Beginner's gear question

[carinapir]

My rear cassette is an 11-34, and the head wrench at my LBS says that certain gears would be easier to shift into if my chain ring had a wider range.

My first thought when I read this was that he was referring to the fact that derailleurs have a harder time lifting the chain when the tooth difference from one cog to the next is more than 1 or 2. When its try to lift from a smaller cog to a much larger one the shifting might not be as smooth.

For example if you have an 8 speed 11-34 you might have the following:

11-13-15-17-20-23-26-34

But if you have a 10 speed 11-34 you would have:

11-13-15-17-19-21-23-25-28-34

You see with the 8 speed you have bigger gaps and there are more instances when your derailleur is changing to a cog with 3 more teeth rather than 1 or 2.

That's just what occurred to me when I read your question and that he meant the cassette rather than the chain ring. I could be wrong.