Monday, December 24, 2007

Idler Upgrade Details

PhattKatt's 1st Upgrade: Idler

A view from below reveals the subtle upgrade from the stock idler:

Idler developed for the Actionbent Tadpole Trike (TW/Bents trikes):

Flange-nuts were machined to accept a 12mm ID bearing (in hand):

Detailed drawing for the Delrin idler (bearing captured with circlips):

This upgrade was very simple and made for a nice clean chainline on PhattKatt. The first adapter/flange-nut fixed the axle solidly in the frame, and the other half captured the idler solid to the axle. A new chainkeeper was added and the stock nylok hexnut finishes the assembly with the tube-clamp.

This idler has proven itself on the ABTT. 1500 miles and virtually no wear.


Steve said...

Nice work on the idler.
I don't own a Catrike but I do read the board often. I've built 4 or 5 recumbents (SWB and LWB) and have toured a fair amount in the US, New Zealand and Ireland. My partner and I are planning a cross-country trip this summer on our Rans Screamer. I'd love a Catrike but my stable's kinda full.
I'm curious about your idler mod because one of my home builts has chain routing issue and I need a new idler (I'm weary of machining old skateboard wheels). The Actionbent site has an idler but it looks different - except for the spindle hole it's solid. Did you do this extra machining as well or is it another idler? Thanks.
-Steve Sussman (; "krispysteve" on the Catrike boards)

Simple Nature Spirit said...

Whenever someone has the space, I will recommend one of two idlers for their bike: The TerraCycle idlers are EXCELLENT and many versions are available... and the Greenspeed idler available from the Hostel Shoppe. You can get the 10mm ID bearing or an 8mm ID bearing. These are 15T idlers.

As for this idler, it is a new compact idler specically sized to fit the Actionbent Tadpole. It is 13T and the bearing ID is 12mm. I stock these idlers as upgrade and sell them for $35-. Adapters can be made for most applications although it is best to get the optimal idler for your specific application.

The Actionbent idler, like some other brand (Optima comes to mind) uses a rubber o-ring to quiet the idler. They also provide an undersized bearing that is not captured. I cannot recommend this idler for any upgrade.