MS660 Clutch Styles

[mattr66]

I've have a few ms660s that I'm working on and I've noticed that there's two different styles of clutches even on factory Stihl parts. One looks to have more mass than the other. Does one design have an advantage over the other? I've attached pictures for reference. The "thicker" edge design looks like it would apply with more authority. Does one design allow for better starting with the chain in a bind?

 

[cscltd]

If you ask a Stihl engineer-yes big improvement
ask a logger-no difference
I’m sure there was some reason, but I don’t think it would be a noticeable difference to average person??

 

[mattr66]

If you ask a Stihl engineer-yes big improvement
ask a logger-no difference
I’m sure there was some reason, but I don’t think it would be a noticeable difference to average person??

So which one is better? I'm interested in max starting torque in a plunge cut where the chain may be in a slight bind on a cut restart.

 

[cscltd]

Need a faller from BC or west coast USA to chime in for that, if there is a difference,

 

[cookies]

Thicker/wider clutch shoes will apply more clamping force due to more surface area if the engine can maintain the rpms up in the cut

 

[huskihl]

Could weigh the shoes and test the springs. Heavier shoes will bite harder at lower rpm’s if the springs are the same