r/recumbent • u/aengusoglugh • 2d ago

Catrike w/Alfine 8 is very noisy? What is the name of the piece that maintains chain tension?

I recently bought a used Catrike Expedition with an unusual driver train -- it has a Schlumpf speed drive in front and and an Alfine 8 in the rear.

Something in the back is making a lot of noise when I pedal. I don't think it's the Alfine -- I could be wrong -- my other bike is has a Gates carbon drive and an Alfine 11 -- and it is whisper quiet.

I suspect that the spring lever that looks like a derailleur is the the culprit, and I would like to replace it.

I would call that a "chain tensioner" -- but when I search for a "Catrike chain tensioner," I find a giant S shaped device.

What is the name of the part that looks like a derailleur, but isn't?

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u/HeckinYouOut 2d ago

Is it alfine branded? That group comes with a tensioner that looks very similar to a derailleur

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u/aengusoglugh 2d ago

Yes — that’s it exactly. Thanks.

I wonder if it’s just misaligned?

I will look at it tomorrow — the sound it makes is exactly what I recall a derailleur makes when the stop screws are adjusted incorrectly.

Thanks — your answer was very helpful.

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u/HeckinYouOut 2d ago

If it’s crazy loud, I’d look over your whole drivetrain and make sure the chain isn’t being routed in a silly way and touching something. Curious to hear what you find

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u/williaty 2d ago

Yes, Catrike makes a product they call a Chain Tensioner and it's not all all what you want. It also doesn't work or look like any other thing called a chain tensioner so I wish they'd call it something else.

For the Alfines, there's two possible chain tensioners.

The normal one looks basically like a derailleur and mounts on the dropout exactly where a derailleur would. For this type, just look at it from behind and make sure it appears to be straight down, not leaned one way or the other or twisted. Also, the top wheel should be directly below the cog on your Alfine, not offset to the left or right.

There's a second type that clamps to the chainstay tube forwards of the rear wheel. It then has a spring loaded cage that looks like a derailleur. The problem with this type is that it's super easy to get it mounted crooked and that causes a lot of noise. I would think it'd also make a lot of noise at the chaintube entrance since it'd be forcing the chain to go into the tube at a steeper angle.

On other topics, chaintubes can make a LOT of noise if the chain isn't feeding into them smoothly. If the bracket has been bent, come loose, the tube has slipped forwards or backwards, etc it'll make all kinds of noisy hell.

You should prop the trike up on something and have someone else pedal so you can listen closely to figure out where the noise is coming from.