Elite Over/Under Idler • TerraCycle, Inc.

Not compatible with flat top chains.

There exists no better over/under idler than the Elite Over/Under Idler from T-Cycle. A hybrid of all the best qualities that T-Cycle idlers offer. Every piece of this idler is exquisitely machined: the beautifully crafted aluminum sideplate on the power side and an aerospace grade ballistic nylon sideplate on the return side, the titanium cog and industrial urethane chainbed, each built for supreme durability, and the immaculately designed inner cores. Elite Over/Under Idlers also come with either the unbeatable resilience and consistency of the precision hybrid ceramic bearings (8mm only) or top-quality ABEC-7 steel bearings(for other sizes). Never has a ride been so smooth and so reliable as with an Elite Over/Under Idler.

FAQ

What's so great about this idler?

Elite Over/Under idlers have a solid metal core surrounded by a very light machined out aluminum frame. The power side chain is supported on a titanium cog and the return side chain runs on a tough industrial urethane bed. This gives the best of both worlds: a 6AL4V Titanium cog for maximum efficiency and long life on the power side, and a simple, super durable chainbed on the return side. Everything runs on a pair of high quality bearings. It's tough, light, and really sharp looking. It's the ultimate idler for any over/under application.
How big is the idler?

The Over/Under idler has an outside diameter of 2.75 inches (70mm) and is 1.18 inches (30mm) thick.
Can this idler be repaired?

Yes, we can replace any element of the idler. With reasonable care and proper alignment, the idler should last tens of thousands of miles, but in the rare instance that something has worn out or been damaged, contact us and we can revitalize your idler!
What about efficiency and noise?

We make exclusively toothed idlers for power side applications because they are both quieter and more efficient that way. There are a host of technical reasons for this, but the biggest and most basic one is that chains are designed to be carried by the bushings. It is a nice, big flat area designed for forces to be applied to it. Chains are not meant to be carried on the edges of their sideplates. It just doesn't work as well. Since the core of the idler is all metal, from the chain bushings through to the bearings, there is no sponginess to soak up power. The chain sideplates aren't used to transmit power down into the idler, so there is no rubbing contact like there is on plain bedded idlers. Noise is a complicated issue, but we expect you'll find these idlers are quieter than other idlers. The cog is specially shaped to smoothly and repeatably mesh with the chain, and unless the chain is being pulled sideways quite a bit, there will be very little rubbing. We always recommend allowing your power side idler to float side to side with the chain as it shifts. Another common source of noise in drivetrains is insufficient contact on the idler. If there is not enough deflection of the chain at the idler, the chain and the idler don't have a chance to mesh properly. This is true for all types of idlers. You'd think that a chain only lightly touching an idler would be quieter, but because of the complex geometries involved, there is a minimum amount of bend or wrap required to get maximum silence. The amount varies with the diameter of the idler, the larger the idler, the smaller the angle required.
What's the difference between these idlers and the Sport Series idlers?

The Elite Series idlers have titanium cogs, hybrid ceramic bearings, and completely CNC machined frames. The cog and frame are extensively hollowed out for lightness. They are designed to look as good as they work. The Sport Series idlers have 7075 Aluminum cogs, top quality steel bearings, and injection molded fiberglass reinforced Nylon frames. They are designed to be simple, high performance, and tough. The look is much simpler, more businesslike than bling.

ADDITIONAL INFO

Available with either 8mm or 10mm ID bearings. The most common bearing size on recumbents is 8mm.
The cog is precision machined, but there is a break-in period while the cog and the chain get to know each other. After that, you can expect your idler to last many, many thousands of miles without needing service.
In case of damage, all parts are individually replaceable. Contact us for details.
The fasteners are M3 x 25 stainless steel socket head cap screws.
The Elite Over/Under Idler weighs 106g
A third bearing can be added to the return side for the rare applications where that is necessary.
Bearing Care: The bearings are shielded, not sealed. Shielded bearings have less rolling resistance because the seal, while super close, doesn't actually rub. True sealed bearings are rare, when people talk about "sealed bearings", they usually actually mean shielded. These are top quality shielded bearings and will last a long time. What kills bearings is solvent, dirt, and water intrusion. As long as you don't spray things on the bearing faces, you will be okay. Regular amounts of dust and dirt getting on the outsides of the bearings won't be a problem, as it's hard for it to get past the shields (the shields really do come *very* close to the bearings). When you clean them, what you want to do is gently wipe dirt off and away from bearings, rather than rub aggressively and push the dirt past the shields. There is no need to lube the bearings, the special grease that's in them is what they need.
The urethane chainbed is very durable, but can be affected by strong solvents. Dumonde Pro lubes apparently have such solvents in them. All the other lubes we and our customers have tried are okay. We don't recommend using Dumonde Pro series chainlubes with this idler.
No maintenance should be required other than occasional cleaning with a paper towel or soft cloth. We recommend keeping solvents and soap and water away from the bearings, they don't need aggressive cleaning and solvents and soaps tend to go after the grease. It's water resistant, but solvents and soaps are harder to deal with.
We recommend setting up your idler so it can float side to side with the chain as you shift. If your existing idler mount doesn't allow for this, we offer a variety of upgrade parts to make this possible.