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The Birth of Dirt (3rd ed.) by Frank J. Berto
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The Birth of Dirt (3rd ed.) by Frank J. Berto, pages 12 & 83
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The Birth of Dirt (3rd ed.) by Frank J. Berto, page 26
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A low gear of 1:1 would be a good start with 26” tires. Some examples:
  1. Breezer Series I: 32 front x 26 rear. Not so good on a 38 pound bike. This is the same as 3rd gear on a 1979 Ritchey.
  2. 1979 Ritchey: 28 front x 32 rear. Good.
  3. Typical 1979 road racing bike: 44 inner x 18 rear, 700c tires. And people wondered why mountain bikes became so popular?
  4. 1981 Schwinn King Sting 5: 40 front x 28 rear. Not a mountain bike.
  5. 1982 Specialized Stumpjumper5: 26 front x 28 rear. Good.
  6. 1982 Schwinn King Sting 10: 40×48 front by 14-38 rear. Schwinn is getting there.
  7. 2021 Mt. Bikes: 34 single front x 52 rear. Super low. And generally heavier than any old-school Ritchey.
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Are modern downhill bikes mountain bikes? They're geared to go one direction only: down. For example, the Trek Session 9.9 (trekbikes) has its lowest gearing of 36×25 on 29“ rims. It simply can't go up. But it has 190mm of travel front and rear…
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Obviously there are some exemptions. See Cunningham for example. However arbitrary, some filtering is needed.
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What about e-bikes? The Trek Powerfly 9.7 weighs 51.5 pounds - with a carbon fiber frame…
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The United States International Trade Commission, which places an 11% tariff on mountain bikes, but only a 5.5% duty on road bikes, defines mountain bikes as: “Bicycles, not motorized, w/both wheels o/63.5 cm in diam., weighing 16.3 kg or more, and/or for use w/tires w/x-sect. diam. o/4.13 cm”. That is, rims >= 26”, weight > 36#(!) and tire width >= 42mm (1.6“). See: link. These definitions are very outdated, but still current. Hybrids get caught within this definition, but not light weight mountain bikes.
test.1635221566.txt.gz · Last modified: 2021/10/25 21:12 by gchandler