Thursday, 3 November 2016

TerraCycle Chain Idler and Chain Tube Guide

TerraCycle Chain Idler and Chain Tube Guide - Intro

I think these chain idlers and chain tubes are mostly used on recumbent cycles, but there is also a benefit to using these on any bike where there is a long run of chain, such as long tail cargo bikes or longtail cargo ebikes.

In fact the latter of these two alternate options is where I am using the TerraCyle idlers and chain tube.
My Bike - Nicer Pictures to Follow

TerraCycle Chain Idler and Chain Tube Guide - Idlers Explained

Idlers are a sprocket which can run on bearing or bushing and provide a mid point upon which the chain may be guided. TerraCycle do two types of idler, one for loaded (power) chain i.e, going towards the pedals under tension, and one for unloaded (return) chain going away from pedals which is normally slack and floppy.

The loaded idlers are toothed, and come with alloy or titanium sprockets, and the unloaded variant come with no teeth.

The mounting brackets for these idlers typically incorporate some sort of lateral slider, so the the idler can move from side to side, but not up and down.

You can buy the idlers separately or buy a kit. The idler will run on a shaft and this shaft is clamped to the bicycle frame. There are a limited number of clamp sizes available. Below nice images courtesy of TerraCycle, terrible blurred scruffy images below courtesy of me.
Note Shaft for Lateral Movement

Loaded chain run over the top of idler. 

TerraCycle Chain Idler and Chain Tube Guide - Chain Tube Explained

The chain tube is used to stop the unloaded chain flopping about during its trip to the rear sprocket. I have often seen these on bike and thought how terrible they are, but in fact they work really well, even on loaded chain, provided the chain does not exit or enter at a steep angle.

Chain Tube
Some very long tails use very long lengths of chain tube. . .

Mega Chain Tube

TerraCycle Chain Idler and Chain Tube Guide - My Setup

So as mentioned I used these on a longtail ebike, I want to introduce a triple chainring up front but I had to divert the chain under the rear foot plates.

Chain Idler used to direct chain under foot plate. 
Through no fault of the idler kit the gearing did not work out, (running 5/6/7 speed chain on a single speed rear sprocket is not pretty or quiet), so I opted for a larger front chainring, optimised to match speed of front hub motor. It is a really good option, and I can use the idler to tension the chain if required.

As above but different angle.
The kit I purchased (for Xtracycle Freeradical) also included a chain tube, which I used to stop the chain slapping against the lower rear chain stay.

Chain Tube - Way better than it looks.
One of the most important things for me is that the idler and tube both run quietly, there is little in any rubbing noises, which I have experienced on say after market chain tensioners in the past.

Most of the attaching for the chain tube is down with zip ties, which means that clamp sizes (as is the case with idlers) do not have to be worried about.

TerraCycle Chain Idler and Chain Tube Guide - Conclusion

Chain tubes are a very easy way to introduce some form of chain management to your bicycle / tricycle / quadracycle, they can be attached with zip ties and simple brackets. 

Idlers are trickier to fit, but if you can buy a kit to fit you model of bike then it should be a doddle. 

They really do make for a quieter and more pleasant ride. 

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