Diagnosing Chain Slap

[Patrick]

I'm having a pretty bad chain slap problem on my MTB. I know some slap is normal on rough terrain,
but on my bike it's a lot more than normal (judging from the clinking noise I make riding next to my
buddies whose bikes are nearly silent in comparison). The chain is sized properly, so I know that's
not the cause. Could the derailleur be contributing? Perhaps the cage is too long? Or the springs
weak? I'm out of ideas, and patience! Suggestions?

-Patrick

 

[Peter Cole]

"Patrick" <[email protected]> wrote in message
news:[email protected]...
> I'm having a pretty bad chain slap problem on my MTB. I know some slap is normal on rough terrain,
> but on my bike it's a lot more than normal (judging from the clinking noise I make riding next to
> my buddies whose bikes are nearly silent in comparison). The chain is sized properly, so I know
> that's not the cause. Could the derailleur be contributing? Perhaps the cage is too long? Or the
> springs weak? I'm out of ideas, and patience! Suggestions?

The couple of times that happened to me were an indication that my freehub fixing bold had sheared
and things were being held together only with the skewer. When I was coasting, the cassette/hub
would rotate slightly, slacking the chain.

 

[Patrick]

> The couple of times that happened to me were an indication that my freehub fixing bold had sheared
> and things were being held together only with the skewer. When I was coasting, the cassette/hub
> would rotate slightly, slacking the chain.

Yes, that's probably a contributing factor - poor cassette movement. I posted a couple weeks ago
about the problem; I'm riding a pretty new set of King hubs, and they're subject to a rather long 60
hour break-in period during which the owner's manual advises there may be slight binding of the
cassette when coasting/backpedaling. The binding is much better than it was a few weeks ago thanks
to a few epic half-day rides upping the hours on the hubs, but the chain slap problem hasn't abated
noticeably.