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Discussion Starter · #1 ·
I looked around these forums, couldn't find anything that helped. Also I looked through my Zinn MTB Repair book, but couldn't find anything, just basic Maintenance and installing new drivetrains. Now that that's outta the way,

Last weekend I rode only 8 miles, and at the end of the ride my shifting was messed up. I noticed it pretty quickly after going over a rough section of trail. Going from the larger cogs (I don't know the correct terms, but the big ones with tons of teeth) to the smaller cogs (the ones with less teeth) there is quite a delay which wasn't there before. I have a SRAM X3 or X4 (I think, I have an all stock giant Yukon 2012). So from the time i click into the next gear switching from the largest cog in back to the next smaller gear it takes half a revolution of the cranks until it shifts. And the shift is rough too, I'd be pedaling and then my foot would slam forward with the crank until everything (chain I guess) got tight so I was propelling the bike forward again.

Shifting FROM a smaller (the ones with less teeth) TO a larger cog isn't as good as it was before either, but it's not nearly as bad as shifting FROM a big to a smaller cog.

Front derailleur and shifting is normal.

Thank you a ton!
 

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Yeah!
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Yeah, first thing you should check is that the derailler cage is still aligned. If the two wheels do not face for/aft in alignment with the frame, and/or if the lower wheel is not in a direct line with the upper wheel, you've got damage to the derailler.

Foot slamming forward... sounds like you are saying the crank is rotating forward faster than it should, as if the chain has come off, then it catches... that tends to be crap stuck between the cogs in the cassette. I experience this in the winter at times when snow builds up in that location... check that your cassette (rear gears) is clean between each cog.

As was mentioned, check that your cable housing is in good condition, lubricated properly, etc. Check that the cable is on the correct side of the bolt that secures it to the derailler. Check that the rear wheel quick release is not loose.
 

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Trail Tire TV on blogger
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Readjust the rear der, I believe it will be fine again after that. Use YouTube for instructions.
the only "readjusting" would be cable tension.. if you are adjusting stops then you have a bend hanger.. once the stops are set they never should be touched as there's nothing there to change or wear.

Might need to set the B screw properly as I've found 80% of the time even shops over look setting it correctly.

if everything is fine, and then it gets worse,.. you've either bent something (hanger most likely, cage possible) or the cables binding...

if the drive train is old, you may have just plan worn it all out.. chain, cassette, possibly rings. but that usually results in skipping type of issue under pressure not just bad/slow shifting.
 

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Trail Tire TV on blogger
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Drive train is just barely been used a year, chain is less than 13 & 1/32" stretch. Cassette is just scratched.

But what do you mean "adjusting stops"?
your high and low stops.. they are just that.. stops and nothing else.. they align the upper jockey wheel to the smallest and largest cassette cog and keep it from traveling beyond those cogs so you don't drop the chain. once set they should never need to be changed again.

there is the "b" screw (it usually in the back of the derailleur) that sets how close the jockey wheel is to the cassette cog. again, once set it should never ever need to be touched, but, as I stated before it is the #1 most over looked adjustment on new bikes and needs to be properly set. Often times it doesn't show as an issue right off until the bike breaks in a bit and the chain starts getting sloppy leading into the cassette.. 90% of the time it's WAY to far off
 

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Trail Tire TV on blogger
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if it's a 9 speed Sram, you take the chain off, shift to the largest gear, and space the tooth of the cassette and the tooth of the jockey wheel 6mm, I just use my 6mm allen wrench, set it against the tooth of the cassette and turn the B screw till the jockey tooth touches..

10 speed some have changed a bit so check the manufacturers info..

78 speed I got no clue, think it's still 6-8mm off the largest cog but not 100% on that...

you said it was a SRAM derailleur...

Service Resources - SRAM | SRAM

on the left side, click on the right "family" to get info on your groupset. (X5, X7,.. what ever)
 

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huh? what? dude,.. you usually have good advise but ,.. ummm huh? :confused: LOL
Just a little joke in reference to El' Cheapo's DIY grip thread, I guess it would have been funnier if I would have said inner tube instead of duct tape. Maybe not.

For the record I think your first post was pretty much dead on and unless El' Cheapo addresses those issues first, and he/she hasn't indicated that they have, it seems semi-pointless to continue troubleshooting.

Given the symptoms, if normal tension adjustments aren't effective it seems very, very likely to be a cable related issue.
 

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Cable housing is the first thing I would check. If you see any of the inside housing, the metal wires, exposed then change them out. also check to make sure that your hanger is not only straight but tight. Also I has a crazy issue where my axle on my rear hub would shift and the drive side axle wouldnt sit in the drop out at all. Took me a while to find that one.
 

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Discussion Starter · #20 ·
^^^^Well I bought the bike used from a guy who rode it less than 10 times, all on pavement. I bought it around last July. He bought it new a few months before that. I've only ridden it less than 130 miles.

Sent from my Nexus 7 using Tapatalk
 
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