absoluteBLACK Premium Oval chainrings for FSA ABS (asymmetric bolt spacing) cranks like Gossamer, SL-K, K-Force. This model fits all 4 and 5 bolt design cranks. 4&5 bolt cranks are identical except the one hidden bolt behind the crank arm in 5 bolt design which is not needed. These are finest FSA compatible chainrings on the market in terms of shifting, stiffness, smoothness of pedaling and manufacturing quality. 10/11/12spd compatible. Di2 Compatible. Made in EU.

How to mount Absolute Black Oval Chainrings to FSA ABS Cranks

First, you need to remove your crank from your bike. Once removed, unscrew the 4 bolts that hold two chainrings together with a T-30 torx key. Remove both original rings. Asymmetric bolt design will prevent mounting the rings with the wrong orientation. The bolt holes on the small chainring are recessed – so the bolt heads will sit flush with the surface of the chainring - these recesses should face you when mounting the bolts 

For Gossamer - Place the big ring first on the spider, then place 4 FSA spacers and then small chainring. Tighten with original FSA bolts.

For SL-K - Place the big ring first on the outer position of the spider, then place small chainring on the inside of the spider. Use the FSA bolt covers and place them from the front on big ring (they are all identical). Tighten with original FSA bolts.

For K-Force Light - Place the big ring first on the outer position of the spider, then place small chainring on the inside of the spider. Use absoluteBLACK bolt covers and place them from the front on big ring. Tighten with provided bolts while holding the bolt covers by hand from the other side (this is important to not to damage the bolt covers).

Tighten all four bolts with force of about 5-7Nm. Mount your crank back to the bike. You may also need to adjust the front derailleur slightly.

Absolute Black always recommends using a new chain when fitting new chainrings.

When mounting absoluteBLACK 4 bolt chainring on 5 bolt crank, leave the hidden bolt hole empty or patch it with waterproof grease. This hole is not important hence FSA removed it with new version of cranks.

• Size (Mass +/-1g):34T (32g), 36T (33g), 38T (38g), 39T (41g)
• Color: Black only 
• Compatibility:All FSA ABS (asymmetric bolt spacing) cranks like Gossamer, SL-K, K-Force, K-Force Light. Both 4 and 5 bolt versions. One model fits them all. Di2 Compatible. 10 / 11 / 12spd compatible. ABS cranks only. 
• Bolts :For Gossamer - use original FSA bolts and spacers.For SL-K - use original FSA Bolt Covers and bolts.For K-Force - purchase absoluteBLACK bolt covers (necessary!)
• Material & Finish: CNC machined 7075 Txxx Aluminum. Long-lasting construction. Type II anodizing
• Ovality : Optimized to each size separately. 34T- 3.5% ; 36T, 38T, 39T- 11.4%; Timing of 108 -110.5° after TDC (top dead center) - Ideal for road climbing. Patent Pending

Important:

• For Gossamer cranks - Use original FSA bolts and spacers. There is nothing else needed to mount these rings.
• For SL-K - Use original FSA Bolt Covers and bolts that will fit perfectly. There is nothing else needed to mount these rigns.
• For K-Force - Purchase additionally absoluteBLACK bolt covers. This is Absolutely necessary as you will not be able to mount these chainrings to K-Force otherwise.

Ramps on big rings are specially configured for combinations: 50/34, 52/36, 52/38, 53/39T 

If you wish to use other configuration it will also work, but shifting will be slower and may require more "adjustments" of front dérailleur to be acceptable. Also remember that front dérailleur can only accept max 16T difference between 2 chainrings - this is how Shimano and Sram designed them.