How many pounds of force would be required to pull a Chevy Trailblazer side mirror off?


#1

So, this may be a question for a mathematician but I’m curious if it is possible to find the answer to this. I was riding my bicycle down a 35 mph road when I was struck on the forearm and elbow which destroyed the drivers side mirror. Any way to determine speed from this? They also took about 75 - 100 feet to stop. Any information helps, or referrals! Thank you


#2

The only way to find out is to subject an identical mirror to a lab test. In college we did many such experiments to determine the “breaking strength” of metal rods, concrete cylinders, etc.

The manufacturer certainly won’t tell you even if they had subjected their mirror to a breakage test.


#3

If you want the info for litigation that would be something for your lawyer to do. If you have medical bills the drivers insurance should be involved. As for breakage there are so many factors involved it might be impossible to have an actual answer.


#4

How bad is the damage? Not too bad I hope.
Volvo’s right about the physics, but there may also be legal issues involved. In many areas, I suspect most, drivers MUST leave room for cyclists. You may want to check this out for your riding area. Having hit you with his/her mirror may subject him/her to liability and possibly citation ramifications beyond the damage to you. I hope you called 911 to get a police report.

Being a former hard-core rider, I’ve been “tested” on occasion by a driver who though I had no business on his/her road by unnecessarily coming as close to me as possible. If this is what happened to you, there SHOULD be legal ramifications.

I’ll have to admit that I’ve also ridden on “club” rides with riders that think they can spread out four-abreast across a narrow road and piss off the drivers. They think lycra gives them special status. I hope you don’t do this.


#5

Well sympathy but the information seems irrelevant. If you were injured, you’ll just need to deal with your/their insurance coverage for compensation. If you are trying to prove the guy was speeding, that is simply not your business and a matter for the police. I can understand being angry but why make it worse than it is?


#6

^I would think the driver is at fault for violating your ROW and hitting you, regardless of if he was speeding or not.


#7

Above posts are correct. And It’s not force that you want, it’s a combination of torque and impulse. Since the mirror sticks out and when breaking off, pivots around the mounting point, then it’s torque that causes it to bend and break. And that occurs over a short time interval, which brings in the impulse part. Very difficult to quantify, as a larger force/torque over a shorter interval will do as much damage as a smaller force/torque over a longer interval.

A hammer blow is an example of impulse.

Hope you’re OK.


#8

I’m a bit curious as to how the driver side mirror hit you. What was the orientation of both bike and car?

As to the stopping distance that’s going to be impossible to sort out due to variables. If the car driver has quick reflexes and stops quickly (while using the higher 100 feet number) I’d guess they were doing about 50 MPH.
That’s a wild guess based on reading a lot of 60 to 0 stopping distances in various periodicals.


#9

@ok4450 I missed the part about drivers side mirror. That brings a lot of questions up.


#10

@ok4450 , @“VOLVO V70” It was the passenger side mirror. I never said the drivers side mirror. Oh I see, I meant it was the driver’s (possessive) side mirror. Passenger side mirror. Sorry about that.

I was following the white line on the RIGHT side of the road. The driver tried to tell the officer I was moving to the oncoming lane. Which I was not. The oncoming lane is a hill. I would FOR SURE get clobbered had I done that. No one can see you if they’re coming over the hill.

I’m just consulting you guys for piece of mind I suppose. I have a lawyer.


#11

They’re plastic . .doesn’t take much to break one.
AND
Don’t try to calculate stopping distance either.
I’ll guarantee you the driver did not instantaneously slam on the brakes. It took a bit for them to wonder . .
: first '‘what just happened ?’'
and then to realize that they should probably stop and investigate.


#12

Your lawyer will have access in necessary to consultants that can do the math.
But I doubt of that’ll be necessary. He hit you. The important parts are damages and your local tort laws.

It’s almost not possible to hit a cyclist with a trailblazer and not be totally on the hook for damages plus pain and suffering… in addition to being cited and/or fined. You’re holding all the aces.


#13

My 03 trailblazer has breakaway mirrors, maybe it is an option. What was the situation with the mirror? Broken off, Broken glass?


#14

So, . . if the mirrors fuctioned as designed ( breakaway ) that still leaves TSM’s comment about fault.
Was he too far right ? were you too far left ? or some of each ?


#15

How many pounds of force would be required to pull a Chevy Trailblazer side mirror off?
cmac47
7:31AM edited 7:33AM in General Discussion
So, this may be a question for a mathematician but I’m curious if it is possible to find the answer to this. I was riding my bicycle down a 35 mph road when I was struck on the forearm and elbow which destroyed the drivers side mirror. Any way to determine speed from this? They also took about 75 - 100 feet to stop. Any information helps, or referrals! Thank you

I appreciate OP clarifying drivers, driver, and driver’s side. As far as the original question of force and determination of speed the answer is “not possible”. I did some brief research and found Chevrolet Trailblazer stock side view mirrors fold back. How could one be “pulled off” in this accident? OP’s court case will be determined by the police report, eye witnesses (who usually disappear quicker than cockroaches when the light comes on) and the Judge or jury if it comes to that. ken green addressed my problem with stopping distance.


#16

I have no doubt the driver is responsible, can’t go clipping cyclists with your mirror, leave plenty of room if possible. Just cutious about more details of the mirror, one person I know had a guy who was mad at her and slammed the breakaway mirror mirror into the car with his hand and cracked the mirror.


#17

hmmm … I’m not saying this is a good idea … but if I wanted to figure it out and calling the car manufacturer and asking didn’t offer up the number – which I doubt it would – then I’d go to junkyard and bring along with me a really strong spring, attach the spring to the mirror and pull on it using a come along. I’d measure how much the spring expanded before the mirror broke off. By calibrating the spring expansion vs a known force (like a 100 lb weight) I’d know how many pounds of force that was.

Then you’d have to figure out how much force you’d exert with your shoulder against the mirror. There’s be more force with higher speeds. In theory this could be cyphered using physics-book formulas, but in practice I think you’d have to do it experimentally, since it would depend on how much “give” your shoulder joint has. The more “give” the more speed would be required to generate a given force.


#18

Well, this is what the OP said: “I was following the white line on the RIGHT side of the road.”

The white line on the right is commonly called the fog line, which means the OP was not on the shoulder but at least partially in the traffic lane. I don’t understand the “moving to the on-coming lane” part, but I don’t think its a foregone conclusion that the driver was at fault. I’ve seen many bike riders in the traffic lane and sometimes two abreast, and can be very confusing on the safest way to go around them.


#19

Many of the roads I used to ride didn’t have a shoulder. The pavement ended at the white line.
Let’s stop challenging the OP’s honesty. I see absolutely nothing in his posts that suggests he’s not being honest.


#20

@Bing: Regardless, the driver overtaking a slower-moving vehicle has to yield to the slower moving vehicle and proceed only when able to do so safely…be that “slow moving vehicle” farm machinery, an Amish buggy, or a bicycle. The bicyclist has ROW, and does not have to utilize a sidewalk, paved shoulder or any other* non-road surface, though they may elect to do so. I don’t see any way that an “unsafe passing” maneuver can be the fault of the vehicle being passed!

*(In some states, a bicycle MUST utilize a bicycle lane, if one is established on that roadway, “when practicable.” The quoted bit is open to debate; I’d argue that a bike lane in the “door zone” of parked cars is not “practicable” by definition, or if you have an upcoming left turn, as bike lanes are typically on the far right edge of the roadway.)