bkkboy

I just took my relatively new bike on a 2,000+ km ride across Europe, took 5 weeks. A few things I noticed, including that the tires and inner tubes were cheap and needed replacing with good brands. Mainly though, the derailleur was crap. While cycling, all day all I could hear clack clack clack ..., as the derailleur tried unsuccessfully to change up or down. If I wanted to go down in gearing once, I needed to go down twice then back up once, on the back derailleur. I could only use two of the sets of cogs on a three speed front derailleur. I took the bike to a repair shop, it worked for 24 hours then back to clack clack clack ... Since I generally walk up hills, is it important to get three sets of cogs on the front derailleur, or will two be sufficient? I plan to upgrade the derailleur in the next week or so.

HillRider

It sounds like a relatively simple cable tension and perhaps limit screw adjustment. I can't believe the bike shop couldn't make it work properly unless the bike is so inexpensive it can't be made to function well or the "repair shop" was incompetent. The fact the tires had to be replace that soon makes me wonder about the quality of the entire bike.

Andrew R Stewart 

A lot of front shifting challenges are due to the rider's lack of best technique. The chain and der want as minimal pedal pressure as possible during the shift attempt. So shifting the front when on a hill is a worst case combo (slow cadence and high pedaling forces). Low grade and flexible ders (and rings) tend to need more technique to work well.

Generally the front sprockets are called chain rings, not cogs (which is usually a reference to the rear sprockets).

How many rings do you need? This is really a gearing question and the answer depends on the rider more then any other factor. Do you need low gearing to pedal up hills? Do you care if you walk instead? Will you become able to shift the front better (whether upgrading equipment or technique)? But don't worry because the industry has already decided this for you by moving from 3x and 2x front cranksets and is now pushing the 1x as the answer/best thing. Andy (trying to not be too cynical)

Iride01 

If you are in the biggest rear cog and the biggest front ring, then chain rub is likely on the front DR. 10 speed and particularly 11 speed rears have more of this being just a thing with them.

I don't know when trim became a thing on shifters, but you do know how to use the trim on your bike don't you? It moves the DR cage slightly when in the big-big combo to help alleviate this somewhat. You have to remember to take the trim out when you shift out of that gear or else you might have rub on the other side with the rest of the gears.

Some bike because of their chain stay length and other things are more susceptible to chain rub and you just have to live with it. My Paramount had a long wheel base and I could get almost all the rub out. My Tarmac has a shorter wheel base and I can't get it as quiet as my Paramount was.

Despite all of this, the bigger issue is if you are having to be in the big-big combo for more than a few minutes at a time, then you don't have the correct range of gearing on your bike. Or you just need to shift to a smaller front ring and a smaller rear cog for the time you need a ratio comparable to the big-big.

There are times that the small-small gears are a similar issue, but usually most have their gripe about the big-big.

OldRailfan

Can't believe this!
There is a certain overlap/close duplication on a three chain ring set up,
I'm certain that shifting will work much easier once one figures out which combos work best.

OldRailfan

Yeah it's a fact on most e-bikes!

Took three chain ring derailments before I went to the "one step at a time" method since that microShift9S didn't seem to like the multi steps. Of course it could be the "wearing in" factor. i.e. it settled down.

bkkboy

Thanks Andy and everybody else.
If I understand correctly, the industry is moving towards 2 and preferably 1 front chain rings, away from 3. I agree that I do not have the best technique, at age 72 I am OK on the flat, but am happy walking up hills. This is my first bike that I bought two years ago.

DaveReading

Indeed. It would be a very strange setup that didn't provide other gear combinations that were close to big-big but without such severe cross-chaining.

For example on my 3 x 8 tourer, big-big gives me a 1.5 ratio, but on the middle ring I can have 1.4 or 1.7, and the difference isn't worth worrying about.