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 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 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 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.

A range of sturdy, affordable cogs is an essential part of a fixie rider's quiver. Origin-8's Track Cog is available in a variety of sizes and is chrome plated to resist rust and increase longevity. Now you can easily tailor your ride for the terrain. And you can choose between 1/8 and 3/32-inch chain widths.

A range of sturdy, affordable cogs is an essential part of a single speeder's quiver. Origin-8's Single Speed Cog is available in 13, 14, 16 and 18T sizes is chrome plated to resist rust and increase longevity. It's designed for Shimano/SRAM style cassette bodies and is made with splined, hardened chromoly steel. Now you can easily tailor your gearing for the terrain.

Origin-8's Ultim8 Single Speed Cassette Cog lets you have your ride any way you like it. This handy cog is dual use — a single speed cog that fits over a Shimano/SRAM freehub body or a fixed cog that bolts on in place of a 6-bolt brake rotor. A wide, zero-flex base design made of forged chromoly steel provides instant power transfer. Enjoy the Ultim8 ride whichever way you like it.

A range of sturdy, affordable cogs is an essential part of a single speeder's quiver. Origin-8's Torq Lite Single Speed Cog is available in wide range of sizes so you can easily tailor your gearing for the terrain. It's designed for Shimano/SRAM style cassette bodies, features a wide, flex-free base, and is made from hardened chromoly steel.

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.

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

• Converts a cassette hub to a single speed • 8 spacers included in various sizes to adjust chain line • Available in black or red anodized 6061 aluminum • Fits Shimano style cassette bodies • Conical spacers for increased cog stiffness

8-speed SIS compatible freewheel

• Easy-on, easy-off • Available in two chain widths and two colors • Available in six teeth sizes

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

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.

Steel 1mm spacer fits Shimano cassette bodies - Great for 10 sp cass on 8/9 sp hubs - Also for many other fit applications

• 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

• Steel • 7-speed

• Steel • 8-speed

5-speed bronze color freewheel

- 7-speed SIS compatible Freewheel - Shimano Equivalent: MF-TZ21

6-speed freewheel 14-28T SHIMANO Equivalent MF-TZ20

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.

SRAM's WiFLi technology accommodates a wider range of gears than a standard short-cage road derailleur. Compared to a triple chainring setup, it provides faster shifts and significant weight savings. Easy to install on any frame; compatible with all SRAM road 22-speed cranks, cassettes and chains. - For riders who already own Red eTap with a short cage rear derailleur and want to switch to a wide range cassette - Includes Medium Cage Rear Derailleur 11-32 Red 11 Speed Cassette and XG-1190 Red 22 Chain