Park SR-1 Chain Whip Review
The SR-1 is a chain whip, which has multiple uses, but it's mostly used for cassette and freewheel removal. This model even has a nice wrench at the opposite end, which matches up nicely to the FR-5 lockring remover (which you need for removal of most modern cassettes. Older cassettes require two chain whips.)
Pros: The SR-1 has a very long handle for extra leverage, which comes in handy. The metal is rock solid as with other Park Tool products, and the plastic cover on the handle makes it comfortable.
Cons: It's a little expensive than other basic tools, especially if you need two. (With older cassettes, you need two chain whips. With newer cassettes, you need two of these chain whips or one plus a big adjustable wrench.)
The Final Word
I'm glad I spent the money on one of these, because cassette removal can be a tough job that puts a lot of stress on the tool - and Park Tools are the strongest out there.
I only use one of these and couple it with an adjustable wrench when necessary, but if you have the money and do lots of drivetrain swaps, get two.