Speed Lab
Trail braking calculator.
Your tires only have so much grip, and braking and cornering share it. Set your speed and corner to see your lean angle, how much brake you have left, and the line pressure that takes.
With the inputs you provided, your maximum speed through this corner could be up to or .
- Cornering load
- v² / (g·R)
- Lean angle
- Brake available
- of upright maximum
- Braking decel.
- Front line pressure
- Front tire load
CorneringBrakingCombined
Available brakeRear lift limit
Release plan
How far to ease off.
The brake you can use at each lean angle, at μ = , with your brake use applied.
| Lean (thin tire) | Cornering load | Brake available | Decel. | Line pressure |
|---|
The physics
The math behind it.
Lean angle
tan φ = v² / (g·R)
φreal = φ + arcsin[ t·sin φ / (h − t) ]
Lean balances gravity against cornering force. A real tire's width moves the contact patch inward, so the bike leans further than the thin-tire value (Cossalter, Motorcycle Dynamics).
Friction circle
√(abrake² + alat²) ≤ μ·g
brake available = √(1 − (tan φ / μ)²)
Braking and cornering share the same grip. The more you lean, the less brake you can use, and it falls away fastest near the limit.
Maximum corner speed
vmax = √(μ·g·R)
With no braking, all the tire's grip goes to cornering. Set v²/R equal to μ·g and solve for v. This is the absolute limit, not a target speed.
Load transfer
Nfront = m·g·f + m·abrake·h / L
rear lift when abrake/g ≥ (1 − f)·L / h
Braking pushes load onto the front tire. On a sport bike, upright, rear-wheel lift is often the real limit before tire grip.
Brake pressure
p = m·abrake·Rtire / (n·2·μpad·Apistons·reff)
Flever = p·Amaster / lever ratio
Pressure is linear in deceleration, so the line-pressure trace should follow the same curve as the friction circle as you lean in.
Model limitsSimplified steady-state model: flat road, all braking on the front tire, constant μ, no aerodynamic drag, suspension pitch, load sensitivity or brake-steer effects. Results are for learning and comparison only, not riding instruction. Practise on a closed track with proper training and protective gear.
This is a model. GPiQ reads the real thing.
Speed Lab shows the physics. GPiQ shows what you actually did: where you braked, how you released, and where the time went.