Bicycle Drivetrain Builder

Apex 1 11-Speed Shifter/GX 10-Speed Derailleur/10-Speed Cassette

Shifter: Apex 1 11-Speed (SB-APX-B1)
Derailleur: GX 10-Speed (RD-GX-T21-A1)
Reviews: Positive
Speeds:10 Use these numbers on a website like gear-calculator.com to find gearing that suits you and is compatible with this combo.
Max Tooth: 36
Unofficial Max Tooth: 42
Chain Wrap: 47

These combinations are not supported by the manufacturer. Use at your own risk.

A friction shifter will be needed if you wish to use a front derailleur. The derailleur supports multiple front chainrings, but there is no matching shifter available for the front derailleur.

This combination has more shifts than cogs. The limit screws will need to be adjusted to prevent these extra shifts from shifting to non-existent cogs.

Cassettes

Cassette Part Number Support
Generic 10-Speed generic-10-speed Not Supported
LinkGlide 10-Speed CS-LG300-10 Not Supported, Exceeds Official Max Tooth
Shimano 10-Speed CS-HG-500-10 Not Supported
SRAM 10-Speed CS-PG-1050-A1 Not Supported

Reviews

TESTING BAD IDEAS THE INTERNET SAID SHOULD WORK

Link to review

Positive review from Path Less Pedaled.

Note: Tested using a Rival 11-speed 1x shifter. Russ is positive on the compatibility, negative on the combination's ability to clear a 50t cog

Compatibility Analysis

Show Compatibility Analysis

Each click of the shifter will move the jockey by 3.83 mm on average. Manufacturers generally to target a cog pitch that is between 0.7% smaller to 6.9% larger than this number.

In practice, no groupset aligns the jockey wheel perfectly for every shift. Manufacturers generally allow the chain to make up to a 1.2° angle from the jockey wheel to the cog.

Pull Ratio: 1.33
Cable Pull: 2.88 mm
Minimum Cog Pitch: 3.80 mm
Maximum Cog Pitch: 4.09 mm
Maximum Chain Angle: 1.2°
Table of relevant compatibility numbers

Generic 10-Speed

Cog Pitch Versus Average Shift

The cog pitch of a Generic 10-Speed cassette is 3.95 mm, which is 3.0% larger than the average shift. This value is within the typical range for measured groupsets.

3.95 mm Cog Pitch 3.83 mm Avg. Shift Range 3.8 mm 4.09 mm
Average jockey wheel movement per shift (left) compared to average cog pitch (right). Compatibility range on the right.

Worst Case Misalignment

This combination with a Generic 10-Speed cassette puts the chain at up to a 0.2° angle to the cog. This amounts to a sideways difference of 0.09 mm between the jockey wheel and the cog. This value is within the typical range for measured groupsets.

0.09 mm 0.2° 1.2° max
Cog and jockey in the worst-case scenario of alignment.

(Positions and angles are exaggerated for illustration. Numbers do not include the free play resulting from the cog being thinner than the rollers.)

Cog Positions vs Jockey Positions

2024-12-08T18:15:31.490629 image/svg+xml Matplotlib v3.9.2, https://matplotlib.org/
Comparison between cog positions and jockey positions for each shift. Cog positions are measured from the outside of the dropout.

LinkGlide 10-Speed

Cog Pitch Versus Average Shift

The cog pitch of a LinkGlide 10-Speed cassette is 4.05 mm, which is 5.4% larger than the average shift. This value is within the typical range for measured groupsets.

4.05 mm Cog Pitch 3.83 mm Avg. Shift Range 3.8 mm 4.09 mm
Average jockey wheel movement per shift (left) compared to average cog pitch (right). Compatibility range on the right.

Worst Case Misalignment

This combination with a LinkGlide 10-Speed cassette puts the chain at up to a 1.0° angle to the cog. This amounts to a sideways difference of 0.58 mm between the jockey wheel and the cog. This value is within the typical range for measured groupsets.

0.58 mm 1.0° 1.2° max
Cog and jockey in the worst-case scenario of alignment.

(Positions and angles are exaggerated for illustration. Numbers do not include the free play resulting from the cog being thinner than the rollers.)

Cog Positions vs Jockey Positions

2024-12-08T18:15:31.667181 image/svg+xml Matplotlib v3.9.2, https://matplotlib.org/
Comparison between cog positions and jockey positions for each shift. Cog positions are measured from the outside of the dropout.

Shimano 10-Speed

Cog Pitch Versus Average Shift

The cog pitch of a Shimano 10-Speed cassette is 3.96 mm, which is 3.2% larger than the average shift. This value is within the typical range for measured groupsets.

3.96 mm Cog Pitch 3.83 mm Avg. Shift Range 3.8 mm 4.09 mm
Average jockey wheel movement per shift (left) compared to average cog pitch (right). Compatibility range on the right.

Worst Case Misalignment

This combination with a Shimano 10-Speed cassette puts the chain at up to a 0.1° angle to the cog. This amounts to a sideways difference of 0.06 mm between the jockey wheel and the cog. This value is within the typical range for measured groupsets.

0.06 mm 0.1° 1.2° max
Cog and jockey in the worst-case scenario of alignment.

(Positions and angles are exaggerated for illustration. Numbers do not include the free play resulting from the cog being thinner than the rollers.)

Cog Positions vs Jockey Positions

2024-12-08T18:15:31.846306 image/svg+xml Matplotlib v3.9.2, https://matplotlib.org/
Comparison between cog positions and jockey positions for each shift. Cog positions are measured from the outside of the dropout.

SRAM 10-Speed

Cog Pitch Versus Average Shift

The cog pitch of a SRAM 10-Speed cassette is 4.05 mm, which is 5.4% larger than the average shift. This value is within the typical range for measured groupsets.

4.05 mm Cog Pitch 3.83 mm Avg. Shift Range 3.8 mm 4.09 mm
Average jockey wheel movement per shift (left) compared to average cog pitch (right). Compatibility range on the right.

Worst Case Misalignment

This combination with a SRAM 10-Speed cassette puts the chain at up to a 1.0° angle to the cog. This amounts to a sideways difference of 0.56 mm between the jockey wheel and the cog. This value is within the typical range for measured groupsets.

0.56 mm 1.0° 1.2° max
Cog and jockey in the worst-case scenario of alignment.

(Positions and angles are exaggerated for illustration. Numbers do not include the free play resulting from the cog being thinner than the rollers.)

Cog Positions vs Jockey Positions

2024-12-08T18:15:32.024970 image/svg+xml Matplotlib v3.9.2, https://matplotlib.org/
Comparison between cog positions and jockey positions for each shift. Cog positions are measured from the outside of the dropout.