I currently have a 9 speed 11-25T cassette on my road bike. I'm thinking about switching to a different cassette with more teeth on the climbing gear. The cassette I'm currently look at is a Shimano CS-5700 10 Speed Cassette.

Can I swap my cassette from 9 speed to 10 speed without swapping my rear derailleur?

Is a 10 speed cassette wider than a 9 speed cassette or is the spacing between the gears wider?

Do I just need to adjust the wire tension in order to alter how much the derailleur moves when shifting in order to accommodate for the difference in spacing?

  • Edited to clarify title since there's a possible duplicate pointing here.
    – RoboKaren
    Dec 20, 2016 at 23:59

7 Answers 7


The spacing between 9 speed and 10 speed is controlled at the shift lever.

A 10 speed rear dérailleur will work with a 9 or 10 speed cassette and shifter. A 9 speed rear dérailleur is not compatible with 10 speed.

The width of the chain and the cogs is the biggest issue. The pulleys on a 10 speed dérailleur are narrower, and a 10 speed chain will not rest correctly on the jockey pulleys of a 9 speed dérailleur.

That does not mean it will not physically work, only that the shifting performance will be slow, you may drop gears unexpectedly, or have the chain skip unexpectedly.

Long story short, 10 speed should be 10 speed all the way throughout your bike for it to work consistently and properly.

Cable tension has nothing to do with cog spacing. That is designed into the shift lever. It is not adjustable, except by replacing the shifter. I hope that helps.

  • So it looks like I have a black Shimano 105 RD-5500, which Shimano lists as a 10 speed derailleur. So does this mean I can safely go from my 9 speed cassette to a 10 speed cassette? Apr 26, 2012 at 19:40
  • If you have 10 speed shifters, yes.
    – zenbike
    Apr 26, 2012 at 21:07
  • 3
    Keep in mind we are talking about Shimano road components specifically here. Shimano Mountain 10-speed derailleurs have a different pull ratio and are not backwards compatible with 9-speed shifters.
    – Benzo
    Oct 26, 2015 at 14:07
  • Of course, the RD-5500 is road kit, so we're not worried about that. :)
    – zenbike
    Oct 27, 2015 at 23:43
  • A 9 spd MTB derailleur is most definitely compatible with 10 speed road shifters. Nov 13, 2015 at 20:33

I just upgraded from a 9 speed to a 10 speed cassette. All I changed was my shifters and my chain. It's the shifters that determine how much the derailleur moves.

The big companies want you to spend money in upgrading everything but that is not needed. I did this on my 2011 Giant Defy that was outfitted with Tiagra group set. I changed the shifters to 10 speed 105, 105 10 speed cassette, and chain. Set it up and it indexed perfectly with the Tiagra 9 speed derailleur.


After a decade of riding, I rebuilt my bike, which came with Ultegra 9-speed shifters and derailleurs.

I replaced some parts, including the shifters. No new 9-speed shifters were available, so put on 10-speed Ultegras.

I kept the 9-speed rear derailleur in place. I took off the 9-speed cassette, put on a 10-speed cassette, and started riding.

Worked fine — no adjustment needed! Go figure.

I've not had any problems in several years and many miles on this hybrid arrangement.


Since 2000, I've been running an XTR long cage rear derailleur on my road bike is STI 105 shifters. I gearing is 11-34 (the max that the derailleur will handle). I'm also running a triple on the front, so I have to be aware of my gears... 53 front, I only use the 11 and four more. Middle, all of the gears... 30, only the lowest gears... 34 down four... works for me...

  • 1
    Welcome to the site, don't forget to check out the tour. I think that you are trying to answer in the affirmative, but can you edit to answer the question's specific points? I.e. are you using a 9 speed XTR rd with a 10 speed cassette and road shifters? how about wire tension? anything to be aware of?
    – Swifty
    Jul 29, 2019 at 11:55

The derailleur itself does not have any say on how many sprockets you can use or the distance between them, it is only limited by how close or how far away from the dropout it can get. For the most part you could probably use the same derailleur, but you might need to adjust the high and low limiting screws.

The real problem is with the shifter. Back in the old days, they only had friction shifters where you, the rider, had to fine tune the location of the derailleur by yourself. If you have that kind of shifter there is no problem. If you have a modern indexing style shifter where you just click a button and it jumps to the location for you then you might have to do a bit of tweaking or totally replace the shifter. Adjusting the cable only fine tunes the alignment of the derailleur to the sprocket and has almost nothing to do with the number of sprockets you can use.

But, before you do anything, check to see if your rear forks are wide enough to take an extra sprocket. You might even need to change the rear wheel altogether. I would take it into a bike shop and let them take a look at it. If they are worth buying from, they will give you some straight advice.


The ten speed cassette is not as wide as the nine speed so you do not need a new wheel. You may need a spacer to insure the ten speed cassette can be tightened properly.


As far as my knowledge stretches, the shifters control how far the derailleur moves with each shift so as long as the number of speeds on the cassette = the number of speeds on your shifters you will be fine. But be careful when selecting cassettes as you need a 10 speed wheel to run a ten speed cassette.


  • Not entirely true. It's more important that the pitch of the shifter be the same. There have been 7/8 speed clusters with several different pitches over the years. Jul 16, 2012 at 11:42

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.