CycleBanter.com - View Single Post - Chain idler efficiency

**Tom Sherman[_2_]** · April 29th 08, 04:21 AM posted to rec.bicycles.tech,alt.rec.bicycles.recumbent

aka Jobst Brandt wrote:
The angle at which the chain enters and leaves front sprockets and
derailleur idlers is the sine of the angle which is the lateral offset
between the two ends of the chain span divided by the free span
length. Therefore, the longer the chainstays and the fewer the gears
on the sprocket cluster, the smaller the angle between chain and
sprocket plane. The angle causes lateral sprocket tooth wear and
idler wheel wear.

Indeed, which is why I would not deliberately ride in cross chain gears
on my ATB with its 43 cm chain line (BB to hub) but will do so on my
RANS Rocket with its 131 cm chain line.

--
Tom Sherman - Holstein-Friesland Bovinia
The weather is here, wish you were beautiful