Re: 2nd gear synchros

["dion fields" <noid@domain.elided>]

>I'd like to know why the second gear synchro is so prone 
>to early retirement. If you look at the tranny internals, there 
>is no diference between the second gear assembly and 
>any of the others, one through five. So owing to the 
>collective understanding of this shifter-shortcoming, has 
>anyone ever suggested a cure? Titanium synchro rings? 
>Radical gear lightening? What is the present thinking?

>>Second is used MORE than the others, so it gets more wear.

>>>Second gear also gets the most abuse because it's a 
>>>straight movement of the shifter from first, and is most 
>>>used for during quick acceleration.  Think about how fast 
>>>you want to usually get from first to second, and compare 
>>>that to your shift from third to fourth.  Second to third, and 
>>>fourth to fifth are naturally slower shifts because of the 
>>>dogleg in the shift pattern.

i believe there is more to it than this.

all the gears in the transmission are always meshed and
spinning.  the synchro mechanisms lock one gear ratio at
a time to the output shaft using a centifugal clutch mechanism
and interlocking teeth.  these dog ring teeth are what you hear
grinding when you blow a shift in a synchromesh transmission,
not the actual gears themselves.  all the synchros are the same,
but the gear ratios are different, thus spinning at different 
speeds and have different torque multiplication?  it is for this
reason i believe that the lower the gear the synchro is on, the 
harder it has to work.  (someone please correct me if i am
wrong in any of this.)

as previously mentioned by others, lightening the gears lowers
the rotating inertia and makes the synchro's job easier
at matching gear/shaft speeds.  it would be nice if stronger
clutch rings and tougher dog ring teeth were available as
well.

ps. it is a beautiful art to master the technique of smooth
       double clutching even if you dont have to.  it has great
       personal satisfaction and impresses passengers.
       every car i have owned except the new automatic
       minivan *ack* has had weak 2nd gear syncros.  even
       my friend's NSX has 2nd and 3rd synchro problems,
       but he doesn't double clutch or heel-toe.

--dion fields
--EDGE disegno industriale
--73 gtv



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