even though the idea of a downgrade is a bit silly I like it
You definetely won`t get a handling or brake performance improvement by doing this.The rear 16" wheel will only fit if it is from a 750 Sport not if it is from a 750 or 906 Paso. The rims are identical but the rear axles aren`t (17mm Sport/ 20mm Paso) so the bearing spacers in the rim and also in the sprocket carrier are not the same.
As Phil said you`ll need the rear brake assembly too as the SS has a 245mm disc and the S a 270mm.
Calipers are not interchangeable due to different mounting hole distances.
Tires are not a problem and a wide one would also fit in the Sport swingarm.
Even if no spacers are needed to center the rear wheel my guess is the chain could be out of line as the front sprockets are not the same and the engine case neither due to a 5 speed gearbox in the S vs a 6 speed in the SS.
The front wheel would require new spacers and another problem you`ll run into is the speedometer drive. The wheel bearings and bearing spacers would be ok if the SS front axle is 17mm. The mounting points for the calipers on the SS are for 320mm discs while the S uses 280mm so this won`t work and there are no 320mm discs that fit the 16" rims unless you have some made. (I always wondered if one could make an adapter ring and use i.e. the ones of a Multistrada)
G.
