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Bicycle accident Radunfall Accident vélo Incidente bicicletta "Crash over the handlebars" caused by a blocking front wheel brake /0e (summary)

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Motto: It cannot be true that producers deliver brakes to the market,
           which should prevent accidents -- and cause one!

Index of this page:

==> Operations

==> Problem "Crash over the handlebars"

==> Solutions for production

==> Individual solutions

==> Index: "brake crash"

==> Definitions

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==> home: Bicycle tips (g)

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Problem "Crash over the handlebars" caused by a blocking front wheel brake

Today's modern rim and disc brakes reach very high decelaration, even if they are wet. Unfortunately they seize so strongly that the front wheel blocks suddenly. On a good road the front wheel sticks so tightly to the ground that the bicycle topples over to the front. The driver crashes at a speed of 6-11 km/h (4-7 mph) -- depending on the rider's ability -- over the handlebars and falls at a speed of min. 20 km/h (13 mph) on his face ==> 2. Physics (g).

No criterion announces the blocking of the front wheel brake. So these brakes got to be too dangerous for every day use. The upswing of the rear wheel is NOT such a criterion because then the front wheel is already blocked. To the cyclist remains a short reaction time for releasing the brake ==> 2.3.2. Crash ... time (g). Which normal cyclist is able to do this?

Therefore some cyclists do not to use the front wheel brake or they use it only in a feeble way. Even trained sporting cyclists are not proof against a crash over the handlebars; a first time is once too often -- regarding the serious injuries which can also mean death. Already 2% of my personal environment has crashed over the handlebars; there seems to be a high unrecorded rate! In the newspapers you will find (quotations): "... toppled without any perceptible reason over the handlebars ...", "... crashed because of an unknown reason. The cyclist couldn't remember any circumstances of the accident ...". ==> 1. Accident reports (g)

After my own accident I analyzed the problem and found that modern front wheel brakes show weaknesses but also a real design fault; there is missing a "brake power limitation". (This does not mean a degradation of brake power ==> 9.15. FAQ (g))! The source of the crash over the handlebars is based on the chosen technology and not on the abilities of the cyclist ==> 3.0. Basics (g).

The producers of brakes and of bicycles, distributors and bike travel agencies are called up to produce, resp. adjust the front wheel brakes in such a way that they will not cause accidents. If not, people will accuse them of accepting a crash over the handlebars!

For those interested in physics: The design of a normal bicycle implies that the centre of gravity with driver is very high. The angle between plumb-line and centre of gravity/ point, where the front wheel touches the ground, totals to ca. 27°. This stands for a max. deceleration of ca. 5 - 6 m/ s^2 ==> 2.4.3.1. Diagramm (g). Modern brakes are able to produce a much higher deceleration, which causes the bicycle toppling over to the front.
On a good road modern front wheel brakes work in two completely different ways.

Picture 01: Brake diagram ==> (2.4.3.1. Explanation) (g)

Area 1: Normal braking. The cyclist may use the brake between zero and a limit of brake power. Here braking is reversible (that means good natured). (At a slippery ground the front wheel gets blocked, but it will slip forward for a short time ==> 2.2. Consequences of blocking (g)). Area 2+3: Toppling = crash over the handlebars. After exceeding the limit of brake power the brake will block the front wheel without any warning. The cyclist will be lifted in an arc. If he does not release the brake in a very short time, he will crash over the handlebars and fall to the ground at the crash speed ((geometrical) sum of riding and falling speeds) ==> 2.3.2. Crash speed and time (g).

Rear wheel brake: A blocked rear wheel slips on every surface. The cyclist hears and feels this. Normally there remain enough time to release the brake. If not the rear wheel slips aside and the cyclist normally falls on his side and not on his face.

Toppling forward -- the crash over the handlebars -- is a "new quality" of bicycle brakes, even for an experienced cyclist but who was used to "old" brakes.
-- He knew that on a slippery ground he will crash in case of incorrect braking. But "modern" brakes block just at best conditions, when the bicycle runs straight forward on a good and dry surface.
-- Till now he fell directly to ground in case of incorrect braking. But "modern" brakes first catapult him upwards.
-- Toppling does not announce itself. It can only be realized after beginning (upswing of the rear wheel).
This is a hidden defect.
-- Toppling forward is not necessary for cycling, but it is counter productive.

Solutions for production.         This is the part of the producers.

==> Appendix: Front wheel Anti-Blocking-System (g)

It avoids securely the blocking of the front wheel. This ABS was developed in 1994 and has been on the market. It was produced by Winora and Thüringer Zweiradwerk Nordhausen (in the catalogue of a mail order house). Another system was built by Biria. But experts and clients didn't take any notice.
In 2004 ==> Biria offered an ABS.

==> 3.2.-3.4.    Proposals for intermediate solutions (g)

At least they could diminish the number of crashes over the handlebars.
My proposal for a fast solution is to install soft brake-blocks into normal bicycles (citybike, trekking bike,...) and the modern aggressive brake-blocks into sporting bikes (racer, mountain bike, ...) ==> 3.4. Two brake systems (g). This solution can also be installed later.

==> 3.5. Minimum solution: Extension of standards, i.e. EN 14764

The front wheel brake has to be softened. Only a known danger can be overcome!
Therefore each operation manual has to contain an ==> "Instruction how to practice braking" (g). Also a red adhesive sign should show the warning: "This brake is very powerful! Practice braking at walking speed."

Individual solutions.                These solutions are at the responsibility of the individual.

==> 4.3.1. Practice how to use the brakes (g)

It is always necessary and important to practice the use of the brakes; there is no alternative.
The bicycle branch has the credo: "Everyone has to practice braking -- afterwards he is able to do so". But this requires preconditions and has its limitations! But it is a tall order, demanding that everybody, i.e. "my grandma", must lern and afterwards know how to brake while having up the rear wheel.

==> 4.3.2. Other front wheel brake systems (g)

Select the "RollerBrake" because it reduces the danger of crashing over the handlebars. It functions nearly independent of weather conditions, but it is heavier and more expensive. As the brake power limit is not adjustable, light drivers may crash over the handlebars and heavy ones may not get the requested high brake power.

==> 4a.     Better dosing of the brakes (g)

Simple and proper dosing of the brakes is a precondition for safety.

==> 4.3.3. Mech. stop for the brake handle (g)

Even if it's only an expedient, at this point in time this is the only reliable provision to avoid a crash over the handlebars. It suits responsible cyclists because it requires regular adjustment. Cost are about € 10,--.

Remark: If a lot of people can talk about their experiences the discussion often becomes emotional ==> 9. FAQ (g).

Index

0.      Summary (this page 0 here)

1.      Accident reports: Who crashes over the handlebars? What are the consequences?

2a.    Physics_a: Why and when do you crash over the handlebars?

2b.    Physics_b: Why topples the bicycle to the front?

3.      Proposals for a "brake power limitation"

4a.    Tips_a: How can I improve dosing my brakes?

4b.    Tips_b: How can I avoid a crash over the handlebars immediately?

5.      Comments:

Why do producers market those accident generating brakes?
Why do the distributors deliver those brakes?
Why do bike travel agencies offer those brakes?

6.      Liability of producer and his product (German law).

7.      Cost liability (German law): Who pays the medical treatment?

8.      Versions / Chronology

9.      FAQ (Frequently Asked Questions) / Comments.

Appendix:

• Synopsis: Basic statements, (ohne Javascript: Synopsis: Basic statements) (in english!)
• Arrangement of an accident report
• Instruction how to practice braking
• Front wheel Anti-Blocking-System (FW-ABS)

Definitions

Normal cyclists: They include two groups, forming the majority of cyclists.
-- Simple cyclists who cycle on unpretentious and known roads to school, to bus or railroad station, to shopping or casually go on an excursion.
-- Experienced cyclists who cycle every day and use complex roads or go on extended tours. Included are sporting cyclists who normally not are members of clubs.

Skilled cyclists who train regularly i.e. braking at the limit especially in associations or courses. Particularly included are sporting cyclists who participate in contests. They form the minority.

Definitions always are disputable. These here are aimed at "brake accidents".

Every liability is excluded, especially for links!
Prices only serve as an orientation. Errors are not excluded!
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Last change: 29th December 2014