Big Old Sale - All Items 15% Off

Tooth Count - the number of teeth on the chainring, the higher the number the harder the gear.

Between Adjacent Bolt Holes - the measurement from the centre of any bolt hole to the centre of an adjacent one, if this measurement is the same as that of your crankset and the bolt count is the same then the chainring should fit.

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter) and is the technical way to determine whether the chainring fits your crankset. To calculate, multiply the distance between adjacent holes (in mm) by 1.709 (you’ll likely need to round the resulting number up or down a little).

Bolt Count - the number of bolts securing the chainring to the chainset. As with the BCD, this must be the same as your chainset.

Chain Width - 3/32” is the standard width for double and triple chainsets, wherease 1/8” chainrings are only found on single ring chainsets, generally for track / singlespeed use and can only be used with a wide 1/8" chain.

Intended Speed - the number of cogs at the back the chainring was designed to be used with. We refer to it as ‘intended’ speed as most double and triple chainsets will actually work with different speeds than originally intended, but the further away you get from the intended speed the more likely you are to experience minor setup issues. The exception being some chainrings intended for 10 speed use or higher, with these it’s better to stick to the intended speed.

Speed - the number of cogs at the back the chain was designed to be used with.

Compatibility - the brand and/or shifting system the chain is compatible with. Universal means the chain can be used with any standard shifting system, as long as the speed and width are correct.

Chain width - the gap between the inner plates where the chain sits on the sprockets. 3/32" has been standard for bikes with derailleur gears since the mid 1900s. When 9 speed was introduced the spacing reduced slightly but if the speed & compatibility are correct this isn't something you need to pay attention to. Single speed, track & BMX bikes will require either a 3/32" or 1/8" chain depending on the width of the rear sprocket and/or chainring. There's also a much wider 3/16" moped chain which can be used as a heavy duty chain for bikes without gears if required.

Chain pitch - the distance between the rollers (the cylindrical parts that roll around the pins). Pretty much every bicycle chain will be 1/2", the only time you will need a different pitch is for very early track bikes that take a 3/16" chain (also known as 'inch pitch'), or Shimano's short lived 10 mm pitch system from the 1970s/80s.

Number of links - the total number of links in the chain. If you're unsure how many links you need, you can measure your old chain (or a bike with a similar setup to yours).

Speed - the number of cogs on the cassette.

Spline Pattern - the shape of the cogs where they slide on to the freehub body, this must match the spline pattern of your hub to able to fit. In the 1980s Shimano introduced Uniglide cassettes that share the same spline pattern as their now standard Hyperglide, but the smallest sprocket threads on to the hub to secure it rather than using a conventional lockring, these will only fit hubs with a threaded section on the outside of the freehub body.

Range - the number of teeth on the smalles and largest cogs, this gives you an indication of how hard or easy the gearing will be, the lower the number the harder the gears. The tooth count of the cogs inbetween are usually evenly spaced, ie: a 6 speed 14-24 freewheel would likely have cog sizes 14, 16, 18, 20, 22 & 24.

Speed - the number of cogs on the cassette.

Spline Pattern - the shape of the cogs where they slide on to the freehub body, this must match the spline pattern of your hub to able to fit. In the 1980s Shimano introduced Uniglide cassettes that share the same spline pattern as their now standard Hyperglide, but the smallest sprocket threads on to the hub to secure it rather than using a conventional lockring, these will only fit hubs with a threaded section on the outside of the freehub body.

Range - the number of teeth on the smalles and largest cogs, this gives you an indication of how hard or easy the gearing will be, the lower the number the harder the gears. The tooth count of the cogs inbetween are usually evenly spaced, ie: a 6 speed 14-24 freewheel would likely have cog sizes 14, 16, 18, 20, 22 & 24.

Spoke Drilling - the number of holes for the spokes, your wheel rim needs to match the hub exactly.

Spacing (O.L.D.) - the width of the hub measured at its widest point, from the outside of the locking end nuts (O.L.D. = Over Locknut Dimension), not including the hub axle. This measurement needs to match the inside of your frame's dropouts. Steel frames can be stretched or squeezed a few mm but it's always best to avoid this if possible, aluminium or carbon frames should never be stretched.

Speed - the number of cogs the hub was designed to be used with.

Sprocket Fitting - for cassette hubs this refers to the spline pattern (the shape of the cogs where they slide on to the hub) and this must match the cassette you intend to use. With freewheel hubs it refers to the thread, ISO is the modern standard and is almost exactly the same as older English/British and Italian thread, allowing you to mix and match between these thread types as long as it's not going to be under extreme force, in which case it's best to stick to an exact match. Freewheel hubs with a French thread must be used with a French threaded freewheel.

Tooth Count - the number of teeth on the chainring, the higher the number the harder the gear.

Between Adjacent Bolt Holes - the measurement from the centre of any bolt hole to the centre of an adjacent one, if this measurement is the same as that of your crankset and the bolt count is the same then the chainring should fit.

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter) and is the technical way to determine whether the chainring fits your crankset. To calculate, multiply the distance between adjacent holes (in mm) by 1.709 (you’ll likely need to round the resulting number up or down a little).

Bolt Count - the number of bolts securing the chainring to the chainset. As with the BCD, this must be the same as your chainset.

Chain Width - 3/32” is the standard width for double and triple chainsets, wherease 1/8” chainrings are only found on single ring chainsets, generally for track / singlespeed use and can only be used with a wide 1/8" chain.

Intended Speed - the number of cogs at the back the chainring was designed to be used with. We refer to it as ‘intended’ speed as most double and triple chainsets will actually work with different speeds than originally intended, but the further away you get from the intended speed the more likely you are to experience minor setup issues. The exception being some chainrings intended for 10 speed use or higher, with these it’s better to stick to the intended speed.