The idea behind the Multi-Purpose Idler Kit is to supply you with everything you need to optimize the chainline on your bike,
even when you aren't sure what you need. You can think of it as an
The Clamp-On Idler Mount allows you to relocate idlers to where they work best.
A Power Idler and a Return Idler give you the adaptability for any configuration. Having separate idlers opens up lots of possibilities for you to perfect your chainline-
Under/Under, Over/Over, and Over/Under combinations are all possible. Finally, a Clamp-On Double-Sided Chain Keeper
enables the idlers to float with the chain for high efficiency and low noise. This combination of beautifully crafted, insanely durable parts ensures maximum configurability so you can find the chainline that works best for you bike.
1. What can I do with this kit?
Lots of different things. Since it comes with a Clamp on Idler Mount, you're
no longer limited to the stock idler position. The idlers can now be in lots of
other positions. Since it comes with independent Power and Return idlers, you
are free to experiment with the chains going over both, under both, or any
combination of both over and under. Clamp on chainkeepers means the chainkeeping
function is independent of the idler mounting function, letting the idlers float
with the chain as you shift for maximum efficiency and lowest noise.
2. What are all the different mounting positions?
The Clamp on Idler Mount lets you position the idlers above or below the main
tube of your bike/trike. The mount has 3 mounting holes, so you can vary the
up/down position as needed. The clamp can be positioned anywhere along the main
tube that is not strongly bent.
3. Talk to me about chainkeepers.
Clamp on chainkeepers considerably simplify chainkeeping. Basically, you can
move the idlers and chains around into whatever configuration you'd like, then
pop the chainkeeper onto the end of the idler mounting bolt and clamp it down.
If you get the double sided chainkeeper, you can run the chains in the
over/under configuration without worrying about the chains coming off. If you
aren't sure what chain configuration you're going to wind up with, we recommend
getting a double sided keeper. If you wind up not needing the double sided
function, it's no problem to have that option there without using it.
The Clamp On Idler Mounts in this kit range from 1.5 inches to 60mm. We also
make some other odd sizes, like 50 and 54mm, that you can order. Just make a
note of that in the area provided.
The clamp on mounts are sized very accurately for the particular tube size,
right down to an allowance for the paint thickness. If there is a question about
the size of your tube, measure accurately, or contact us to see if we know the
If you know you only need to relocate one idler, and don't need both a Power
and a Return, it is possible to purchase only the parts you need from the
Chain Management Accessories sections of our website.
The clamp on mounts are made for round tubes that are straight or nearly
straight. If your main tube is curving where you'd really like to put the
idlers, it is unfortunately not possible to clamp there. For the clamps to grip
strongly, the fit is very exact, and there's just no way to predict that on a
Generally, it's valuable to allow the power side idler to float inwards as
much as possible. The position of the chainline in the lowest gear is usually
very close to the level of the outside of the main tube. For that reason, these
mounts are designed to put the idler mounting options in as close to the frame
as possible. This means the idler mounting holes in the clamp on mounts are
either above or below the main tube and not near the centerline.
If it is absolutely necessary to have the idlers somewhere near the
centerline of the main tube, or to have them radically above or below the main
tube, we do offer an Adjustable Idler Mount. Right now, we only make them in two
sizes, 1.75 and 2.0 inches. This is an extra cost option, but does give a
wider range of mounting positions. Unfortunately, to do this necessarily
requires increasing the minimum closeness to the outside level of the main tube
by about 3/8 inch (10mm). If you have a hub gear, this will be OK, but for most
deraileur systems, this would put more side bend in the chain in lower gears
that you will probably want.
To most easily experiment with idler positions, put one of the idlers on the
provided idler bolt. Holding the bolt in one hand, push the chain up or down
with the idler and move the idler around to different places and see the effect
on the chainline. When you have identified a promising spot, attach the clamp on
idler mount there and see how it works.
This kit is for the many bikes where a) the way they are configured (boom
position, chainring sizes, etc.) strongly affects how you want to set up the
idlers, b) the many small run bikes we just don't have formal kits for, and c) some of the brands
of bikes where the model name may be the same, but the details change
frequently (Performer, TW Bents, Actionbent, some others).
provides maximum reconfigurability to enable maximum experimentation.