Hoosier Mountain Bike Association

The Den => Tech Bench => Topic started by: Mahk on September 14, 2013, 11:17:38 AM

Title: shifting problems
Post by: Mahk on September 14, 2013, 11:17:38 AM
I am a new rider (started last fall) with a new bike (also last fall, a Trek Top Fuel) and in the past two or three months have had a lot of problems shifting gears, especially in the rear.  Sometimes it doesn't shift at all, sometimes two or three hundred yards after I pump the lever, sometimes  I pump the lever two or three times and then it will shift two gears and I have to shift the other way, sometimes the chain skips, and occassionally the chain falls off of the front chain ring. 
 
I've had things adjusted numerous times, had the cassette replaced once, the chain replaced twice, rerouted the shift cables so they are as straight and direct as possible, and had the cables pulled out of the casing and then cleaned and lubed. 
 
I ride a fair number of miles, but before every ride I brush the cassette, wipe and oil the chain and still have problems.  It seems to be associated with the dust from the dry trails.  The shift cables are exposed along some parts of the frame and someone said that every time the cable comes goes from exposed to enclosed there is an entry point for debris that has built up on the exposed cable.  They suggested that I have the shift cables completely enclosed.  That would involve drilling out the stops that are on the frame to allow the cable to pass through, so there would be no reversing the process. 
 
This made sense, paticularly since it did shift better (albeit for a short time) after the cables had been pulled and cleaned.  But, it also made me wonder why the cable was exposed at all.  So, two main questions:
 
1) does anyone know if enclosing the entire length of the shift cable will help it shift more smoothly, and
 
2) if that does help, why is the bike manufactured with the cables exposed?
 
Thanks for any suggestions.
Title: Re: shifting problems
Post by: DeepVI on September 14, 2013, 01:16:04 PM
I am a new rider (started last fall) with a new bike (also last fall, a Trek Top Fuel) and in the past two or three months have had a lot of problems shifting gears, especially in the rear.  Sometimes it doesn't shift at all, sometimes two or three hundred yards after I pump the lever, sometimes  I pump the lever two or three times and then it will shift two gears and I have to shift the other way, sometimes the chain skips, and occassionally the chain falls off of the front chain ring. 
 
I've had things adjusted numerous times, had the cassette replaced once, the chain replaced twice, rerouted the shift cables so they are as straight and direct as possible, and had the cables pulled out of the casing and then cleaned and lubed. 
 
I ride a fair number of miles, but before every ride I brush the cassette, wipe and oil the chain and still have problems.  It seems to be associated with the dust from the dry trails.  The shift cables are exposed along some parts of the frame and someone said that every time the cable comes goes from exposed to enclosed there is an entry point for debris that has built up on the exposed cable.  They suggested that I have the shift cables completely enclosed.  That would involve drilling out the stops that are on the frame to allow the cable to pass through, so there would be no reversing the process. 
 
This made sense, paticularly since it did shift better (albeit for a short time) after the cables had been pulled and cleaned.  But, it also made me wonder why the cable was exposed at all.  So, two main questions:
 
1) does anyone know if enclosing the entire length of the shift cable will help it shift more smoothly, and
 
2) if that does help, why is the bike manufactured with the cables exposed?
 
Thanks for any suggestions.


Not to sound like an ass, but are you doing the work or a shop? 


1) Yes, in the long run.  As there's less access points for your cables to gunk up.  However a lot of crud has to get in before causing the problems you're talking about.  Unless you're dropping lube into the cables.  With the super dusty conditions there has been, lubing your cables could accelerate the gunking process.
2) Some do, some don't.  It's a matter of tradition I think with frame makers.  If you want to give it a test run before taking a dremel to your frame there are products such as these. http://www.universalcycles.com/shopping/product_details.php?id=40212&category=1613 (http://www.universalcycles.com/shopping/product_details.php?id=40212&category=1613)


More to the point of the problem.  It sounds like you have tension issues(caused by cable stretch of a new bike), maybe complicated by limit screw issues.  If your limit screws aren't set properly, then you'll never get your tension right.   Here's an article from Park Tool.  http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur (http://www.parktool.com/blog/repair-help/rear-derailler-adjustments-derailleur)


Oh and one final thought.  If you're RD hanger is bent or twisted, the above things will never get right.  It could be just slightly bent and be causing those issues.
Title: Re: shifting problems
Post by: Mahk on September 14, 2013, 01:53:25 PM
Thanks for the links.
 
The work was done first at the shop where I bought it, then, when they couldn't get it to shift properly, a second shop. 
 
I'm an ok mechanic, and wondered if something was just a little out of adjustment, but I don't know anything about bikes and didn't want to make it worse. 
Title: Re: shifting problems
Post by: David Kuehnen on September 14, 2013, 01:57:25 PM
Bent deraillieur hanger or damaged deraillieur are much more likely culprits than dirty cables.  :
Title: Re: shifting problems
Post by: Shark on September 14, 2013, 03:18:01 PM
I replace the shifter cable and housing at least once per season.
Yes, check the hanger with a tool (I have one, maybe we can check it at the park one day).

Measure your chain. New is exactly 12" pin to pin. Once it is over 1/16" wear, time to replace. If +1/8", likely a nee chain won't mesh right onto an old cassette as things have worn together.

Fyi, I run full cable housing and it stays nice and clean inside all season.
Title: Re: shifting problems
Post by: gmcttr on September 14, 2013, 05:42:30 PM
...and had the cables pulled out of the casing and then cleaned and lubed....

...2) if that does help, why is the bike manufactured with the cables exposed? ...

What the other's have said...plus....if I'm having shift problems that I can't correct with the barrel adjusters and I've been riding heavily for a year, I look for obvious problems/damage to the derailleurs and correct functioning of the shifters. If these are OK (and they usually are), I check the derailleur hanger with the Park tool and replace the cables and housings. The cable housings are wear items that need replaced every year or two and I replace the cables at the same time because it easier to feed new cables through the housings.

Why do the manufacturers use interrupted housing instead of continuous? Housings compress and the longer the housings are, the more they can compress. The shorter the housings, the crisper the shifting and brake feel with rim brakes. Full length housings do work with a slight trade off in performance. To give it a try, you can zip tie the cables to the frame.

If you live in the Columbus area, I'd be happy to check the derailleur hanger and give it a look over with you.
Title: Re: shifting problems
Post by: DeepVI on September 14, 2013, 07:33:39 PM
Had another thought. Since this problem seemed to have just popped up.

Make sure your housing is fully seated in the housing ferules.  If you took a spill or turned too sharply, the housing could have pulled out of the ferule then not reset all the way.  All can look normal, but if the housing is resting on the ferule, it will mess up your tension.  Speaking from experience.
Title: Re: shifting problems
Post by: Wall on September 14, 2013, 08:52:34 PM
I use Jagwire kit that fully encloses the shift cables.  No need to drill out cable stops.  Check your derailleur hanger it may be slightly bent in causing shifting problems and slipping in the rear.
Title: Re: shifting problems
Post by: Mahk on September 14, 2013, 11:44:49 PM
Yes, check the hanger with a tool (I have one, maybe we can check it at the park one day).

Thanks, that would be very helpful. 
 
Measure your chain. New is exactly 12" pin to pin. Once it is over 1/16" wear, time to replace. If +1/8", likely a nee chain won't mesh right onto an old cassette as things have worn together. 

I just replaced the chain last week (the 'old' one looked worn and would catch on a rag when I wiped it down) but that didn't change things. 
 
  Fyi, I run full cable housing and it stays nice and clean inside all season. 

I'm leaning towards doing the full cable housing.
Title: Re: shifting problems
Post by: Wall on September 15, 2013, 10:21:32 AM
Scott stocks these at ICS:
 
http://www.universalcycles.com/shopping/product_details.php?id=13598 (http://www.universalcycles.com/shopping/product_details.php?id=13598)
 
 
Title: Re: shifting problems
Post by: chuckdlou on September 15, 2013, 01:44:21 PM
this is going to likely rile some people up, but i don't really care...but chains and cassettes need to stay matched to one another as the pins wear grooves on your cassette with age...a new chain on an old cassette will not work the way you want it to as the distance between pins will differ on the new chain...some will tell you i'm wrong, and that if you replace the chain often enough this will not be an issue...i disagree...chains and cassettes need to be mated for life...
Title: Re: shifting problems
Post by: Wall on September 16, 2013, 08:04:03 AM
Hahahaha.  Which company do you work for, SRAM or Shimano? ;)
Title: Re: shifting problems
Post by: David Kuehnen on September 16, 2013, 08:09:17 AM
I've always heard that a chain has 1/2 the lifespan of a cassette.  That said, you should but 2 chains for every cassette and alternate them every few hundred miles so that chain wear is never an issue.



Title: Re: shifting problems
Post by: Shark on September 16, 2013, 08:20:00 AM
this is going to likely rile some people up, but i don't really care...but chains and cassettes need to stay matched to one another as the pins wear grooves on your cassette with age...a new chain on an old cassette will not work the way you want it to as the distance between pins will differ on the new chain...some will tell you i'm wrong, and that if you replace the chain often enough this will not be an issue...i disagree...chains and cassettes need to be mated for life...

To a point i agree, but once you go past that wear point that everything is meshed together, you really need to ride it out. But swapping out $14 chains can double the life of a cassette & chainring.

I did that one time a few years ago, same chain, cassette, & ss chainring. Had probably +3K miles on the setup over 2 seasons. shifted fairly well.
I eventually had to put a new chain on & it made some serious grinding noises for about 100 miles until it wore onto the chainring. eventually replaced the whole setup.

I've found using a good oil-based chain lube helps to prevent wear instead of the crappy wax based stuff that doesn't last 20 miles of riding.
Title: Re: shifting problems
Post by: Fett on September 16, 2013, 10:29:46 AM
Mahk,
I also have a Park Derailleur Alignment Gauge (DAG-1) that you can borrow to check out.  A bent hanger can make everything else of sync. I will try to remember to throw it in my car for the next time I see you out at the park.
Title: Re: shifting problems
Post by: Mahk on September 16, 2013, 12:51:43 PM
Thanks for all the replies. 
 
Just to clarify--I asked a shop to, among other things, replace both the cassette and the chain about...mmm 5-6 weeks ago.  I was still having problems, so, about a week and a half ago I went to a another shop and they said that the chain was not a good one, was worn, and suggested that it be replaced.  Even though the chain was only 4-5 weeks old I thought they may have been right because when I wiped the chain with a rag I could feel nicks and burs that caught on the fibers of the rag.  I don't know how long a chain should last, but I am riding about 100 miles a week, more some weeks, so that would mean the chain had about 400-500 miles on it.  Seems it should last longer than that. 
 
The hanger seems a likely culprit.  I've crashed a couple of times.......well, several times.........ok, a bunch, which could have bent it.  Also, I've looked at other bikes and talked with other riders and they seem to be handling the dust without any of the issues that I am having. 
 
Thanks again for all the input and offers.
Title: Re: shifting problems
Post by: chuckdlou on September 16, 2013, 12:58:35 PM
i had a chain on a rocky mountain pipeline that lasted well over 5 years and had 7 powerlinks in it by the time i broke the frame on the bike...
Title: Re: shifting problems
Post by: tony on September 16, 2013, 01:26:31 PM
Just curious, are you avoiding being cross geared?  Talking about being in the large chainring and the biggest cog, or the smallest chainring and the smallest cog?  There are certain combinations that just won't work that great.

At TRTP, I often see riders roll up in the biggest chainring and biggest cog...
Title: Re: shifting problems
Post by: Mahk on September 16, 2013, 08:10:53 PM
Yes, I avoid cross-gearing, but I'm not sure about the terminology.  Chainrings are front, and cogs are back? 
 
The bike has three chainrings, 9 cogs, but I rarely use the big chainring.  The other two have some overlap between them, so when I am in the middle cogs I may be in the middle or the smallest chainring.  But, when I am at either end of the cogs I always try to be in the corresponding chainring. 
 
TRTP??
Title: Re: shifting problems
Post by: Raleighguy29 on September 16, 2013, 08:20:45 PM
The only time I've ever had shifting problems is once when I zip tied my hand pump to my top tube and pinched the rear shift cable. Or when I've bent a hanger. Funny about chains. My hard tail still has the stock chain on it at about 1300 or so dirty ruff miles. I broke the frame before I broke the chain. But the first time I took my stumpy to bcsp in February it had about 30 miles on it and the chain broke before I got to hp.
Title: Re: shifting problems
Post by: David Kuehnen on September 17, 2013, 08:12:12 AM
Agreed, the last bit of cable housing nearest the rear deraillieur can cause a lot of shifting problems.  A bit of fraying at the end will allow it to move around relative to the ferrule which will play havoc on shifting. 

The only time dirt in the cable has ever been a problem was when using the old looped cable casing (i.e. the long cable housing that did a 180į) from the seat stay tot eh rear of the derailleur).  if the radius was too tight, a little dirt in it could really make it difficult to shift.
Title: Re: shifting problems
Post by: Kswiss on September 17, 2013, 08:38:33 AM
I ran into an issue with my Full Suspension that would always give me fits until I solved the issue.  When the bike was put together the cable and housing were not long.  When it was up on the bike stand it was fine, but when I was on it it stretched the cable out and made it shift.  It was only short by a few cm, but it still makes a difference. 


So my suggestion is to verify that your cable is long enough.
Title: Re: shifting problems
Post by: David Kuehnen on September 17, 2013, 10:01:57 AM

 
.....TRTP??


Town Run Trail Park


other  acronyms you are likely to see on this forum:


BCSP - Brown County State Park
VSP   - Versailles State Park
SWW - Southwest Way park
Title: Re: shifting problems
Post by: Mahk on September 18, 2013, 01:59:54 PM
I spoke with the shop that last worked on the bike and they confirmed that they did check the derailleur and hanger and they were fine. 
 
At this point I think I will wait until the Breakdown and speak with the Trek rep.  Hopefully s/he'll be able to determine what is causing the problem. 
 
Thank you for all of the suggestions. 
Title: Re: shifting problems
Post by: Raleighguy29 on September 18, 2013, 08:58:39 PM
Oh, see there's your problem it's a trek.  ::)
Title: Re: shifting problems
Post by: Mahk on October 05, 2013, 02:42:17 PM
I took the bike directly to the Trek tent on the vendor/demo day (Saturday) at the BCB.  Trek's head mechanic suggested silicone cables and kindly installed one for me while I waited.  I did a short test ride (North Tower Loop and Pine Loop, about 5-10 miles) on Saturday and the cable worked ok, but not flawlessly.  The few glitches could have been attributed to the fact that I hadn't cleaned or lubed the drive train after my last ride, and both the cassette and chain ring were still very dusty and dry.     
 
On Sunday, however, despite a good cleaning and thorough lubrication, the new silicone cable quickly succumbed to the incessant rain and ubiquitous mud (and I had a ton o' fun!!!).  Shifting was completely unreliable and I am still uncertain what is causing the problem.  Shark told me about a different chain lube and I am going to try that. 
 
Thanks again for the suggestions. 
Title: Re: shifting problems
Post by: DeepVI on October 05, 2013, 03:03:03 PM
I'd still be really surprised if it's a lube issue.  I'm really bad about lubing/cleaning my drive train and it has yet to cause anything other than accelerated wear.
Can't remember if it's been mentioned.  Have you checked your pivots?  If they are a little loose and flexing, that could also cause some ghosting shifting.  It could possibly be your RD as well.  Maybe the pivots are worn and causing slop, as could the tension spring be worn out.  If you can get your hands on a loaner, it might be something else to look at.
Title: Re: shifting problems
Post by: AL on October 06, 2013, 03:24:47 AM
You mentioned your chain was damaged and marred after a few hundred miles.  You may want to inspect your front chainring for a damaged tooth or ramp.  While a bad tooth can cause chain skip on the rear cog it would not explain the chain problem you have moving up and down the rear cogs.  Like others have said that sounds like a cable tension or limit screw issue.  However, poor shffing under power can damage chains and chainrings.
Im with the previous poster DeepIV, that you may need to try putting another rear mech and or shifter on.  Even a used or borrowed one to help figure out whats going on.  I wouldnt spend money  on new parts tell you get it diagnosed. Also, search your make and model and year of bike on the mtbr.com forums.  Maybe others have had cable routing issues.  Even the big bike makers have design issues/flaws.  In the end it maybe best to take it to a good mechanic.  Ask others in your area who is a good bike mecahnic who knows how to work on full suspension MTBs.  Its really hard to diagnosis and fix these problems over a forum there are just too many variables.
Good luck!
Title: Re: shifting problems
Post by: mtbikernate on October 08, 2013, 05:51:27 PM
My shifting was nearly flawless with Gore Ride-On cables/housing that are probably older than they should be.  My wife's shifting was spot on with XTR cables/housing.  High end cables and housing really are worth it, IMO.  I won't ride anything but fully sealed or full housing on my bikes from now on, due to the reliability of the Gore cables.  Unfortunately, they don't make them anymore so I'll have to go with another brand.
Title: Re: shifting problems
Post by: David Kuehnen on October 08, 2013, 06:22:17 PM
Have you considered that the shifter itself could be the problem? reading back through this thread, I did not see it addressed.   It is the "brains" of the operation. and may be the cause of the problems.
Title: Re: shifting problems
Post by: firefighter56 on November 15, 2013, 02:14:40 PM
I'm kinda digging up bones here but after reading about everyone's fixes for their cables and spending a ton of money on them I figured I'd throw in my easy cheap fix.  I always had problems with my cables and the shifting on my bike and was just about to switch to sealed cables but I figured I'd try one more thing first.  I bought a grease needle that attaches to a tube of grease and filled the cable housings before pushing the cable in.  Yes, most of the grease comes out when I push the cable in but what does stay in there lubes the cable forever and seals out the dust, moisture and mud.  I've been running the same extremely cheap cables and housings for over 2 years now without a single problem.  Before this I was changing my cables and housings a few times a year and fighting shifting problems constantly.  Not sure this would fix anyone else's problems but it fixed mine and was ultra cheap!


Doug
Title: Re: shifting problems
Post by: Mahk on January 24, 2014, 09:28:17 AM
 
Last week I brought the bike in for an early spring tune up. The mechanic said that he was aware that the bike wasnít shifting properly and he wanted to try his hand at fixing it (this was one of the two LBS's that had worked on the bike last summer / fall although this particular mechanic had not looked at it yet). He went through the usual possibilities (hanger, derailleur, cables etc) but couldn't find anything that appeared to be wrong. He then decided to start replacing parts one at a time until he found what was causing the malfunction. He thought it was the derailleur itself. When he replaced the old one with a new one everything seemed to work smoothly on the stand.
 
I haven't given the bike a real test ride yet, but the mechanic was confident that the problem is fixed (he did a test ride around the parking lot).  I'm hoping he is right, although a parking lot ride is short, clean, and easy.....
 
Thanks again to all that contributed their thoughts and suggestions. Itís certainly shown me the complexity of a mountain bike and the camaraderie of mountain bikers.
 
 
Title: Re: shifting problems
Post by: Mahk on May 12, 2014, 09:44:13 AM
I've ridden numerous times now since that last post and, sad to say, the problem is still there.  Shifting is irregular, inconsistent and unreliable. 
 
I took it to another LBS, the mechanic replaced all of the cables and housings, said that it needed a new chain (odd since it wasn't that old), replaced that as I waited and then spent 25 or 30 minutes going up and down through the gears while the bike was on a bike stand, rode the bike around a parking lot, fiddled with adjustments, cable length, sprayed the shifter, checked the hanger, the derailleur, the wheel, more adjustments, more spinning on the stand, and, to his credit, said that he still couldn't get it right.  And didn't know why.  He noted that the teeth on the cassette (which also wasn't very old) were sharp, which indicated that something was just a little bit out of alignment.  I wondered out loud if the frame was tweaked and he said that he would call Trek and talk to them. 
Title: Re: shifting problems
Post by: DeepVI on May 12, 2014, 10:38:31 AM
I wondered out loud if the frame was tweaked and he said that he would call Trek and talk to them.


With all that you've done and the problem is still there, that seems to be the most likely culprit.
Title: Re: shifting problems
Post by: Mahk on July 08, 2014, 08:28:33 AM
Long story to the end, but the problem is fixed and all is well. 
 
Trek balked at looking at the bike, so we were back to fiddling and cussing.  The mechanic (Matt) took the bike out for a ride at BCSP so he could actually see what was happening and he agreed something was way out of whack.  He noted that the new derailleur was actually a step down from the original and wasn't keeping enough tension on the chain, so he replaced that derailleur with one that was similar to the original. 
 
I took the bike to see if the (second) new derailleur helped at all, but, while there was some marginal improvement, the shifting was still erratic.  The mechanic then decided to replace the shifter.  Problem solved.  Uphill, downhill, muddy, dry, lubed, no lube, it shifts well and stays in gear when I'm not shifting. 
 
A week or two later, while riding at O'Bannon, the left crank arm fell off.  Matt called Shimano about the crank arm, found it was under warranty and Shimano agreed to replace the crank arm and cover labor as well. 
 
I wondered if the shifter was also under warranty and called the LBS where I bought the bike.  This was the LBS that had put on the first replacement derailleur which didn't help and which was itself  replaced by Matt.  I explained that the problem had actually been the shifter and asked if that was still under warranty.  They checked their records and said that it was.  They said that if I could get the original derailleur from Matt they would send that back to Shimano and get a replacement.  Much to their credit, and without my asking, they also said that they would take back the derailleur that they had put on (which didn't work) and give me a refund for the part. 
 
 
Title: Re: shifting problems
Post by: Fett on July 08, 2014, 09:16:11 AM
It took a while, but is sounds like some pretty good customer service all the way around.