Extra timing roller on 944S/S2, 968

[argiopeweb]

944-105-241-02-M40, an extra timing roller which mounts on the spring tensioner, is specified for the 944S/S2 and 968, but not the 924S or 944 (despite the fact that my 924S's spring tensioner is capable of mounting it).

Does anyone know what's up with this extra roller?

[v2rocket_aka944]

2 cams maybe put more strain on the belt, causing it to orbit off the timing gear?
ive worked on a few 16v cars that didn't have it for a while but i always put them back on.

if it was there from factory it probably had a reason on those cars.

[argiopeweb]

While searching a picture of the 2 cams (I've never seen a 16v engine in person), I noticed you've had this conversation before on Rennlist...