Time For Service, Need Part Recommendations

[wantin150]

Shift and stand up to pedal. If you hit the top tube, your chain is slipping/skipping. You'll know it. If you suspect something is wrong, it probably is. Replace the chain AND cassette.

The "crunch" may actually be your bottom bracket or rear hub. To check the BB, grab the crank arms and try to pull the out and away from the bike. If they move, it's the BB.

Also, you may just be getting a little chain rub depending on your gearing. Try adjusting the front derailleur when in the small/big combo. Check it again in the big/small combo.

Also check your headset. Hold the front brake and try to rock the bike back and forth (front to back). If it's loose, have it adjusted.

 

[The Critic]

Originally Posted By: wantin150
Shift and stand up to pedal. If you hit the top tube, your chain is slipping/skipping. You'll know it. If you suspect something is wrong, it probably is. Replace the chain AND cassette.

If I stand up, pedal and shift, it shifts into the next gear fairly hard. Almost a snap type sound, it makes you feel uneasy. What's a top tube?

Originally Posted By: wantin150
The "crunch" may actually be your bottom bracket or rear hub. To check the BB, grab the crank arms and try to pull the out and away from the bike. If they move, it's the BB.

OK, it passed the BB test. No problem there. I did repack the rear hub recently, maybe I adjusted it too tight?

Originally Posted By: wantin150
Also, you may just be getting a little chain rub depending on your gearing. Try adjusting the front derailleur when in the small/big combo. Check it again in the big/small combo.

The chain does touch the front derailleur a bit when it's in the 3rd chain ring (largest) and the 8th cog. I tried adjusting the front derailleur with little success. I think it might've been that way since new, I can't remember though.

Originally Posted By: wantin150
Also check your headset. Hold the front brake and try to rock the bike back and forth (front to back). If it's loose, have it adjusted.

No problem here.

Thanks!

 

[tom slick]

Quote:
What's a top tube?


It's the top tube of the frame, the one your family jewels would hit if you fell straight down.

 

[The Critic]

Got it.

Thanks for everything guys. I just ordered all the stuff. Here's what I bought:

 

[rpn453]

Originally Posted By: The Critic
If I stand up, pedal and shift, it shifts into the next gear fairly hard. Almost a snap type sound, it makes you feel uneasy.


Ouch! Don't shift under power. If the chain jumps a tooth, it will happen under power without shifting. It's quite a dramatic event, so you probably won't mistake it for anything else! It should only happen when your chain and cassette (or even a chainring) are severely worn, if the chain is damaged, or if you install a new chain on a cassette that is too worn to mesh with the new chain.

Originally Posted By: The Critic
OK, it passed the BB test. No problem there. I did repack the rear hub recently, maybe I adjusted it too tight?


For a quick-release hub, set the bearings so that there's just a little bit of play when the wheel is off. If there's no play, it's too tight. Tightening the QR skewer will eliminate the play when you install the wheel. If it doesn't, it's too loose.

 

[rpn453]

Originally Posted By: The Critic
I've noticed that on some gears, when I ride at a very low speed I can feel a "crunch" type feeling. It's limited to the higher gears though, IIRC, is that a sign of skipping?


No, it sounds like something is just out of adjustment, or maybe bent. The rear derailleur could even be set too close to the gears and is hitting them. That usually happens in the lowest gears though.

 

[The Critic]

Thanks. When I get the old cassette off, I'll take some pictures of it and post them. I guess if it's still okay, I can always reuse it next time.

 

[wantin150]

Something to remember about mountain bikes:

They HATE the extreme gear combos, i.e. big ring/big ring and small ring/small ring, especially with the jump in gearing range. This makes for a pretty unnatural chain angle and can wear stuff out a little quicker. This is probably why you get the chain rub in the big ring (front). To fix this, use the limit screws on the derailleur. It take patience to get it right but you will know when you do. Just don't adjust so much that you overshift and drop the chain down the crank arms.

 

[The Critic]

It's all done.

I installed the new cassette, chain, brake pads, tires and grips last Friday at the campus bike co-op. On the ride home it still didn't shift quite right, the brakes howled like a bus and I got a flat tire , so it went back to a different shop on Saturday for some adjustments. After adjusting the rear derailleur, adjusting the brake pads and bedding in the pads, everything's work great now. It truly rides like a new bike now.

Thanks again for all the help!