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Cogs and Gearing?(5 posts)

Cogs and Gearing?escape_alcatraz2
May 6, 2003 9:34 AM

So if I wanted to add a lower gear, can I jsut change the one cog ring I want changed or do they all have to be sequentially lowered?

Basically I want to get a lower gear on my bike, do I need to shift everything down, or can I swap low, for lower?

probably need a whole cassetteDougSloan
May 6, 2003 9:39 AM
Depends on what you have; most cassettes these days have several of the larger cogs attached, either in 2's or 3's.

What cassette do you have?

re: lower gearFredrico
May 6, 2003 10:05 AM
Hey, Escape, if you just stick on a larger cog, the jump up to it will be clunky and you'll have to make a major adjustment in leg speed when you go into it or come out of it. Better to sequentially lower the next two or three cogs, or replace the set, as Doug suggests. Then the jumps between gears are evenly spaced.
more economical to swap cassettes.jw25
May 6, 2003 12:17 PM
Assuming you've got modern, 9 speed stuff. A 9 speed, 105 or LX level cassette runs for around $25 online, whereas tracking down a new cog or section of cogs (Ultegra and D-A have several larger cogs grouped together on an alloy carrier) could run you the same.
There's a 12-27 105, I believe, and there should be 12-28 MTB cassettes around. Spacing's the same, so they'll fit your hub. The one thing to check is your chain length - if you keep it in the small ring up front, you can handle a 28 with a short-cage road derailleur, but a misshift to the big ring could tear the derailler, or worse, the dropout, right off.
You could also switch to a triple rear derailler, as these have a longer cage, or use an MTB rear, along with an MTB cassette. A 12-34 should get you up most climbs, but here again you'll need to check the chain length, and the larger jumps between cogs can wreak havoc on your pedaling.
re: Cogs and Gearing?Chen2
May 6, 2003 3:03 PM
Yes it is possible to add one larger cog, depending on what you have now. Parts are available for customizing cassettes from As the others have said, if you can get a new cassette with the cogs you want, that is probably the better solution. You probably won't save money building a custom cassette but you might build one that fits your needs better than a new one. I do my own and run 13-25 and 13-26 9-speed Shimano cassettes. My wife runs a 14-28 9-speed that I put together. They all shift great.