More and more top models are rolling out of the factory with just one chainring. No matter whether noble Enduro or fast-as-an-arrow race hardtail: manufacturers are increasingly equipping their higher-priced bikes with single drivetrains. Sram currently offers the XX1, X01 and the cheaper X1 three single groups. The fact that the single drives function perfectly and are well thought out has been proven by the XX1 already in our innovation check proven. With Shimano you can the new eleven-fold XTR even with one chainring. But does the "less is better" slimming trend make sense for every biker? We don't think so for every biker. Because by losing two chainrings at the front, you lose a lot of overall gear ratio. And many bikers need this on never-ending climbs or transition stages on tarmac.
Little new with triple circuits
Little has changed in terms of triple gear ratios over the past two years. Sram is sticking to its 44/33/22 gradation, which is not suitable for 29-inch wheels. Shimano, on the other hand, reacted to the larger wheels last year and launched a 40/30/22 crank on the market. This provides a good alternative to Shimano's classic triple gradation with 42/32/24 teeth. 29er riders in particular had requested the 22 tooth crankset for climbing on their triple drivetrains.
Many variants for double translations
34 per cent come from according to our online survey with sensibly matched double gear ratios. The fact that more and more bikers are able to cope with 20 gears is due to the larger range of double cranks with suitable gear ratios. Both Sram and Shimano have recognised that not everyone can and wants to pedal 39/26 or 40/28. That's why there are now cranks with 38/24 or 34/24 teeth for the Shimano XTR, XT and SLX groupsets. Sram also has cranks with 36/22 and 38/24 gradations for its X.0 and X.9 groupsets. In combination with an 11-36 cassette, these double drivetrains offer 20 usable gears with a total gear ratio of around 500 per cent. So if you don't want to do without your 22 t cassette for climbing, you don't have to. In most cases, you simply leave out a few gears "at the top". But even with 36/22, you can still crank along at 90 revolutions per minute at 37 km/h with the highest gear (36-11).
Translation lexicon: an overview of the most important terms
Total ratio/bandwidth
It describes the range of your drive, i.e. from the lowest to the highest gear. The largest gear is larger than the smallest by the specified value, for example as a number (5.71) or in per cent 571%. Triple drivetrains have the largest total gear ratios at around 600 per cent, while single drivetrains such as an XX1 only have 420 per cent.
Wheel circumference
The wheel circumference depends on the wheel and tyre size and influences the wheelbase. This means that with the same gear ratio and the same tyre, 26, 27.5 and 29-inch wheels will have different wheel sizes. The choice of tyres also has a considerable influence on the wheel circumference. Narrow 2.0 tyres sometimes have significantly smaller circumferences than wide 2.35 tyres.
Unfolding
These values indicate how much distance is travelled per crank revolution and are the most important parameters for calculating the appropriate gear ratio. To do this, multiply the wheel circumference by the pure gear ratio (quotient of chainring and sprocket teeth).
Unfolding table
What do I currently ride, what can I tune? In the table you will find the maximum and minimum gear ratios of all common single, double and triple gear ratios. The gear range indicates how much distance you can cover with one complete revolution of the cranks. Different wheel circumferences result depending on the wheel size.
This is what the latest groupsets cost
If you want to convert your drivetrain, you sometimes have to dig deep into your pockets. The top-of-the-line 11-speed groupsets from the two shifting giants Shimano and SRAM are no bargains. However, if you look around for parts for the ten-speed XTR now, you can buy high-quality shifting components at a favourable price. In the table you will find the RRP without brakes and hubs.
You can find the complete article on translations in BIKE 2/2015 from 3 January at newsstands, in the DK-Onlineshop and as a digital edition for all end devices.
