Cassette Change

Jeremy W. Stone has Shimano 105 gears and has bought some new wheels and is considering changing his cassette, his question is whether he will be able to do this without having to make many adjustments to his present set-up.

Question:

Hello-I have a Shimano 105 R5501 rear derailleur and an 11-25 cassette.  I have ordered some new wheels and was thinking about putting on an 11-28.  Will I have to make any adjustments to the derailleur or lengthen the chain? 

Thanks…Jeremy.

Hi Jeremy,

Changing from a 25 tooth to a 28 tooth sprocket may not cause a problem; you probably won’t need to adjust the rear derailleur as the spacing on the cassette should be the same, but the position of the cassette on the hub maybe slightly different. When you fit the wheel, run through the gears and you will know straight away if adjustments need to be done. 

First check that the chain doesn’t come off the inside or outside sprockets when you change gears. At this point you will also find out if the chain is long enough, put the chain on the large sprocket at the back and the large chain-ring on the front, if it will do this then all is OK. If the chain will not go on to the large sprocket or that the jockey wheels on the rear derailleur are pulled to their limit then you should fit an extra two links.

As you are fitting a new cassette it maybe a good idea to fit a new chain anyway as the old chain might not run well on the new cassette. Its not a good idea to fit any new chain links to an old or worn chain as it will probably jump on the cassette, get a new chain at the same time as the wheels and the cassette and you could get the bike shop to fit it and then they will make sure that everything works well.

You should also check the indexing works well. If the gear changes perfectly from the smallest sprocket to the next smaller sprocket then all is good. If it doesn’t move over far enough then tighten the cable adjuster to take up a little more cable. If it over changes then you need to loosen the adjuster.

 

I hope this answers your query and we hope you enjoy your new wheels.