How much lean does a normal road bend need?
Road builders pick the tightest allowed bend radius from the speed limit. On the tightest bends the standard allows, you need somewhere between about 7° and 18° of lean at the limit, and a good deal less when you ride slower. Most road bends are calm to lean through.
About the numbers. Every angle is a model value from the calculator’s formula (g = 9.81 m/s²). Your line and speed will differ, so read them as a guide. The minimum radii come from the Norwegian road standard N100 and the cycling speeds are scenarios we picked. Krengo shows your lean angle in a corner.
The road is drawn for a speed
The Norwegian Public Roads Administration’s handbook N100 Veg- og gateutforming (road and street design) ties the smallest horizontal curve radius to the speed limit.1 The table repeats the minimum radii from the May 2019 edition. N100 has since been revised (the current edition is N100:2023), and the change logs for 2022 and 2023 list no changed minimum radius for streets or main roads. These are minimum requirements for designing for motor vehicles; real roads often have larger radii, and the table says nothing about any particular road.
| Speed limit | Minimum radius | Table in the 2019 edition |
|---|---|---|
| 40 km/h or less (streets) | 40 m | Table B.1, p. 17 |
| 50 km/h (streets) | 60 m | Table B.1, p. 17 |
| 60 km/h (streets) | 125 m | Table B.1, p. 17 |
| 50 km/h (local road L2) | 60 m | Table C.10, chapter C.4.2 |
| 60 km/h (main road Hø2) | 125 m | Table C.3, p. 32 |
| 80 km/h (Hø1 and L1) | 225 m | Table C.3, p. 32 |
| 80 km/h (national main road H1) | 250 m | Table C.3, p. 32 |
| 90 km/h (H5 in 2019) | 400 m | Table C.3, p. 32 |
| 110 km/h (H3) | 800 m | Table C.3, p. 32 |
Newer editions of N100 calculate the 90–110 km/h classes by their own requirement, so the 400 m for 90 km/h is the 2019 value.
What that means in lean
Put the speed limit and its minimum radius into the formula θ = atan(v² / (g · r)), with speed v in m/s, radius r in metres and g = 9.81 m/s², and you get the lean in the first table below. Speed enters squared, which is why a long bend at a high limit can ask for less lean than a short bend at a low one. Cross-check: 50 km/h on 60 m is 18.1°, the same figure as in the descending technique article. Try your own numbers in the lean angle calculator.
| Speed limit | Minimum radius | Lean |
|---|---|---|
| 40 km/h | 40 m | ≈ 17.5° |
| 50 km/h | 60 m | ≈ 18.1° |
| 60 km/h | 125 m | ≈ 12.8° |
| 80 km/h | 225 m | ≈ 12.6° |
| 80 km/h | 250 m | ≈ 11.4° |
| 90 km/h | 400 m | ≈ 9.0° |
| 110 km/h | 800 m | ≈ 6.8° |
So the tightest bends the standard allows ask for under 20° at the limit, and the wide ones for under 10°.
Your speed asks for less
A bike is usually slower than the limit. The table shows the lean for cycling speeds on the radii above. These speeds are scenarios chosen by us, not a recommendation. At 30 km/h on a 60 m bend the lean is about 6.7°, and at 40 km/h on a 125 m bend about 5.7°. The main message: most road bends are ridden with single-digit lean, and double digits arrive in tight bends or at high speed. Most bends ask for less lean than you might think.
| Radius | 40 m | 60 m | 125 m | 250 m | 400 m |
|---|---|---|---|---|---|
| 20 km/h | ≈ 4.5° | ≈ 3.0° | ≈ 1.4° | ≈ 0.7° | ≈ 0.5° |
| 25 km/h | ≈ 7.0° | ≈ 4.7° | ≈ 2.3° | ≈ 1.1° | ≈ 0.7° |
| 30 km/h | ≈ 10.0° | ≈ 6.7° | ≈ 3.2° | ≈ 1.6° | ≈ 1.0° |
| 35 km/h | ≈ 13.5° | ≈ 9.1° | ≈ 4.4° | ≈ 2.2° | ≈ 1.4° |
| 40 km/h | ≈ 17.5° | ≈ 11.8° | ≈ 5.7° | ≈ 2.9° | ≈ 1.8° |
| 45 km/h | ≈ 21.7° | ≈ 14.9° | ≈ 7.3° | ≈ 3.6° | ≈ 2.3° |
| 50 km/h | ≈ 26.2° | ≈ 18.1° | ≈ 8.9° | ≈ 4.5° | ≈ 2.8° |
| 60 km/h | ≈ 35.3° | ≈ 25.3° | ≈ 12.8° | ≈ 6.5° | ≈ 4.0° |
Turn the question around
Turn it around and ask which speed gives a given lean. As a reference, 10° is a nice “light lean” level. The table is a speed reference for a bend, not a limit.
| Radius | 5° | 10° | 15° | 20° | 25° |
|---|---|---|---|---|---|
| 40 m | ≈ 21.1 | ≈ 29.9 | ≈ 36.9 | ≈ 43.0 | ≈ 48.7 |
| 60 m | ≈ 25.8 | ≈ 36.7 | ≈ 45.2 | ≈ 52.7 | ≈ 59.6 |
| 125 m | ≈ 37.3 | ≈ 52.9 | ≈ 65.3 | ≈ 76.1 | ≈ 86.1 |
| 250 m | ≈ 52.7 | ≈ 74.9 | ≈ 92.3 | ≈ 107.6 | ≈ 121.7 |
Your line is not the road’s radius
The radius in the tables is the radius of your own line. A wide arc through a bend gives a larger radius than the road’s centre line and less lean; a tight line does the opposite. See the descending technique article for how line changes the radius. Which line is best depends on the situation, and the tables take no side.
Cycle paths and roundabouts
N100 (2019 edition) recommends a smallest radius of 40 m on a walking and/or cycling path (D.2.2, printed p. 66 in that edition).1 On 40 m, 20 km/h gives about 4.5° and 30 km/h about 10.0° (scenario). For roundabouts, N100 gives a through-driving curve under 80 m (vehicle track 2 m), and under 50 m where many people walk or cycle (D.1.2.4, p. 57 in the 2019 edition). For radii under 20 m, see roundabouts and hairpins.
See your own lean
Krengo shows your lean angle in a corner. Ride a bend you know, note the lean and compare it with the row for its radius and your speed. It is a quick way to build a feel for what ordinary bends ask for. The lean angle glossary explains the terms, and how far can a road bike lean covers the limits, pedal touch-down included.
Try it yourself
Put your own speed and radius into the lean angle calculator and compare with the tables. Learn new speeds on a quiet road with permission to ride there.
Frequently asked questions
What is the tightest bend on a 50 km/h road?
N100 (2019 edition) gives a minimum radius of 60 m on streets. At 50 km/h that is 18.1° of lean in the model.
How much lean does a 110 km/h motorway bend need?
The minimum radius is 800 m, which gives 6.8° at 110 km/h. A bike usually rides slower; see the cycling-speed table.
How much lean at 30 km/h on a typical bend?
On 60 m 6.7°, on 125 m 3.2° (scenario, not a limit).
Sources
- Statens vegvesen, Håndbok N100 Veg- og gateutforming (Vegdirektoratet, May 2019 edition; the current edition is N100:2023). Used for the minimum radii (Table B.1, p. 17; Table C.3, p. 32; Table C.10), the cycle-path radius (D.2.2, p. 66) and the roundabout curves (D.1.2.4, p. 57). Table and page references are to the 2019 edition (printed page numbers); newer editions number their requirements differently (chapter 3, tables 3.3.3-x). Read on 5 October 2026.
The lean formula is a standard textbook model and is not taken from N100. The angles and speeds are Krengo’s own model values from site/calc.js, rounded to 0.1°. The cycling speeds and the assumption that your line has the road’s minimum radius are scenarios; a real bend is neither perfectly circular nor flat.