I agree with everything Bill says (that seems to happen a lot), although IME with a 1x system you can generally run the chain one or two links longer than "big-big plus two pins," since you don't have to worry about maintaining chain tension in the granny ring/small cog combination, and a longer chain means the rear derailleur maintains a more reasonable cage angle even in the low gears.
My first guess about the dropping issue would be a worn out chain. As a chain wears it develops more lateral flexbility, and more lateral flexibility means it's more likely that a chain link inbound to the chainring at an angle will miss a tooth and derail. I've definitely worn out cheaper 8sp chains (e.g. SRAM PC 830) in less than a year on bikes that get ridden regularly. There's also a theoretical argument to be made that 1x with a wide range cassette probably wears out a chain faster than, say, a triple, because you spend more time in gears with less-than-optimal chainline. But a lot of that probably depends on the individual's drivetrain setup and shifting patterns. On Wednesday, September 20, 2017 at 10:51:26 AM UTC-7, Bill Lindsay wrote: > > Such problems are usually straightforward to diagnose with the bike in the > stand. Can you have a good mechanic look at it? If you can't, my > remote-diagnosis questions would include: > > What exactly do you mean "dropping the chain"? Do you mean you are 'just > riding along' and it falls off the chainring? Do you mean that it skips > under load? Do you mean you shift the rear der, and the chain jumps off > the front while you shift? Something else? > > Whether or not the chainring is worn out is an empirical question. If you > don't know how to determine that from looking at it, have a mechanic look > at it. If you want us to look at it, post a photo. > > Whether or not the chain is worn out is an empirical question. Use a > chain checker tool to determine if it is. If you don't have one and don't > want to buy one, have a mechanic check it for you. If you want to check it > yourself for free, hold a 12" ruler up to 24 pins worth of chain. If 24 > pins worth of chain are more than 12-1/8", it's worn out. If it's a lot > more than 12-1/8", then other drivetrain bits may also be worn out. > > For just about all drivetrains with a Rear Der, the recommended chain > length is the same. Put the chain around the big ring + big cog (without > running through the RD). Figure out the minimum chain length that you > would be able to connect in that big-big combo, and add two pins worth of > chain to that. If you did not make sure your chain length was "right" when > you set up your 1x drivetrain, it might be wrong. > > A bent or unusually stiff chain link can cause a chain drop. A bent or > otherwise damaged chainring tooth can cause a chain drop. A > freewheel/freehub with a lot of drag in it can drag the chain forward as > you coast, which may lead to a chain drop. All these are checkable in the > stand, and should be easy to correct. > > best of luck > > Bill Lindsay > El Cerrito, CA > > On Wednesday, September 20, 2017 at 9:17:08 AM UTC-7, Jazzman Ruben wrote: >> >> Rivies, >> >> Are any of y'all using a 1x friction shifting setup? What are you using? >> Does it work well? >> >> I've been doing this for about a year/year and a half now. I pulled off >> the front derailer and cable, the stock rings off my Sugino and put on a >> "USAMade" (link >> <https://www.google.com/url?q=https%3A%2F%2Fusamade.myshopify.com&sa=D&sntz=1&usg=AFQjCNEQzmnjjxscMTYWpSyGGa4YALXJ7A>) >> >> chainring on with some single speed crank bolts. Otherwise, the drivetrain >> (silver shifters and antique Deerhead RD, 8 speed wide range cassette) >> remained in tact. Initially, I didn't have any chain drops. Lately, I've >> been dropping the chain a few times a week. >> >> I can't imagine that I wore out the chainring this fast. I wonder if the >> ol' Deerhead is getting tired? Do I need an RD with a clutch? >> >> -JR >> > -- 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 post to this group, send email to rbw-owners-bunch@googlegroups.com. Visit this group at https://groups.google.com/group/rbw-owners-bunch. For more options, visit https://groups.google.com/d/optout.
