A 7-speed bike is a great bike for a person who rides on tricky terrain. It's main purpose is to let the bike adapt to rough conditions and accommodate inclines, bumps and other difficulties. On a 7-speed bike, the lower gears make it easier to pedal and the higher gears allow for better movement going downhill.
In a 7 speed set up you have a single front sprocket and 7 at the rear (of different ratios, or number of teeth) with a single gear shift lever. In the 21 speed you have 3 sprockets with different gear ratios in front and 7 at the rear wheel, therefore 7X3=21.
A 21-speed bike has three front gears and seven in the rear. Image Credit: Dmitry Naumov/Hemera/Getty Images. A multispeed bike allows you to comfortably ride at different speeds across varying terrain. Each speed on a bike refers to a different combination of gears.
A 7-speed bike is one that has a single chain ring (the round component that the chain sits on, and the cranks and pedals attach to) at the front, and 7 cogs at the back. This collection of cogs is referred to as a 'cassette'. Because the cassette is made up of 7 cogs (speeds) it provides 7 different gears.
For riding on flat roads, it is recommended to use the middle gear. It is a common choice among bikers as it helps you reduce pressure from your feet onto the pedals.
Ride the bike around slowly to get a feel for the pedal tension. Move the shift either one number up or down while you pedal forward. Listen for the derailleur to activate. Seven-speed bikes have just one derailleur on the rear wheel.
Bikes generally have 1, 3, 18, 21, 24, or 27 speeds. (10- and 15-speeds are obsolete and you don't see them on new bikes anymore.) Lower numbers are the low gears, and higher numbers are the high gears.
On the handlebars of a 21-speed bike (the most typical), you'll see a left-side shift lever with the numbers 1, 2 and 3, and a right-side shift lever with 1 through 7. The lever on the left controls the three chainrings on your front derailleur, and drastically change how easy or hard it is to pedal.
Low Gear = Easy = Good for Climbing: The “low” gear on your bike is the smallest chain ring in the front and the largest cog on your cassette (rear gears). In this position, the pedaling will be the easiest and you'll be able to pedal uphill with the smallest amount of resistance.
A multiple-geared bike like a seven-speed cruiser has a lot more range than a single speed bike in terms of your pedaling. Because you can shift into lower gears for uphills and higher gears for downhills and flat roads, you'll have a much easier time negotiating changing terrain.
ZF Friedrichshafen AG delivers the 7-speed manual transmission for Porsche's new 911 models. This is the first manual transmission with 7 gears that is available for passenger cars.
A 21-speed bike has three front gears and seven in the rear as well as a total of 21 gears in all. A gear setup refers to the combination and placement of each cog on your bike which is why it's so important when adjusting 21-speed bike gears.
The newly developed seven-speed automatic transmission increases acceleration from 0 to 100 km/h by up to 0.3 seconds and allows significantly quicker intermediate sprints from 60 to 120 km/h. Shifting is also smoother and more comfortable than with the automatic transmission presently used.
The most obvious difference between both bikes is the different number of gears and different gear setups. Both differ by one rear gear. 21-speed bikes have 7 sprockets with 3 chainrings at the front, while 18-speed bikes have 6 rear sprockets with the same number of chainrings.
Shifting your gears while standing still stretches the cables and strains the derailleurs. Remember, you have to be pedaling before the bike will change gears.
There are two areas in which gearing can be customised: at the chainset (which we've already alluded to), and the cassette. Fundamentally, a lower number of teeth on the chainrings results in an easier gear, while conversely a lower number of teeth on the cassette provides more resistance, and therefore a bigger gear.
Based on your anticipated speed and minimum tolerable cadence, are the gear ratios on your bike sufficient? A common setup on a road bike adapted for climbing is a compact road crankset with 50-34 chainrings and an 11-32 cassette, which gives a lowest gear of 34:32 or a ratio of 1.06:1.
A road bike will have either a triple, double or compact crankset. This refers to the number and size of chainrings (located by the pedals). A triple crankset has 3 chainrings; it is often paired with a 9-speed cassette on the rear wheel to give it a total of 27 gears.
Gear Ranges on Bikes
Broadly speaking, mountain bikes have lots of low gears so you can climb steep hills more easily, while road bikes have more higher gears to boost top-end speed. More gears means more choices, but also more complexity for riders (and shop techs).
Low Gear. The low gear is the "easy" gear and is primarily used when climbing. The low gear is the smallest chain ring in the front, and the largest cog on the rear cassette. In this position pedaling will be easiest and the least amount of force will be required to push the pedals.
This cycle features 21 speed gears, a front disc brake, and high quality MTB tyres for a thrilling experience on the city roads. The Shimano 21 speed gears allow you to adjust the gears according to different terrains like hills and narrow trails.
This allows you to use the full range of rear gears. Number 1 on your right shifter is the easiest gear for climbing hills, as it puts your chain on the largest rear sprocket. Number 7 on your right shifter is the hardest gear for going really fast, and it puts your chain on the smallest rear sprocket.