When it's time to replace your 9-speed cassette, check out SRAM's PG-950 cassette. It delivers solid shifting and durability ride in and ride out for your 9-speed rig.

Shimano's Dura-Ace 10-speed Cassette is comprised of an aluminum cog carrier, 4 titanium and 6 steel cogs (from largest to smallest respectively). This makes for a super-light and stiff cassette that makes your derailleur shift like a dream so you can dance up the climbs as easily and efficiently as your chain climbs up and down these cogs.

Shimano's 105 10-Speed Cassette delivers excellent shifting and durability. The cogs are made of long-lasing, smooth-running steel. They have Shimano's engineered tooth shapes for precision shifting. And for lightness, the cassette has an aluminum carrier for the top cogs and nylon spacers.

Shimano's Ultegra 10-Speed Cassette delivers pro-level shifting and durability. The computer-enhanced tooth shapes and tough cogs mean you can shift quickly, precisely and smoothly even under pressure.

When it's time to replace your old 8-speed cassette, check out SRAM's PG-850. Its steel construction and SRAM's PowerGlide technology combine to deliver miles of solid shifting and outstanding durability.

• Chromoly steel • CNC fabrication • 1.29" x 24tpi left hand thread

• Stainless steel with high-polish finish • 1.37" x 24tpi right-hand thread • Requires a lockring (sold separately) • Compatible with 1/8-inch chains

- Chromoly steel with black oxide finish - 1.37" x 24tpi right hand thread - Requires a cog lockring (sold separately) - Compatible with 1/8-inch chains

• Stainless chromoly steel with high-polish finish • CNC fabrication • 1.29" x 24tpi left hand thread

Campagnolo's Chorus Cassette offers precise, fluid shifting for your 11-speed drivetrain. The teeth have been exquisitely engineered and machined from steel, then coated with a nickel-chrome surface treatment and mounted on an aluminum carrier for flawless shifts and excellent durability.

- Optimized 11-speed tooth design for shifting speed and fluidity. Evolved sprocket timing reduces stress on the chain and allows for easier shifting through the higher cogs - Top six cogs are divided into sets of three and are mounted on aluminum carriers. This increases rigidity by 180% and the individual cogs are 70% more resistant to torsion - Cogs are steel with a nickel-chrome treatment - Only compatible with 2015+ mechanical drivetrains and no EPS, due to chain wrap capacity Cassette Body Type: Campagnolo 10/11-speed Cassette Cogs: 11-12-13-14-15-17-19-21-23-26-29 Cassette Spacing: Campagnolo 11-speed Range: 11-29 Weight: 230g

While the greatest focus is generally given to the moving parts of the groupset, the drivetrain is not complete without the cassette. And a Campagnolo groupset is not complete without an extremely efficient, reliable and high-performance cassette. This is why the Centaur groupset offers high-quality solutions to meet the needs of even the most demanding cyclist. - Built with one steel triplet and 8 steel single sprockets. - Includes lockring - Drivetrain Speeds: 11 - Weight: 291 grams

Steel single sprockets with galvanized finish. - Lockring included - Cassette Body Type: Campagnolo 9 Speed - Drivetrain Speeds: 9 - Weight: 212 grams (12-23)

- Extended range aluminum cog for those wanting 1x10 with a full range of gears - Only fits Shimano XT/XTR 11-36t (M771/M980) or SRAM X5/X7/X9/X0 11-36t 10sp cassettes (not compatible with 2011 and older SRAM derailleurs) - Requires removal of the 17T or 15T cog and spacer from existing cassette - Longer B-screw (sold separately) only needed for about 50% of Shimano derailleurs - May require a longer 10sp chain. Very tight fit on Stans 330 rear hub splines - Designed and manufactured in the USA from 7075-T6 aluminum alloy

We did our homework on this cog and we think you will be pleased with the result! This 16t cog smooths out the cog to cog transition when using our GC and a standard 10 speed 11-36 cassette. You should expect this to shift well and last as long as the rest of your cassette cogs of similar size. Here are the transitions WITHOUT the 16t cog (4 tooth max jump): - Remove the 15t -> 11-13-17-19.... - Remove the 17t -> 11-13-15-19... Here are the transitions WITH the 16t cog (3 tooth max jump): - Remove 15t & 17t-> 11-13-16-19... Compatibility: Shimano 10 speed cassettes - XT 11-36t (CS-M771) - XTR 11-36t (CS-M980) - Other 11-36t Shimano cassettes like SLX HG81 11-36t - Modification required (must drill out rivets holding the 17t to the larger cogs) SRAM 10 speed cassettes - PG 1030, 1050, and 1070 - 11-36 and 12-36 - X0 11-36t(XG - 1080) - Remove the 14t rather than the 17t

The GC line of cassette extender cogs allow you to modify your 10 speed cassette into a wide range cassette. To achieve the optimal shifting, the GCs are optimized for Shimano or SRAM cassette. Compatibility: - Compatible with SRAM 10 speed cassettes - Compatible with all 10 speed rear derailleurs and chains - Note that you may need a longer chain that you currently have on your bike - Chain stretch should be less than .5 when installing a new GC - Can be run in 2x configuration with a long cage rear derailleur - These fit very tight on certain Stan's No Tubes hubs like the 3.30 and the Easton X4 hubs. With a little filing and some grease they will go on.

Shimano's Sora cassette is an incredible value for your 9-speed drivetrain. Crisp shifting and a low weight keep your mind focused on having fun on your bike and not adjusting it. This cassette comes in a range of sizes to suit your riding style and terrain.

• Four carbon carriers and six titanium cogs for reduced weight • Nickel-plated finish for corrosion and wear resistance • Dyna-sys 11-speed cassette with "Rhythm step" gearing for closer gear ratios and smoother shifting performance • Fits Dyna-sys 11 and current Shimano 9/10-Speed MTB hubs • The largest cog (40t) is positioned inboard and above the drive-side flange • Hubs with tall drive-side flanges may not be compatible due to spoke interference • Range: 11-40

Shimano's Claris cassette is an incredible value for your 8-speed drivetrain. This cassette comes in a range of sizes to suit your riding style and terrain.

Shimano's Tiagra cassette offers crisp shifting and lightweight performance. Hyperglide sprockets incorporate computer-designed shift ramps and tooth profiles for improved shifting. This cassette comes in a range of sizes to suit your riding style and terrain.

Dependable, quick shifting awaits with Shimano's Saint/SLX 9-Speed Cassette. It features chrome/nickel-plated steel sprockets mounted to a aluminum carrier for an ideal blend of durability and low weight. Plus, the cogs are ramped and machined for those flawless shifts that Shimano is known for.

Shimano's Ultegra 11-Speed Cassette delivers pro-level shifting and durability. The computer-designed tooth shapes and tough cogs mean you can shift quickly, precisely and smoothly even under pressure. Rider-tuned gearing options offer a range of cassettes to suit your riding style.

SRAM's PG-970 DH 9-Speed Cassette is the perfect replacement for the worn-out gears on your downhill or freeride bike. It features a rugged steel construction for awesome durability and SRAM's PowerGlide technology for smooth, precise shifts.

Once again, SRAM pushes the envelope with their Powerdome X XG-1090 10-Speed Cassette. Light, stiff, quick, and quiet thanks to the ultra-strong, hollow, one-piece design and StealthRing elastomers, this cassette is worthy of even the nicest road machines. SRAM has added elastomer rings between every cog to provide a 'bed' where the plates of the chain interface with the cog. These elastomer StealthRings make for whisper-quiet operation. It's light, too, with the small 11T cog separate, and the remaining 9 cogs milled from a solid block of tool-grade steel pressed onto a single aluminium cog (the largest one). And, to REDuce even more weight, excess material in the space between each cog is milled away.

Reliable, perfect shifting awaits with Shimano's Deore XT Dyna-Sys Cassette. It features chrome-plated steel sprockets mounted to two aluminum carriers for an ideal blend of durability and low weight. Closer gear ratios in the middle of the cassette ensure you'll have the perfect gear for the trail's ups and downs. Plus, the cogs are ramped and machined for flawless, lightning-fast shifts.

Shimano's SLX Dyna-Sys 10-Speed Cassette features chrome-plated steel sprockets mounted to an aluminum carrier for an ideal blend of durability and low weight. Closer gear ratios in the middle of the cassette ensure you'll have the perfect gear for the trail's ups and downs. Plus, the cogs are ramped and machined for flawless shifts with the 10-speed chain and Shadow rear derailleur (both sold separately).

You've got to have the right ratio for the track, and Shimano's Dura-Ace cogs come in a range of tooth counts so you can always be prepared. Manufactured from durable chromoly steel, each cog is machined to run perfectly straight.

• Steel construction on all but the largest aluminum gear • Nickel-plated finish for corrosion and wear resistance • Dyna-sys 11-speed cassette with "Rhythm step" gearing for closer gear ratios and smoother shifting performance • Fits Dyna-sys 11-speed and current Shimano 9/10-Speed MTB hubs • The largest cog (40t) is positioned inboard and above the drive-side flange • Hubs with tall drive-side flanges may not be compatible due to spoke interference

Shimano's Ultegra 9-Speed Cassette delivers pro-level shifting and durability. The computer-enhanced tooth shapes and tough cogs mean you can shift quickly, precisely and smoothly even under pressure.

Shimano's 11-speed SLX cassette features the same computer-designed shift profiles that have made Shimano shifting synonymous with speed and accuracy. - Series: SLX - Average Weight: 467g