Rear derailleur capacity calculator

1. What is rear derailleur total capacity?
2. Is my derailleur SS or GS?
3. What is derailleur chain wrap capacity?
4. How do I choose a rear derailleur?
5. What is the difference between long and short cage derailleurs?
6. Can I use any derailleur for my bike?
7. Can I use 10 speed derailleur with 11 speed cassette?
8. Can I use an 8 speed derailleur on a 7 speed cassette?
9. What does Shimano SGS stand for?
10. Can I change derailleur cage length?
11. Do I need a long or medium cage derailleur?
12. Can you use a 9 speed derailleur on a 7 speed bike?

What is rear derailleur total capacity?

your drivetrain capacity is the maximum amount of slack chain the rear derailleur cage can handle. The more potential slack, the bigger a derailleur cage you need. For example: If your drivetrain has a 44-22 chainring on the front and a 32-11 cassette on the rear, then...

Is my derailleur SS or GS?

The difference between SS and GS is technically as follows. To make it easy to remember, SS (short cage) is compatible with cross ratio road sprockets, while GS (medium cage) is compatible with wide ratio sprockets.

What is derailleur chain wrap capacity?

Chain-wrap capacity: up to 33 teeth. Click for an explanation of chain-wrap capacity. An important part of a rear derailleur's job is keeping the chain taut as you change gears. Chain-wrap capacity is a number that tells whether or not a derailleur will be able to do this on the drivetrain you plan to use it on.

How do I choose a rear derailleur?

When buying a new rear derailleur be sure to match it with your drivetrain 'speed'. 10-speed drivetrains use narrower chains than 9-speed so you'll need a mech to match. Most rear mechs are made of a polymer and alloy mix but you'll find carbon fibre in top-end models to shave even more weight.

What is the difference between long and short cage derailleurs?

In addition, the difference between the long, medium, and short derailleurs is the length of the cage. The cage is those 2 idler wheels on the rear derailleur. In a short derailleur, the idler wheels are closer to together while a long derailleur they are further apart.

Can I use any derailleur for my bike?

A derailleur for your mountain bike should match the specifications on the original derailleur. That is, while it doesn't need to be the same model of derailleur, it does need to be the same brand, in almost every case. It also needs to match the number of gears, or have more intended.

Can I use 10 speed derailleur with 11 speed cassette?

10-speed rear derailleurs do not work accurately with 11-speed cassettes when coupled with index shifters. The only exception are SRAM's 10-speed exact actuation road derailleurs which have the same rear shift ratio as SRAM's 11-speed road (exact actuation) and 10-speed MTB (exact actuation) derailleurs.

Can I use an 8 speed derailleur on a 7 speed cassette?

Although 8 speed can be made to work with a 7 speed cassette, it's not ideal. Get a 7 speed shifter. Once you've got the appropriate parts, make sure to set up the limit screws and indexing properly, so that you don't go off the edge of the cassette.

What does Shimano SGS stand for?

Shimano MTB rear derailleurs last letters will be GS or SGS, which stand for "Short cage" or SGS for long cage. A XTR rear derailleur will be RD-M970-GS (for short cage) or RD-M970-SGS (for long cage)

Can I change derailleur cage length?

Its not just the tooth capacity, the maximum sprocket size the derailleur is rated for can also change with the cage size in the same product line (i.e. they're not just changing the cage), with the maximum sprocket size going up with cage length.

Do I need a long or medium cage derailleur?

If you are in-between the capacity ranges of the two, which is often the case with mountain bikes, then note the following: long cage derailleurs will accommodate a wider gear range and deliver a better chain line, while medium cage derailleurs are less likely to be hit by rocks on the trail.

Can you use a 9 speed derailleur on a 7 speed bike?

Can I use a 9-speed derailleur on a 7-speed cassette? The answer is yes because the rear shift ratio of 9-speed and 7-speed derailleurs is the same if you stay within the same brand.