The Complete Guide to Chain

5.2.3 Outboard Roller Chain Top Roller Type

Free Flow Chain: Automotive industry, precision equipment industry, general uses

Application Example

Outboard Roller Chain with Top Rollers (Top Roller Chain) is used primarily in the automotive and precision equipment industries for free flow conveyance (Figure 5.12).

Construction and Features

Top Roller Chain is based on the standard chain with extended side plates (SK-1 attachments). Top rollers are installed on the pins that connect SK-1 extended plates. Pallets with conveyed objects are loaded on the top rollers. Table 5.4 shows some of the base chains that are available.

Figure 5.12 Outboard Roller Chain with Top Rollers
Top: Plastic Top Roller
Bottom: Steel Top Roller
Figure 5.12 Outboard Roller Chain with Top Rollers
Figure 5.12 Outboard Roller Chain with Top Rollers

Table 5.4 Outboard Roller Chain (Top Roller)
Base Chain Top Roller Spacing Top Roller Material Chain Pitch *Max. Allowable Load (kN)
RS Roller Chain Every Pitch, 2nd Pitch Steel, Plastic 12.7~31.75 2.65~17.1
Double Pitch Chain Every Pitch Steel, Plastic 25.4~63.5 2.65~17.1
Engineering Chain Every Pitch Steel 75~200 4.2~35

*Maximum allowable load listed in this table for RS Roller Chain and Double Pitch Chain is the same as that of standard carbon steel chains. For the Engineering Chain, it is one-seventh of the average tensile strength of standard chains.

RS (single pitch) Top Roller Chain can only be equipped with an S-roller. R-rollers and S-rollers are available for RF (double pitch) Top Roller Chain.

The features of Top Roller Chain include the following points:

  1. High maximum allowable tension.
  2. Economical cost.
  3. Lower stability than Side Roller Chain, because Top Roller Chain is narrower.
  4. Snap covers are not available for Top Roller Chain. It is difficult to prevent small objects from falling in between chain components.
  5. Noise levels during operation are higher than those for DOUBLE PLUS® Chain. (Noise is about equal to Side Roller Chain.)
  6. Top Roller Chain installation kits, including the guide rails and other components, are not commonly available.


Standard sprockets can be used with RS (single pitch) chain and with RF (double pitch) chain with S-rollers. Other types of Top Roller Chain require special sprockets.

Selection and Handling

Top Roller Chains are available with R-rollers and with S-rollers. The use of R-rollers is preferred, especially if either of the following conditions exists:

R-rollers have lower coefficient of friction (without lubrication, R-roller: 0.12; S-roller: 0.21).

Chains for Special Applications

Top Roller Chains can be made of stainless steel, carbon steel, or plated carbon steel.

LAMBDA® Top Roller Chain is available for lube-free operations. Engineered plastic top rollers should be used in this construction because they are lube-free.

Two types of Top Roller Chains have higher stability than standard Top Roller Chains (Figure 5.13). They are:

Please refer to Plus α Alpha catalog for additional information.

Double Strand Top Roller Special Attachment for Prevention of Turnover

Figure 5.13 Types of Higher Stability Top Roller Chain