , but then I also have a rear view camera on the back of the TM.

I can see something less than a foot behind the rear bumper and out to LOS.

 

[scrubjaysnest-TMO]

interesting question. Just took the flash light and keys out to the ram and came up with 85" center to center. Don't use clip ons, just the stock. Works great. Have clip on for the Cherokee from when we used it to move the Outback which is wider then the TM.

 

[tentcamper]

I always found it is easier backing up straight with mirrors that stick out past the width of the camper. You can see when the rear begins to move in a direction and make a slight correction. If the mirrors are to short you have to wait until the rear moves enough to clear the blind spot and then make larger corrections.