cassette and chain help!!

[lukewiens]

so after a wild season of racing and punishing my xc bike i decided to change out my chain and cassette. i swapped the chain on my kona king from the stock shimano to a new sram 971. knowing the rule of changing the cassette and chain at the same time, for some reason i thought i might be able to get away with just the chain (brain fart!!).

during my ride on the SJT on sunday every time i came out of a turn and stomped on the pedal the drivetrain slipped badly flying down 4-6 inches before catching again. after getting back to the car i decided that i wasn't going to get away with just the chain swap.

tonight i put on a sram 980 cassette, a change from the stock shimano lx. the installation went as easy as expected, shifts on the money....one problem though!! i am getting a weird sound when i get on the bike and ride it. it almost sounds like the chain isn't seating right or like a light popcorn sound. the sound isn't apparent though when it is in the stand. i wonder if the stress i put on the chain on my (one) ride on sunday stretched the chain out or something. everything seems to working ok....parking lot tested, however the thing just doesn't sound efficient....a little scary as a matter of fact.

any help would be appreciated, although i am thinking i need to take it in for someone to hear the sound. i just hope i didn't blow the chain with that one ride...

thanks.

[Red Hot Sloth]

Did you do your chainrings as well?
You may not have stressed the chain from one ride like that, but usually when you do the cassette and chain, you need to do the chainrings as well, this can cause some strange sounds.

[Rob]

Sounds like the cassette and chain are still breaking in. Go take a new bike for a spin and see if it's the same sound.

[Rob]

Could also be the tension on the der cable. Do you have a stand so you can get the bike up and pedal it while you adjust the tension?

[Dizzle]

I rode an juan on sunday, I ate it hard. anyway your frame might be flexing under load. try adjusting the barrel adjuster on the shifter while riding.

[BoingBoing]

I'd measure the old chain. If 12 full links measure 12-1/8" or more, I'd follow Red Hot Sloths advice and change the chain rings (especially the granny). If not, I'd ride it more and see if Rob is right about it breaking in.

Oh yeah, did you check the length of the new chain. I hear you sometimes have to take a link or two out of a new chain for it to fit. http://sheldonbrown.com/derailer-adjustment.html shows the procedure in the section "Chain Length."

Good Luck

[26'er Zen Master]

I highly doubt that you damaged your chain. Is there lube on it? the factory lube works great but wears fast. I would turn your barrel adjuster a click one direction see if that works if not try going back to the original setting and turn the barrel adjuster the other way one click. Or just eyeball the alignment between the top pulley and the cassette make sure the chain looks straight

[el_d00der1n0]

Is the sound in certain gears? I had a prob with the smaller cogs and I noticed they were just a little loose. When I had it on the stand they wouldn't make noise, but when I put force on them they would make a little noise. So, I just torqued the cassette down some more.

Another prob I had was a broken spoke. It hadn't completed the break yet, and there was a popping sound that seemed to be coming from the hub. If you can reproduce the sound on the truing stand you might want to look there. Pluck your spokes to make sure the music is the same.

[soul rider]

get new chainrings...does it slip in the middle ring the most?

[Cableguy]

The last cassette (SRAM 980) is new, correct? If not, you need to get a brand new one. I had the same problem until I put in a new one (high quality, not the cheap stuff).

You should also make sure the chain is new. Old ones stretches to fit the existing cassette. If you don't want to spend the money, make sure you use the cassette/chain combo that was on the other bikes.

The other thing you should check is the pins on the chain. If you are using Shimano, make sure the pins (especially the breakable one you put in) isn't hitting the hub side of the cassette. Same with SRAM chains.

[lukewiens]

the sound only becomes apparent when tension is applied to the drivetrain. for example, if i apply the brakes slightly while rotating the crank on the stand or when i am riding the bike.

it kind of reminds me of the sound your bike would make when the rear der. sits all the way down on the cassette.

hell....i don't know!!

[BSki]

You can just change a chain, no problems.

The rule is, when you change your cassette, change your chain as well. The chain seems to marry to the cassette.

Are you sure the chain has the same amount of links as the one you took off?

[Rob]

Is it doing it in all of the gears? Maybe you need more B Tension. You should have 4-6 mm of space between the top pulley and the cassette teeth(with the chain on)

When you tighten the B Tension screw, rotate the der clockwise as to take the weight off the screw from the der. hanger.

[Upsidedown1]

Had the exact same problem. Put on a new wheelset and SRAM 990 cassette with a new xtr chain. Rear end kept making what seemed to be a crunching noise that I could feel through the pedals. Put on new chainrings...same thing still. Did what others suggested to you and went on a ride. The noise did go away. After a couple of rides everything is as smooth as can be.

[Schecky]

A wise man once told me that 90% of shifting issues can be corrected with the barrel adjuster.

[xxx]

I just changed the derailluer(Shadow), XTR chain, XT cassette and middle chain ring. Worked great in the middle ring under load. Was going up Black Mountain in the small ring and I am hearing that "rattle" that has me trying to adust the rear derailluer barrel adjuster to no avail. My buddy riding with me says he sees the chain "jumping" not in the rear but in front off the bottom of the small ring. I picked up a new ring at Beyond Bikes yesterday but have yet to install it. I am sure that is the problem because the small ring had some "shark finning" that was causing the ring to suck up the new chain. Good ruck.

[Laggdawg]

Do all the FREE stuff first!

• Ask everyone on STR (done)
• Run your fingers along the chain and inspect it closely. The last time my chain made popcorn noises was about 5 minutes before it snapped from a dead link;
• Adjust the barrel forward 1 turn and ride; try it backwards and ride;
• Check pulley alignment and indexing; then B screw;

Now that you have satisfied yourself with the basic...

• Change the chainrings because that is where the problem is (most likely)

Seriously, what do they say..."Keep It Simple Stupid" the most obvious solution is usually the right one. There are countless stories of cassette and chain upgardes that are not accompanied by a chainring swap (myself included) that always come back to the same answer.
Good luck, be sure to let us know what happens!

[CalEpic]

Assuming the cable tension is correct with the barrell adjuster, double check the pulley clearance with the b tension screw. If the noise persists check to see if it is in all the chainrings. My guess is it's just in the middle. Replace the chainring.

It is possible to change the chain, cassette, and chainrings independently of each other if they're not worn too badly but I usually wait until they're good and worn then replace the works. Ironically that middle chain ring will be the cheapest part to replace.

Onew last longshot - when pedaling backwards make sure the chain doesn't slacken due to a bound up free hub that needs service.