Question about making minor derailleur adjustments
Tonight I FINALLY was able to conquer the derailleur. Well, sorta. I picked up a Motobecane Fantom Cyclocross and was able to make all of the initial adjustments myself, not counting a quick consult phone call to my friend. What was cool was that when he answered, I pretty much had figured out the problem. I had NEVER been able to get as far as I did until tonight, and that was after over a year of trying to figure it out.
For anyone who needs help adjusting derailleurs, I HIGHLY recommend Zinn and the Art of Road (or Mountain) Bike Maintenance. I had previously checked out Youtube videos, Parktool, and Sheldon Brown, but it didn't all come together until I read Zinn's stuff on derailleur adjustments.
A couple of quick questions. On my test ride after setting up the initial shifting, there were some instances of the derailleur being a little sluggish when shifting to a higher gear for the rear derailleur. My initial thought was to let some tension out of the cable, but then I wondered if I should loosen the high stop screw instead. The one thing that threw me for a loup was that it seemed like shifting was also little stubburn when shifting back to a lower gear as well - nothing major, just a little hesitancy.
On a related note, I had planned to do some barrel adjustments while riding, but I noticed the Sora shifters didn't have any barrel adjusters where the cables meet the shifters. The barrel adusters appear to be part of the cable housing. I did play with them a little, but are you supposed to pull out and turn, or just turn to the right or left to decrease or increase cable tension?
Anyway, in spite of some minor glitches, it was an amazing feeling to jump on a bike that shifted relatively well...that I set up the shifting on. It was like, "wow, I actually did this". So if you are someone reading this who has struggled with derailleur adjustments, don't give up, and make sure to check out Zinn's books, even if you have to go to the library to get one! And of course, it is nice to be able to fall back on this forum for additional questions on things that stump you a little!
The High/Low screws are just stops, they have nothing to do with actual shifting other than to make sure you don't go over the large ring or under the little ring.
Sluggish shifting is usually one of 3 things..
- Bad/improper, or dirty cables
- Improper "B" screw adjustment
- Slightly bent Hanger
Also some people complain about slow shifting and it's just they aren't pedaling fast enough.. if the drive train isn't turning, the chain can't move up the cassette
Thanks. Any tips on adjusting the B screw? It wasn't clear to me what effect tightening/loosening the screw had on the derailleur, and I doubt the hanger is bent, although they did include an extra with the bike. We can rule dirty cables out, since they are brand new.
Just to clarify, I'd say it is more accurate to say that the derailleurs were "skipping" a bit, rather than being sluggish.
Last edited by getagrip; 07-26-2012 at 07:19 AM.
"B" screw is easy, pop off the chain, shift the rear derailleur to the largest cog, stick your 6mm allen tool between the tooth of the cassette and the upper jockey wheel tooth... adj B screw so it's just touching both teeth.
Originally Posted by getagrip
Hanger bent .. well it's surprising how many brand spanking new bikes I've seen with slightly bent hangers, well not bent, just out of alignment. Can happen in shipping, boxing, unboxing, slight mold defects.. what ever. they are usually not all that bad, but enough to cause problems when something else is slightly out, it'll compound the issue. it's super easy to fix by flexing the hanger back into alignment, but ya need the tool.
New cables... again, if they were factory done you probably need to go and open up the ends of the inner liner of the housings. there is a nylon type liner in almost all housing now that gets pinched when the cable is cut to length. need to go and take something a open it up, more kinda bring it back to round. can use something as simple as a nail to do it... just lightly push it into the housing end and spin it once or twice... now not talking about the ferrel, but the actual raw cable housing.
if you are getting light skipping, most likely B screw, Hanger, or Chain too long .. gunna probably guess a combo of the B screw and very slight hanger out as almost every new bike I've worked on has had those 2 issues.. (usually right out of a shop unfortunately )
Also check out Parks Big Blue Book.. I have both it and the Zinn and the Parks one seems to be easier to find the info and get a grip on the issue faster.. though I still use both for references and when i get stumped by something
If you don't feel like buying a book, Park's website has great tutorials on most of the basic stuff (and some non-basic stuff). I always refer to it when I blank on how to adjust derailleurs.
true... very true my only issue is I don't have a puter out in my garage.. though I have printed out a page or two from their site more than once
Originally Posted by fireball_jones
The Park Tool website helped me adjust my RD shifter indexing to absolute perfection. I copied the text to the notes on my iPhone and used that as a reference. FD, I am still not that good with but that will come with time.
Free people must travel the road to productive social relations at the speed of a bicycle.- Ivan Illich
Don't get me wrong, that's a very good list for most people's problems but your problem with your shifting is simply cable tension. New bike with new parts, I'm assuming; that means you just need to play with the tension.
Originally Posted by thomllama
I'll reiterate that first sentance, the limits are exactly that: limits. They set the maximum movement of the derailleur at the top and bottom of the range. They are not to be adjusted unless you can't enter the highest or lowest gear or if you overshoot one of them. The high limit should be set with the derailleur cable unattached and the high limit should be set by trying to pull or push the derailleur off the big cog by hand.
The B tension screw is rarely to be played with, I wouldn't touch it unless you knew you had an issue with it. Could reasonably be a bent hanger, I'd seen and had many new bikes out of the box with bent hangers. If the bike isn't new then replace the cable and housing (always as a pair).
Don't you hate it when a sentence doesn't end the way you think it octopus?
yup.. pretty much what ya said... could be all that...
Originally Posted by zebrahum
but... I have yet to see a "mail order" (and many out of a shop too) that didn't need the B screw adjusted.. it's almost always all the way out giving a 1 Inch gap, causing chain slap/skipping between the cassette and the top jockey wheel... SRAM seems to be a bit more sensitive that Shimano to B screw adj being out also.