Do motorcycles brake better than cars?

Craig Lowndes races Casey Stoner brake

There has always been conjecture about whether a motorcycle can brake in a shorter distance than a car.

Many experienced riders believe they can stop faster than a car which is probably why they tailgate cars.

Meanwhile, rider trainers warn their students to keep a safe following distance because a car can stop faster.

So who is right?

The arguments

The argument for a motorcycle is that they are much lighter and have bigger brakes for the size of the vehicle.

The argument supporting a car is that they have much bigger contact patches with the ground because they have four wide tyres.

Both arguments have merit.

However, it depends on the bike and the car.

The truth

If we look at the ultimate race vehicles — a Formula 1 car and a MotoGP bike — the answer is that the race car can brake with up to 5.7g of force and the GP bike with only 1.8g.

G-force is the pressure that gravity exerts on an object when it is accelerating relative to freefall. A sneeze is about 3g and a cough about 3.5g.

The physics

Jeromy Moore fuel economy brake
Jeromy at work

For a scientific explanation, we went to Jeromy Moore, former Craig Lowndes race engineer and now with the Porsche world endurance champions.

“It is clear that a car has the potential to brake with more deceleration due to having more rubber, less weight transfer for the same deceleration due to a low centre of gravity height versus wheelbase,” he says.

A hard-braking sportsbike will shift most of its weight to the front tyre and even lift the back wheel off the ground.

So it’s not just two skinny tyres versus four wide ones, but one tyre contact patch versus four!

Jeromy also points out that a race car has significant aerodynamic downforce which puts more weight and traction on the tyres.

The real worldFollow too closely tailgate downhill

But that’s physics and not the real world.

In the real world there are passengers, luggage loads, rider and driver skills, surface traction, panic and technology to consider.

In fact, some suggest that a standard car (whatever that is) and a standard motorcycle have about the same braking force of about 1g.

But to extract 1g of braking force from a motorcycle, a rider needs to be highly skilled.

Almost any novice driver can simply slam on the brakes of a modern car and pull up with the same force as a highly skilled rider.

The conclusion

What this all means is that you may be able to out-brake a car if you practised hard and were aware when you needed to emergency brake.

But in the real world, panic can set in and it is much easier to lock up a front wheel and crash a motorcycle than it is in a car, especially with all the braking technology fitted to modern passenger vehicles.

So go out and practise your emergency braking skills until it becomes second-nature.

Meanwhile, don’t tailgate.

13 Comments

  1. We performance test cars and bikes with GPS gear, vbox, and the like. Most decent sportscars can pull up from 100 in near to 30m. Most bikes can’t do much better than 40m. The best we’ve found are cruisers because of their rearward weight bias; two brakes being better than one, as in sportsbikes. The lighter the cruiser the better. Without checking I think 36m and change is the best figure we’ve achieved using ABS. It’s too risky to test non abs bikes but few are without now anyway.

  2. I used to be of the opinion that most bikes can out brake most cars but recent advances in tyres and abs in most cars has put a very large caveat in that opinion. There is the odd situation that a large heavy car could out brake a small lighter vehicle quite significantly because it forced more weight into the front tyres reducing the skating effect. Skating effect is similar to aquaplaning gasses balls of rubber and such actually lift the tyre off the ground reducing grip. A motorcycle is far less susceptible to this than a car due to the high weight to contact area. ABS has altered this scenario however .
    Now most bikes can out brake cars not because of the vehicles abilities but because an experienced rider is more likely to be on the brakes seconds before a driver has even noticed a danger.

  3. “G-force is the pressure that gravity exerts on an object when it is accelerating relative to freefall”

    Please consult a school physics textbook before publishing sciencey-sounding nonsence.

    g (always lower case, G is something different) is acceleration due to gravity, thus one accelerates downwards at 1g in freefall in a vacuum. You could say g is force per unit mass, but it’s not a force per unit area, which would be the definition of a pressure.

    as such g is not a force, if you’re looking at the force exerted on an object due to gravity, that would be its weight.

  4. Going back to my apprenticeship days, (ok get off my case, yes we did have apprenticeships way back then) a wise old instructor asked this simple question, after having walked through the car parking area for the students) Which tyres will offer better grip under acceleration, braking and cornering?

    Same car, same tyre make, same model designation, same construction and compound, the standard 175/75/13 tyres or the same car with 195/75/13 tyres?

    All us young start ass apprentices said the wider 195/75/13. Wider and larger contact patch means more grip.

    Wrong, he then proved mathematically our mistake, in conclusion the wider tyres contact patch had less pounds per square inch downward force, than the narrower tyre.

    Just saying, something else to add to the mix and ponder over.

      1. That’s quite and in depth paper. The TL;DR is tyres stick by adhesion (chemically bonding), viscous deformation, elastic deformation and eventually tear, and all 4 behavours are nonlinear.

        I’ll conceed that even a cheap semi-modern bike has better tyres and better brake friction material than a typical family car. This is an advantage in achieving the braking performance limits of the chassis, that is wheelbase and weight distribution factors that result in the vehicle pivoting catastrophically in the form of a stoppie/endo

        If both vehicles have perfect ABS, allowing maximum braking performance to be extracted, a performance motorcycle may have an advantage over a ‘family’ car in some areas, particularly sustained braking from high speed, but the car wins on initial deceleration and on fade-free tests such as 30mph (50kph) to 0 which are typical reacting to traffic scenarios.

        Furthermore few bikes have modern ‘cornering’ ABS, and ABS has only recently become mandatory in Europe on large motorcycles, so motorcycles are less likely to have ABS. Whilst a skilled racer can outperform substandard ABS, most of us can’t, so again the cars have a lead.

        The major danger of following a car too closely is there is little penalty for stamping on the brakes on a car without ABS and no penalty for stamping on the brakes of a car with ABS, whereas the dynamics of a motorcycle require a more progressive brake application and snatching the brakes on a motorcycle without ABS can be fatal.

        It’s certainly safe to say a car dynamics react to emergency braking events more quickly and more safely than that of a motorcycle.

        All of that said, an ER6 stops a little bit faster than this Holden https://www.youtube.com/watch?v=loaJVp4ARZA

        A sporty BMW M1 pisses on an S1000RR https://www.reddit.com/r/motorcycles/comments/1nhqx3/an_excellent_illustration_of_motorcycle_vs_car/

        In the latter video, both the rider and driver have had professional racing careers, although the rider has been just a bit more successful.

  5. Back in the day when cars had 4 drums or disks at the front and drums at the rear, I would have said yes, but times have changed and the tables have turned somewhat.

  6. I think some people in charge of motor vehicles, car or motorcycles, rely heavily on braking and usually drag the brakes (over brake) for far too long when approaching even a simple set of traffic lights with no hazards, confusion or panic triggers in sight. Timing is the key & reading the road ahead. Sometimes good old momentum and correct gear or revs can have you simply flow through many intersections without too much halting at all.

  7. Whilst a bit of side point, what still has me stuffed is the rider training in Queensland says don’t cover your brakes. Quite frankly the difference between being able to brake immediately and having to open your grip and close it again is large (not to mention if your already holding on to the grips it, is likely to tighten)

      1. The rider training advice to not cover brakes is global. British advanced riding instructors and British police riding instructors will all tell you not to habitually cover your brakes. It’s a bad idea. If something spooks you and you tense up, you potentially just locked a wheel. Having to open the hand and/or move the foot gives time to calculate a controlled braking response or choose an evasion. It’s not about reflex times, it’s about choosing the right action and executing it skillfully.

        It’s different when you are negotiating a complex hazard and are already contemplating whether a roll-off is enough or a braking action is required, but habitually and unconsciously riding with fingers on the brake “just in case” carries more risk than reward.

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