This question is regarding single and double flanged rollers on a Case 850D track dozer. The sequence that I removed was: Sprocket-D-S-S-S-D-Idler But it was not like that from the dealer/factory I can't find any documentation on this topic. In my parts/service manuals, it only shows single rollers being used. Any recommendations? I've read in other threads Sprocket-S-D-S-D-S-Idler is preferred, as the sprocket could damage the double. But I don't think that is an issue here.
None of the Case guys have commented so here goes. I will preface these comments by saying "if it was a Cat dozer, the following would apply." However I see no reason why the same "rules" should not apply to your machine. I reckon the Cat equivalent to your 850D would be something around a D4C model. This from the Cat Undercarriage Manual.......... From the chart which follows, you will note that the rear roller (the roller nearest the sprocket) is usually a single flange roller. If a double flange roller were used as the rear roller, interference could occur between the inner flange and the sprocket teeth. Therefore, a double flange roller should not usually be placed in the rear position.
Yes, well, I don't think Case really state exactly how the layout should be. I have taken a look in some older service manuals, as these tend to explain how things work a little better than newer manuals. As I recalled, there is no clear instruction....I did find different layouts showing the double flanges being as @Nige has illustrated above & also showing them in the One & Six positions as well - & showing single flanges only, in a five roller configuration. Top pic - early 1150 Lower pic - early 850 Interestingly, these pages discuss "rotating" the rollers at about 50% of their life to get maximum wear life - I doubt anyone has ever done that & likely ever will! Personally, I've always fitted the double flange at front & rear, & never had any issues that were reported back to me.