[A/S] Wheels - Bearings - Brakes - general topic - related thread - Tom lost wheel

[estatewagons@xxxxxxx]

Ben - it's hard to know what happened to Tom's trailer - until it's fully 
looked into.

Yes - we've heard about improperly torqued wheels before - and it certainly 
is one of the most logical "culprits" for Tom to look into.

However - I would not use the words "a locking brake hub will not cause the 
lug pins to shear off"...without knowing all the facts around a particular 
situation.  (and I am talking in general here - as Tom apparently did not 
lose his brake hub - just a wheel)

Chances are - particularly on a multi-axle trailer (where the axles share 
the load) that if a "brake system" locked up on "one" wheel - the first 
thing to go would be the tire...it would flat spot...and then shred 
itself....and if the trailer was not stopped right away...as so often 
happens - since on a multi-axle trailer the driver often does not know 
they've lost a tire - eventually it would be down on it's bare rim.

(we've heard more than one report of driver not knowing they're having a 
tire problem....and a passing driver has had to alert the trailer driver 
they've lost something)  

(on an Airstream - this probably says something about the quality of the 
overall design of the suspension etc.  You'd think the rig would 
immediately start fishtailing - but as I mentioned - the Airstream driver 
doesn't always know.  Terry Tyler told us about losing a wheel in Alligator 
Alley - and not knowing it right away - and if anyone is "at one" with 
their trailer towing combo - it's Terry)

So - it's probably the typical situation when a wheel and tire are "lost" 
(and nothing else) - that one of the big culprits to look at is poor lug 
maintenance - they eventually shear off - and the wheel then takes off.

However - here is why I would suggest it's best to not say to the public 
that a locked brake hub does not have the potential to shear lug pins.  Not 
all situations fit a "typical scenario".  If a bearing seizes up - it's not 
the same action as a brake suddenly being applied - like in a panic stop.  
The brake system tends to apply itself as designed - equally and forcefully.  
A wheel bearing that goes bad - first it's a wild card....and it's probably 
generating a lot of heat - and then who knows what the "shock" force could 
be when it seizes - it could be totally "unequal" in the way it suddenly 
applies it's force to the rest of the axle.  If the bearing also starts to 
destroy itself - then the hub assembly may go through a process where it's 
not in it's designed alignment with the axle and pavement and who knows 
what forces are placed on the rest of the axle and rim.  Finally - if a 
bearing really implodes - there is a chance that the whole hub - including 
the wheel and tire - could simply shear off and go flying.

What if the lugs were not torqued right - but had not yet become a major 
problem - and then...a bearing seized up....and in the resulting 
shock...the loose lugs sheared off?

Obviously this did not happen in Tom's case - fortunately - but for the 
sake of looking at wheels and bearings and brakes and hubs in general - it 
might be best to keep a wide approach to the possibilities - rather than 
say "never"...as that is just when Murphy's Law pays a visit

Best Wishes.  RL