Sub-frame; fix or replace

[Beemeridian]

6789

[MikeCam]

The physics of collisions are governed by the laws of momentum; and the first law is known as the impulse-momentum change equation. The law can be expressed this way:

In a collision, an object experiences a force for a specific amount of time which results in a change in momentum. The result of the force acting for the given amount of time is that the object's mass either speeds up or slows down (or changes direction). The impulse experienced by the object equals the change in momentum of the object. In equation form, F • t = m • v.

Therefore,
 
In a collision, objects experience an impulse; the impulse causes and is equal to the change in momentum.
AND
In a collision, there is a force on both objects which causes an acceleration of both objects. The forces are equal in magnitude and opposite in direction, yet the least massive object receives the greatest acceleration.

Now I don't really know what any of that means but I think it says the bike got whacked by a 1 1/2 ton object and the damage is more than superficial!

[Ves]

This is the reason that insurance companies total motorcycle that seem very repairable, because they don't really know what else is wrong with it, it would cost too much money to find out (are you going to take it apart and look for microscopic cracks), and they don't want the liability of of saying it's fixed and then having something fly apart a month or year later.

Me... I'm a guy who bought a salvaged bike and put it back on the street. But mine didn't have any bent wheels or frame parts.

Still, if you're going to take the risk, I would buy a subrame instead of trying to straighten it.

Good Luck.

[Biff's R]

Here is a used one.

http://www.beemerboneyard.com/46512335858.html

[towerworker]

Gosh I wonder what poor dope that "catywompus" R belongs to?

Dave I was going to either call you or shoot an email this evening---just got back in from having dinner with Rosa.


The r in question now belongs to the insurance company and is being lovingly transported away tomorrow morning. The insurance company made me an offer I couldn't refuse this morning.

I am planning a trip to Minnetonka Mn.


Catywompus Towerworker

btw----I am walking with about the same amount of port-side list as the R

[Beemeridian]

56789

[towerworker]

I really had made plans to keep and repair the bike. Beemeridian graciously gave me a muffler and I was in process of locating the other needed parts.

The total loss claims adjuster called me back after he had given me the settlement numbers and advised me against keeping the bike. I had already told him the frame had a slight twist. He told me that his company would really need to re-examine the bike in light of the additional damage I reported to them. If the damage exceeds 75% of value then the title goes to "reconstructed". Then I have to go thru a tough process by the DMV to be able to re-title and tag it. By virtue of the fact that I am not a BMW mechanic and will do the work myself he said they will go thru the bike with a fine tooth comb and stand a good chance of not being able to put it back on the road. Then I will simply have a "parts bike".

On top of that the the settlement was more than I expected so that made the pain a bit easier to handle. My leg still hurts like hell but I got away very lightly all things considered.

Wayne

[Brownw3]

There is no such thing as a fixed bent subframe. If its been put under stress and moved from side to side "fixing" it will weaken it further.

I crashed my Rockster last year and the passenger footpeg mount was bent slightly. They replaced the subframe. Now, they might have just wanted the extra dough from Progressive, but I also trust their judgement with my life.

[Beemeridian]

5687

[R4R&R]

The physics of collisions are governed by the laws of momentum; and the first law is known as the impulse-momentum change equation. The law can be expressed this way:

In a collision, an object experiences a force for a specific amount of time which results in a change in momentum. The result of the force acting for the given amount of time is that the object's mass either speeds up or slows down (or changes direction). The impulse experienced by the object equals the change in momentum of the object. In equation form, F • t = m • v.

Therefore,
 
In a collision, objects experience an impulse; the impulse causes and is equal to the change in momentum.
AND
In a collision, there is a force on both objects which causes an acceleration of both objects. The forces are equal in magnitude and opposite in direction, yet the least massive object receives the greatest acceleration.

Now I don't really know what any of that means but I think it says the bike got whacked by a 1 1/2 ton object and the damage is more than superficial!

OK, you lost me at:

The physics of collisions are governed by the laws of momentum; and the first law is known as the impulse-momentum change equation.

[towerworker]

I just knew I should have gone ahead and finished my degree in "rocket science"!


Instead I pursued the study of the "female anatomy".

(much more fun)


Wayne

[Brownw3]

Beemeridian:
I look at my BMW tech just like I look at the parachute riggers we had in the army. I'm very selective about who I let touch my bike. Its always someone I trust working on something where a failure means pain. So, yep, you better trust the guy with your life. If not, I would look for a new tech.

[Beemeridian]

67

[Ves]

OK, you lost me at:

The physics of collisions are governed by the laws of momentum; and the first law is known as the impulse-momentum change equation.

[/quote]

Cause I'm bored and there's snow on my car outside...

It's kind of like this. Moving objects have energy. The energy is calculated by taking the Mass (weight) of the object and multiplying by the speed (Velocity) at which it's traveling... So, a 3000 lb car traveling at 10 mph has a lot more energy than a 500 lb bike traveling at the same speed.

Then there's conservation of energy, which says that in this collision all the energy that both vehicles have has to go somewhere. You can see this when playing pool. The cue ball hits your target ball. If the cue ball stops the target ball goes flying. Energy was transfered between the two and because the balls weigh the same, the target ball pretty much takes off at the same speed that the cue ball hit with. If the target ball was half the weight then it would go flying off at twice the speed of the cue ball. A collision between a car and a bike is like a really big cue ball hitting a really small target ball... the target ball is going to go flying...

In the collision energy can go to several places. If the car was braking before it hit you then some of that energy was absorbed by the brakes. Some of the energy went into creating the noise of the crash, some of it went into sending you and the bike flying, the rest of it went into bending of metal parts, cracking of plastic, etc...

The point is, all the energy of that moving car went somewhere. Obviously you can see some of the places that energy went; bending your frame, bending the metal on the car, etc.. The question is how much energy was absorbed by the braking of the car and how much by the bike, and how much damage was done that is not obvious... You just don't know.

... Time for Turkey yet?....

[towerworker]

This discussion is very interesting but a moot point. My bike is now sitting in a salvage yard somewhere most likely already disasembled and parts heading gracious knows where.

Kinda like loseing a close pet you've had for years.

Wayne