When to Use the Optimal 21-Speed Gear Adjustment on Flat Roads?

[Dianne]

Here are several scenarios for 21-speed gear adjustment on flat roads: 1. Low gear, suitable for starting, riding against the wind, or climbing hills: Use the smallest chainring paired with the largest 3 cogs on the cassette. Avoid pairing the smallest chainring with the smallest 4 cogs, as this will reduce the lifespan of the chain, chainring, and cassette. 2. Normal riding gear, suitable for daily flat road riding: Use the middle chainring paired with the middle 3 cogs. Avoid pairing the middle chainring with the smallest 2 cogs or the largest 2 cogs, as this will reduce the lifespan of the chain, chainring, and cassette. 3. High gear, suitable for riding with the wind or downhill: Use the largest chainring paired with the smallest 3 cogs. Avoid pairing the largest chainring with the largest 4 cogs, as this will reduce the lifespan of the chain, chainring, and cassette. Additional information: 1. Gear system: A 21-speed bike refers to a gear system with 3 chainrings and 7 different-speed cogs on the cassette. 2. Gear shifting: It is commonly believed that 3X7=21, hence the term 21-speed gear system. However, in practice, you cannot use all 24 speeds because the correct method is: if the front is in 1st gear (chain on the smallest chainring), it is best to pair it with 1-2-3 gears at the rear (where the chain on the largest cog is 1st gear, followed by 2,3,4,5,6,7 gears).