Gear inches = (chainring / cog) × wheel diameter. A 50/34 chainring with 11-30 cassette gives a gear-inch range from about 30 to 122. Modern trends favour 'compact' gearing even for strong riders, because low cadence grinding up climbs is a larger performance leak than slightly-short top gears on fast descents. Mountain bikes use 1x setups with huge cassette range; gravel bikes are moving to 1x or sub-compact (46/30) 2x.
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