flyagaricus

Hi - I'm very new to bike repair. I'm trying to do a shifting tuneup on my mountain bike. Despite all my attempts, I can get the rear derailleur to smoothy shift up to the larger gears, but when coming back down, I have to click the paddle twice. I'm wondering what might be the cause of this? I've followed several tutorials on setting the limiters and indexing, but this is the best I can get. Very frustrated.

Iride01 

Well you shouldn't normally touch the limit screws if the bike was already set up and working correctly previously. Especially for things that don't happen in the biggest or smallest cog.

Typically when I have an issue like you describe it's because of a frayed cable in my STI shifter. Being a mountain bike, I don't think you have STI's and I don't know if that happens also to the type shifters you'd have on yours.

It can also just be something causing the cables to bind up briefly. As you shift from the larger gears to the smaller gears, hold onto the bare cable come along the downtube... if you have bare cable. If while shifting it goes slack for a long moment then that shows it might be a binding issue. Not definitively, but it helps.

Crankycrank

First thing to try is screwing in the cable tension adjuster about a 1/2 turn (or you may need to turn more so try a little at a time). This effectively gives the cable more slack allowing it to release the derailleur farther downward when shifting. Could also be something like the cable or derailleur is sticking or something else but try this first. Also if you find after the adjustment that shifting to the smaller cogs now works great but shifting up has become worse turn the adjuster 1/4 turn out and check again.

Bill Kapaun

Cable too tight or too sluggish because it need a clean/lube.
Also a frayed cable/very worn housing can contribute.
Spring tension in the RDER is what causes the upshifts. IF the cable doesn't slide freely enough, they may be delayed to the point of not happening.
RDER may also need a bit of cleaning/lube if it doesn't pivot freely.

shelbyfv

Failure to readily move to a smaller cog is most often a cable issue. Cable (inner) is either frayed or gunked or there is a kink. The shifter can force the derailleur toward a larger cog but the spring cannot as easily overcome the obstruction when dropping to a smaller cog.
Edit- yep what he said^^^^

Andrew R Stewart 

All good advice. No mention of the bike's shift system or age though. I do wonder if the shifter pods are getting gummed up? Andy.

flyagaricus

It's an old (1997) Kona Kileau. I've had it serviced a couple times with good results, but would like to start to learn to do some of this stuff myself.

flyagaricus

Thanks everyone for the replies. I'll definitely be looking at the cable for snags - makes sense.

Bill Kapaun

Often, the short piece of housing near the RDER is a major contributor because of the sharp bend. The cable tends to wear into the housing.
IF you haven't replaced the housing in several years, do it. You might as well do the full run with a new cable.

flyagaricus

Thanks - any advice on how/where to source cables and housing?

veganbikes

Your local bike shop will have cables and housing. These are what I recommend: https://jagwire.com/products/diy-cable-kits. Specifically the Pro or Elite Link as they are a fairly low cost upgrade which can do some big cost improvement to shifting and braking. Jagwire is now owned/distributed by QBP so unless you have a funky shop they more than likely have a QBP account and can order you anything if they don't already have stuff.

Plus now is an excellent time to support your local shop. With bikes being hard to get right now we could all use some support from the community which we serve so we can continue supporting you. If you don't have a local shop for some reason then look for a shop online that has a brick and mortar presence. Jeff Bezos and those in positions of power at Amazon don't need your money and those who are doing the work don't see your money so why support that?!

cxwrench

Really? How about a bike shop? Or online...pretty much any online shop or Amazon or Ebay. Google searchers aren't hard.

Iride01 

Buy your cables and housings together. Which is usually how they are sold. One brands shifter cable might not fit another's housing well. So you'll still be in the maybe it's the cable or maybe not world.

flyagaricus

Isn't the whole idea of forums to share knowledge and information with others? I'm here because I'm completely new to bike repair. Maybe I could do some googling, and end up buying the wrong parts, or from an unreputable vendor etc... OR I can get some good advice from an online community and save myself some time and money.

Dirk de Chablis

Is your mech hanger bent? It doesn't take much to bend one and that will make gear changes seem out. Before undertaking repairs yourself see if you local bike shop needs a saturday boy and go work there and get the mechanic to teach you the ropes

Andrew R Stewart 

Let's view this from another angle. By going to a LBS you save time and insure that if you do somehow end up with the wrong stuff you can return/exchange at minimal added effort. And by asking a pro you have a FAR better chance of not making that wrong purchase to begin with. But, hey, it's your money and time. Personally I see no difference between asking us here and a shop parts counter person except that you can get more detail in faster time at the shop too. The hope of saving a few dollars only pans out when you know what you're doing.

To tangent and as one of those LBS guys I continue to find the aversion of using the LBS as a source of both parts and advice to be sad. I grew up in a medical family. For some reason I can't see people asking a dentist forum what drill to use for filling one's own cavity... and thus save some serious money Andy

cyccommute 

You just haven’t developed a good filter system yet. It comes with experience here on the Bike Forums. There’s lots of good advice here. Just ignore the unhelpful ones.

On cables and housing, there usually isn’t a bad product out there. I wouldn’t suggest anything that is branded “Clark” but just about anything else is good stuff.

flyagaricus

Fair enough. I do like to support local business. Unfortunately my local bike shop closed it's doors during covid. The nearest one is a bit of a hike and they're all weird about customers coming inside now which takes the enjoytment out of dealing locally and in person. Sign of the times I guess.

Iride01 

Not every individual that comes and posts about a problem wants to necessarily do their own DIY. Some simply think they are saving themselves money even for things bike shops charge little for. Some aren't capable of doing the stuff because they lack the specific tools or current skill set.

All sorts of types will come asking questions and we have no way to assess their skills and capabilities or even what their actual desires are. As another said, it's life. And it happens on every forum. Ignore the advice you know isn't what you want or applies to you and use the advice that makes sense for your knowledge, skills and tools available to you.

cxwrench

It's shift cable and housing...nothing mysterious about it at all. There are probably a thousand posts about it on here, even w/ the barely-functioning search it would be easy to figure out. To make you feel better hit up your local shop, 100% they'll have them.

Bill Kapaun

Or maybe you could do some Googling first and then ask a question if you still had one.

dedhed

I haven't had any issues using Clark's brake cables on my 68 Raleigh. The double ended cables aren't something I can buy in my LBS.