I had a similar symptom somewhat recently. I'd get chainsuck when downshifting, sometimes. During my winter overhaul, the chain was stretched out, so I replaced it, and the chainsuck got way worse. The teeth on the small ring had worn, and replacing the small ring solved it.
So my advice is inspect the rings and measure the chain. Just as checklist items. On Wednesday, February 19, 2014 3:40:20 PM UTC-8, Jim Bronson wrote: > > True, the nubs might be bigger on the 8 speed pins. I don't know. One > reason that I was thinking of a 9/10 compatible big ring. > > The front shifting is not indexed. > > > On Wed, Feb 19, 2014 at 5:24 PM, dougP <[email protected] <javascript:>>wrote: > >> JIm: >> >> Yea, I'd leave it alone until after your event, as long as you can deal >> with it. You are correct in that if you really jammed it up you could be >> in serious trouble. I've seen chains locked so tightly between the ring >> and the stay that the chain had to be broken to get it loose. >> >> I've used a 9 speed chain on an 8 speed without even realizing it was >> wrong, with no issues. But I think that was with flat rings, no shifting >> aids. Your description of the chain getting hung up on the pin sounds like >> it's not clearing the pin. Perhaps on a 9 speed ring the pin does not >> stick out as far as on yours? If it's always the same pin, some file or >> Dremel time may solve it. >> >> Is your front indexed? If so, maybe it doesn't let the FD move inward >> far enough? Sounds like a micro-millimeter situation, which can drive you >> nuts running it down. >> >> dougP >> >> >> On Wednesday, February 19, 2014 1:00:04 PM UTC-8, Jim Bronson wrote: >> >>> The cranks are all original, they were new in the box 6 moths ago. >>> Thanks for the heads up on the spacing though, I was thinking maybe I >>> should replace the big ring with a 9/10 compatible ring, but your post >>> gives me some pause if spacing is going to be a problem. Probably more >>> trouble than it's worth on an $85 crankset. >>> >>> I think the BB spacing is probably a good explanation. It's 113 but >>> looks like it could be 110. Chainline doesn't look ideal from just >>> eyeballing it. >>> >>> I took it to the shop to see what they could find out. I don't have time >>> to mess with it before Saturday, when I am riding a 400K. Better for >>> marital harmony to spend time with the wifey than out in the garage jacking >>> with the bike, sometimes. >>> >>> >>> On Wed, Feb 19, 2014 at 12:34 PM, Michael Hechmer <[email protected]>wrote: >>> >>>> Do you have the original rings on the crank? Mixing Shimano rings and >>>> Sugino cranks, or vice versa, can cause spacing problems. It is possible >>>> the crank was set up with a 1 or 2 mm spacer beneath the middle ring. >>>> This >>>> is often needed to avoid jamming between the middle and small rings, but >>>> may be causing a problem for you. Checking this is not hard but requires >>>> a >>>> few special tools - pedal wrench, bolt extractor and 5 mm allen wrench. >>>> You need to remove the pedal, the crank arm and the small ring to get at >>>> the big-middle combo. >>>> >>>> Michael >>>> >>>> >>>> On Wednesday, February 19, 2014 1:07:23 PM UTC-5, Jim Bronson wrote: >>>>> >>>>> I am having some problem with my chain jamming when I downshift from >>>>> the big ring to the middle ring on my Sugino XD600. I have been >>>>> observing >>>>> this, and it appears what is happening is the chain is wrapping >>>>> completely >>>>> around the pin that is supposed to facilitate upshifting. >>>>> >>>>> Now, the XD600 is said to support 7/8 speed, and I am running a 9 >>>>> speed drivetrain, but from everything I've always read on here, it >>>>> shoudn't >>>>> pose an issue. Perhaps it is the chain I am using? It's a SRAM PC971. >>>>> I >>>>> was thinking of trying a KMC or Shimano chain just to see if it >>>>> eliminates >>>>> the problem. >>>>> >>>>> I really like this crankset otherwise, the 46/36/26 works really well >>>>> for the riding I do. I just think the jamming is potentially hazardous. >>>>> For now, I just really ease off the pressure when shifting chainrings, >>>>> and >>>>> then if it does jam, it doesn't throw me for such a loop. >>>>> >>>>> Any advice? >>>>> >>>>> -- >>>>> Keep the metal side up and the rubber side down! >>>>> >>>> -- >>>> 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 [email protected]. >>>> To post to this group, send email to [email protected]. >>>> >>>> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >>>> For more options, visit https://groups.google.com/groups/opt_out. >>>> >>> >>> >>> >>> -- >>> Keep the metal side up and the rubber side down! >>> >> -- >> 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 [email protected] <javascript:>. >> To post to this group, send email to >> [email protected]<javascript:> >> . >> Visit this group at http://groups.google.com/group/rbw-owners-bunch. >> For more options, visit https://groups.google.com/groups/opt_out. >> > > > > -- > Keep the metal side up and the rubber side down! > -- You received this message because you are subscribed to the Google Groups "RBW Owners Bunch" group. 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