Does anyone know what double syncros are? Are they good?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Jwbetley &raquo;</TD></TR><TR><TD CLASS="quote">Does anyone know what double syncros are? Are they good?</TD></TR></TABLE>

Nice Napoleon Dynamite avatar BTW. Just saw that movie last week, hilarious

So to your question:

The purpose of a synchronizer in the manual transmission is to accelerate the inputshaft/clutch disc up or down to the speed of the next gear. This must happen quickly and smoothly, so the trans needs some sort of a "clutch" to do this. The synchro is essentially a cone-shaped clutch.

As you select the next gear, the resistance you feel is primarily due to the synchro as is accelerates the rotating mass of the inputshaft and disc. To change the rotating speed of anything requires torque - and obviously the quicker the gear change and/or the larger the acceleration needed (eg going from 4th to 2nd instead of 3rd) the more torque required. The effort to change the gear is roughly proportional to the torque required.

So, in an effort to reduce shift effort, you must either 1) reduce the torque by reducing the rotating mass of the disc, and/or 2) add synchronizer cones to reduce the total work done by each cone. Since #1 is difficult to do, typically transmissions employ 2 or even 3-cone synchros on some of the gears.

 

thanks for clearing that up for me