Advanced Motorcycle Riding Course: Cornering - left-handers

More riders mess up on lefthand bends than in just about any other situation. Panic has a lot to do with how we can get things wrong and then make things worse

It was a warm dry lunchtime on a road much used by bikers for the smooth road surface, national speed limit and multitude of corners that make riding a bike so much fun.

In the apex of this bend there was a Ford Mondeo, with both the nearside wheels on their relative nearside grass verge.  The damage was all focused around the front offside of the vehicle.  The offside headlamp assembly was missing and the bodywork in this location had crush damage where the striking object had intruded into the vehicle. The bonnet was folded up and buckled around the point of impact and the front bumper was missing.

Slightly ahead of the Ford in the opposite carriageway was the Suzuki GS 500 motorcycle lying on its nearside. There were a series of scratches and gouges in the road surface leading from the rear of the Ford to the Suzuki. The front wheel and fork assembly has been broken at the headstock and wasw now lying in front of the Ford. The rest of the damage to the bike was mainly focused around where the front wheel appeared to have been pushed back into the engine before completely separating itself from the rest of the bike.

The initial account from the Ford driver was that as he navigated the right hand bend, a bike approached from the opposite direction, the rider had lost control and rode across the solid centre white lines and collided with the front offside of the Ford.

There were no marks generated by the bike to suggest its position prior to the collision. The first clue were two tyre scuffmarks at the rear of the Ford. The nearside mark was 7 metres long and led up to the front nearside tyre. The second mark was only 2 metres long and was set 1.43 metres apart from the first tyre scuff.  This separation in the marks matched the track width of the front wheels of the Ford. Tyre grinding to the front wheels confirmed the driver had applied emergency braking during the collision.

The rider was taken to hospital prior to our arrival but his position had been marked 12 metres behind the Ford in the opposite carriageway.

With better road positioning and observations this could have been easily avoided

And he was only doing 27mph

Physical evidence doesn’t lie; the car was clearly in its post impact position and to arrive there, the driver must have been emergency braking. Most importantly the Ford was entirely on its correct side of the road and clearly in a bid to avoid the approaching motorcycle, the driver had actually steered towards the nearside kerb and ended up with his wheels on the grass verge.

The position of the debris, the marks in the road surface leading to the bike, along with the obvious impact points between the Ford and the Suzuki explain what had happened.

 The absence of marks generated by the bike meant that it was upright with the wheels rotating prior to impact.  (The rider may well have been braking but until the wheel locks no visible marks are generated). The front wheel of the bike struck the front offside corner of the Ford in the area of the headlamp assembly.  The bike was stopped instantly and then pushed backwards at about 45 degrees to the car, the scratch and gouge marks generated as it slid across the carriageway to its final resting position. On impact the rider carried on forwards with a glancing blow to the Ford before landing 12 metres further up the road.

The damage did not suggest high speed. The distance the rider travelled, provided a speed in the region of 27 mph.

So what exactly went wrong? Why was the rider on the wrong side of the road while negotiating a lefthand bend?

Entry speed is the determining factor

First, let’s consider the theoretical speed the bend could be negotiated at. This was calculated to be 56 mph, so the rider was well below that threshold. Vehicle examination ruled out any form of mechanical failure.

The answer would therefore seem to be that although the bike was not travelling too fast for the nature of the bend, it was too fast for the rider.

So how can we avoid such things happening? The answers is easy, slow down and enter the bend at a speed you’re happy with. But in reality how do you assess the correct entry speed?