Climbs on the small chainring · 70/80 rpm — speed, VAM and watts per cog (5–10%)
At Velo-Perso.com, the #1 question is simple to ask but tricky to answer: which chainrings should I choose for my riding? Your use case is unique: natural cadence, body weight changing through the season, headroom for improvement, mountain data (Strava), one or several climb goals, and whether you use a power meter. This comparator was designed to simulate your gearing and help you move from intuition to a precise choice.
Shimano/SRAM covers most needs but can be restrictive. Our selection includes smaller cranksets (e.g. 48/31) to keep a good cadence in the mountains even at modest fitness, and conversely larger chainrings for powerful climbers seeking mechanical efficiency — often paired with a wider, less evenly spaced cassette.
Attention to detail, in the service of enjoyment and progress
Our obsession: make every ride more enjoyable and help you improve. The ideal tool is a custom modular power meter crankset: adjustable crank lengths, interchangeable chainrings (50/34, 52/36, 53/39, 54/42, 56/44… or 48/31), and the option to try oval chainrings to smooth the dead spot.
What is VAM and how to use it here?
VAM = Average Ascent Speed (vertical meters gained per hour). If you don’t have a power meter, VAM is an excellent way to size your gearing.
- Find on Strava your climbs of about 1 hour at a steady effort (e.g. 800 m/h).
- In the tables, choose a crankset + cassette that lets you reach ~800 m/h on the largest cog at 8%.
- If the largest cog forces you to ride at ~900 m/h, review the small ring or the spacing (you’ll run out of gears too soon).
Note: a power meter remains more precise: at equal power, your VAM slightly decreases as the grade eases (aero and rolling matter more).
Calculation: Velo-Perso.com — 700×25C wheel (2.105 m) · masses: bike 8 kg + gear 1 kg + rider (55/65/75/85 kg) · Crr=0.004 · ρ=1.226 · CdA=0.245 · drivetrain losses 3%. Cogs ≥ 13 teeth (≤12 excluded).
Need a fine-tuned setup for your terrain?
We’ll help you choose cassette, chainrings and crank lengths according to your target VAM, body mass, cadence and routes.
