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With the T-Cycle Bacchetta Idler Kit you can say "Goodbye!" to the days of power-robbingly soft cogs, unlabeled bearings and the cheap look of a stock idler system. Our idler kit won't just make your bike look like the multi-thousand-dollar machine that it is, it'll make it feel like one. T-Cycle idlers help Race Across America (RAAM) racers every year power through grueling competition with rigorous durability and unparalleled efficiency. Many Bacchetta riders treat their bikes with a religious veneration that often borders on cultish devotion. If this describes you, then award your bike the idler kit it deserves. With a combination of precision machining and loving hand assembly, the power efficient all metal cog, top-of-the-line bearings and chic design, your ride will feel like a million bucks. The Bacchetta Idler Kit is simple to install, but the effects on your soul are profound.


1. What's so much better about this idler than the stock one?

The stock idler is OK. It's got decent bearings and it's pretty durable. What's better about this idler is it's not spongy, and carries the chain on the bushings instead of the edges of the sideplates, so it's more efficient. The bearings are  better, and in the case of the Elites, much, much better. And then there's the bling, especially on the Elite. One piece plastic is cost effective, but no bling.

The efficiency thing is important. Every bit of squishy in your drivetrain costs you, and there's no squish here. Carrying the power side on a cog keeps the edges of the plates from rubbing in opposite directions on an  idler bed as the chain bends and then straightens again. The stock idler isn't real squishy, it's better than most, but it does squish and it does cause plate rubbing.

2. If it's so good, why don't all the racers use them?

A lot of racers do use them. John never did because he wanted to show off the bikes as they came stock, which is fine.

3. What about noise?

A toothed idler has a different noise, true. It's part of the not being squishy thing. On a Bacchetta, the main source of noise is the light contact with the idler in the smaller gears. Chain lube plays a role, too, light lubes tend to let the chain clatter. Most people find there is some more noise in some gears initially, but that it goes away and is the same or quieter overall after a few hundred miles.

4. Why no cog on the return side then?

Three reasons for that. The biggest is that when you shift the front deraileur, the amount of chain wrapped around the front changes. If an Over/under idler were cogged on both sides, the extra chain couldn't come and go from the takeup at the rear deraileur. The second reason is the side angle of the return chain. The return chain runs on the outside, to let the power side run straight. Making the return chain come in as sideways as it does to a cog would invite jumping and noise. Running it against an abrasion resistant plastic plate is better overall. Since the tension in the return side is so low, the rubbing isn't a big factor. Lastly, cost. A plain bed is less expensive than titanium or aluminum, even if it is made from really tough urethane.

5. I get the bling and the efficiency. What else is there?

The stock idler is pretty durable, but these idlers generally outlast them by several times. Oh, and they are lighter than the stock idler by a few grams.


Installation requires two Allen wrenches and about 5 minutes.

  1. Turn the Allen wrenches in opposite directions to remove the shaft and the old idler.
  2. Inspect the shaft, then put on your new idler, the new spacer, and the chainkeeper.
  3. Bolt the shaft back onto the bike, using the wrench on the shaft to help keep the chainkeeper lined up as you tighten the 6mm bolt from the other side of the frame tab.

The idler itself doesn't need maintenance other than occasional cleaning. When cleaning, be sure to wipe the bearing area carefully. The bearings are sealed and will last a long time if dirt, water, and solvents don't get in. You should always avoid using pressure sprays or solvents around bearings. A gentle wipe with a soft cloth or cotton swab is all they need.


  • This is one of our simplest idler kits. It consists of an Over/Under idler and a new spacer. It is a drop in replacement for the stock idlers.
  • First year Bacchettas had a slightly smaller diameter idler, with a slightly smaller chainkeeper. If you have a first year Bacchetta, you will need a new, slightly larger chainkeeper. We make a nice matching keeper for this. All other years do not need a new chainkeeper, but you can upgrade any year bike if you wish.
  • The Bacchetta idler mount consists of  a special shaft with internal threads. One end of the shaft looks like a round headed Allen bolt, but the other end  has internal threads. The internally threaded end is secured to the chainkeeper and the frame tab by a regular 6mm Allen that pulls from the other side. The idler is allowed to float side to side on the shaft so it can track with the chain as it shifts.
  • There are two occasional issues with the idler mount. One is that the plating on the shaft can eventually wear off. When it does, the shaft is uneven and the idler doesn't float well anymore. The other is that on first year bikes, the frame tab can get bent from strenuous pedaling or from the bike falling over and hitting something. If the tab is not flat, the idler mount won't be straight and the idler won't float.
  • If you have a worn shaft, you can order a new one from Bacchetta, or use one of our stainless shafts. If the mount is bent, Bacchetta has a repair kit for that.
  • This kit is compatible with all Bacchetta models except the Bella, and Bella ATT with the wide bed power side idlers. For first year Bacchetta's, a new chainkeeper is required as the old one is smaller than the new ones.