Thanks for purchasing the ASpecial Parts adjustable swingarm pivot height rearset brackets for Aprilia RS 660!
These brackets are 100% compatible with Aprilia accessory and Spider aftermarket rearsets and fit any model/year RS and Tuono 660 models, including “Trofeo” bikes.
The RS660’s swingarm pivoting axle passes through the engine case, where adjustment inserts are placed from the factory on both sides.
Parts List
- A “+/- 2.75mm” small inserts
- B LH and RH spacers
- C “0mm” big and small inserts
- D Fixing screws
Technical Concept
This kit replaces the standard brackets and allows adjustment of the swingarm pivot height, thus modifying the bike’s “chain pull” and anti-squat characteristics.
Because the rearset brackets are fixed to the swingarm spindle, they must move with the spindle. The unique design of the Gabro Racing brackets accommodates this via smaller adjustable inserts at the engine mounting points.
Adjustment Positions
The swingarm pivot height can be set to 3 different positions:
- Stock Position (-2.75mm): Use the “A” small inserts oriented downwards.
- Reversed Position (+2.75mm): Use the “A” small inserts oriented upwards.
- “Zero” Position (0mm): Use the “C” big and small inserts (drilled in the middle).
Chain Slack Procedure (CRITICAL)
After installation, check chain slack! The stock OEM reference for chain slack is only good for the stock shock length and stock swingarm pivot height.
If you increase shock length or change pivot position, you MUST check for chain binding to avoid damage.
- Unload the Suspension:
Hang the rear of the bike to completely unload the rear wheel (or use rearset lifts). Remove the rear shock. - Find the Tightest Point:
Raise the swingarm to the position that creates the longest distance between the transmission output shaft & rear axle. This should be a straight line between pinion shaft -> swingarm pivot -> rear axle (note: with chain runners, it may be just above or below that point). - Check Binding:
If at that point the chain binds (is too tight), then the slack setting was too tight. Adjust rear spindle position to get a minimum chain slack even in this critical position. - Set New Reference:
Once adjusted, reconnect the shock, lower the rear of the bike and note the actual chain slack now at riding height.
This measurement will be your NEW reference number from now on for your present setup.
Attention:
This is a race product to be used only on closed circuits at your own risk.
NOTE: If competing in a race series, before using those parts check for compliance to the specific technical rules.
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