Bicycle Tutor

Hi, another newbie here with a shifting issue. This may be too much detail, but will add it in case it is helpful.
I have a Bianchi Advantage Mixte (Cross) bike from (yikes!) 1994, with a Shimano Alivio shifter/derailleur system. It is a one owner model in very good condition, and hasn't gotten a lot of use--lately have used it more with the Walkydog to exercise my dog. Also have used it on blacktopped trails, but very little offroad use. It has been stored in the garage, never outside.

Last year I noted it was not shifting well, so took off/cleaned the chain, cleaned sprockets very thoroughly and reconditioned with Boeshield T9, rode it a bit. It was still not shifting totally right, but it was too late in the fall to finish, so waited till this summer. I reconditioned the chain as looked a bit dry, have spent spent some time online (reading about others' recommendations/mistakes) then have spent an entire afternoon working on it per:
http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur.

I set limit screws and am working on indexing but running into problems. I took it out for a short ride and brought back inside but still with the same problem. The problems might be inter-related:

1--In all 3 front sprockets/chains, it skips from the rear smallest sprocket to the 3rd one when shifting toward the larger sprocket, and from the rear 3rd smallest sprocket to the smallest when shifting in the other direction. It may rub a bit on the" second to the smallest" sprocket but shifts skips right out of it. So, when shifting toward the largest rear sprocket, the gear showing up on the back sprocket shifter is "2" rather than "1". In the smallest sprocket, the gear does show up correctly as "7"

2-- I've also been working with the rear sprocket index settings. I wondered if the skipping gear was due to not tightening the cable enough. If I tighten the rear adjusting barrel by 1/4 turns enough for the chain to reach the rear biggest sprocket, it will still skip 2nd gear but shifts well from 3rd smallest sprocket to the next largest and up to the largest sprocket.

If I continue to increase tightness, I can tell that it is actually too tight sometimes on the rear largest sprocket, as there is no play at all in the lever to click it from "2" to "1" --too tight!

But if I loosen the cable too much more to see if the chain will stay in the second smallest sprocket, it will start skipping another sprocket. I move the shift lever a full click, and it misses the second smallest sprocket; at the next click, it misses the fourth smallest gear and goes directly to the fifth smallest, then goes up to the 6th and then the seventh sprocket as it should.

Do you think it is a problem with the shifter?

Or should I adjust the H or L screw again? I was very careful to make the adjustments for the best setting, but don't know what else to do. I am hesitant to take it out for a longer ride at present as don't want to jam things up.

Thank you very much!

When someone brings me a bike with a tale like that I would start from scratch.
first I would true the rear wheel, then I would break out my derailleur alignment tool and make sure it is correct.
In your case replace the cable, check all housing and end caps for wear and deformation. If bad replace housing also. If this has never been done replace anyway.
set your high and low limit screws again. When you set your limits make sure the cable is not attached. set the H so the jockey pulley is not directly under the smallest cog but off center about 1mm or so towards the outside, set the L so it is centered under the largest cog.
now string your new cable and make sure your housing is seated in the bosses. pull cable and pop shifter to make sure it is in the highest gear.
spin the barrel adjuster all the way in and back out one turn. put cable thru and attach. pull tight but do not move derailleur while securing.
pedal bike and shift one gear, it may or may not go. either way spin a 1/4 turn on the barrel adjuster until it starts making noise on the third smallest cog then back off until noise stops. now shift up and down the range. if hard to climb the largest open L screw 1/4 turn. Much easier to show than to tell

7 or 8 speed rear?

Do NOT cross chain - for example do NOT use the largest sprocket in the front with the largest in the rear, nor the smallest in the front with the smallest in the rear.

I would replace the chain, shifter cable (making sure to properly lubricate it) and possibly the shifter and cassette/freewheel. '94 is an awfully long time for cables.

Get the RD to put the chain in the center sprocket at the rear (#4) or #4 if 8 speed, #3 if 6 speed.

Now adjust the cable length using the screw adjuster so that the RD indicates the proper gear, and everything is smooth and quiet as you turn the pedals. This the correct length for the RD cable, now adjust the B screw, H and L limit screws - google Shimano Tech Docs for detailed instructions.

(Jul 22, 2012 07:29 PM)nfmisso Wrote:  7 or 8 speed rear?

Do NOT cross chain - for example do NOT use the largest sprocket in the front with the largest in the rear, nor the smallest in the front with the smallest in the rear.

I would replace the chain, shifter cable (making sure to properly lubricate it) and possibly the shifter and cassette/freewheel. '94 is an awfully long time for cables.

Get the RD to put the chain in the center sprocket at the rear (#4) or #4 if 8 speed, #3 if 6 speed.

Now adjust the cable length using the screw adjuster so that the RD indicates the proper gear, and everything is smooth and quiet as you turn the pedals. This the correct length for the RD cable, now adjust the B screw, H and L limit screws - google Shimano Tech Docs for detailed instructions.

---

Thank you for your expertise!
Did wonder about the Sr. Citizen cables after reading more posts. This bike has nowhere near the mileage of other posts where people seem to be living on their bike, but still...
This is a 7 speed rear.
Well, now I know that my work is cut out or me! I'll give it another go but will need a couple of weekends to get that done, and then will post back with my progress. Have read also to get only Shimano/and not mix manufacturers, so will follow those recommendations as well.Prefer to do myself and learn, but there is a good shop close as well.
Thanks again!

I mix manufacturers all the time.

The SRAM MRX shifters work better with Shimano derailleurs that Shimano twist grips do.

I have had better performance and quality with Sunrace freewheels than Shimano. My World Tourist has a SRAM MRX shifter, Shimano RD and Sunrace freewheel. Our T50 has SRAM MRX shifter, Shimano RD and Suntour cassette.

Lots of mixes work well together, but there are some that do not. Understanding the specifications allow you to mix and match.