Side mirror length considerations

[Blue~Go]

I started to de-rail another one of deppsteins threads, but thought the better of it so decided to start a new thread related to side mirror length vs. visibility. Both real-world observations and US laws (sub-link to Canadian ones). This might be something to consider if changing side mirrors.

In general, the longer the mirror, the better you can see behind you (straight behind you, or to some extent behind you but over a lane). What I mean is, if you take the same width vehicle, and you put a longer mirror on, then you could see a car say, X distance behind you. If you put a shorter mirror on, that distance will go to 2X (rough concept, obviously depends on exact lengths/widths).

My buddy used to have an E-450 based Class C. This was one of the "traditional" large box shaped ones. Much wider than our Chinooks. Interestingly, the builder had put on the same length (ie projection) Velvac mirrors as on our 21' Chinooks. I had noticed him cutting people off when we were caravanning. Or he would contact me on our FRS radios to say "Where are you?" when I was right behind him (but not all that close). I couldn't believe he could't see me, which is when I noticed the relatively short-stalked Velvacs for his width (112" IIRC; we are ~90" in our 21-ers).

So we did an experiment.

I had him stand in the center of "my lane" behind my Chinook and then move forward toward my rear bumper until he disappeared (in my side mirror view). We then measured the distance between my rear bumper and him (IOW how far behind me he was when he got so close he disappeared).

Then I stood in the center of "his lane" behind his wider RV (with the same projection Velvac mirror as our Chinooks, so effectively a shorter mirror arm). I moved forward until I dissapeared from his vision. We measured that distance.

Result was that I was much MUCH farther behind him when I "disappeared" than he was behind me in the same scenario. No wonder he was cutting people off - and couldn't see me behind him. He then ordered the next longer horizontal projection stalk size of Velvacs (so it would be the same proportion to width as the ones that came on our Chinooks), installed them, and then his "disappearing" distance shortened to the same as mine on my Chinook. He was a happy camper (and so were the rest of us on the highway with him).

Obviously though there is a limit. If I drove with mirrors on 6' stalks no-one would ever disappear..... but my Chinook would be 19' wide

I like the Velvacs that were put on the Chinook because they give me a relatively short "disappear" distance and also I know if I can get my mirrors through then I'm not going to scratch the Chinook body. They fold in if I need to get into a narrow garage, or pass a tree on a trail. To each their own, but I just wanted to mention why Chinook chose the longer ones (which I'm sure weren't cheaper). Perhaps they used the longer ones to comply with Washington law.

While typing this, I got curious about whether there were any laws about this. An extreme case would be when you see someone towing a wide trailer with skinny little car mirrors on a sedan. It's obvious they can't see a thing .

So here (below) is a link to all the USA rules by state (within that there is a link to Canada's laws). I only skimmed but I see a lot of them say you must be able to see 200' For example, here is Arizona's law:

A motor vehicle that is constructed or loaded in a manner that obstructs the driver's view to the rear of the vehicle from the driver's position shall be equipped with two mirrors located in a manner to reflect to the driver a view of the highway for a distance of at least two hundred feet to the rear of the vehicle.

I don't really understand what they mean by "at least" 200' Because obviously it's easier to see farther back, and more difficult to see what's closer behind you (requires wider mirrors). I feel like I must be missing something about the language and it must mean that while you aren't required to be able to see something 199' behind you, you must be able to see something 200' behind you (and then obviously anything further than that would also be visible).

But then I never understood "moving back" a date to mean shifting it further into the future, which seems to be the way everyone else means it. So likely it's just me

https://ecomodder.com/wiki/Mirror_Laws_by_State_(U.S.)

BG

PS: Why not air a pet peeve? My buddy-of-the-ever-changing-vehicles bought a new F-150. Full tow package, largest possible mirrors (huge, power fold, telescoping, the works). Well guess what? They only allow you to see down the length of an 8' wide trailer. Towing one of the common, legal, 8.5" travel trailers? Sorry, no visibility for you! I found lots of people lamenting this (when I went searching for a solution). Seems that Chevy does the same (or did at least in 2018). Looked like Dodge had longer mirrors. To make it more annoying, he then bought a new F-250 the next year. Now this is truly meant to be a towing machine. All kinds of special trailer options, you can tow a house, etc. Ford really sells this a the ultimate towing vehicle (price to match). But guess what? The mirrors still only allow you to see anything if you are towing a trailer 8' wide or narrower Glad I have my Velvacs (though the telescoping was niiiiiice, if only it had telescoped far enough).

[deppstein]

Blue! You ol Dog!...I never would have thought about this on my own!
Good thing I haven't gotten rid of the old 96" mirrors yet. After reading this new post, I will definitely be going out to do some stationary and real road testing (carefully) to see what my visibility parameters are with the new mirrors. I promise to be super careful, and will report out my findings/opinions. Thanks for bringing this to my (our?) attention--very helpful.
David

[Blue~Go]

At least I started a new thread

Seriously though, thanks for being open to checking this out -- even though you have already installed the new ones. It would have been so easy for you to poo-poo the whole idea.

Be interesting to see what you find. If you want me to check the "disappear" distance with the stock mirrors for comparison I'd be happy to.

[deppstein]

Yea, will be interesting to see what I think. I’ll go out for a run on The 95 for an hour or so to see how it goes. I measured across the stern outside tail light to outside tail light and dang if I didn’t come up with 86”! I swear, no funny business with the tape . So it’s right on the cusp of what Valvek recommends.
And, yes, just for added fun, let’s compare the “disappear line when standing in middle behind the Rig. No rush.

[chin_k]

For the disappearing distance, you can see where you can't see the side mirror. If you can't see the side mirror, the driver can't see you on it. At least that is what the sign on some tractor trailer warning people about blind spot.

I wish the side mirror have the length adjustment. It can be easily engineered, and should not cost more than $50 in cost, and I don't mind paying $100 more for the feature. But I guess people rarely need to adjust that, so may be there is no market for that.

[BobW9]

I can't believe you guys sucked me in to this, I really had no interest, but then curiosity took over. I found a link or two that talks about a truck having a blind spot of at least 30 feet and a maximum of 200 feet, so I think that 200 is indeed what is meant by Blue's link on state laws. Whoever wrote that has poor English communication skills, that's for sure. I wonder if they got someone from the people that created those standardized tests we used to take in school?

Below is a link for RV's, which I found interesting. There are a few states where you can have a side mirror stick out too far, though for most states it seems like a side mirror is given an exception for safety reasons. PA states 'Permits mirrors and sunshades to extend up to 6" on each side of vehicle', which I guess means if we drive through there in a Concourse with the standard mirrors, we'd need to pull them in a bit to be legal (where I have mine now is just about that 6", with them bent back so only the mirror itself sticks out).

I'd also always wondered about the width of the Concourse at 7'7" vs the Glacier and others at 8'6". From looking at this RVIA info, it appears the others at 8'6" (102") aren't allowed to be driving on roads less than 12' wide in 8 states, including Maryland where I am. For me, that means quite a few areas of city and suburban development are okay in the Concourse but not in the larger models (because many roads have been re-drawn narrower, to add an extra lane during rush hour, or a bike lane).

https://www.rvia.org/system/files/media ... 0Width.pdf

[Blue~Go]

I can't believe you guys sucked me in to this, I really had no interest, but then curiosity took over.

We've done our job then

Whoever wrote that has poor English communication skills, that's for sure. I wonder if they got someone from the people that created those standardized tests we used to take in school?

I feel better now. It was reasonably obvious what they must have meant, but the way it was stated.... Maybe they all copied each other because that is in the text of many states' rules.

PA states 'Permits mirrors and sunshades to extend up to 6" on each side of vehicle', which I guess means if we drive through there in a Concourse with the standard mirrors, we'd need to pull them in a bit to be legal

I'm going to guess that applies to fixed mirrors, vs. the "breakaway" type we have? I couldn't even begin to have a legal field of view with 6" mirrors. But there is certainly a difference in a rigid mirror vs. something like our Velvacs that just "break" away. (Then too, the Velvacs look like they stick out a mile, but that's because they are mounted on the narrow cab, not the Chinook body.)

Interesting about the width restrictions. Bet those don't get called out much.

chin_k: Good point about just being able to see when the mirror disappears. That also would "equalize" the fact that if we all tried it and reported back, there would be a (slight) variance depending on where one puts one's seat (fore and aft). Of course too, a car is wider than a person. Anyway, when my buddy and I did the test, it was like he was fairly close to my Chinook when he "disappeared." When I did the test on his RV, I had to go practically over the hill and through the woods before he could see me. We could barely shout to each other. It was a really noticeable difference.

[BobW9]

I'm going to guess that applies to fixed mirrors, vs. the "breakaway" type we have? I couldn't even begin to have a legal field of view with 6" mirrors. But there is certainly a difference in a rigid mirror vs. something like our Velvacs that just "break" away. (Then too, the Velvacs look like they stick out a mile, but that's because they are mounted on the narrow cab, not the Chinook body.)

Ah, breakaway, makes sense.

Years ago I went through Heathrow in London and was changing terminals in a shuttle bus. He was flying along, just about as wide as the lane, when another shuttle came the other way... their mirrors were on flexible stalks, something like ours, but the impact on both mirrors was so fast and hard that the mirrors shattered before the stalks were pushed back. Every time I'm in a tight situation in the Concourse I seem to remember that impact and flinch a little. I think that's probably why since I bought it I've always had the mirrors pulled in some.

[deppstein]

OK then! We got BobW9 to bite...with fewer casts that what I imagine 68Camero has to lay out when he is out there trying to snag some poor trout in the middle of winter But like 68Camero, we are catch-and-release guys...so BobW9, we'll totally understand if you decide to wriggle off of this hook.

As a result of the recent spate of posts, I went out again and did some more reconnoitering and measuring. Here is what I found:

The outer edge of the new Velvack 86 inch mirrors I installed project 14 1/2 inches from the driver's window...that is 6.5 inches further out than the widest part of the Chinook body...so, mirrors still act as "cat whiskers" to let us know whether or not we are able to clear an opening.

I took measurements across the back of the Rig in 2 places:
--Tail light to tail light--This time I got 88 inches, being more conservative
--Width of rear higher up where side of Rig tapers slightly--86.5 inches (Note: This is about same level as mirror head)
Either one puts us quite a bit beyond the 77 inches listed as the width dimension in Chinook literature (I'm guessing here that 77 is the interior width???)...but also a couple of inches beyond the Velvac 86" for the 86" mirror recommendation, and at least 8 inches shorter than the Velvac 96" mirror recommendation.

Then I went behind the Rig and did my best to measure the distance where the mirror disappeared from my view (lots of variables here...being in middle of back, vs. to side where I tried to estimate where side of a car might be...not to mention my trying to lay tape straight in rocky driveway). For this back-blind distance I came up with 38-35 feet respectively.

Next step for me will be to do a field test by taking the Rig through town and up The 95 for a run tomorrow or Sunday to see how I feel about these new mirrors in the real world.

Much as I don't want to prejudice my test with an opinion, I must admit that I can feel one creeping into my head...I think these new mirrors are going to give me good vision along the side of the Rig, and for side lanes on either side (most critical for me when switching lanes on the Interstates); and feel a whole lot more relaxing as I cruise by parked cars and bikers doing their thing in bike lanes adjacent to the roadway. Not sure how I'll feel about 35-38 feet of blind space directly in back...but since I don't know what I had before, I'll just have to see how it feels. In past, I have used the back door window as a gauge for this to some extent, so will see how that feels relative to what I had before.

...all of you still hooked on the topic, stay tuned!
David

[Blue~Go]

I took measurements across the back of the Rig in 2 places:
--Tail light to tail light--This time I got 88 inches, being more conservative
--Width of rear higher up where side of Rig tapers slightly--86.5 inches (Note: This is about same level as mirror head)
Either one puts us quite a bit beyond the 77 inches listed as the width dimension in Chinook literature (I'm guessing here that 77 is the interior width???)

The 1998 manual lists the 21' Chinook as being 7'7" wide (or 91"). When the width of vehicles like this is stated, it normally does not include the mirrors but only the fixed body.