Cycling math and gear takes. For road, gravel, and mountain riders who care about the numbers behind their setup, not influencer fashion.
Cycling content online is dominated by two voices. Pro-influencer reviews of $10,000 bikes (irrelevant to your $1,500 entry-level Roubaix). Or beginner forums regurgitating myths (108 PSI in your road tires because that was a Tour de France myth from 2008).
Middle ground is the math. Frame sizing by inseam, not by bike-brand sticker. Gear ratios for your terrain. Tire pressure based on weight and width, not what the sidewall says. Chain wear measurement so you replace it before the cassette eats itself.
Tools
Frame Size Calculator
By inseam, bike type (road/gravel/mountain), and reach preference (upright vs aggressive). Tells you the size range that fits, not the brand-marketing answer.
Tire Pressure Calculator soon
By rider weight, tire width, surface (paved/gravel/dirt), and tube vs tubeless. Lower than you think for most setups.
Gear Ratio Calculator soon
Chainring + cassette combinations with gear-inch and development output. For finding climbing gear gaps before you buy a bigger cassette.
Plain note about money: Some product links are affiliate (eBay Partner Network). Small commission on purchases. Doesn't change your price. Reviews come from actual rides. The $3,000 race wheelset isn't faster than the $400 for most riders; I'll say that here knowing some brands won't love it.