We've logged a lot of Gravel miles preparing for races and rides like Almanzo and Dirty Kansa and we wanted to share details of the 1x (single front chainring) drivetrains we use. As with mountain biking, 1x allows you to eliminate the weight and clutter of the front derailleur and cable without giving up the gear range of a conventional double chainring drivetrain. After riding 1x setups for several years now, we are thrilled with the performance so 2x drivetrain for gravel/CX bikes is a thing of the past.
Below you will find some considerations on gear range, some help on chainring size selection, the best 1x Shimano setup, and the best 1x SRAM setup.
Gearing Range Improvement
- The 2x setup on the far left would be "typical" 2x gearing. Note how much gearing overlap there is with this setup.
- The second setup from the left is a 2x wide range with the RoadLink or Tanpan (note with Tanpan, you can even do an 11-40 cassette with 2x for a super wide range!)
- The right 4 are 1x options that cover most or all of the usable gear range for All-Road or Adventure-Road riding.
Chainring type and size selection
- Wolf Tooth Drop-Stop® chainrings have the widest range of fitment options for Road/Gravel/CX including both round and elliptical chainrings.
- Cyclocross cranksets are typically 110BCD or 130BCD
- We also offer SRAM Direct Mount, Shimano 110 BCD 4-bolt, and Cannondale Direct Mount.
- Typically, the size is labeled on the stock chainring you are replacing, but you can also measure the BCD using the instructions in our guide.
- We found that 40T front chainrings work great for the rolling hills in Minnesota
- 42T or 44T if you need more top end speed
- 36T or 38T if you want a smaller climbing gear
- Most people over gear and select too big of a chainring. At a cadence of 100, your top pedaling speeds are as follows
- 44 x 11 = 33 mph or 53 kph
- 42 x 11 = 32 mph or 50 kph
- 40 x 11 = 30 mph or 48 kph
- 38 x 11 = 29 mph or 49 kph
- Top speed numbers are from our gear charts and thee 650b x 2.2 tire numbers are quoted above as that is roughly equivalent to a CX size tire. Bigger tires would be about 1mph/1.5kph faster
Here are our 2 favorite Shimano setups:
1. With our RoadLink you can use your 10- or 11-speed in a wide range cassette 1x application. The details of the RoadLink can be found here. The basics are that this little engineering trick allows any Shimano road derailleur to work with up to an 11-40 cassette in a 1x applications. As with the SRAM, sometimes we run an 11-36t cassette, but with hilly courses, we pull out the 11-40. With 10-speed, this means having a standard 11-36 cassette and also our GC40 cassette and 16t cog available. With 11-speed, there are stock 11-36 (only SRAM, but works great) and 11-40 cassettes. Note that Shimano does not offer a Road/CX clutch solution, but for gravel and all-road use the chain retention of our ring with the non-clutch derailleurs is excellent. If you want extra security, a simple small chainguide can be added.
2. With the Tanpan, the range can get even wider than the RoadLink. The Tanpan allows Shimano 10- and 11-speed road shifters to work with 10- and 11- speed mountain bike rear derailleurs. This brings some very wide range options like 11-speed 10-44 or 11-45 modified cassettes. Additionally, mountain bike rear derailleurs offer better chain security when equipped with a derailleur cage roller clutch (Shimano does not offer this on any road groups).
Here is our favorite SRAM setup
SRAM 10-speed road shifters have the same cable actuation as SRAM 10-speed mountain bike shifters so you can use a mountain bike rear derailleur with road shifters. The clutch on the rear derailleur will help prevent chain suck when the lube is worn off your chain and the also eliminate the annoying sound of the chain banging on the chainstay. A short cage derailleur works great with a typical 11-36T MTB cassette but a medium cage will be needed if you want the extra low range of a 40T or 42T GC. With respect to 11-speed, SRAM offers several 1x road/Gravel options that work great with our Drop-Stop® chainrings on your current crankset.