How do I identify a Shimano Ultegra rear derailleur?
John Castro
Published Feb 11, 2026
How do I identify a Shimano Ultegra rear derailleur?
To determine what model you have, look on the back side of the cage. If it’s not stamped there, it is somewhere else on the derailleur. If not, and assuming the entire group is the same vintage, you can find the number on say, the back side of the rear derailleur parallelogram.
Can I use any Shimano rear derailleur?
Always use Shimano rear derailleurs with a Shimano drivetrain. Always use SRAM rear derailleurs with other SRAM components. Yes, also only use Campagnolo rear derailleurs with Campagnolo cassettes and shifters.
What is a GS rear derailleur?
“-GS” refers to medium-cage rear derailleurs, built with a maximum chain capacity of 37T to 39T or less. This is usually the longest cage offered for road bike rear derailleurs, but also the default “short” option offered for their mountain bike counterparts.
What is Shimano RD?
The mechanism rear derailleur, SHIMANO SHADOW RD, is intended for more aggressive riding. Because of its low profile and single tension construction, the derailleur does not hit the chain stay in rough riding conditions. The result is smooth and silent performance.
Is Alivio shifter compatible with Deore RD?
Yes. You can take any 7-9 speed Shimano rear derailleur and use it with any Shimano 7-9 rear shifter. And the Deore front shifter will pair fine with the Altus FD.
Which is better SS or GS?
For your particular gearing range (50/34 compact double and 12-25 cassette), an SS will work. GS is for wider gearing ranges that will result in more chain slack when the drivetrain is crosschained small-small, like on triples or if you are running a very large cassette on a double.
Is Alivio better than deore?
Alivio is only one step down from the more well-known groupset Deore (M6000), which appears on entry-level racing mountain bikes all over the world. As one might expect, it’s a little bit better again relative to Acera and the groupsets further below. Smoother, faster, slightly more reliable – you get the idea.
What does Rd mean in bike?
Rear Derailleur: Also known as Rear Der on the picture, also known as Rear Mech or Mechanism. Rear Shock:The rear suspension on a full suspension bike, it adsorbs the bumps.
