Toughest Kenworth

I don't own either of these models but I do know people who do. Depends on what work you want to do with them. The 909 and 659 run the same engines and driveline. The 659 is built as a more rugged truck. I think you can spec the 659 with slipper front springs which for off road are second to none. Things like they don't run intergrated sleepers because they put alot stress on cab mounts and to reduce cab vibrations. Also 659's run set back front axels and 909's set forward. 659's are alot more simple inside with less bells and whistles. Both will do the job brilliantly just depends on how much you want to spend. If you are doing alot of off-highway work I wouldn't go the SAR.