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7 Speed Bike vs. 21 Speed Bike

man in black jacket riding on black bicycle on road during daytime photo

Bikes are an excellent way to get around and explore nature. They promote a healthy lifestyle and come with a huge amount of benefits. The cycling industry is growing consistently, and more people are turning to bikes in their spare time than ever before, which in our opinion, is great.

Bikes can be very confusing when looking at specifications, and it can take a lot of research to understand what you need to look for. We often get asked what’s the difference between a 7-speed and a 21-speed bike. In this article, we’ll explain the difference between the two alongside helping you understand bike gearing.

What does the term Speed mean?

Speed refers to the number of different gear ratios you have on the bike. A 7-speed bike will offer you seven different gear ratios, some will be low for going up a hill, and others will be high for descending a mountain. 

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How do Bike Gears work?

man riding black and gray bicycle photo
Photo by Dan Russo from Unsplash

Bike gearing can be complicated to understand. Bike gears work by using a series of different-sized cogs and, depending on the sizes, will change the amount of resistance the pedals will have.

Here’s how it works:

Starting with the rear cogs, you will have between 7 and 13 cogs on modern bikes. Let’s say we’re riding on a flat road, and the pedaling frequency stays the same. The larger the cog you use, the easier the pedals will be to turn, but the less the wheel will rotate. The smaller the cog, the tougher the pedals will feel but the faster the wheels will rotate. 

On the front, you have a different story and the complete opposite. The larger the cog, the harder it will be to pedal, but the faster you will go, and the smaller the cog, the easier it will be to pedal, but the less the wheel will rotate. 

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What is a 7-Speed Gearing Setup?

A 7-speed setup will typically be a single chainring at the front and a 7-speed cassette at the rear. The cassette will be fairly large, and you will have one single gear shifter that will allow you to go through gears one to seven. It will offer some light gear ratios for climbing and also offer some heavy gear ratios for descending. 

What is a 21 Speed Gearing Setup?

A 21-speed setup will have a cassette on the rear with seven speeds; up on the front, you will have a chainset with three cogs on. Suppose you have three cogs on the front and seven on the rear. That gives you 21 options of different gears, even though some will feel the same as others. You will have two shifters on the bike, one for the front cogs and one for the rear. The 21-speed gearing will offer a huge amount of gear ratios for climbing and a huge amount of gear ratios for descending. 

What’s the difference in gear ratios between a 7-speed and 21-speed gearing setup?

Although you might think that with 21 speeds, you get a huge amount more as ratios go, you would be surprised as the difference is not much. A good way to understand the amount of gear ratios you get is by using this diagram.

Pros and Cons

Before you choose either a 7-speed or a 21-speed, you must understand their pros and cons. Although the 21-speed might seem like the go to option, it isn’t always the best.

7-Speed Pros

  • Lightweight
  • Easier to use
  • Cheaper to buy
  • Maintenance is cheaper and easier
  • Less to go wrong 

7-Speed Cons

  • Limited gearing 
  • Front chainring wears quicker

Overall

The 7-speed setup is basic, and it does make it very cost-effective, but it is limited when it comes to the number of gears you get.

21-Speed Pros

  • Lots of gearing options
  • Very high and low ratios
  • Front chainrings last longer
  • Two shifters to work with

21-Speed Cons

  • Heavier system
  • Harder to use
  • More things to go wrong

Overall

The 21-speed system gives you many options and ratios but is harder to use and comes with more parts to maintain. 

person riding on bicycle on road
Photo by Flo Karr from Unsplash

7-Speed or 21-Speed, which is better?

If you live in a hillier area, you will get a lot more benefits from having a 21-speed gearing system, as it will give you many more options for climbing up hills and getting down hills very fast. If you ride in flat terrains, the better gearing for you would be the 7-speed gearing system. 

Conclusion

When it comes to 7-speed bikes and 21-speed bikes, there’s a big difference in the number of gearing options, and if you live in a hillier area, they can be very useful to have. We highly recommend both systems, and before buying a bike, try both. 

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Robbie Ferri

Robbie Ferri

Robbie Ferri is a cyclist living in Norfolk in the UK. From breaking World Records to competing in some of the hardest Bikepacking races in the world he is not shy of riding the miles. He has been lucky enough to work at some amazing shops and with some big cycling brands. Alongside this he even had input in designing bikes and has also been a tester for unreleased products. He absolutely loves cycling and believes everyone should have a bike.