The heavy-duty R-series range includes multiple model families developed for multiple applications.
 Alongside the standard conventional (R-190, R-200, R-210, R-220), a "D" denoted models with diesel engines and an "F" denoted tandem rear axles; an "H" was used for heavy-duty models.
 Other R-series models were developed primarily for heavy-duty applications, including the R-306 (developed for fire trucks), and the long-nose RD-305/405 (to fit Cummins diesel engines).
 An "RC/RDC/RDFC" model family was a COE, derived from conventional-cab trucks.
   
The R-series served as the basis for other model ranges, including the V-series; introduced in 1956, the V-series was developed to accommodate the introduction of V8 engines from International, receiving a slightly restyled hood and redesigned grille.
 
Following the introduction of the S-series, the heavy-duty R-series underwent several model revisions.
 After becoming part of the S-series, the R-series COE was replaced by the DCO-400 "Emeryville" tilt-cab COE in 1957.
 In 1960, International began to consolidate several heavy-duty models of the R-series and V-series, creating the construction-oriented F-series; the 1962 introduction of the Fleetstar short-hood conventional also was phased in as a replacement for mulitple models of the R-series.
 In 1965, the construction trucks dropped a letter prefix, becoming the 210/230 series; the model line was produced through 1972, when it was replaced by the Paystar.
The heavy-duty R-series range includes multiple model families developed for multiple applications.  Alongside the standard conventional (R-190, R-200, R-210, R-220), a "D" denoted models with diesel engines and an "F" denoted tandem rear axles; an "H" was used for heavy-duty models.  Other R-series models were developed primarily for heavy-duty applications, including the R-306 (developed for fire trucks), and the long-nose RD-305/405 (to fit Cummins diesel engines).  An "RC/RDC/RDFC" model family was a COE, derived from conventional-cab trucks.    
The R-series served as the basis for other model ranges, including the V-series; introduced in 1956, the V-series was developed to accommodate the introduction of V8 engines from International, receiving a slightly restyled hood and redesigned grille.  
Following the introduction of the S-series, the heavy-duty R-series underwent several model revisions.  After becoming part of the S-series, the R-series COE was replaced by the DCO-400 "Emeryville" tilt-cab COE in 1957.  In 1960, International began to consolidate several heavy-duty models of the R-series and V-series, creating the construction-oriented F-series; the 1962 introduction of the Fleetstar short-hood conventional also was phased in as a replacement for mulitple models of the R-series.  In 1965, the construction trucks dropped a letter prefix, becoming the 210/230 series; the model line was produced through 1972, when it was replaced by the Paystar.
International R series