Bottom Bracket Parts

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

Bottom Bracket Type - ‘square taper’, as the name suggests have square shaped axle ends that slot 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.

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 cups, they often 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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.

We've been safely sending orders around the world since 2010. There's a handy shipping calculator on the shopping cart page so you can see the cost of postage as soon as you've added it to your basket. Your order will be carefully packed and sent with tracking & insurance, we despatch most orders within 2-3 days but larger items and orders placed before the weekend can take an extra day or two to process.

We accept returns, please notify us within 14 days and ensure the item arrives back with us no later than 30 days after the order was received.

We don't charge VAT, however, if buying from outside of the UK please remember that there may be import fees to pay directly to the delivery company before receiving the order. Unfortunately we can’t advise on the exact costs as it varies from country to country, so please check your national rates before purchasing.

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.