https://www.bodyworldsboston.com/the-complete-guide-to-cycling-performance-drivetrain-mechanics-gear-and-safety/
——From the metaphysics of gear ratio to the black technology of gear shifting
What is a flywheel?
“Yesterday, I helped a novice rider change his flywheel. He stared at the gears and asked, ‘Is this the heart of the bike?’ – To some extent, it is!” Modern bicycle flywheels are not simple gear combinations, but products of precision engineering. Take Shimano’s Hyperglide+ system as an example. Its special tooth design can increase the gear shifting speed by 33%, and there will be no “clicking” noise when shifting gears when climbing a slope (tested and effective!).
Core Features :
Overall system : The flywheel pieces must be replaced as a set (replacing a single piece will cause speed failure)
Black technology of shifting : SRAM’s X-Range and Campy’s ETS systems each have their own unique features
Material evolution : From steel to titanium, my 10-52t mountain bike flywheel has lost 40% weight
Gear selection: from road to mountain
Last Saturday, I took a newbie to climb Jietai Temple. His 11-28t road cassette made him grin with pain, but I climbed to the top easily with my 11-34t cassette – this is the magic of gear ratios!
2025 mainstream configuration :
| Model | Typical gear ratio | Applicable scenarios |
| Road bike | 11-30t | Flat sprint/gentle slope |
| Endurance Road Bike | 11-34t | Long distance/medium slope |
| Mountain Bike | 10-52t | Steep/technical terrain |
| Melon Cart | 10-44t | Mixed road |
Purchase suggestions :
Commuter Choice 11-32t (Price/Performance)
Climbing freaks must buy 10-52t (but pay attention to rear derailleur compatibility)
Competition enthusiasts should pay attention to Hyperglide+ (faster gear shifting)
High-end VS affordable flywheel test
Last month I tested a domestic brand (200 yuan) and a XX brand (800 yuan) flywheel at the same time:
Precision : High-end product shift error <0.3mm (cheap product about 1.2mm)
Lifespan : After 3000km of riding, the wear rate of high-end products is only 20%
Weight reduction : Titanium flywheel is 160g lighter than steel flywheel (equivalent to carrying two fewer bottles of water)
But be careful :
the more expensive, the better! My commuter bike uses a 300 yuan steel flywheel, which is durable and affordable.
Maintenance tips :
Clean the flywheel gap with a special tool every month (3 grams of sand was removed last time!)
The chain should be replaced every 2000km (a worn chain will accelerate the failure of the flywheel)
Be sure to wipe it dry after riding in the rain (my 10-52t flywheel has extended its life by half a year because of this)
https://www.bodyworldsboston.com/the-complete-guide-to-cycling-performance-drivetrain-mechanics-gear-and-safety/