t.del

Okay, this is kind of embarrassing; I fix bikes as a small summer business kind of thing, and I just got hired to tune a specialized crosstrail mountain bike. It looked easy enough - straighten out the brakes, clean, new grease - all in all a 20 dollar job maximum. Then I got home and realized that the bike did not shift higher than 4th gear (as in it can shift to gears 4,5,6,7,8 but not 1,2, or 3). My first reaction was to check the rear derailleur because I figured that the tuning screws were blocking the derailleur prematurely. That was totally discredited when I disconnected the cable completely and the problem persisted. So it's something in the shifter for sure... and after opening it up I decided that taking it completely apart was a little beyond my comfort zone. The shifters are those standard mountain bike shifters (the clicky ones, not twisty) by shimano. Additionally, when I opened up the shifter housing, I observed that the shifter mechanism goes through its entire range of motion (from one metal stop to the next) as it shifts from gear 4 through gear 8, almost as if the shifter mechanism is really a 5 speed that somehow got put into an 8 speed housing. The left hand shifter has a similar problem; it feels like a 2 speed shifter mechanism housed in a 3 speed housing.

Any ideas would be a great help. Also, if this explanation didn't make any sense, please tell me so cause it was sort of a strange thing to explain.

JReade

I think that getting the internal of a shifter mixed up would be very very hard to do, and hopefully woudl have been noticed far before it got to you. Did it click 5 times?

jimc101

Would suggest that if you are operating a business as a bike mechanic, and you can't diagnose and fix simple things like gears, it isn't the business for you.

You need to provide more info about what you are working on, what Shimano model number, have you looked it up on the Tech Docs, or on the Park Tools how to's.

If you want to be a mechanic, go do a course, so you know what you are doing, https://www.bbinstitute.com/index.php otherwise you are a liability to your customers and yourself.

Al1943

If the shifter was not in the small cog position when the cable was attached to the derailleur, that could account for the problem.
Hosing out the shifters with WD40 may help and often does.

Kimmo

I'd suggest the problem encountered here (if it's actually as described) would stump most folks and your condescension is unwarranted.

Shimano index shifters (DT and bar-end aside) are not simple. In fact, the degree of their complexity is stupid; STI internals are a bad joke compared to Ergo.

jimc101

The OP is offering a paid for service, and obviously can't do it, nothing condersending about that, just a lot of concern that the OP is in the wrong line of work. being a full time bike mechanic requires you to to be able to diagnose and fix all type of bikes, in this case, the OP hasn't been able to fully diagnose the issue, for STI's being fixable, you don't know if it is possibe until the issue has been diagnosed, and there is the rub.

CHenry

Did you try to set up the rear derailleur cable with the shifter at the least tensioned position and the derailleur at low normal (assuming this is the de-tensioned position, otherwise, top-normal) and the limiting screws at mid position? In setting up my STI flat bar shifters, this is a good start that gets me the range I need, and it works front and rear.

You ought to get eight clean clicks from the rear shifter across the range with a little tension on the cable.

This sounds like the cable was either too tight and restricting movement to the less-tensioned range of cogs on the cassette, or conversely, under-tensioned at the normal least-tensioned part of the range, preventing derailleur travel to reach the opposite end of the cassette.

CHenry

You weren't offering any helpful advice, only your criticism of his choice of work. Obviously if the OP can't manage the repair, he should return the fee, but what he needs is to know how to sort out the problem with this shifter. i thought he was pretty clear about this kind of thing not being his full-time or year-round job.

jim hughes

t.del, not sure what you mean when you say "I disconnected the cable completely and the problem persisted. ". If you just pull on the cable by hand (not using the shifter) does the derailleur move through its entire range?

wrk101

+1 With the cable disconnected, you should be able to push the derailleur through its entire range. Or just pull the cable with your hand (leave it connected to the derailleur).

MTB shifters on the other hand can be a can of worms. Sometimes you can revive them, sometimes you will need to replace them. If you are going to do a quickie $20 service, I would have an exception for parts. Worn out or broken parts don't tune up.

t.del

Yes, the derailleur functions perfectly well. When I say I disconnected the cable, I mean that I am now working on the shifter without it being attached to anything, just seeing if it clicks through its entire range. Either way, I know what the problem is now. Basically, when shifting up from gear 8, the clicker pushes on one of the teeth on the round cog which actually tensions the cable. Then, when pressure is release from the clicker, it falls back down to the next tooth on the cog so that it can keep going. In my case, the grease is so thick that the clicker has difficulty falling back down to the next tooth and instead stays on the same one, preventing it from ever shifting more than 4 gears. So it seems like whoever my 'client' took her bike to previously had used the wrong type of grease on the shifters, which brings me to part two of my post.

jimc101: not much to say, but I'd like to clear a couple things up. Do you work in a bike shop or have worked at one? Cause that would explain your belligerence. Let me assure you that I am not trying to pose a threat to bike businesses; I am a 17 year old kid who has been fixing and maintaining his own bike for 4-5 years and as a result, family friends and neighbors occaisonally hire me if they want a cheap tune-up. If I find something which I can't fix (especially if they did not mention it, as it was in this case, since normally I would not take a job I do not think I can do) then I tell them, "I did this, this and this, but found this which you should bring to a professional to fix" that rarely happens because I'm savvy enough to finish 99% of my jobs. And if it does happen, I waive the fee, which isn't a problem because I'm certainly not doing this for the money (20 bucks every other week is a little light), I'm doing it because I am going to go to college with an applied physics major in mind and I love solving mechanical problems. If you were genuinely concerned that I might be doing harm to my customers or myself, you should have told me so in a more appropriate tone, however; the level of bitterness in your posts leads me to believe that such was not your intention.

Thanks everyone for the helpful answers, al1943, your post is what led me to look at what kind of greasing job had been done inside the shifters, so thanks in particular to you.

Al1943

Shoot it full of WD40. This remedy has cured many STI shifting problems.

jimc101

That is quite a lot!, not being bitter, just very concerned that you are undertaking an endevor you are not (yet) capable of, do you have liability insurance (you would if you were running as a business) for when someone has an accident related OR not to your repair, if you do, great, but I suspect not, and that could come an bite you, which I and I suspect everyone else on here would prefer did not.

Kimmo

Pfff... it's a shifter.

As I implied, the fact that t.del is unfamiliar with Shimano's stupid sticky STI grease says absolutely nothing about his ability to perform general bike maintenance, all of which is child's play relative to understanding STIs.

Your 'concern' that he's endangering his 'customers' (if that's what you can call friends and family paying a token fee) is insulting.

As for the mention of public liability insurance, that just sounds crazy paranoid... but then again, I live in a civilised country with health care; maybe American friends and family will sue if you're such an utter schmuck you can't set up a bike safely.

Jeff Wills

+1. Shimano's shifter grease is known to go bad over time. Clean out the shifter with WD-40 or similar solvent, re-lube with light oil. If that doesn't work, replace the shifter.

motobecane69

WD40, fill the shifter full of it. then put some on a stick and roll the sitck around in a sandbox. proceed to shove the stick up Jimc101's rear end without the aid of any additional lube. that should solve all problems

jimc101

Getting a bit personal there! motobeancan

wrk101

One thing to consider in the future if you are going to work on MTB shifters, the WD40 route is a common approach. If it fails, an alternative is to just replace the shifter. On six and seven speed bikes, I use the Shimano Tourney trigger shifters. I really like them, and you can buy them complete with cables and housings for less than $13 at Niagara Cycle. If you do much service, you will probably end up doing business with Niagara, as they are the cheapest source I have found for chains, bearings, cables and housings, and tires.

Just be prepared for SLOW service. Niagara orders take me 2 to 2 1/2 weeks to get. So I try to order BEFORE I am out of parts. I screwed up recently, and am now out of chains (did a lot of bikes recently).

I wish I would have picked up bike maintenance as a hobby back in my college days. Instead of working minimum wage, I could have made decent money, on campus, on my schedule, working on bikes.

mechBgon

That's been my experience too. I routinely revive gummed-up Shimano trigger shifters at work. I wouldn't cast any aspersions on t.del for asking his question, because I've worked in shops through the entire era of Shimano indexed mountain shifters and don't remember seeing that failure mode myself.

t.del, if it doesn't respond to being de-gummed with WD-40, and there's no obvious debris jamming things up, you may just need a new shifter or brake/shift assembly, like some of the guys mentioned. But one other possibility to look for real quick, is if the "piano wire" strands that make up the cable housing have sneaked through the end-cap on the cable housing, and are intruding into the shifter along with the inner cable. I'm really reaching with that one, but it would only take a minute to verify. If you already have the housing out of the picture, then that's not it.