Ted thanks for the confirmation on the barcons with Shimano 9 speed. Looks like the Shimano 9sp Rd's have a ratio of about 1.72.
I got the 4.34mm cog spacing from the Shimano exploded view drawing of a 2.56mm spacer and 1.78mm cog for a 9 speed cassette. John Hawrylak Woodstown NJ On Tuesday, November 29, 2022 at 4:00:33 PM UTC-5 Ted Durant wrote: > On Tuesday, November 29, 2022 at 2:36:34 PM UTC-6 John Hawrylak wrote: > >> Did you measure the RD ratio's or are they a published value somewhere?? >> > I have seen some published, but my memory is that I measured them from the > total distance between cogs and the total amount of cable pulled. > > >> Do you happen to know the ratio for a Shimano Deore M-591-SGS?? I have >> this with a Shimano 9sp road cassette (4.34mm cog spacing). >> > Classic Shimano 6-7-8-9 (and 10 Road) derailers are 1.72. > > >> The RD ratio would have to greater than 1.39 for the SunTour barcon 25mm >> travel to shift the 8 cog spacings on the 9 speed cassette (8 * 4.34)/25 >> = 1.39 >> > Well, I have Shimano 9 at 4.35, not 4.34, but otherwise I concur :-) My > spreadsheet says you need 20.2mm of cable pull to shift a Shimano 9-sp > derailer across a Shimano 9-sp cog set, so BarCons should have plenty of > capacity. Just don't try to put a SRAM road derailer on that setup - you'll > be a couple mm short. > > Newer derailers are using lower actuation ratios so that more cable pull > is required for each shift, so that there is more room for error. So, any > derailer that pre-dates the 11-speed era, other than SRAM "Exact Actuation" > will probably be a good match with BarCons. > > Ted Durant > Milwaukee, WI USA > -- 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/d56f3a0d-2250-41cf-98e1-f5349e754a38n%40googlegroups.com.
