Pair this cog with your Shimano-compatible rear hub, spacers and a lockring (sold separately) and discover the joy and simplicity of a singlespeed without the cost of a new wheel. Machined from heat-treated chromoly and then chrome plated, these seriously tough cogs are strong, shiny and they come in sizes from 13T to 22T so you can pick the perfect gear.

At a full 5mm thick, the Surly Fixed Cog Lockring doesn't mess around with cog security. It's CNC-machined from premium stainless steel for serious strength and durability. This sucker will hold tight through hard sprints and crazy skids. It's a small part, but an important one and Surly makes it right.

Machined from heat-treated, chrome-plated chromoly, these seriously tough cogs will hold up to massive track sprints and crazy skid-stops. Surly's Track Cogs are strong, shiny and they come in two widths and sizes from 13T to 22T so you can select the perfect gear.

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

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

8-speed SIS compatible freewheel

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

- 3-spline steel cogs for use with Sturmey 3-speed (and 5-speed) internal gear rear hubs - Flat or dished for tuning chainline. Xylan coating for greater durability

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 105 11-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.

- MODEL NO: CS-R7000 - SERIES: SHIMANO 105 R7000 Series - Average weight: 284 g (11-28T), 304 g (11-30T), 320 g (11-32T), 269 g (12-25T) - Combination: 11-12-13-14-15-17-19-21-23-25-28T, 11-12-13-14-15-17-19-21-24-27-30T, 11-12-13-14-16-18-20-22-25-28-32T, 12-13-14-15-16-17-18-19-21-23-25T - Combination name (Group name): 11-28T, 11-30T, 11-32T, 12-25T - Compatible chain: HG-EV 11-speed/HG-X11 - Speeds: 11-speed - Spider arm QTY (pcs): 1 - Type: HG-EV

- MODEL NO: CS-HG400-9 - SERIES: SHIMANO ALIVIO M4000 Series - Compatible chain: HG 9-speed - Speeds: 9-speed - Type: HG

- MODEL NO: CS-HG201-9 - SERIES: SHIMANO ALTUS M2000 Series - Combination: 11-13-15-17-19-21-24-28-32T (bo), 11-13-15-17-20-23-26-30-34T (bn), 11-13-15-17-20-23-26-30-36T (bw), -, -, -, - - Combination name(Group name): 11-32T (bo), 11-34T (bn), 11-36T (bw) - Compatible chain: HG 9-speed - Speeds: 9-speed - Type: HG

- MODEL NO: CS-HG41-7 - SERIES: SHIMANO - Combination: 11-13-15-18-21-24-28T (ac) - Combination name(Group name): 11-28T (ac) - Compatible chain: IG/HG - Speeds: 7-speed - Type: HG

- MODEL NO: CS-HG50-8 - SERIES: SHIMANO CLARIS R2000 Series - Compatible chain: CN-HG71 - Speeds: 8-speed - Type: HG

• 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

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 XT CS-M770 9-Speed Cassette - Aluminum carrier reduces weight and increases rigidity - Cassette Body Type: Shimano/SRAM 8, 9, 10 Speed - Drivetrain Speeds: 9 - Weight: 323 grams

Shimano HG-800 11-speed cassette. - High-performance gear combinations provide superior rider choice - With hub body for MTB to fit a variety of bikes from MTB to road - Average Weight: 335 grams

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.

- MODEL NO: CS-HG200-7 - SERIES: SHIMANO TOURNEY - Combination: 12-14-16-18-21-24-28T (bm), 12-14-16-18-21-26-32T (bp) - Combination name (Group name): 12-28T (bm), 12-32T (bp) - Compatible chain: IG/HG - Speeds: 7-speed - Type: HG

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.

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.

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.

SRAM's PG-1030 10-Speed Cassette is a great choice. It's constructed of light and durable materials and boasts SRAM's PowerGlide tooth profiles and shift ramps for quick and positive gear changes every time. This trick cassette is available in four configurations perfect for riding off road, including one with a 36-tooth largest cog for super-easy climbing.

SRAM's 1050 10-Speed Cassette is a great choice. It's constructed of light and durable materials and boasts SRAM's PowerGlide tooth profiles and shift ramps for quick and positive gear changes every time. This trick cassette also sports a semi-spider construction for a maximum stiffness-to-weight ratio and is available in myriad configurations to suit all your riding. There are even models with 36-tooth largest cogs for super-easy climbing.

SRAM's 1070 10-Speed Cassette is a great choice. It's constructed of light and durable materials and boasts SRAM's PowerGlide tooth profiles and shift ramps for quick and positive gear changes every time. This trick cassette also sports a semi-spider construction for a maximum stiffness-to-weight ratio, a lightweight aluminum lockring, and is available in myriad configurations to suit all your riding. There are even models with 36-tooth largest cogs for super-easy climbing.

SRAM's PG-1130 11-Speed Cassette is constructed of heat-treated steel cogs and boasts SRAM's PowerGlide tooth profiles and shift ramps for quick, positive gear changes. This excellent cassette also sports an aluminum spider construction for a maximum stiffness-to-weight ratio, a durable steel lockring, and comes in three wide ranges to suit your riding style.

SRAM's 1170 11-Speed Cassette is constructed of light, durable materials and boasts SRAM's PowerGlide tooth profiles and shift ramps for quick, positive gear changes. This excellent cassette also sports a semi-spider construction for a maximum stiffness-to-weight ratio, a lightweight aluminum lockring, and is available in three ranges to suit all your riding.

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.