If you’ve been watching MotoGP recently, you’ll have heard the commentators talk about the rear ride height device, and you might have seen one in action too. Particularly now Suzuki have finally jumped on the bandwagon. But if you’re wondering what it is, where it’s come from and why the riders are all so desperate to have one, you’re not alone. Hopefully this’ll shed some light on it…
To understand why they work you have to understand a little bit about motorcycle geometry; but it really is only a little bit. The lower a bike’s centre of gravity is, the less likely it is to wheelie. And when you’ve got 250bhp, wheelies are fairly commonplace. And fairly annoying, when you’re trying to ride a MotoGP bike as fast as you can. But by lowering the bike with the rear ride height device, you can accelerate harder with less wheelie, and therefore go faster. Easy.
No. People have been lowering bikes to avoid wheelies for years, it’s nothing new. You won’t see a drag bike with masses of suspension travel and motocross racers have been using ‘holeshot’ devices for years. The rear ride height device works on a very similar principal.
And that’s no coincidence. Because the rear ride height device is just a continuation of the holeshot devices that MotoGP riders have been using for years (and MX racers have been using for decades). They are quite simple really. All you have to do is compress the forks (usually by pulling the front brake on the warm-up lap) and then pull a lever which engages a hook to lock the forks. The hook is spring loaded so that as soon as you brake for the first corner, it disengages and the suspension reverts back to normal operation.
The benefits are massive off the start line, when the biggest limiting factor on acceleration is wheelie. And because the benefits were so massive, some teams started to think about other ways to temporarily lower the centre of gravity to improve acceleration during the ‘wheelie phase’. It wasn’t long after that, that we started seeing these rear ride height devices in MotoGP racing. You may remember Jack miller running one back in 2018, but you might not, because Pramac Ducati didn’t go shouting about it.
Pros and cons
But these rear ride height devices weren’t just helping the riders avoid wheelies during the race start. According to anyone that’s used them, they’re a big benefit during any ‘wheelie phase’, which is any time you’re accelerating hard in a low gear. That’s why you’ll often see the rear of a MotoGP bike squat very deliberately on corner exit. The rider simply presses a button and a mechanical or hydraulic system allows the rear to squat, lowing the centre of gravity. Any additional mechanical grip is also extremely welcome in racing. This means less electronic intervention and, ultimately, a faster lap time. That’s lovely.
These systems are not without their disadvantages. Like anything you bolt onto a bike, it’s going to add some weight. And GP bikes are really sensitive to extra weight. But it also alters the geometry of the bike until you brake hard and it disengages the system. That means the moment you grab the brakes, the attitude of the bike isn’t what it would normally be. That might mean altering your body position to suit it, or braking in a slightly different way. That said, with all the manufacturers now using these devices, you’d have to say the pros must outweigh the cons.
One of the ideas behind manufactures racing prototype machinery is to develop technology that will eventually find its way into consumer products; i.e. our road bikes. But this is something that’s so specific to riding super-fast bikes on track at a world class pace, I’m not sure Joe Bloggs will ever need it on his Gixxer 1000. Then again, there’re plenty of road bikes in the showrooms with wings bolted to them…