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How to Upgrade my Shimano Drivetrain

To upgrade your current drivetrain you need to know the following:

About your bicycle. . .

  • How many rear cogs are on your bike
  • How many chainrings are on your bike
  • What the rear spacing is of your bike
  • What front derailleur clamp size/type is on your bike
  • If you are upgrading the crankset (may be required by some other drivetrain upgrades) you need to know both your current bottom bracket type, and/or your frame's bottom bracket shell width

About what you want to do. . .

  • Number of cogs in the upgraded set
  • Number of chainrings in the upgraded set
  • Bottom bracket type of the upgraded set

Most drivetrain upgrades are covered by our upgrade chart.

Other things that are nice to know:

  • SRAM chains and cassettes are fully Shimano compatible
  • SRAM derailleur/shifter sets are compatible with Shimano chains and cassettes (however for the shifter and derailleur must be the same brand as each other. e.g. SRAM shifter with SRAM derailleur)
  • For best results always replace the cables when upgrading any drivetrain part
  • Shimano mountain bike rear derailleurs are fully interchangeable with road shifters, so select the derailleur based on the size of the cogs. For instance if you want to run a 11x32 cassette on your touring bike you can still use your road shift levers on your drop handlebar, but you would need to swap out the rear derailleur to a mountain bike type to handle that size of rear cog
  • Shimano mountain bike front derailleurs are not compatible with road shifters. Road front derailleurs are not compatible with mountain shifters

Upgrading Shimano Drive Trains

Shimano Upgrade Compatibility Chart

  • Required = must be replaced with the part designed for the upgraded number of speeds
  • Recommended = old part may work with the new system, but maximum performance may not be achieved
  • Not Required = old part is 100% compatible
  • Items shown assume that the same number of chainrings will be used

Shimano 7 to Shimano 9 Shimano 8 to Shimano 9 Shimano 8 to Shimano 10 Shimano 9 To Shimano 10
Chain Required Required Required Required
Cassette Required Required Required Required
Shift Lever Required Required Required Required
Rear Derailleur Required Recommended Required Recommended
Front Derailleur Required Recommended Required Recommended
Crankset Required Confirm Compatibility some cranks are 8/9 Compatible Required Recommended
Rear Hub Required Not Required Most 8 speed hyperglide hubs will fit a 10 speed cassette but uniglide hubs will not Not Required*

*Some non-Shimano components may not be fully compatible

Number of Cogs

Bicycle cog diagram Count the number of cogs on your rear hub. If you have 7 cogs or less you must measure your rear spacing to confirm that the upgraded set will fit.

Rear Axle Spacing

Rear axle spacing diagram Measure the rear spacing on your frame.

  • Most mountain bikes are 135mm but there are still some older 130mm bikes around
  • Most road bikes are 130mm but there are still some older 126mm bikes around
  • In some cases it will be 132.5mm which can take either 130mm, or 135mm spaced hubs
  • To upgrade a mountain bike to 8 or 9 speed your frame needs to measure 135mm or 132.5mm
  • To upgrade a road bike to 8, 9 or 10 speed your frame needs to measure 130mm or 132.5mm

*If your bike does not have the spacing required please contact our product support department either by calling 800-553-8324 or emailing productsupport@performancebike.com

Front Derailleur Mounting

Front Derailleurs attach to the frame in 3 different ways:

  • Braze-on front derailleurs bolt directly to the frame, freqently carbon bikes or odd aluminum bikes will be a braze-on derailleur attached to a seperate clamp
  • Clamp-on front derailleurs have a clamp that goes around the seat tube and tightens with a bolt. There are 3 sizes of clamp-on derailluer
    • 28.6mm - 1 1/8 inch: older steel road and mountain bikes
    • 31.8mm - 1 1/4 inch: some modern aluminum and carbon frames
    • 34.9mm - 1 3/8 inch: some modern aluminum and carbon frames
  • E-type front derailleur mounts to the bottom bracket

Front derailleurs come in either double or triple and must match the number of chainrings

  • double = 2 rings
  • triple = 3 rings

Mountain Bike front derailluers have 2 additional distinctions--
Pull is from what direction the cable comes to the derailleur:

  • Top-pull = cable comes from above the derailleur
  • Bottom-pull = cable comes from under the derailleur

Swing refers to where the derailleur cage pivots:

  • Top-swing = cage pivots above the clamp
  • Bottom-swing, or traditional = cage pivots below the clamp

New model Shimano mountain bike front derailleurs come in a multi-clamp model that includes shims to fit any clamp size, and can take the cable pull from either the top of bottom. You just need to get the proper swing for your bicycle.

Bottom Bracket Threading/Shell Size

Bottom bracket threading and shell size diagram

  • 68mm wide = English Threading
  • 68mm wide = English Threading
  • 68mm wide = English Threading

*Take note if you have an "E-Type" bottom bracket mounted front derailleur.