I'm new to all this, and frankly, am having an issue:

I just got home from the LBS. I had ordered a 36h rim because I kept breaking spokes.

Now, before we start, I'm trying to build a touring style bike on the cheap, but, want/hope for something that works.

I'm trying to learn mechanics as I go, so I ask questions and am hoping to take a class this fall being taught by a local bike mechanic/salesman.

Here's the thing, they couldn't mount my old cog set to the new rim. My bike is a Giant Revel 2 and had a 14x34 7 speed cassette. The crankset is 28-38-48.

The new cassette is a Shimano Hyperglide CS-HG20-7...a 12x32 7 speed.

When I mounted the new rim(and cassette) I found I had a fair amount of apparent chain vibration when in the big ring and small cog. This seems to disappear when I shift to middle ring or to a different cog.

Frankly, I'd love to have the smaller cog, because I'm guessing it might give me just a slight bit more road speed.

I've also read that this could be due to the chain needing adjusting(lose a link or two). However, this wasn't an issue before.

I should also note that lately, I've noticed shifting difficulties with the front derailleur which seems at times to need to be tightened only moments later needing to be loosened. Granted this could be a whole different issue.


At any rate, the vibration seems to occur in the rear derailleur pulleys. There is no apparent grinding, I can't see any rubbing and it rides okay, and frankly, I've just had a couple of days off...but it seems to ride a bit faster with the 2nd smallest cog riding like my former largest cog...

I appreciate any help, and plan to talk to the LBS tomorrow anyway...but I'd really like to...hope to, fix the problem on my own....


Thanks for taking the time to read this, thanks for any advice...Happy cycling!