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Components - Rotor cranksets

On this page: Rotor 170mm RS4X crankset

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Rotor 170mm RS4X crankset with 30/39/50 chainrings and Italian bottom bracket. Lightly used, $1,200.00

The crankset comes with the owner's manual, which we have also posted below the crank pictures.

Rotor crankset owner's manual.

As the crank rotates, this brilliantly designed crankset has the top crank arm zip over the top so that it is 15 degrees past top dead center when the other (lower) crank is at the bottom.

The result? The dead spot when the crank arm is at the top of its revolution and the leg exerts little downward (rotational) force is eliminated. The crank arms move relative to each other and do not remain collinear.

Rotor crank

Here's a drawing of a Rotor crank showing the left arm past top dead enter while the right arm is at the bottom of the stroke.

  • Rotor claimed that this crankset's design gave a 10% boost in available power while climbing and accelerating.
  • This crankset has an Italian bottom bracket.
  • Because it is out of production, bottom brackets of other threadings are virtually unavailable.

Rotor crankset

Here's our lightly used Rotor crankset.

Rotor crankset

From behind

Rotor crankset

Here's a look at the backside of the crankset.

Rotor crankset

From a slightly different angle

Rotor crankset

Close-up of the mechanism

Rotor crankset

Another view

Rotor crankset

It's not made like other cranksets.

Rotor crankset

It was originally mounted on a Mondonico bike. Here's how it looks installed.

Rotor crankset

We still have the box it came in.

Rotor crankset installation warning

Here's the warning that comes with the crankset. Installing this crankset is not like installing other cranksets.

Here's the Rotor RS4X crankset owner's manual:

It has installation & maintenance instructions as well as a parts list and exploded drawings of the parts.

Rotor MManual cover

Here's the cover

Safety warning

A warning to use care when installing or using your Rotor crankset

Table of contents

Table of contents

Rotor installation manual

Rotor Manual page 1

Rotor manual

Page 2

Rotor manual

Page 3

Rotor manual

Page 4

Page 5

Page 5

Rotor manual

Page 6. The crankset is installed.

Rotor care and use

Info on Rotor crankset care and use

Rotor manual

More maintenance info

Rotor manual

Specs

Spare parts list

First page of the spare parts list

Spare parts list

Spare parts list page 2.

Rotor manual

First page of exploded crank parts

Rtor manual

Second page of exploded crank parts


Rotor crankset

Third page of crank parts drawings

Rotor crankset

Fourth page of crank parts

Rotr crankset warranty

Warranty page

Back cover

Back cover