Hmmm... downhill with low-load and brand new components is definitely weird. I'd suspect a stiff chain link before blaming an inherent design flaw.
(And just to restate it, we're talking about chainsuck with the chain not letting go of the chainring from the 6 o'clock position, and climbing up into the chainstay from below. Not simply jumping off the ring during a shift.) On the other hand, it may have something to do with where the bottom bracket is with respect to the shifty bits... Most mtb's have reasonably high bottom brackets - certainly when compared to the RBW designs. And Grant's bikes have lengthy chainstays. Combine that with wide range gearing and you probably end up with a bit more slack and less tension in the drivetrain. So, you are coming from a "lower" point, which could wrap an extra tooth or two. With no chain tension drawing the chain towards the derailleur, you start wrapping things up. It's less than a 1/4 turn of the cranks, so it can happen fast. Any "sharkfinning" on the chainring would of course exacerbate that. Pure, unadulterated conjecture on my part. - Jim / cyclofiend.com On Sunday, March 10, 2013 11:54:11 PM UTC-7, samh wrote: > > >I guess I must have good enough technique to not to have experienced it > ;)< > > I really don't think it has anything to do with shifting technique. I > have triple's on mountain bikes that get muddy, and I've never experienced > chain suck while riding them. Sometimes my mountain bikes are sporting worn > chainrings, cog sets, or chains. Sometimes those components are new. I > have doubles on my other road bikes, and they've never experienced chain > suck. > > I've switched gears in every conceivable situation, high load, low load, > wrong direction, right direction, while double shifting, or single > shifting--no chain suck ever. I've snapped chains while mountain biking > due to bad shift choices, but I've never experienced chain suck. However, > while riding my Rivendell on its maiden voyage, I experienced chain suck > during a low load shift while riding downhill. Based on all the damaged > chain stays I see in pictures of used Rivendells, it appears to be a common > problem. > > That's been my experience. I'd welcome a commercially available device to > prevent chain suck on my Rivendell. Perhaps they should be standard > equipment? > > > > > On Friday, March 8, 2013 8:05:20 AM UTC-7, Garth wrote: >> >> >> I've been riding triples since the early 80's ... never once have I >> experienced "chain suck" . I keep my FD perfectly tuned however, and I >> guess I must have good enough technique to not to have experienced it ;) >> > > On Friday, March 8, 2013 8:05:20 AM UTC-7, Garth wrote: >> >> >> I've been riding triples since the early 80's ... never once have I >> experienced "chain suck" . I keep my FD perfectly tuned however, and I >> guess I must have good enough technique to not to have experienced it ;) >> > -- 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 http://groups.google.com/group/rbw-owners-bunch?hl=en-US. For more options, visit https://groups.google.com/groups/opt_out.
