Jaxx317

Hello out there!

I am the proud owner of a shiny new 2013 DownTube 9FS, and newbie to biking in general. I ordered the bike online from DT directly, and took the bike in to my LBS for tuning before riding it (about 2 weeks ago), and everything seemed to check out fine. I rode a few blocks to my apartment right after getting it back from the shop, once more around my neighborhood the next day, and then for about a mile, maybe less, 2 days ago without any noticeable issues. Yesterday, I took it for a much longer ride (about 7 miles total), and noticed my gears were seriously slipping. I tried to be conscious of not pedaling while shifting gears, and that didn't seem to help. Today I checked out the instructions for adjusting the derailer on DT's website, and followed all the steps. The gear shifting seems much smoother (though I haven't ridden it again yet), but now the bike won't go past 7th gear. I can shift up to 8 & 9, but the chain just stays on 7! No problems with lower gears. I've adjusted the cable tension, and the H & L screws several times over, but nothing seems to work. It's possible that it may work itself out once I ride again, but I'm dubious since I can't get it to do that by just spinning the pedals. Any help would be greatly appreciated!

bargainguy

First of all, welcome to the fold, and congrats!

I'll clear up one misconception first. Derailleur systems require pedaling while shifting. Conversely, hubs don't like to be shifted while pedaling, though some will do so grudgingly. The first rule of thumb - keep pedaling your derailleur bike while shifting.

If you can't get to the largest sprockets, one of two things is happening: the cable tension is set way too low, or the L limit screw (Low gear = largest sprocket) is too far in, preventing the derailleur from traveling further inward. Try increasing some cable tension via barrel adjusters (either on the rear derailleur or on a cable stop; you might have both) and see if it helps (increase tension by turning the barrel adjusters counterclockwise). If cable tension is OK, then it's the limit screw as above. Between the two you should be able to get it back to normal.

There is an outside chance that your rear derailleur is misaligned - not perfectly parallel with the frame. If it's way out of whack, no amount of cable tension adjustment or limit screw twiddling will help. If it's reasonably close, not the issue.

Don

badmother

My guess is your gear cable stretched (that is normal) after they adjusted it and you rode the bike. In my opinion adjusting the barrel is just a temporary fix, I prefer to shorten the wire (have the LBS do it). That way it is still possible to adjust the barrel if needed and also a barrel adjusted all the way out (if the wire is to long you adjust that by "lenghtening" the housing- this is done with adjusting the barrel) is a weak spot.

Of course it could be the limit screws but since it worked fine after it came from the LBS I doubt that.

Also rear der can be knocked out of position but I doubt this would happend without you noticing.

Jaxx317

Thank you both for the replies!

@bargainguy - I have just the opposite issue: I can't get to the smallest sprocket (the one closest to the frame). I can manually put the chain on the smallest one, but it seems to always "default" back to the 7th. Though, upon further inspection it seems that the derailer may have some slight misalignment - it seems to be ever so slightly twisted such that the top portion is not directly in line with the bottom portion. In which case, best to take to the LBS at this point? Might it need replacement altogether?

bargainguy

Then you have the opposite problem -- too much cable tension and/or the H limit screw dialed in too far. As far as the rear derailleur, no need to replace if it's new - your LBS has a tool (Park DAG-2) that can restore proper alignment if it's off. As my handle implies, I'm cheap, so I'd try letting out some cable tension first and/or backing off the H limit screw. My guess is that either one will get you right.

Badmother is also correct: If the degree of cable tension is way off, then best to release the RD cable bolt and retighten the cable at the proper tension, because the barrel adjusters only have so much play and perhaps not enough to resolve the issue.

Don

Jaxx317

thanks bargainguy! yeah, i decided since i have two eyes and two hands and a brain, i could probably follow some simple-sounding instructions on how to fix my situation rather than immediately going to my (slightly over-priced) LBS. i'll keep noodling and see if adjusting the tension helps. thanks again!

bhkyte

Some hubs,( Sram Dual drive internal hub for example), are quite happy changing under full load also.

fietsbob

No, quite the opposite , IGH shifts better with a hesitation of power,

forcing the chain sideways, under load, often enough, and the chain pin end
pulls out of the plate and you are walking.

bhkyte

Mines quite happy under full load.

-=(8)=-

My Downtube was obviously returned by someone and then reshipped to me. It took a lot of time to set up mostly due to stuff being very, very bent up after 4 shippings. On mine, getting the cage aligned correctly was what finally made it shift correctly-for a while

bhkyte

"Sheldon harris" web sites are a gem of information for this sort for adjustment and maintence.

bargainguy

I'm a mechanic, and one of the best investments I ever made was the Park DAG-2 rear derailleur alignment tool, after I saw it being used at my local LBS on brand new bikes.

Seems even new bikes are misaligned, sometimes quite badly, and even if you tweak everything else correctly (cable tension, limit screws etc), if the derailleur body is not parallel to the frame, index shifting will never work properly, sometimes with odd results - like the biggest & smallest sprockets will shift fine, but the middle won't, that kind of thing.

I work on a lot of used bikes, and the most typical scenario is that the rear derailleur is pushed in at the bottom, such that the lower jockey pulley is much closer to the wheel than the derailleur body. One of the first things I check on an indexed shifting bike. On friction shifting, I'll still correct it, but not quite as critical.

Don

Jaxx317

-=(8)=- how terrible! yeesh! they should not be selling returned bikes as brand new. sooo not ok! sorry to hear that, but good to know the root of the problem seems to be the cage.

bhkyte

hi,
I thought folders tend to suffer from bent cagers also.
but i guess the drailler hanger will get bent frequeny if bike falls over, or gets bashed about as folders do etc ?

bargainguy

Probably more a function of being folded/packed and the entire drivetrain being closer to the ground with the folder's smaller wheels, so a little more prone to trauma. My guess is that folding/packing generates more RD hanger trauma than typical riding & use, unless you're in the habit of laying your bike down on the drivetrain side, thereby pushing in the RD. Whenever I travel with my Bike Fridays in a suitcase, I'll remove the RD entirely to avoid such issues.

Don

Jaxx317

yes, bargainguy, i can def see that! i am always extra careful when carrying my bike up & down stairs, and folding/unfolding to make sure the rear wheel and RD is off the ground so as not to cause damage.

an update: took the bike out for about a 6mi ride today and gearing seems totally shot now. chain still only getting up to 7 even though I can shift up to 9, and had lots of trouble with middle-lower gears (6-3). I could go on 7, occasionally 6, and 1, sometimes 2, but rarely anything in between middle gears seemed to get stuck on 1/2 gears, which only going all the way up or all the way down seemed to fix. not sure what I have done now to completely screw up my gearing but now it seems worse than before. RD situation appears to be the same. off to the LBS!

bhkyte

You might be aware of this information, but anyway........

Have you got the rear mech range limit screws set up incorrectly.
The mech should be able to shift by pressing it with your hand in to lowest gear. (maybe with the cable disconected or loosened). When you let go with your hand it should go in to highest gear on the spring pressure alone. If you can not obtain 1 first gear adjust the "low" or "L" screw on the mech, if not highest gog engaged alter the LOW or L screw.

Once these limits are correctly set it should be a matter of pulling enough cable tension thorugh to allow 1st gear to be selected and then the adjustments on the cable adjuster screw should address the indexing isuses.

bhkyte

Having done above and refiited the cable.

Does the mech fail to spring back into higest gear once the cable is reattached?
If so then the cable or cable routing is maybe to blame.
Get rid of frayed cables, check grommits,use light oil on inner cable. Or swop to teflon linned cables.

badmother

Reading your description again I am not sure the bike worked properly when you recived it. The short rides you describe could have been done without shifting much- or without shifting at all. The 7 mile ride is when the problems started and my guess is that this is when you noticed becouse on a longer ride you often need more gears. My guess is the hanger got bent in the transport (Ill be suprised if there is frayed cables on a brand new bike) so I think you should take it to a LBS to have them look at it. If they say it is bent you should look into contacting seller and transport company about it. In that case you should hurry up as they are going to claim you did something to the bike yourself. You could use this thread as "proof".

I do not know what you can hope to get from them but if you do not have the bike fixed soon you may end up hating it- an maybe bikes in general and that is sad..

This is one of the reasons why a lot of peopel (including me) like iGH`s on folding bikes. I did some adjustments on my sons new folder last night and noticed the new short cage folder specific rear der is quite stiff, much stronger than what I am used to. Must get one for my white folder.