Quick over view. I have an 03 Orbea Liege w/Ultegra components and Cane Creek Volos wheelset. About 9 months ago I changed out the chain, cassette, and chain rings. At the present time the parts have about 1000 to 1200 miles on them. Back in Oct or Nov of 08 had the new (Shimano) chain break off while climbing back to back hill passes at one the local bike rides. At one of the rest stop the mechanic slapped on a SRAM chain and I continued the ride with no other problems other than beat up bambinos and inner thigh contusion. I have noted that since the incident I have had issues with the ghost/phantom shifting which downs shift 1-2 gears. I normally feel it happen while I have heavy pressure on the cranks while climbing. On the flats its pretty okay(very rare to exprience ghost shifting). So I took the bike to the LBS and I was told that the rear derrailler cable was stretch and need a mild adjustment. All that corrected the phantom down shifting.
However, some reason now I am experiencing when shifting up to my upper lower gears (21-23) a slight lag or lost of resistance on the chain and it feels like I am freewheeling forward. Again I only feel this when the crank is under pressure/heavy load while climbing in a seated or standing position. Any ideas of whats going on with the drivetrain? Could it be that the cassette is not tight? Bad freewheel/Hub? High and Low limits on derrailer not right? Take it back to LBS?
I try to avoid going to the only LBS in my town because they are not good at Dx problems unless you the customer tell them what you want done to the bike. Please advise.
A SRAM Chain should work OK with a '03 Ultegra drivetrain. Cable stretch is a good call for the downshifts. The other problem that you have could caused by the RD being misadjusted after they adjusted the RD cable. I have seen more than one LBS tech short cut by checking the adjustment in only a couple of gear combos rather than all of them. Have your LBS recheck the adjustment.
Remove the rear derailleur (leave the cables & chain attached) ... you'll need a 5mm Allen wrench.
Inspect the rear derailleur hanger -- Is it bent?
A quick but imprecise gauge is to put a straight edge against the derailleur hanger and see if it (the straight edge) is parallel to the bike's central plane. If the derailleur hanger is bent, then replace it & hopefully the ghost shifting will have been exorcised.
Basically, you want to try to eliminate one possibility at a time -- e.g., put your current rear wheel on another frame or another rear wheel in your Orbea, etc.
check out bicycletutor.com's article about derailer adjustment. Its a pretty simple process, and if you don't feel like making the fix yourself, the tutorial will at least tell you how to check to see if you have an adjustment issue (help narrow down the cause.) I haven't had my LBS touch my bike since I found this site 🙂
Just curious, what part of south Texas are you in? I'm in San Antonio and am always looking for people to ride with...
