[V8] Goodyear Tires

Wed Oct 26 20:36:03 EDT 2005

Thanks for all the information guys as I said before I know nothing 
really about tires I was beat silly with a stupid bat when it came to 
that kinda stuff. When it comes to computers thats what I know heh.

Well thanks for the help I replacing my tires on monday as well as a few 
other things.

Buchholz, Steven wrote:

>... I was thinking that I should not have sent that earlier message ...
>oh well ... guess that's what happens when I'm in a hurry ... 
>
>I was pretty clear that I was talking about a 5kQ ... by definition that
>means the car had a manually lockable open center diff.  No question,
>with that car you could never lock the center diff ... but given that
>you did not, the car ran just fine for a very long time ... after all,
>what is a differential for?  I was just quoting that as an example of an
>extreme situation.  
>
>I guess what I was trying to get across is that I don't think its right
>to come in with an unsubstantiated "understanding ... difference causes
>stress on the drivetrain" either.  The AWD system has to be designed to
>deal with a certain amount of difference in the diameters of the tires
>at the corners ... so as long as you did a careful analysis of the
>difference in the diameters of the wheels it might very well be possible
>to have different profile tires on the same car and not risk damaging
>the drivetrain.  Would I recommend doing it?  No, I've always used and
>recommended having all four wheels be the same size with the same
>profile tires ... to minimize the risk of dynamic (handling) issues.
>The justification would have very little to do with risking the drive
>train.  I have toyed with the idea of having different profile tires on
>front and rear to change the handling characteristics, but never had
>time to follow through.  
>
>>From reading some of these responses I sense that some folks are not
>100% clear on how Torsen differentials work ... Torsens are *not*
>locking differentials ... they will and do allow differentiation.  Due
>to the way they are designed, a Torsen diff will tend to pass more
>torque to the output shaft that is turning more slowly.  I know that
>I've heard of cars with Torsen center diffs having them be damaged from
>towing long distances with one axle or the other stationary while the
>other is turning ... I've wondered if the risk of damage is as much due
>to the fact that the Torsen is working "backward" in those situations
>... one output shaft is spinning while the other is stopped.  In any
>case, remember that most V8s don't have center Torsens.
>
>Steve B
>San Jose, CA (USA)
>  
>
>>I don't see how that could have lived very long at all.
>>What kind of center diff did it have?
>>If it was a torsen, it would have been trying to lock all the time
>>    
>>
>wouldn't
>  
>
>>it?
>>If you had a electronic lockup, and it NEVER locked, it might work for
>>    
>>
>a while
>  
>
>>but I again would have guessed that the center diff eat itself up
>>    
>>
>quickly.
>  
>
>>The stresses on CV joints and the whole drivetrain would be
>>    
>>
>tremendous.
>  
>
>>With the center diff locked, the drivetrain would have to explode in
>>    
>>
>short
>  
>
>>order. There has to be somewhere for all that stress to go.
>>My experiences with more traditional 4WD trucks and Jeeps says that
>>    
>>
>the
>  
>
>>drivetrain binds up quick if there is any difference at all from front
>>    
>>
>to
>  
>
>>back.
>>
>>Dave
>>
>>
>>Quoting "Buchholz, Steven" <Steven.Buchholz at kla-tencor.com>:
>>
>>    
>>
>>>.. do you have any data that demonstrates what sort of increased
>>>      
>>>
>stress
>  
>
>>>is created on a drivetrain that has tires of different diameter?
>>>      
>>>
>I'm
>  
>
>>>sorry, but it does bother me to see this sort of statement without
>>>      
>>>
>any
>  
>
>>>data to substantiate it.
>>>
>>>Here is my data point ... I owned a 1987 5000 TQ which had the
>>>      
>>>
>proper
>  
>
>>>rear diff but the transmission from a non-turbo ... i.e. a final
>>>      
>>>
>drive
>  
>
>>>ratio of 4.11:1 in front and 3.89:1 in back.  I don't know how long
>>>      
>>>
>it
>  
>
>>>was in that configuration, but I do not expect that even this
>>>      
>>>
>magnitude
>  
>
>>>of a transgression did anything to the overall longevity of the
>>>drivetrain ...
>>>
>>>The only things that I can think of to bear in mind ... the ABS
>>>      
>>>
>system
>  
>
>>>does tend to expect all four wheels rotating at the same speed ...
>>>      
>>>
>I'd
>  
>
>>>imagine that on the V8 the transmission controller might want to
>>>      
>>>
>lock
>  
>
>>>the center diff on an automatic when enough variation is seen ...
>>>      
>>>
>that
>  
>
>>>and the Torsen diff will tend to shift power away from the larger
>>>diameter wheel.
>>>
>>>Steve B
>>>San Jose, CA (USA)
>>>      
>>>
>>>>My understanding is that tires need to have the same circumference
>>>>        
>>>>
>in
>  
>
>>>4
>>>      
>>>
>>>>wheel drive applications.  Changing circumference changes the
>>>>        
>>>>
>final
>  
>
>>>drive
>>>      
>>>
>>>>gear ratio. Tires should be *very* close to avoid strain on the
>>>>        
>>>>
>>>drivetrain.
>>>      
>>>
>
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