TBerk

Folks, I've been an avid rider for many decades but this is my first post here.

I use a Hybrid 'Mountain' Bike frame (fixed) w/ a 7 speed rear cassette I moved over from the previous rim.

The front end is a three ring, but really I usually leave it on the largest gear up front & just work the Rear Derailleur.

(I have a feeling I should go outside and count the teeth on all these gears...).

My riding is done on City Streets, hardly any off-road, more pot-hole/curb/speed-bump jumping, moderate to steep hill climbing of short duration, and that Last-Mile from the Bus/Train or in-between gigs during the day.

My trouble, to finally get to it, is that almost any selection of Rear gearing, when used with the MID Front Gear will slip, pop, & jump the chain. Medium but still seated pedaling is not possible on the middle range, front gear, at all.

The Largest Front Gear is where I live most of the time, but If I stand up and really crank on the pedals I can get the chain to pop off, so to speak. It's a really bad thing to have happen when navigating traffic, I can tell you.

The Front's Little Gear is a pretty trouble free part of the bike, It's used to climb Overpasses w/ Groceries strapped to the rack or pretty much 50% of San Francisco's landscape.

I'd replaced the Chain a year or more ago- I'm harboring a sneaky suspicion that it's too long and needs some links taken out. (How would I know if a chain is the right length?)

Might the Rear Derailleur be failing to pull back enough tension on that chain, keeping it wrapped on the gears?

I ride most every day for transportation, but my legs aren't super massive; it's crazy that I'm overpowering the drive train...

Thx in advance,
TBerk

trailangel

Worn Cassette, worn front chainrings. Worn chain.
Chain length here:
Javascript Bicycle Chain Length Calculator

TBerk

(insert Sad Face Emoticon -here-) Cool, thx; I bookmarked the link.

I'm liking those new 11 speed setups and am looking into retrofitting to a Single Front gear/ Wide Range Rear cassette w/ appropriate Derailleur & chain.

trailangel

Don't be sad. It's times like this that you will talk yourself into a new bike.
If you are in SF take a drive to:
https://blackmtncycles.com
Pt Reyes and test ride some bikes, just for the heck of it.

Lakerat

I had that happen when I replaced the chain with a Campy chain on a 9 speed Daytona group. Didn't happen with the old chain and the chainwheels didn't look very worn. New chainwheels and the problem was gone. I suppose worn chainwheels teeth get more sloped and ramp the chain up when its loaded. Can't visualize why a worn chain with the rollers further apart wouldn't be a problem. Somehow the greater distance between rollers keeps them off the worn sloping part of the tooth. Maybe because when they are on the chainwheel the wear makes them closer together.

rayooo

Whenever I'd replace a chain...and had waited a bit too long before doing so, I'd have skipping/jumping on cassette. Replaced cassette and in each case problem was gone.
I've begun to replace chains now much sooner and in doing so I have not had the issue.

DaveSSS 

New chain skip is a common problem. It can be avoided by alternating the use of several chains, so a new chain is never installed on a well worn cassette. As long as each chain gets a decent amount of use, the cassette will last for the life of all the chains in the rotation and each chain can be used longer.

cudak888 

In addition to the existing comments here (which are all pretty much correct - though it's ridiculous to invoke "New Bike Excuse" on this alone), I'd bet the wear between the new chain and the old cassette is contributing to the skippage/chain skate in all gears.

Swap the cassette (or freewheel, as it may be) with a new 7-speed unit. If the chain hasn't been prematurely worn over that first year of use, the problem should go away. If not, put on a new chain along with the cassette/freewheel. Problem solved.

-Kurt

TBerk

Thx everyone. (I had written more but fumbled the 'quick reply' function, so 'poof').