Gear Ratios: How to Choose a Touring Bike Gear
Gear Ratios: How to Choose a Touring Bike Gear
The granny gear is the smallest gear on the front crankset of the bike. If you’re not already best friends with it, you may need to start! How to Choose a Touring Bike Gear? The article will tell you about.
The gear ratio of a touring bike depends on many factors: where you plan to go, the terrain, your experience, your strength as a rider, and of course, the amount of gear you carry.
I recommend a gear selection on all occasions, that is, a gear low enough to climb the steepest hills, and high enough so you don’t “slip” when the wind is on your side.
If you’re going to fix everything, you’re never going to have a low enough gear. A good granny outfit is so small that you can move at walking speed while using it.
Part 1: Gear Ranges and Ratios
Gear inches and knowing your gear ratios
The best way to compare sprocket and cassette combinations between bikes is to check their gear inches. They are easy to calculate: it is the diameter of the wheel times the size of the front sprocket, divided by the size of the rear gear. Armed with this information, you can compare bikes with different wheel sizes and drivetrain setups. On a touring bike, 18″ is a good low range and 113″ is a good high range.
Gear Inch Comparison in Drivetrain
Given that the touring triple crankset (48-36-24) has a range of 18-113 inches, how does this compare to drivetrains on different bikes capable of bike touring?
Typical road bike gearing
Traditional Road – 53x39t w/ 11-23t = 44 to 126″
Semi-Compact – 52x36t w/ 12-25t = 38 to 114″
Compact – 50x34t w/ 12-25t = 33 to 110″
Compact w/long cage – 50x34t w/ 11-32t = 28 to 119 inches
Road Triple – 50x39x30t with 12-27 tons = 29 to 110 inches
Traditional road, compact road and road triple crank.
Typical off-road gearing
Traditional CX – 46x36t and 12-30t = 32 to 104″
CX1 – 38t and 11-36t = 28 to 93″
Traditional CX and CX1 cranksets.
Typical mountain bike gearing
Single – 32t and 11-40t = 22 to 79″
Single XX1 – 32t & 10-42t = 21 to 89″
Dual – 38x24t and 11-36t = 19 to 96″
Triple – 42x32x24t and 11x36t = 19 to 106″
MTB single crank, double crank and triple crank.
Alfine 8s – 38t 20t = 27 to 84″
Alfine 11s – 38t 20t = 27 to 111″
Rohloff 14s – 40t 16t = 19 to 100″
Alfine 8, Alfine 11 and Rohloff hubs.
Recommended gear ratios for bike tours
It really depends on where you ride, the terrain, your experience and how strong you are. This is my guide for the “average” rider looking for enough gear to hit the hills on the Tour.
Without Pouch: 33 to 110 inches 5 kg
Pouch: 29 to 110 inches
10kg bag: 25 to 110 inches 20
Pouches of kilograms or more: 20 to 100 inches
Off-road travel: 18 to 100 inches
Disadvantages of wide range gears
While touring bikes generally require a wider range of gears, it’s also worth noting that the gap between each gear is greater than that of a low-range drivetrain. These gaps are most noticeable on flat terrain when you’re looking for the perfect gear to keep your pedaling rhythm going. For many cyclists, a wide-range drivetrain isn’t an issue, but if you’re primarily traveling on flat terrain, it might be worth considering a narrow-range cassette to fine-tune your cadence.
Part 2: Components
7, 8, 9, 10, 11, 12 speed
Modern drivetrains use 9, 10, 11 and 12 speed chains, cassettes and chainrings. Manufacturers are phasing out 7 and 8 speed drivetrains, but spare parts for lower quality materials will always be available. Although drivetrains with more gears use narrower chains, they prove to be as strong and reliable as the output gears.
Note, however, that an 11-speed drivetrain requires a wider cassette body than a 10-speed system, so compatibility with older wheels can be an issue.
Measure the difference in width between the 10-speed and 11-speed chains.
Another problem with running 10 and 11 speeds on a touring bike is that not all shops around the world have these somewhat modern parts available. Head to Backcountry Cycling to learn more about this topic.
Travel cranksets have a wider range of gears than mountain or road bike cranksets. The smallest chainring is usually 24 tons, the largest is 48 tons, and the intermediate gear is 36 tons. Touring cranksets require a long-cage MTB derailleur to make up for the huge difference in chainring size.
One, two or three links
Touring bikes typically use three chainrings on the front, although the new chainring/cassette technology allows for a wide range of gearing with single and dual chainrings. Most MTB twin cranksets will give you enough gearing to get you up any hill with a pack. With a single sprocket drivetrain you will have to sacrifice some high or low gearing compared to 2x or 3x. A single sprocket setup is often best left to light touring bikes for relatively flat travel.
Some manufacturers, such as White Industries, use a splined interface to mount the chainrings to the cranks instead of bolting the chainrings. The system allows for various sprocket configurations, with a maximum pitch of 24 teeth between the largest and smallest sprockets (eg 48x24t or 50x26t). The system allows the same range as a triple travel crankset.
Splined cranksets offer a wide range of gears with just two rings.
Bolt Circle Diameter (BCD)
BCD is the bolt measurement for different types of chainrings. MTB and road chainrings are not compatible because their respective BCDs are different. Conventional road and compact road chainrings are also not compatible.
Below is a list of standard sprocket BCD sizes:
104/64bcd: MTB 4-arm crankset
110bcd: Compact and semi-compact 5-arm road cranks
130bcd: Traditional 5-arm road crankset
130/74bcd: Road triple 5-arm crankset
135bcd: Campagnolo 5-arm road crankset (triple included)
The bearing interface where your crankset rotates on what’s called a bottom bracket. The BB screws directly into the threaded BB housing on the bike frame. Old-style BBs are often referred to as square cones. The square cone system works great and most bike shops around the world have spares.
Next is the outer BB still screwed into the BB shell, however, the larger bearing is located outside the BB shell. The system is robust and reliable. Using external bottom brackets, I’ve managed to ride 20,000km before needing to replace them. External BBs are standard on many modern road and mountain bike cranksets.
The latest technology in bottom brackets is the press fit, where the bearings are pressed into the bottom bracket shell of the frame rather than screwed into it. You probably won’t find this feature on many touring bikes, but it’s become very popular on trail bikes, road and mountain bikes.
Square tapered, external and press-fit bottom brackets.
As the bicycle industry pushes to move away from triple-sprocket drivetrains, cassettes are getting wider and wider. Wide cassettes finally allow people to successfully tour on double sprocket setups.
Road and MTB Tapes
Standard road flywheels typically have a maximum weight of 27 tonnes, however, road flywheels now weigh up to 32 tonnes (you must use a long cage road derailleur). MTB cassettes are available from 11-32 to 11-36t (long-cage MTB derailleurs are required for dual and triple setups).
Wide range of tapes
Shimano and SRAM have recently introduced cassettes with 40t and 42t cogs. These wide range cassettes are primarily designed for mountain bikes to run a single front sprocket. While the SRAM cassette requires you to use a specific hub with an XD driver, the Shimano cassette will fit existing 11-speed hubs.
Road cassettes, MTB cassettes and wide range cassettes.
11 speed cassette
In order to fit an 11-speed cassette, your hub needs a wider hub body. Before setting up your bike, check that your hubs are compatible.
Wider range of cassette modifications
To turn a stock 10-speed 11-36 cassette into an 11-40t, many companies popped up to make room by removing a smaller cog (16t or 17t) from a larger cog (40t or 42t). This setup has been proven and works well on a single drivetrain. Check out Hope or OneUp for more information.
A 42 ton gear has been added to this MTB flywheel.
Not all derailleurs work with all cassettes and chainrings. Derailleur cages come in a variety of lengths, depending on the cassette you want to use. A long-cage transmission is a must with any triple drivetrain.
Short Cage Transmission: Accepts flywheels up to 28-30 tons.
Long-cage road transmission: accepts flywheels up to 32 tons
Long-cage mountain bike derailleur: accepts cassettes up to 40 tons.
SRAM 1×11 derailleur: only works with 10-42t cassette
Short-cage, long-cage and SRAM 1×11 derailleurs.
Internally Geared Hubs and Gearboxes
Bikes with internally geared hubs typically have a reduced gear range compared to touring cranksets and wide-range cassettes. Rohloff hubs are the only ones with a 526% jump from smallest to largest gear. By comparison, Shimano’s Nexus 8 has 309 percent range and 11-speed 411 percent.
The minimum gear ratio that can be used with Shimano hubs is 1.9:1. So a 26-inch 8-speed bike is geared as low as 26-79 inches, and a 700c bike is geared as low as 27-84 inches. 26-inch 11-speed bikes are geared as low as 26-105 inches, while 700c bikes are geared as low as 27-111 inches.
The minimum gear ratio that a Rohloff hub can use is 2.5:1. So on a 26-inch Rohloff bike you can go as low as 15-95 inches, and on a 700c bike you get 19-102 inches.
The pinion gearbox has a large range (636%), offering lower and higher gears than Rohloff hubs.
Part 3: Cycling in remote areas
In the western world it is getting harder and harder to get good quality 7, 8 and 9 speed spares, however, in the rest of the world – you may have a hard time getting them
If you’re going on a big adventure in a remote part of the world, I’d recommend a 9- or 10-speed drivetrain as parts are in abundance. You are more likely to find chains, sprockets, links and sprockets.
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