tiger woods crash news...may be more than meets the eye....

[JimL]

I was reading the news where the SRS ECU (airbag center sensor, which stores data in a crash where airbag deploys) showed 85+ mph.  I am sure all the news will jump on that number and crank out the theories.

The problem I see, is similar to a case I was involved with involving a V8 Tundra.  The crash data showed a vehicle speed of 150 mph when the young driver fatally impacted a tree, after going off the road, through some rocks etc...before the impact event.

In those days, one of my jobs was to dig into crashed vehicles and pull the data for court or engineers to look at.  I told them that the 150 mph could not be real, even if the rear wheels were both off the ground.  The speed limiter in the ECM is set for the production tire speed rating....nowhere near 150 mph.

I went to the crash site (there was still some debris around) and found part of the left rear wheel at a large rock.  The wheel had crushed and broken up on that impact (about 50 yards before the tree was hit).  At that point I knew the truck speed was about 75 mph when it left the road.  When the left rear wheel crushed, it stopped the left side axle rotation, which spun the right rear wheel up to double speed.  The ECU records the highest individual wheel speed, via the ABS computer output (sent to the engine ECM).  Everything on the road with ABS, for many years, runs the speedo and ECM speeds from ABS output data.

Anyway, that's how it is with a differential.

Tiger Woods crash could have been a "dopey/sleepy" drift into the left side retainer, foot gets on the gas pedal instead of brake, right front wheel is unloaded during impact...while the left front wheel/hub is crushed.  At 42-44 mph vehicle speed, the SRS ECU will store that right front wheel spinning up to 85 mph range.

I have driven that road he crashed on, down through the years.  45 mph is fast enough in those turns to need your attention.

Of course, we will never know....but it is interesting to see how the black box data could be wrong.  Obviously....it has happened before, as I learned from experience.

Just thought you folks would find it interesting that actual mechanics are seldom asked what really happens with a car.  Most people would rather listen to a talking head on some news network....sometimes even the judges!  In that case I worked on, the judge turned to the attorney representing the plaintiff (in the lawsuit) and said, "Can you prove this information wrong?"  The guy said, "No, I can't."  Case was dismissed, and my hands didn't stop shaking until I got out of there.

I do think this is food for thought about running open diffs at high speed and getting in trouble with a spin or whatever.  The gyroscopic precession of suddenly spinning one wheel up to double speed could be pretty bizarre, and throw some strange twists and turns into the vehicle attitudes. 

You can find really good formulas to calculate the forces in Canadian Maritime Pilots manuals and exam requirements.  It all explains clearly why side winds slow down our motorcycles more than a head wind does.  Another one of those strange things I learned from experience.

[manta22]

Interesting...I had not thought about that.

[Stan Back]

Great to hear from JimL.  We'd all be better off if he posted more often.

[donpearsall]

Side winds slow down motorcycles more than headwinds? Can you expound on that?

I know when I ride with side winds I have to countersteer (lean into the wind). Does that cause more drag than a head wind?
Very interesting.

Don

[JimL]

Don, when we have to lean the bike and counter-steer it applies a twisting force into the front tire contact patch.  Gyroscopic precession is trying to turn the front wheel into the lean.  The pressure we apply to the handlebars is actually force applied against the ground, in lb-ft. (and that is some pretty strong drag).

The harder you are pushing on the windward handlebar, the greater the drag loss against the surface.  My last APS-PF 650 record in 2013 had a first run in the high 140s due to very strong sidewind (bad enough I had to downshift to 4th gear in the middle of the 2nd mile).  The next morning was a very small headwind and the bike ran almost 164 mph.  I didn't change anything on the bike after that poor first run.

The smaller the engine (and lower torque), the greater the noticed effect.  Just imagine riding a small bike with 12 lb-ft torque while the engine is turning 5252 RPM, while you are pushing on the windward end of a 1 foot long handlebar....with a 12 lb push.

You have no available power left to accelerate that 12 horsepower bike.

This is one of the reasons I ran my bikes with no flywheel.  ANYTHING that you spin fast, and lean, is going to exhibit gyroscopic precession and try to turn the spinning component into the lean...and that adds up to lost horsepower during that run.  A big flywheel, spinning fast and leaning, is trying to twist the entire motorcycle in the direction of the lean.

Strangest planet I've ever lived on.  Everywhere I go, signs on the floor say "stand here 6 feet" and here I was.... born with only 2 feet and no place to stand.

[desotoman]

"I was reading the news where the SRS ECU (airbag center sensor, which stores data in a crash where airbag deploys) showed 85+ mph.  I am sure all the news will jump on that number and crank out the theories.

"Most people would rather listen to a talking head on some news network...."

JimL, Thanks for the post, very informative.

The sad part of our society now is that most people believe what the media is telling them. When in fact it could be the persons opinion or not fact checked.

Thanks again for the post,

Tom G.

[floydjer]

Interesting read.

[PorkPie]

MEDIA....


the only interest the media got....is, to make money.....

...if the story is true or fake....

...doesn't matter....

....important is....that the check shows up in the letter box.....

....today sad reality.....

[JimL]

I noticed the pics are out of the car being picked up.  Left front wheel is driven back into wheel well and obviously jammed.

How can you crash at 85 mph and not even break a window?  In fact, it looks like the doors will still work.

I've had to look at a number of high speed crashes, back in the day, and this is either the strongest car ever sold....or ?

As I said...we will never actually know.  My guess is just based on past experience....and  as they say "your mileage may vary".

Ain't it fun to speculate?!  Keeps us old folks entertained.

[noboD]

I think all of this information and maybe more has to do with why they are not charging him with anything.

[Stan Back]

A very complete story of the report in the LA Times had the sheriff stating, among other things, that they were not able to issue a speeding ticket to someone if an officer had not witnessed it.

[Beef Stew]

From today's (April. 11, 2021) Los Angeles Times. "Tiger Woods was driving at nearly twice the posted speed limit of 45 mph before he hit a sharp curve and crashed on the Palos Verdes Peninsula in February, the Los Angeles County sheriff said."

Get ready for the lawsuits.

[floydjer]

Interesting side note...Mack AC Bulldog trucks w/chain drive had a feature    wherein you could remove the left side floating axle and install a pin into the dif. case that held the side gear stationary. Instant 2:1 overdrive for high speed dead- heading.