# Which gears not to use in a 2 X 9 gear bike

I am new to biking. I bought a hybrid bike with 9 gears at the back tire and 2 gears at the front. For reference lets say gears at front (chain ring) are numbered 1-2 and gears at back are numbered 1-9. As the numbers increase the the cycle becomes harder to pedal (for both front and back). For example if you switch from 1 to 2 at front cycle is harder to pedal. And if you switch from 2 to 3 at back tire, the cycle is harder to pedal.

Now my question is this. Are there certain gear combinations, I should not be using. Can you write those combinations down for me like (1 back, 5 front). So I can use that for reference. The particular problem I am having is that when I am at around 7-9 at back and 1 or 2 at front the cycle starts making a weird noise. Is it normal? Any other combination I should not use?

• The word is peddle. paddle is what you do on a canoe. Commented Feb 14, 2015 at 17:27
• Try and stay out of big big but I ride big in front as much as I can to use big in the back. On the cassette you tend to wear out the small gears first. Commented Feb 14, 2015 at 20:19
• @Blam - you're right. Peddle is to sell, pedal is what you do on a bike. Commented Feb 14, 2015 at 21:52
• @Batman Cool I edited the question. What is funny is that my English is terrible. Commented Feb 14, 2015 at 22:27
• If you had a triple in front you'd want to avoid big-big and small-small, because of the chain angle. With only a double it's not so critical, but not ideal. You may begin to hear a sort of click/rasp from the chain and sprockets. But if you're getting noise from the chain the first thing to do is to check that the derailers are properly adjusted, as misadjustment can cause this noise. Commented Feb 15, 2015 at 2:44

The general rule is that you don't want the chain angle to be extreme (i.e. the chain should be running as parallel to the frame as possible) - when the chain is at an extreme angle, it is called cross chaining. This is a good read.

For example, you don't want to use the little ring in the front and the little cog in the back (this increases wear on both of them). Likewise, if you want to use the big ring in the front and big ring in the back, you may want to go to the middle ring in the front instead and remain near the center in the rear (if you had it -- for a double in the front, there will be a point where you'll prefer to shift down in the front and then stay near the middle of the cassette).

The most important thing to do is to avoid small-small combination though - modern drivetrains aren't too unhappy with cross chaining, but its still not good practice.

Also, note that the gears you use at the time depend on the terrain and what not -- try to aim for a cadence of about 70-90 RPM (how fast the pedals turn).

• Batman smallest at front and back is the (1f,9b) combination which you said I need to avoid. Also I need to avoid (2f,1b) combination. Are only these two to be avoided? because I also experience noise at (1f,8b), (1f,7b), (2f,8b) and (2f,9b). Is that normal? I understand I need to avoid (1f,9b) and (2f,1b). But should I be avoiding any of the other gear combinations mentioned as I get a weird noise from them or just the 2 you mentioned.
– Rain
Commented Feb 14, 2015 at 18:17
• When the chainline becomes not straight, you may get some rubbing in the front derailleur which makes some noise. On a friction shifter or a brifter, you might be able to trim it a bit to avoid that. 1f8b 1f7b 2f8b and 2f9b are nearly as extremely angled as 1f9b and 2f1b, hence the rubbing. The noise will go away if the chain is more straight. Commented Feb 14, 2015 at 19:13
• So basically I don't need to worry about it and its normal and keep using those combinations?
– Rain
Commented Feb 14, 2015 at 19:35
• When you want to use, say 1f,8b, it would be better to use 2f and something towards the middle in the back. If you shift properly and the derailleurs are properly adjusted, the rubbing should be minimal. Commented Feb 14, 2015 at 19:44
• I understand thanks. I am just going to be using this cycle for commuting short distances, nothing too extreme. So I think I can avoid easily the combinations which are troublesome. I just wanted to check if there was anything wrong with the bike itself so i can get it fixed. thanks :)
– Rain
Commented Feb 14, 2015 at 20:03

Provided that the chain length is adjusted correctly, with a 2-chainring crankset you can freely use the entire range of gears.

The "dangerous" gears are the ones causing cross-chaining. These are: small sprocket at front + small sprocket at the back, and big sprocket at front and big sprocket at the back. Especially the latter can cause trouble when your chain is too short. But it's more of a problem if you have a 3x crankset, where a chain on gears 1 and 3 is further from its perfect line.

I have a 2x9 drivetrain in 2 of my bikes and using all gears whenever I want to. I haven't noticed any quicker wear and haven't had any problems with this setup for the past 5 years. Though I did have a problem with a previous bike with a 3x crankset, when I snapped chain riding a 3-1 gearing...

• Well, small-small wears things down extremely quickly. Commented Feb 14, 2015 at 17:37
• I haven't noticed it myself, but if you ride it for extended periods, this may be the case. I spend most of my time off road so the wear is +/- even on the drivetrain. Commented Feb 14, 2015 at 17:42
• I normally avoid small ring +2small sprockets and big r+2big sp. as the drive produces noise. Noise meaning excessive wear and low efficiency. Commented Feb 19, 2015 at 17:37