Andy, I think you're onto something with the long tail of that particular mech. It appears to be a clone of the "9-speed" Shimano 105 that Riv used to spec on their triples 15-20 years ago, and they had a problem with them landing on the chainstay because of a combination of low BB (creating a steaper stay angle) and 46t big rings (instead of 52). Which is to say I'll bet most mountain triples would work better on that frame.
Joe Bernard On Wednesday, May 26, 2021 at 5:39:41 PM UTC-7 ascpgh wrote: > Real world gearing has lower tooth count/smaller circumference than big > brand OEM spec. The profile of front derailleurs caters to precisely what > they choose as your gearing, even MicroShift: > [image: Screen Shot 2021-05-26 at 8.10.13 PM.png] > That derailleur expects to be at a 52t chainring's radius (plus 1/8"for > tooth clearance) above the BB. Don't have to see it with those specs to > know there's a lot of cage tail to cope with possibly meeting the chainstay > when lowering it on your seat tube. > > > When you choose smaller chainring combos it requires moving the FD down > the seat tube to the right proximity of your big ring and if you've gone > below manufacturer's recommendations (or have a low BB) the tail of a > triple may hit the chainstay. > > As viewed from above, larger rings intersect the out angling stays if not > on longer spindles. Reduce those rings' toothcount and you just bought > clearance from the stay and you can lower your Q with a shorter spindle. > Max outward reach issue negated. > > This is how i've come to use old road double FDs on my compact > drivetrains. > > Andy Cheatham > Pittsburgh > On Wednesday, May 26, 2021 at 3:48:55 PM UTC-4 Tom Wyland wrote: > >> Um, it seemed like the cage wouldn't clear the stay? Also it didn't >> appear to move far enough for the "low" gear when I pushed it all the way >> in. Maybe it could be modified. I could re-purchase it (LBS) and try >> again, I supposed. Seems like you're all saying that most of them should >> work. So user error on my part, maybe? >> Here's the model: Microshift 539 Triple 9-speed: >> https://www.jensonusa.com/Microshift-R539-Triple-Front-Derailleur >> >> Tom >> >> On Wednesday, May 26, 2021 at 2:43:23 PM UTC-4 Joe Bernard wrote: >> >>> Tom, what exactly is/was the problem with the Microshift you tried? >>> >>> Joe Bernard >>> >>> On Tuesday, May 25, 2021 at 6:27:10 AM UTC-7 Tom Wyland wrote: >>> >>>> OK, I'm still struggling to find a FD. I tried a Microsoft R9 and that >>>> didn't seem to work. The local bike shop said 10 speed won't work with 9 >>>> speed (which is all they had). I'm running friction. >>>> >>>> Leah was nice enough to show how her older Deore (9 speed triple >>>> mountain?) was set up. Has anyone purchased a FD that works for them? I'm >>>> having a hard time with all of the different variations (on ebay) or the >>>> myriad of 10-speed triples new. >>>> >>>> Thanks! >>>> Tom >>>> >>>> >>>> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. To unsubscribe from this group and stop receiving emails from it, send an email to rbw-owners-bunch+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/rbw-owners-bunch/3870301f-6829-42f6-905c-f56f95d98c0cn%40googlegroups.com.
