More Miles from Your Bicycle's Cassette

Nine speed cassettes (rear cog set) for your bicycle are not prohibitively expensive, but it would be nice to get a few hundred or more additional trouble free miles from them. A particular pattern of wear caused by the chain on the cog teeth creates problems that show themselves as chain skipping or hopping and poor shifting or hesitations in the movement of the chain from one cog to the next during shifting.

Pictured below is the profile of the gullet between two teeth on a typical cog.

Step 1 The Hook

Over time and use, a hook wears into the gullet profile as shown by the red color. This keeps the chain from sliding out of the gullet smoothly on every tooth during use. This hook does not need to be very pronounced for it to affect performance.

Comments

[larcrun]

Heh Phil. I'm only familiar with one type of cassette, the shimano m760 9 speed and the rivet heads on outer side are flat with cog(so you would have to also grind cog face) and on the inner spoke side most heads are visible but indented into plastic spider so can't reach with grinder. Wondering what kind of cassette you have and/or how you do this rivet removal. Also, are you saying you only have to remove the small cog rivets? Not on mine.

Would sure like to try this and get more life out of cogs. Thanks for the excellent post.

[Phil B]

Thank you for your comment and inquiry. It has been a couple of years since I did this last. The cassette was stock from the factory on my 2006 Specialized Allez Sport triple (27 speeds--9 speed cassette--Shimano equipped). I do not have the model number of the cassette. As I remember, the rivet heads on the spoke side were round rather than flat. I did not find the plastic spider you mention. I think I got a couple hundred extra miles out of my old cassette by grinding the hooked teeth on my old cassette. This does not give an unlimited life extension. I think this fix was worthwhile, but I also remember that when it was really, really time for a new cassette, the new cassette was a very nice improvement.

[larcrun]

Yes, I have since learned that not all cassettes have the spider that blocks rivet head access that my XT unit has. Just saw a Sram PG970 9 speed that has a very small 1.5mm allen head screw on back that allows individual cog removal. I'm surprised you only got a couple hundred miles.

[iKill]

if you take the hooks off wont it work even worse

[Phil B]

No. The hooks interfere with the smooth release of the chain from the cog teeth.

[nagutron]

If the cassette rings are symmetrical, you might be able to double their life simply by flipping them over. Can you think of problems with that?

[Phil B]

Your idea is clever and makes good sense. But, the experience I had in putting the cogs back on the spline is that they will not go onto the spline if they are wrong side up, that is flipped. They will go on only in their factory ordained position. Thanks for the suggestion, though.

[Phil B]

I understand what you are saying, or, they say in the South, "I hear ya'." I biked a lot in my 20's and some in my 30's. Then I began to think I was too busy. I jogged, but eventually I tired of that. The weight began to accumulate around my middle. 28 months ago I decided no one was going to do it for me, so I began riding. It puts me into a mellow state of mind when I am out on the bike. I have racked up 7,000 miles since and try for 100+ miles per week. My "new" bike (parts shown here) now has 5,000 miles on it. Find a route you like or a time of the day when you can ride a route you like without too much traffic, and ride for enjoyment. The health benefits will come with it.

[toekneebullard]

I look forward to the day I have to replace parts due to too much usage. Nice 'ible, thanks for the info!