Cerro de la Muerte
from San Isidro de El General
- Distance
- 27.6 mi
- Gain
- 8,691 ft
- Avg
- 6.0%
- Max
- –
3 h 09 min216 W · 8.8 mph · VAM 841 m/h
159 lb (72 kg) rider on a 20 lb (9 kg) bike. Run it with your numbers →
Cycling, explained with numbers
Everything you need to know about your bike
Clear guides to set up, choose and maintain your bike, legendary climbs with your estimated time, up-to-date bike laws and the tools to get your tire pressure, frame size and gearing right.
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Guides
Learn to set up, choose and maintain your bike
Straight answers with real numbers, and the calculator set up for your case at the end of every guide.
Gearing and drivetrainBike Gear Ratios Explained: Chainring, Cog, Wheel and Cadence
A gear tells you how far the bike travels per pedal stroke. A 50x17 with 28 mm tires is 78.3 gear inches, or 6.25 m per pedal stroke, and at 90 rpm you're doing 21 mph (33.7 km/h).
Bike setupBike Tire Pressure: How Much PSI to Run for Your Weight and Bike
A 165 lb (75 kg) rider on 28 mm road tires with tubes needs about 55 psi front and 65 psi rear; on 40 mm gravel tires, about 31 and 37 psi. More weight needs more pressure; wider tires and rougher ground need less.
Choosing a bikeWhat Size Bike Do I Need? How to Find Your Size and Measure Your Inseam
At 5 ft 9 in (175 cm) you're a size M on road, gravel, mountain and city bikes. To fine-tune, measure your inseam: multiplied by 0.665, it gives the classic road frame size in centimeters (a 32 in, or 81.3 cm, inseam × 0.665 = 54.1).
E-bikesWhat Drains an E-Bike Battery: Assist Mode, Hills, Cold and Wind
Assist mode drains the battery more than anything: with 500 Wh on rolling terrain you go from 86 miles in eco to 38 miles in turbo. Wind, climbing and cold come next; weight and tires matter much less.
Training and powerWhat Is FTP in Cycling and How to Do an FTP Test Step by Step
FTP is the power you can sustain for about an hour. You estimate it with a 20-minute test (95% of your average) or a ramp test (75% of your best minute), and it anchors all of your training.
MaintenanceWhen to Replace Your Bike Chain and How to Measure Chain Wear
Replace it when it has elongated 0.5% (11-13 speed) or 0.75% (5-10 speed). Over 24 links, that's 306.3 mm vs. 304.8 mm (12 in) for a new chain: a millimeter and a half decides whether you save your cassette.
Gearing and drivetrain1x vs 2x Drivetrain: Gear Range, Jumps and Weight Compared
With the same low gear (25 gear inches), a 48/31 double with an 11-34 cassette jumps 10.8% on average between gears and a 40-tooth 1x with a 10-44, 14.5%. The 2x is finer; the 1x is simpler.
MaintenanceBike Maintenance Schedule by Miles: What to Check and When
Tire pressure and brakes before every ride; a clean, lubed chain every week; chain and brake pad wear every 300 miles (500 km); bolts and cables every 600 miles (1,000 km); and a full tune-up once a year or every 100 hours of suspension use.
Bike setupHow to Adjust Bike Seat Height: Symptoms, Steps and Fine-Tuning
If your hips rock or the back of your knee hurts, the saddle is too high; if the front of the knee hurts, it's too low. Start from the calculator's number, check that your knee bends 25-35° at the bottom of the stroke and adjust 2 mm at a time.
By topic
Climbs
Legendary climbs: how long would it take you?
Elevation profile, difficulty and history of the climbs every cyclist wants to ride, from the Alps to the Rockies, with your estimated time based on your watts.
United StatesExtreme · 29.1
Mauna Kea
from Hilo · Mauna Kea volcano- Length
- 42.3 mi
- Gain
- 13,766 ft
- Avg
- 6.2%
- Summit
- 13,780 ft
Col de l'Iseran
from Bourg-Saint-Maurice · Graian Alps (Vanoise)- Length
- 29.8 mi
- Gain
- 6,414 ft
- Avg
- 4.1%
- Summit
- 9,068 ft
Colle del Nivolet
from Locana · Graian Alps (Gran Paradiso)- Length
- 25.2 mi
- Gain
- 6,558 ft
- Avg
- 4.9%
- Summit
- 8,570 ft
Resources
Beyond the calculators
Glossary in 6 languages
230 technical terms translated into Spanish, German, French, Italian and Portuguese.
Open the glossaryUS bike laws
Helmets, lights, e-bike classes, safe passing and riding on the road, with the official sources.
See the bike lawsKids' bikes
What wheel size your child needs, age by age, from 2 to 12 years old.
See kids' bike sizesWhich bike should I buy?
Seven questions and we tell you which type of bike, size and budget fit you.
Take the quizData studies
Sales, prices and how many days of wages a bike costs in each country.
See the studiesReference charts
Size charts by height and by brand, tire pressures, gear ratios, training zones and standard measurements, ready to print.
See the chartsTools
Calculators that get it right the first time
Tire pressure, frame size, saddle height, gearing, power or e-bike range. Save your bike and they fill themselves in.
Tire Pressure
Front and rear psi (and bar) by rider weight, tire width, rim and terrain.
Bike Size
Your frame size from height and inseam, for every type of bike.
Saddle Height
Saddle height with three methods, adjusted for crank length.
Crank Length
The crank length that fits your inseam and riding style.
Kids' Bike Size
Wheel size in inches from your child's height and age.
Gear Ratios
Chainring × cog chart with gear inches, development, speed and drivetrain comparison.
Chain Length
How many links your chain needs from chainstay, chainring and cog.
Tire Size
ETRTO, inch and 700c equivalents, plus the circumference for your bike computer.
Spoke Length
Left and right spoke length from ERD, flange and cross pattern.
Your bike, with its own shop sheet
Pick your type of bike and enter your measurements: we give you tire pressure, saddle height, frame size, gearing and chain length, ready to print.
Or start with your type:
Why BikeRatio
- Answers with numbers, not opinions
- Every formula explained and sourced
- Climbs and laws checked against several sources
- Free tools that run in your browser
- No sign-up and no paywalls
- Your data stays on your device
Frequently asked questions
What is BikeRatio?
A website for cyclists: guides to set up, choose and maintain your bike, climbs with their elevation profiles, US bike laws, a glossary in six languages and free calculators.
Is it free? Do I need to sign up?
It is free and there is no sign-up. The calculators run in your browser, and whatever you save in My Bike stays on your device.
Where does the data come from?
The formulas are published ones (Berto, LeMond, Martin and others), and the climb, law and market data are checked against several sources that we cite on every page. All the details are in our methodology.
Does it work for e-bikes, mountain bikes or kids' bikes?
Yes. There are guides and tools for road, gravel, mountain, city, electric and triathlon bikes, plus kids' sizes from 2 to 12 years old.