Pre-1987 (Eroica Compliant)

Pit to Pit - this measurement is taken from the centre of one armpit to the other, across the chest with the jersey laid flat.

Top to Bottom - this will always be from the very top of the collar to the very bottom hem, we provide measurements for both the front and back, always taken with the jersey laid flat.

Shoulder Seam to Sleeve End - this measurement is taken from the shoulder seam down to the very end of the sleeve on the outside.

Across Neck - for consistency on all neck shapes we gather the front and back together and lay them flat, then measure across the stitching (as shown in the supporting photos).

Across Sleeve End - measured across the sleeve end, laid flat.

Cable Routing - non-aero means the cables come out at the top of the brake levers, meaning the cables are on show. With aero levers the cable comes out of a small hole by the handlebar, allowing the cables to be hidden under the handlebar tape.

Bar Clamp Size - this should be close to the outside diameter of your handlebars at the point the brake levers will be fitted. This will rarely present a problem with drop bars as 23.8 mm is standard, and a 24.2 mm clamp will fit just fine as they do have a little adjustment in them. There are some older sizes to watch out for but these will be noticeably different.

Drilling - the number of holes for the spokes.

Rim Size - the sizing given by the manufacturer, these can be confusing so we also give the ISO diameter too for clarification.

ISO Diameter - the diameter of the rim at the point where the tyre is seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

Valve Type - presta valves are the thin ones and Schraeder are the fatter ones. Schraeder valve holes will also accept the older Dunlop/Woods type valves.

Rim Width (OD) - the width of the rim, measured from the outside of one wall to the other.

Rim Height - the overall height of the rim, measured to the highest point of the rim’s profile.

Cable Routing - non-aero means the cables come out at the top of the brake levers, meaning the cables are on show. With aero levers the cable comes out of a small hole by the handlebar, allowing the cables to be hidden under the handlebar tape.

Bar Clamp Size - this should be close to the outside diameter of your handlebars at the point the brake levers will be fitted. This will rarely present a problem with drop bars as 23.8 mm is standard, and a 24.2 mm clamp will fit just fine as they do have a little adjustment in them. There are some older sizes to watch out for but these will be noticeably different.

Cable Routing - non-aero means the cables come out at the top of the brake levers, meaning the cables are on show. With aero levers the cable comes out of a small hole by the handlebar, allowing the cables to be hidden under the handlebar tape.

Bar Clamp Size - this should be close to the outside diameter of your handlebars at the point the brake levers will be fitted. This will rarely present a problem with drop bars as 23.8 mm is standard, and a 24.2 mm clamp will fit just fine as they do have a little adjustment in them. There are some older sizes to watch out for but these will be noticeably different.

Cable Routing - non-aero means the cables come out at the top of the brake levers, meaning the cables are on show. With aero levers the cable comes out of a small hole by the handlebar, allowing the cables to be hidden under the handlebar tape.

Bar Clamp Size - this should be close to the outside diameter of your handlebars at the point the brake levers will be fitted. This will rarely present a problem with drop bars as 23.8 mm is standard, and a 24.2 mm clamp will fit just fine as they do have a little adjustment in them. There are some older sizes to watch out for but these will be noticeably different.

Cable Routing - non-aero means the cables come out at the top of the brake levers, meaning the cables are on show. With aero levers the cable comes out of a small hole by the handlebar, allowing the cables to be hidden under the handlebar tape.

Bar Clamp Size - this should be close to the outside diameter of your handlebars at the point the brake levers will be fitted. This will rarely present a problem with drop bars as 23.8 mm is standard, and a 24.2 mm clamp will fit just fine as they do have a little adjustment in them. There are some older sizes to watch out for but these will be noticeably different.

Drilling - the number of holes for the spokes.

Rim Size - the sizing given by the manufacturer, these can be confusing so we also give the ISO diameter too for clarification.

ISO Diameter - the diameter of the rim at the point where the tyre is seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

Valve Type - presta valves are the thin ones and Schraeder are the fatter ones. Schraeder valve holes will also accept the older Dunlop/Woods type valves.

Rim Width (OD) - the width of the rim, measured from the outside of one wall to the other.

Rim Height - the overall height of the rim, measured to the highest point of the rim’s profile.

Drilling - the number of holes for the spokes.

Rim Size - the sizing given by the manufacturer, these can be confusing so we also give the ISO diameter too for clarification.

ISO Diameter - the diameter of the rim at the point where the tyre is seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

Valve Type - presta valves are the thin ones and Schraeder are the fatter ones. Schraeder valve holes will also accept the older Dunlop/Woods type valves.

Rim Width (OD) - the width of the rim, measured from the outside of one wall to the other.

Rim Height - the overall height of the rim, measured to the highest point of the rim’s profile.

Intended Side - some brake levers have a designated side to go on, although most can be used on either the left or right.

Cable Routing - non-aero means the cables come out at the top of the brake lever, meaning the cables are on show. With aero levers the cable comes out of a small hole by the handlebar, allowing the cables to be hidden under the handlebar tape.

Bar Clamp Size - this should be close to the outside diameter of your handlebars at the point the brake levers will be fitted. This will rarely present a problem with drop bars as 23.8 mm is standard, and a 24.2 mm clamp will fit just fine as they do have a little adjustment in them. There are some older sizes to watch out for but these will be noticeably different.

Pit to Pit - this measurement is taken from the centre of one armpit to the other, across the chest with the jersey laid flat.

Top to Bottom - this will always be from the very top of the collar to the very bottom hem, we provide measurements for both the front and back, always taken with the jersey laid flat.

Shoulder Seam to Sleeve End - this measurement is taken from the shoulder seam down to the very end of the sleeve on the outside.

Across Neck - for consistency on all neck shapes we gather the front and back together and lay them flat, then measure across the stitching (as shown in the supporting photos).

Across Sleeve End - measured across the sleeve end, laid flat.

Pit to Pit - this measurement is taken from the centre of one armpit to the other, across the chest with the jersey laid flat.

Top to Bottom - this will always be from the very top of the collar to the very bottom hem, we provide measurements for both the front and back, always taken with the jersey laid flat.

Shoulder Seam to Sleeve End - this measurement is taken from the shoulder seam down to the very end of the sleeve on the outside.

Across Neck - for consistency on all neck shapes we gather the front and back together and lay them flat, then measure across the stitching (as shown in the supporting photos).

Across Sleeve End - measured across the sleeve end, laid flat.

Chainring Count - the number of chainrings on the chainset. Fixed gear track bikes, single-speeds and some geared bikes use a single chainring, road bikes commonly use a double (two rings) and most touring bikes and mountain bikes will use a triple chainset (three rings).

Tooth count - the number of teeth on the chainring(s), the higher the number the harder the gear.

Chain width - this is only relevant for chainsets with a single chainring - if this is ⅛” then you must use a ⅛” chain. All double and triple (and some single) ring chainsets will use a standard 3/32” chain.

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter) and is only really needed when changing chainrings. To calculate the BCD, measure the distance in millimeters from the centre of any chainring bolt to the centre of an adjacent one and multiply it by 1.709 (you’ll likely need to round the resulting number up or down a little to get your BCD measurement).

*Intended speed - the number of cogs at the back the chainset 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 chainsets intended for 10 speed use or higher, with these it’s better to stick to the intended speed.

Crank arm length - this is measured from the absolute centre of the bottom bracket hole to the centre of the hole for the pedal.

Pedal threads - the thread type to match that of the chainset, this must match and is usually stamped on the pedals themselves and most bikes use a standard thread of 9/16” x 20 tpi. The exceptions being older French bikes, bikes with cheaper one-piece type chainsets and Shimano’s Dyna Drive system (easily identifiable as the pedal holes are about an inch wide!).

Bottom bracket type - ‘square taper’, as the name suggests have a square shaped axle that slots into the chainset and ‘cottered’ axles are round and secured by pins - pretty much every bike up until the 1990s would use one of these, cottered being the much earlier system. Since then, different manufacturers have introduced their own systems that are not interchangeable so you must use a chainset that matches.

Chainring Count - the number of chainrings the crank was designed to fit. Fixed gear track bikes, single-speeds and some geared bikes use a single chainring, road bikes commonly use a double (two rings) and most touring bikes and mountain bikes will use a triple chainset (three rings).

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter), and this needs to match the BCD of your chainring(s). To calculate this, measure the distance in millimeters from the centre of any chainring bolt hole to the centre of an adjacent one and multiply it by 1.709 (you’ll likely need to round the resulting number up or down a little to get your BCD measurement).

Crank Arm Length - this is measured from the absolute centre of the bottom bracket hole to the centre of the hole for the pedal.

Pedal Threads - the pattern of the thread that your pedals screw into, this is usually stamped on the pedals themselves and most bikes use a standard thread of 9/16” x 20 tpi. The exceptions being older French bikes, bikes with cheaper one-piece type chainsets and Shimano’s Dyna Drive system (easily identifiable as the pedal holes are about an inch wide!).

Bottom Bracket Type - ‘square taper’, as the name suggests have a square shaped axle that slots into the crank and ‘cottered’ axles are round and secured by pins - pretty much every bike up until the 1990s would use one of these, cottered being the much earlier system. Since then, different manufacturers have introduced their own systems that are not interchangeable so you must use a crank that matches.

Chainring Count - the number of chainrings on the chainset. Fixed gear track bikes, single-speeds and some geared bikes use a single chainring, road bikes commonly use a double (two rings) and most touring bikes and mountain bikes will use a triple chainset (three rings).

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

Bottom Bracket Type - ‘square taper’, as the name suggests have a square shaped axle that slots into the chainset and ‘cottered’ axles are round and secured by pins - pretty much every bike up until the 1990s would use one of these, cottered being the much earlier system. Since then, different manufacturers have introduced their own systems that are not interchangeable so you must use a chainset that matches.

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter) and is only really needed when changing chainrings. To calculate the BCD, measure the distance in millimeters from the centre of any chainring bolt to the centre of an adjacent one and multiply it by 1.709 (you’ll likely need to round the resulting number up or down a little to get your BCD measurement).

Crank Arm Length - this is measured from the absolute centre of the bottom bracket hole to the centre of the hole for the pedal.

Chain Width - this is mostly only relevant for chainsets with a single chainring - if this is ⅛” then you must use a ⅛” chain. Almost all double and triple (and some single) ring chainsets will use a standard 3/32” chain, the only exception being old chainsets designed for 3 or 4 speed freewheels.

Pedal Threads - this must match the thread of your pedals and is usually stamped on the pedals themselves, most bikes use a standard thread of 9/16” x 20 tpi. The exceptions being older French bikes, bikes with cheaper one-piece type chainsets and Shimano’s Dyna Drive system (easily identifiable as the pedal holes are about an inch wide!).

*Intended Speed - the number of cogs at the back the chainset 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 chainsets intended for 10 speed use or higher, with these it’s better to stick to the intended speed.

*Bike Type - this is just a guide, any chainset can technically be used on any bike as long as everything's compatible.

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).

Drilling - the number of holes for the spokes.

Rim Size - the sizing given by the manufacturer, these can be confusing so we also give the ISO diameter too for clarification.

ISO Diameter - the diameter of the rim at the point where the tyre is seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

Valve Type - presta valves are the thin ones and Schraeder are the fatter ones. Schraeder valve holes will also accept the older Dunlop/Woods type valves.

Rim Width (OD) - the width of the rim, measured from the outside of one wall to the other.

Rim Height - the overall height of the rim, measured to the highest point of the rim’s profile.

Size - this is the manufacturer’s sizing and must match the size or your wheels. This can be confusing as tyres have had different sizing systems over the years, and there are many (sometimes conflicting) sizes available. For this reason it’s important to check the ISO diameter too for clarification, especially for 26” wheels.

Bike Type - the type of bike the tyres were designed to be used on. Road tyres will generally be narrow with minimal tread, touring tyres wider with a bit more grip in the tread, and cyclocross & MTB tyres wider still (especially the latter), with a much more pronounced tread pattern.

ISO Diameter - this relates to the diameter of the wheel rims at the point where the tyres are seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

TPI - stands for threads per inch and refers to the thread count of the tyre casings. A high thread count usually means more supple and lighter tyres, this can be anything as high as 320 tpi. We can’t always provide this information however, as it’s not always possible to know for sure.

Drilling - the number of holes for the spokes.

Rim Size - the sizing given by the manufacturer, these can be confusing so we also give the ISO diameter too for clarification.

ISO Diameter - the diameter of the rim at the point where the tyre is seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

Valve Type - presta valves are the thin ones and Schraeder are the fatter ones. Schraeder valve holes will also accept the older Dunlop/Woods type valves.

Rim Width (OD) - the width of the rim, measured from the outside of one wall to the other.

Rim Height - the overall height of the rim, measured to the highest point of the rim’s profile.

Drilling - the number of holes for the spokes.

Rim Size - the sizing given by the manufacturer, these can be confusing so we also give the ISO diameter too for clarification.

ISO Diameter - the diameter of the rim at the point where the tyre is seated (bead seat diameter). This is a universal measurement, often displayed on tyres as 28-622 or similar, 28 referring to the tyre width and 622 being the ISO diameter in millimetres.

Valve Type - presta valves are the thin ones and Schraeder are the fatter ones. Schraeder valve holes will also accept the older Dunlop/Woods type valves.

Rim Width (OD) - the width of the rim, measured from the outside of one wall to the other.

Rim Height - the overall height of the rim, measured to the highest point of the rim’s profile.

Cap Type - we refer to the classic cycling cap type as summer/under helmet, although they can of course be used all year round. When worn under a helmet they provide comfort, sun protection and are sweat-wicking too. Winter hats will usually cover the ears and are referred to as 'Belgian' caps. Baseball caps were often worn by support teams or sold as branded merchandise.

Construction - the number of panels the cap body is made up of, not including the peak.

Cap Type - we refer to the classic cycling cap type as summer/under helmet, although they can of course be used all year round. When worn under a helmet they provide comfort, sun protection and are sweat-wicking too. Winter hats will usually cover the ears and are referred to as 'Belgian' caps. Baseball caps were often worn by support teams or sold as branded merchandise.

Construction - the number of panels the cap body is made up of, not including the peak.

Cap Type - we refer to the classic cycling cap type as summer/under helmet, although they can of course be used all year round. When worn under a helmet they provide comfort, sun protection and are sweat-wicking too. Winter hats will usually cover the ears and are referred to as 'Belgian' caps. Baseball caps were often worn by support teams or sold as branded merchandise.

Construction - the number of panels the cap body is made up of, not including the peak.

Valve Type - there are 3 types of valves; Presta are thin with a little knurled nut on the end, Schrader are wider (the same as you would find on a car), and the less common Woods (aka "Dunlop"). Pumps designed for Presta valves can be used on Woods valves. Some pumps use hose connectors, these are available for all valve types.

Pump Mount Type - 'peg fit' pumps require pump pegs or 'umbrella' clips to fit to the frame, 'frame fit 'pumps are designed with curved ends to mount between two tubes (although these often have holes for pegs too). If mounting directly you'll need the correct length to fit your frame, or a clip/peg to hold one end.

Mount Location - frame fit pumps usually mount to the seat tube with the ends compressed between the top and down tube, they can however be mounted on other tubes as long as there's something supporting the handle end. Some head tubes have a little nipple or a small enough gap for under top tube mounting (this can be replcated with a simple strap or cable tie), and of course pump pegs or clips can be fitted anywhere!

Length (Min-Max) - the length of the pump fully compressed and uncompressed, measured at the points of support. The space you to intend to mount the pump should be within 1 cm of the minimum or maximum length to allow the pump to be securely mounted and dismounted.

Valve Type - there are 3 types of valves; Presta are thin with a little knurled nut on the end, Schrader are wider (the same as you would find on a car), and the less common Woods (aka "Dunlop"). Pumps designed for Presta valves can be used on Woods valves. Some pumps use hose connectors, these are available for all valve types.

Pump Mount Type - 'peg fit' pumps require pump pegs or 'umbrella' clips to fit to the frame, 'frame fit 'pumps are designed with curved ends to mount between two tubes (although these often have holes for pegs too). If mounting directly you'll need the correct length to fit your frame, or a clip/peg to hold one end.

Mount Location - frame fit pumps usually mount to the seat tube with the ends compressed between the top and down tube, they can however be mounted on other tubes as long as there's something supporting the handle end. Some head tubes have a little nipple or a small enough gap for under top tube mounting (this can be replcated with a simple strap or cable tie), and of course pump pegs or clips can be fitted anywhere!

Length (Min-Max) - the length of the pump fully compressed and uncompressed, measured at the points of support. The space you to intend to mount the pump should be within 1 cm of the minimum or maximum length to allow the pump to be securely mounted and dismounted.

Valve Type - there are 3 types of valves; Presta are thin with a little knurled nut on the end, Schrader are wider (the same as you would find on a car), and the less common Woods (aka "Dunlop"). Pumps designed for Presta valves can be used on Woods valves. Some pumps use hose connectors, these are available for all valve types.

Pump Mount Type - 'peg fit' pumps require pump pegs or 'umbrella' clips to fit to the frame, 'frame fit 'pumps are designed with curved ends to mount between two tubes (although these often have holes for pegs too). If mounting directly you'll need the correct length to fit your frame, or a clip/peg to hold one end.

Mount Location - frame fit pumps usually mount to the seat tube with the ends compressed between the top and down tube, they can however be mounted on other tubes as long as there's something supporting the handle end. Some head tubes have a little nipple or a small enough gap for under top tube mounting (this can be replcated with a simple strap or cable tie), and of course pump pegs or clips can be fitted anywhere!

Length (Min-Max) - the length of the pump fully compressed and uncompressed, measured at the points of support. The space you to intend to mount the pump should be within 1 cm of the minimum or maximum length to allow the pump to be securely mounted and dismounted.

Valve Type - there are 3 types of valves; Presta are thin with a little knurled nut on the end, Schrader are wider (the same as you would find on a car), and the less common Woods (aka "Dunlop"). Pumps designed for Presta valves can be used on Woods valves. Some pumps use hose connectors, these are available for all valve types.

Pump Mount Type - 'peg fit' pumps require pump pegs or 'umbrella' clips to fit to the frame, 'frame fit 'pumps are designed with curved ends to mount between two tubes (although these often have holes for pegs too). If mounting directly you'll need the correct length to fit your frame, or a clip/peg to hold one end.

Mount Location - frame fit pumps usually mount to the seat tube with the ends compressed between the top and down tube, they can however be mounted on other tubes as long as there's something supporting the handle end. Some head tubes have a little nipple or a small enough gap for under top tube mounting (this can be replcated with a simple strap or cable tie), and of course pump pegs or clips can be fitted anywhere!

Length (Min-Max) - the length of the pump fully compressed and uncompressed, measured at the points of support. The space you to intend to mount the pump should be within 1 cm of the minimum or maximum length to allow the pump to be securely mounted and dismounted.

Shifting system - friction means your gear levers don't click when you change gear, when they do click it's referred to as indexed shifting. If you have indexed gear levers they must use the same system as the rear derailleur, if you're using friction levers you can mix and match.

*Speed - the number of cogs at the back the derailleur was designed to be used with. This is important with indexed shifting, but with friction shifters you can in theory run any rear mech with any number of cogs, but you are more likely to have issues running high numbers of cogs with mechs from earlier eras.

Max cog size - the amount of teeth on the largest cog of your freewheel/cassette can be no greater than this to work with this derailleur.

Chain wrap - subtract the size of your smallest rear cog from your biggest, then do the same with your chainrings, add the 2 numbers together and you have your chain wrap.

Chain width - generally speaking, derailleurs designed for more than 3 speed use will fit a standard 3/32'' chain, the exception being some Cyclo & Simplex models from around the mid 1900s.

Axle Type - for square tapers, the ISO introduced a standard for European makers in the early 90s, JIS then did the same in Asia. Before then it was not so simple, and although there is a degree of interchangeability, the best way to make sure you have the right axle is to stick to the same brand from the same era, ideally the proprietary model.

Axle Length (D) - your crankset dictates the axle length you need and the recommendation should be used to avoid issues with chainline. If you're replacing an axle that works perfectly then this can be matched, otherwise you'll need to check the manufacturers spec, a good resource for older bikes is Velobase.

Centre (B) - measured from the outside of the 'shoulders' of the bearing races, as seen in the diagram.

Drive Side (C) - the right side (with any logos etc on the axle facing you), your right crank and chainrings will mount to this side.

Non-Drive Side (A) - the left side, where the left crank arm will be mounted.

Shell Width - the width of the bottom bracket shell the axle was designed to fit, measured at its widest point.

Seatpost Diameter - this needs to match the internal diameter of your frame’s seat tube closely, it should be possible to insert the seatpost without force but the fit should be tight enough so it doesn’t just drop in, with no play once inserted. If you have a post that fits the measurement should be stamped somewhere near the bottom, if not you’ll need to measure with a caliper or seatpost sizing tool as the sizes go up in 0.2 mm increments.

Length (Centre of Rails to Base) - measured from where the centre of the saddle rails will sit once installed, all the way to the bottom of the seatpost. Normally there’s a mark to tell you how much of the seatpost needs to be inserted in the frame, however this isn’t always the case so we’d recommend allowing a minimum of 6 cm.

Skewer type - quick release skewers allow you to remove the wheel without any tools, whereas allen key and security skewers require a tool to allow the wheel to be removed.

*Spacing - this should be within a few milimetres of your frame's outer dropout spacing (measured from the outside where the skewers clamp down). The measurement provided was taken with the exiting hole of the end nut flush with the end of the skewer. There will be some wiggle room to allow a narrower or wider dropout spacing to fit, we've provided the threaded section and end nut measurements to give you an indication of how much.

Threaded section - the amount of thread on the skewers for the end nut to be threaded onto.

End nut length - the total length of the nut from end to end.

Chainring Count - the number of chainrings on the chainset. Fixed gear track bikes, single-speeds and some geared bikes use a single chainring, road bikes commonly use a double (two rings) and most touring bikes and mountain bikes will use a triple chainset (three rings).

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

Bottom Bracket Type - ‘square taper’, as the name suggests have a square shaped axle that slots into the chainset and ‘cottered’ axles are round and secured by pins - pretty much every bike up until the 1990s would use one of these, cottered being the much earlier system. Since then, different manufacturers have introduced their own systems that are not interchangeable so you must use a chainset that matches.

BCD - stands for Bolt Circle Diameter (sometimes referred to as PCD - Pitch Circle Diameter) and is only really needed when changing chainrings. To calculate the BCD, measure the distance in millimeters from the centre of any chainring bolt to the centre of an adjacent one and multiply it by 1.709 (you’ll likely need to round the resulting number up or down a little to get your BCD measurement).

Crank Arm Length - this is measured from the absolute centre of the bottom bracket hole to the centre of the hole for the pedal.

Chain Width - this is mostly only relevant for chainsets with a single chainring - if this is ⅛” then you must use a ⅛” chain. Almost all double and triple (and some single) ring chainsets will use a standard 3/32” chain, the only exception being old chainsets designed for 3 or 4 speed freewheels.

Pedal Threads - this must match the thread of your pedals and is usually stamped on the pedals themselves, most bikes use a standard thread of 9/16” x 20 tpi. The exceptions being older French bikes, bikes with cheaper one-piece type chainsets and Shimano’s Dyna Drive system (easily identifiable as the pedal holes are about an inch wide!).

*Intended Speed - the number of cogs at the back the chainset 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 chainsets intended for 10 speed use or higher, with these it’s better to stick to the intended speed.

*Bike Type - this is just a guide, any chainset can technically be used on any bike as long as everything's compatible.

*Matching Bottom Bracket(s) - if known, based on standard rear spacing of the period. For square tapers, ISO and JIS standards were introduced in the early 1990s; earlier cranks were designed to fit the proprietary taper. Alternatives can achieve the same chainline and clearance if the axle has the same taper and dimensions, and sticking to the same manufacturer and era will help. Mixing tapers is not recommended, as it can damage the cranks.

NB: “ITA” refers to Italian-threaded frames (70 mm BB shell).

Rim Size - this should match the size your bike frame is designed to fit. Standard/full size tubulars only come in one wheel size, these are often referred to as 28" or 700c (sometimes even 27"). These are all the same size, the next size down is 26", so any rims larger than 26" will be standard/full size tubulars.

Bike Type - this is really just a guide, as technically any wheels can be used on any bike as long as everything's compatible. Within reason of course - we wouldn't recommend riding a set of skinny tubular road wheels down a mountain!

Drilling (F/R) - the number of spokes in each wheel (front/rear).

Spacing (O.L.D.) (F/R) - the width of the hubs measured at their widest point, from the outside of the locking end nuts (O.L.D. = Over Locknut Dimension), not including the hub axle. These measurements need to match the inside of your frame and fork’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 rear 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.

Seatpost Diameter - this needs to match the internal diameter of your frame’s seat tube closely, it should be possible to insert the seatpost without force but the fit should be tight enough so it doesn’t just drop in, with no play once inserted. If you have a post that fits the measurement should be stamped somewhere near the bottom., otherwise you’ll need to measure with a caliper or seatpost sizing tool as seatpost diameters go up in 0.2 mm increments.

Length (Centre of Rails to Base) - measured from where the centre of the saddle rails will sit once installed, all the way to the bottom of the seatpost. Normally there’s a mark to tell you how much of the seatpost needs to be inserted in the frame, however this isn’t always the case so we’d recommend allowing a minimum of 6 cm.

Thread Type - this must match the bottom bracket thread on your frame. The 3 common thread types on classic and vintage bikes are English (also known as British or ISO), Italian & French, and are usually (not always!) found on frames built in their respective countries. If you're replacing a bottom bracket the cups should have the thread type stamped on one of them, if not there are a couple of things to look at; bottom bracket shell width (English & French = 68 mm, Italian = 70 mm) & drive side cup thread direction (English = left, Italian & French = right). The only curveball to watch out for here, although pretty uncommon, are Swiss threads (also found on some French frames, Motobecanes being one) which will have the same shell width & thread direction as an English thread frame but the actual thread pitch will be different. If none of the above matches what you have, there are a few lesser known varieties that will require some further research.

Axle Length - your crankset dictates the axle length you need and the recommendation should be used to avoid issues with chainline. If you're replacing a bottom bracket that works perfectly then this can be matched, otherwise you'll need to check the manufacturers spec, a good resource for older bikes is Velobase.

Axle Type - you can tell which type of axle you need just by looking at the shape of the bottom bracket hole in your crankset. The square taper axle came in two variations; JIS which was produced for cranksets made in Asia and ISO for cranksets made in Europe, these taper down to a slightly smaller end than JIS axles. There are a few exceptions such as some Sugino cranksets that required an ISO axle and some older Dura-Ace cranksests which used a shorter 'low profile' variation of the JIS taper. Ofmega/Avocet also had their own variaton of the ISO taper which is not compatible with any other type.