Riding always comes with risks. Sometimes other vehicles are the risk. Sometimes road debris are the risk. Often, when riding alone through winding roads, the curves are the risks. The most common crashes in high speed curves are either target fixation, highsides, or lowsides. In today's news, we saw MotoGP racer Marc Marquez take a nasty highside crash while warming up for Indonesian GP. Luckily, Marquez walked away relatively unscathed although with concerns of a mild concussion, was declared unfit to race in the Indonesian GP. In this article, we'll go over what highsides and lowsides are and what causes them.
Watch Marc Marquez highside while warming up for Indonesia GP below:
Lowside
A lowside crash is where the bike slides under you and ends up on the same side of the road you're turning on. This occurs when the front or rear wheel slips, usually as a result of excessive braking into the corner, excessive acceleration into or out of the corner, or simply too high speed into the corner for grip available (this may be because the surface is changing, for example if there is gravel or dust on the road). To avoid lowside crashes, brake and downshift before arriving at the turn.
A lowside crash is generally less damaging than a highside crash, all things being equal, because with a highside crash it can throw the rider through the air in front of the bike.
If you brake in a straight line, it's much harder to have a lowside crash. Riders typically experience lowsides if they continue to brake when they begin to turn. A lowside during straight-line braking can occur on an elevated road or on a road with enough camber for a locked wheel to slip sideways.
Front wheel
As you can see in the video below, the front wheel loses grip and spins inward when the rider leans the bike too much. You can hear on the audio that the rider is still on the throttle in the turn. A little less speed and less angle would have resulted in the rider staying on the bike. The bike lays on its side and both the rider and the bike slide off to the side of the road. In this particular case, the speed was quite low and the rider had nothing solid to hit when he slid off the road. The bike body and handle are damaged. The rider wore full protective gear and walked away unscathed.
Rear wheel
Rear wheel lowside crashes are almost always caused by too much acceleration. In this case you can hear rider applying the accelerator and the bike loses grip in the rear, spinning out and causing panel damage. Again, the rider is wearing full protective gear and it’s a fairly slow speed corner.
A lowside can also happen if the rider drags the peg on the road surface because this lifts the bike, reducing the grip. Whether it’s the front wheel or rear wheel that slides will depend on the centre of gravity of the bike and the location of the peg.
Injury risks with a lowside crash
Injuries tend to be less severe in lowside crashes. The rider usually slips behind the bike and if proper protective clothing is worn, roadrash can be avoided. If speeds are high, the rider may slide into something fixed like a railing or a tree, or if turning left, they may slide into the opposite lane into oncoming traffic. Riders who choose not to wear a full face helmet risk serious facial injuries in a lowside, as the crash will cause the rider to fall sideways onto the tarmac.
When the rider falls, bruises may occur on the hip, elbow, knee and ankle on the lower side. If the ankle is trapped under the bike, it can cause more serious injuries such as fracture or breakage.
Highside
A highside is caused when the rear wheel loses lateral grip then regains it violently. A highside can be caused if the wheel locks up if the engine seizes or the chain comes off. A highside crash is more dangerous because the rider is usually flung over the bike, often in the path of travel of the bike. If the rider hits something solid and stops, the bike can then hit the rider at speed causing serious injuries. The highside is more violent on the bike, too.
It is most common when the rider over-corrects a rear-wheel slide. The bike suddenly grips and sends the rider the other way.
In this video you can see the biker’s point of view. The rear wheel suddenly loses grip and slides out, but then regains grip flinging the rider headfirst off the bike. This video has an excellent slow motion component explaining what’s happening, from about 2 minutes in.
A loose chain can cause a wheel to lock which can initiate a skid that could cause a highside.