Frequently Asked Questions- Bacchetta Idler Kit
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
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.