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  • A giant leap for bike drivetrains – SRAM Eagle drivetrain

    All technology tends to creep along with slight advances made every year, and then someone breaks the mould and the entire industry has to run like hell to catch up as the mould breaker makes a significant advance in that technology. 15 years ago every mountain bike had vee brakes, then someone invented the disc brake. Now every mountain bike has them, and even many of the Tour de France racing bikes will have them as road bikes have been freed by the racing authorities to follow the path of the mountain bikers.

    Late last week, the bicycle drivetrain company SRAM signalled the end of front derailleurs on mountain bikes with the Eagle drivetrain. In around 5-10 years’ time mountain bikes with front gears and gear changing systems will be history and every machine will have just one cog on the pedals with 12 or more cogs on the rear.

    The Eagle has landed

    The number of cogs on the back wheel has gone up over the years. My last, 15 year old machine had 7 on the back. My current one, a two year old 29er, has eight on the back. The Eagle XX1 has 12 cogs ranging from 10 teeth for the smallest fastest gear to 50 teeth for the steepest of climbs.

    On current bikes with three cogs on the front, every gear change is a messy business. In theory you should have the front cog on the biggest ring for the top three (smallest yet fastest) gears on the rear, switch to the middle ring for the next three, and then for the steepest climbs you should switch to the smallest gear on the front, as well as the biggest two cogs on the rear for the biggest climbs. Confused yet?! In reality I use the biggest gears for long fast downhill stretches, a wide range of gears on the middle ring for moderate climbing, and a fair range of gears on the smallest front cog for the biggest climbs.

    The drivetrains that follow the Eagle will just mean that you use the rear derailleur, climbing cog size for different steepness of hill and going to the smaller gears for the flat / downhill stretches. For beginners this will be simplicity itself – less confusing even than a car’s gear stick!

    If like me you like a bit of fun at weekends and don’t want to spend silly money on a new chain and cassettes then don’t get your wallet just yet. The SRAM Eagle costs over £1000 for the XX1 and just over £900 for the X01. This is not the cost of a bike – this is just the cost of the drivetrain for the bike!

    The Eagle’s babies

    As with all giant technological leaps the first generation costs silly money to the Early Adopter generation of users. Bike designers will already be designing the £700 fun in the hills / commuter bikes of the future with only the rear derailleur and a single cog on the crank set. You can bet that SRAM’s arch rivals Shimano will be ready to roll out the 1×12 drivetrain in the next few months and then the two companies will compete to sell the first mass market 1×12 drivetrain. It is people like you and I who make those companies money, not the Early Adopters with carbon, feather light bikes. Good things come to those who wait!

    Written by Cycle Injuries


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