Brian — Do you have any pictures to share? If the FD is so low as to be touching the chainstay and you're having trouble shifting from the middle ring to the large ring, I wonder if that derailer is mounted a bit low. In the past I've had to install FDs with a larger gap between the top of the outer chainring and the lower edge of the derailer cage than I thought appropriate. Looked wrong but it needed to be higher to shift cleanly. After this was fine-tuned I didn't have issues dropping the chain
On Wednesday, February 5, 2025 at 11:43:40 AM UTC-5 Garth wrote: > I post this for reference, do save or download it for reference. It > applies to the most cartridges like Shimano and Tange and most others, save > SKF, Phil Wood/ > Mathematically, the difference between the 113 and 110 is 2.5mm on the > driveside. Given a certain amount of leeway in measuring, easily could be > read as 48mm chainline. > I saved it as both a photo file and pdf so choose whichever. > > Also note, that with cartridge BB's I use DS spacers all the time. I have > them from .5mm to 2mm. This allows me to use a shorter length if > applicable. > > Still, even a road triple FD should shift a 47-48mm chainline easily. I'd > check the cable install, ends and tension. Even my road FD's can easily do > that chainline. > > On Wednesday, February 5, 2025 at 9:29:52 AM UTC-5 lconley wrote: > >> Sounds like you are assuming that bottom brackets are symmetrical, side >> to side. They are not necessarily symmetrical. Some sizes are, some sizes >> are not, and not all brands are the same, size for size. The only real way >> to figure out what your chain line is, is to measure it. >> >> I addition, the type of gearing you are running has an impact. I am >> working on getting my half step plus granny Sugino triple working. It was a >> 24-34-44 with an Alpina D before I switched. I was quite surprised to find >> that the existing bottom bracket was a 107. I am about to try a 70s >> Campagnolo Nuovo Record front derailleur on the half step gearing. Frame >> is a Bombadil, 3x7 gearing. >> >> Laing >> Delray Beach FL >> >> >> On Wed, Feb 5, 2025 at 6:40 AM iamkeith <keith...@gmail.com> wrote: >> >>> >>> >>> On Tuesday, February 4, 2025 at 2:02:34 PM UTC-7 Brian David Lewis-Jones >>> wrote: >>> >>> >>> ... When talking with Riv, they mentioned that bottom brackets for >>> shipped framesets would be 110 - for a 45mm chainline. >>> >>> Fast forward, I didn’t think to measure it myself. But another thread >>> recently had me second guessing… Sure enough, measured, and voila, 113! >>> >>> So that answers a lot of my own questions on rough shifting! Next up, >>> I’m trying my hand at a 47.5 Altus triple FD and expect it to be smooth as >>> butter. And if not… well, I’ll certainly let ya know! >>> >>> >>> If a 110 spindle yields a 45mm chainline, then all other things being >>> equal, a 113 spindle would give you 46.5 - not 48. Maybe you realized >>> that, but it wasn't clear from your post. I can't imagine that this is >>> your issue, as long as you're within the range provided by the limit >>> screws. The longer chainstays on Rivendell bikes are more forgiving in >>> terms of chainline variations. It doesn't need to be perfectly in spec >>> because the chain isn't being forced to flex as much between disparate >>> chainring/ cog combinations. >>> >>> On the other hand and if I'm visualizing correctly - you might be better >>> off using any derailleur in the bottom/inner part of it's allowable swing >>> range, because the arc will be less "vertical" between adjacent >>> chainrings. But I guess it depends on the geometry of the specific >>> derailleur - whether it's top swing, bottom swing, how long the arms are, >>> etc. If you're having trouble because the angle between the seat tube and >>> chainstays is non-typical, and the chainstay is keeping you from mounting >>> it as low as you like, then you're looking for something that moves >>> side-to-side with the least amount of up-and-down. Some pics could help us >>> armchair a diagnosis a lot easier. >>> >>> Other random thoughts: >>> >>> Shimano made some "side-swing" derailleurs that had almost no vertical >>> movement, that I've used for this precise chainstay clearance problem, but >>> it was much more of an extreme combination of factors than you're dealing >>> with. Also, the cable routing is wonky. >>> >>> A couple of years ago, Bill did a detailed post about shortening the >>> shift cage so it would have more chainstay clearance. Maybe he'll chime in >>> or you can find that thread. >>> >>> Lastly, Before spending a lot of time and money, you might want to >>> measure the actual chainline yourself, to know what you're working with: >>> measure from the center of the middle chainring to the face of the seat >>> tube, and add half the seat tube diameter. >>> >>> >>> >>> -- >>> >> 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-bun...@googlegroups.com. >>> To view this discussion visit >>> https://groups.google.com/d/msgid/rbw-owners-bunch/57fbea91-874a-4192-85f4-1a9e8ec47e9cn%40googlegroups.com >>> >>> <https://groups.google.com/d/msgid/rbw-owners-bunch/57fbea91-874a-4192-85f4-1a9e8ec47e9cn%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> >> -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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