On Monday, August 12, 2019 at 9:15:27 AM UTC-5, AMuzi wrote:
On 8/11/2019 3:22 PM, wrote:
Did a gravel ride on Saturday morning. 43 miles total, about 30 was gravel. Lot of rough gravel, very few hard, smooth, compacted stripes on the gravel road. I'm accustomed to gravel roads having well worn tracks where the cars drive. Nope.

For the final 6 miles of pavement, the rear derailleur did not work. When shifting up and down the cassette, it did not want to find the cog and jumped around a lot. I'd click and nothing happened. I'd click again and nothing happened. I'd click again and it would sort of grind and jump around looking for a cog. So I'd have to shift a bunch to get it to settle down into one cog. It did not go thunk into the next cog when shifting the STI levers.

And when shifting down to the small ring, the chain drooped on the bottom. The spring in the rear derailleur to pull it backwards and take up the chain slack was not working correctly. It wasn't strong enough to pull backwards with enough force. Had to ride the big ring only for the final miles, with the bad between cog shifting too. I basically had a single speed.

I cleaned the bike with the garden hose afterwards thinking maybe it was just the gravel dust that ruined everything. Have not had a chance to test the shifting in the basement shop. Will also try taking the derailleur off and re-lubing everything and really cleaning everything with gasoline. And spraying lubricant into the STI levers. And oiling the cables.

Questions: Can any 10 speed Shimano rear derailleur work? Dura Ace, Ultegra, 105, Tiagra, AND all of the mountain bike rear derailleurs? Nashbar has a lot of 10 speed rear derailleurs for sale. Thinking maybe a mountain will be better than road for gravel and mud? Its a short cage rear derailleur. But I was thinking maybe going medium or long if I could. Yes, no? I've never noticed any shifting difference between derailleur lengths. Current rings are 46-36 with 12-28 cassette. But maybe I will want to go 46-33 rings (110mm bcd five arm crank) and 11-32 or 11-34 ten speed cassette.. Make it my second mountain climbing bike. But its a heavy steel frame....


Santana uses Deore XT with Ultegra levers which is an
excellent setup and they did the same in 10 and 9 speed.
(There are other formats, Saint Shadow SL Alternate Marvel
Universe etc)

That said your gear range is not excessive so you should be
OK with a GS road changer. You're about at the chain length
limit for an SS.


For future, but unlikely, gear changes, I went with a new medium cage Shimano 105 rear derailleur. I've always had the exact same perfect shifting with both short and medium and long cage rear derailleurs. So no reason to stay with short cage if there is any chance of needing more range.


Get your eye behind the rear changer and see if the cage is
parallel to the chainrings. Also see if the lower pivot
spring works or is sticky. Your description indicates that
maybe the top spring works and the bottom does not maybe.
The most common cause of that is chain too short with a
mis-shift to big-big but I assume you didn't run it short.

I did not check the rear derailleur cage alignment. But will check it with my Park tool once I get ready to put on the new Shimano 105 medium cage 10 speed rear derailleur. Its possible that was causing the mis-shifting between cogs with the STI and rear derailleur. But the bike was shifting perfectly at the beginning and middle of the ride. It was just at the end when everything fell apart. And I did not drop the bike and bend the rear derailleur hanger. I'm pretty sure its the bottom spring mounted in line with the top pulley. It just does not pull the cage backwards hard enough to take up the slack on the bottom of the chain. And the rear derailleur just is not shifting between cogs correctly. Chain is definitely not too short. And I am positive I did not shift into big-big ever. Maybe big ring and second or third biggest cog at the max. Never big-big. I think the rear derailleur just got filled up with gravel dust and the springs are not working right anymore. Unsure how to clean it too. The bottom spring is sealed up inside.



--
Andrew Muzi
www.yellowjersey.org/
Open every day since 1 April, 1971