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Basic Gearing Questions(7 posts)

Basic Gearing QuestionsJMG1000
Feb 1, 2003 7:44 PM
I hope you won't mind answering a couple of basic questions.

My bike has two sprockets by the petals and seven sprockets on the rear wheel (I'm not sure if "sprocket" is the right term to use, but I'm referring to the round device with "teeth" that the chain attaches to).

1. I assume from the above that my bike has 14 gears. Is that correct?

2. I also assume that the lower the gear, the easier it is to pedal up hills...i.e. you would be more likely to use first gear up a steap hill than the fourteenth gear. Is that correct?

3. Now, if my first two assumptions are correct, where is the chain located for each gear? For first gear, is the chain located on the smaller of the two sprockets by my pedals and the smallest of the seven sprockets on the rear wheel? If so, when I change into second gear, the only change is that the chain moves to the second smallest sprocket on my rear wheel? Is that correct?
re: Basic Gearing Questionsseyboro
Feb 1, 2003 8:28 PM
1. Yes
2. Yes, but the term 'first gear' might become confusing.
3. Let me clarify what I am talking about: the big 'sprockets' by the pedals are called 'chainrings'. The little ones on the back are called 'cogs' or 'cog set' or 'cassette'. In cycling, both the chainrings and cogs get their name from the number of teeth on them. So, your chainrings will probably be the '39' (for the little one by the pedals) and the '53' (for the big one).
In the back, you have 7 cogs, with the smallest probably being the '12' and the largest maybe the '25'.
You will be in your easiest gear with the chain in the 39 in the front and the 25 in the rear. This is also called the lowest gear, because you won't go as far with one turn of the cranks.
Your next, higher, gear will keep the chain on the 39 in the front and on the next smaller cog in the rear...and so forth.
In general, you will use your 53 chainring on flat and/or faster rides and your 39 for slower/more hilly efforts. Hope this helps.
re: Basic Gearing QuestionsJMG1000
Feb 2, 2003 6:52 AM
Now, here is what I don't understand. You indicated that the easiest gear has the chain in the 25 (the largest cog) in the rear. Logically, it would seem to me that the smaller the cog (i.e. the fewer the teeth), the easier the gear. In other words, it should require less work to turn a smaller cog with fewer teeth one revolution than a larger diamater cog with more teeth. Why isn't the easiest gear when your chain is in the 39 in the front and the 12 in the rear?
Take a course in Physics!!!Rusty McNasty
Feb 2, 2003 8:16 AM
or maybe just ride your bike...collinsc
Feb 2, 2003 10:20 AM
It wont take long for you to see for yourself which gears are the easiest.
re: Basic Gearing Questionsseyboro
Feb 2, 2003 8:27 AM
In the 25 cog, you are required to pull the chain a little over twice as many cogs as you would in the 12. Riding the same distance (let's say one rotation of the wheel at the same speed), you will spread the same workload out over a longer part of the chain engaged in pulling the wheel around. This makes the cranks turn faster, but the required power outpout lighter.
It's like lifting 200 lbs in one rep, as opposed to 10 reps. The more reps, the lighter the weight for the same load. The more turns of the crank, the easier the pedaling for the same distance/speed.
Try it on the bike, you will see for yourself.
Go here for infoMel Erickson
Feb 2, 2003 5:44 AM
http://www.sheldonbrown.com/articles.html

Look under Gear Shifting. You'll probably have many more questions related to cycling and Sheldon Brown can answer most of them. You'll find his site invaluable.