£50 to £100

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.

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.

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.

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.

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.

Chainset Type - the number of chainrings the derailleur was designed to work with. ‘Double’ derailleurs are actually capable of working on ‘triple’ chainsets but they may struggle when shifting, especially if there’s a big step down from the middle to inner ring, so it’s better to match these correctly.

Frame Fixing - the way the derailleur fixes to the frame, if you have a tab on your frame to mount the derailleur to you need braze-on. If there’s no tab then you require a clamp-on type (also referred to as band-on or clip-on), these come in different sizes to match the diameter of your seat tube.

Pull Type - the direction of which the cable needs to ‘pull’ the mech in order to shift. If your cable runs up to the derailleur from the bottom bracket area then you need bottom pull, if your cable comes down from above you need top pull. Some later derailleurs can be used for either setups, these are referred to as dual pull.

Designated Speed (9 Speed & Above) - the speed of the chain that the mech was designed to be used with. This only becomes relevant for mechs marketed as 9 speed or above when chains became narrower, as the derailleur cage plates became marginally narrower too. We refer to it as ‘designated’ speed as technically you can use (almost) any derailleur with any chain, however if you want optimum performance it’s best to stay close to the manufacturers recommendations.

Indexing System (Shimano Only) - this is only applicable when using Shimano shifters that have an indexed left shifter such as STI or Rapidfire. For the indexing to work correctly when using these shifters the derailleur and shifters must be of the same type, so Shimano drop bar shifters need to be matched with a Shimano ‘road’ derailleur, and Shimano flat bar shifters must be used with Shimano ‘MTB’ derailleurs.

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.

Fixing Type - if you have small mounts on either side of the frame’s down tube you need braze-on shifters, if there are no mounts you’ll need clamp-on (sometimes referred to as band-on). Some 'aero' frames have mounts fixed to the top of the down tube, for these frames you require top mount shifters for the correct boss type (see below). There are also 'Clamp-Over' shifters that allow front & rear shifters to be used on a frame that only has a single braze-on.

Shift Type - friction shifters don't click into gear when you change, when they do click it's referred to as indexed shifting. For this to work correctly you must use the same system as your rear derailleur, if you're using friction levers you can mix and match. You don't need to worry about the front derailleur as left downtube shifters aren't indexed.

Speed - the number of cogs at the back the right shifter is designed to be used with. This is important with indexed shifting but with friction shifters you can in theory run any shifters with any speed setup, although the right lever will need to be pulled back further to shift into the larger cogs.

Shifter Boss Type - the shape of the mount (for braze-on fixings only). Campagnolo / ISO is standard and easily identified by the flat sections on either side, usually combined with a square base for the backing stop plates to fit. There are also Shimano ones with a keyhole shaped base and much less common French ones that are round with no flat sections.

Boss Thread Size - M5 (5 mm) is standard for Campagnolo / ISO bosses, but Shimano bosses will often have M4.5 (4.5 mm) threads and the French bosses would likely have 5 x 1 mm threads.

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.

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.

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.

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.

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.

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.

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 by looking at the shape of the bottom bracket hole in your crankset. 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.

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.

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.