Braking – How fast can you stop?

As part of the CBT, and as part of your licence training, braking effectively is taught rigorously. On your test at the MMA, 2 braking exercises are given, a controlled stop, and an emergency stop.

The question lies though: how quickly can you stop? Modern bikes have 2, 4 even 6 pot front brakes, and may have a drum brake, or disc brake on the back. A fair few new bikes come with ABS, but how does this help YOU as a rider?

Ok, lets think physics for a second… Most modern cars are capable of stopping with up to 1g of force with an average car weight of lets say 1800kg. Bikes are also only capable of stopping at 1g of force, but with an average weight of 200kg. Does that mean they stop as quick as each other?

Probably not… For the most part, bikes will stop faster than cars, simply because of the huge weight differential (there may be some exceptions), and a few other factors, despite cars usually having the mechanical advantage (4 wide contact patches, bigger engine braking force, multitudes of electronic equipment etc.). So, if bikes can stop faster, how fast can they actually stop?

Based upon a video published by an Australian (I think) bike training school, the following (roughly) applied:

On average, a new rider stops with approximately 0.5g of force.
An experienced rider, with near 0.7g of force.
And an expert rider can stop with around 1g of force.

So lets put that into a speed/distance.

0.5g at 15mph = 15 feet (4.5m)
1g at 15mph = 8 feet (2.4m)
0.5g at 30mph = 60 feet (18.2m)
1g at 30mph = 30 feet (9.1m)
0.5g at 45mph = 135 feet (41m)
1g at 45mph = 67 feet (20.5m)

As you would expect, for the expert rider, it’s half the distance of a new rider, given the breaking force. Easily proved that one. Now for the kicker: At around 50mph, a new rider will take the length of approximately 2 tennis courts, or 2/3rd of a football pitch to stop effectively. That’s an awful long distance… And no, it doesn’t map to ‘Braking Distances’ published by the DVSA (I’ll let you make up your own mind why that may be).

The point here? Braking will get better with experience, but there’s absolutely no substitute for giving yourself room from other road users. Only a fool breaks the two second rule…

Ride Safe!

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