Honda CBR 1000F-P

Dual Combined Braking System explained: the hand lever operates the front calipers and 'overflows' onto the rear caliper; the brake pedal operates the rear and one piston of each front caliper. Simple It Isn't

The new Honda CBR1000 is identical to the luxo, gloss-covered, smoothie missile of last year, except for its brakes: brakes that, if you'll excuse the pun, break new ground. On paper they are the most technically ambitious, most radical, most complicated ever devised. They are the NR750 of brake systems, and because of it, I doubt you'll ever see their like again.

Put it this way: the back brake now operates the front and the front brake now operates the back. But the back brake operates the back brake as well, as does the front... operate the front brake that is. And that's the simple bit.

It's all called the Dual Combined Braking System, or Dual CBS for short. It has nothing whatsoever to do with the ABS anti-locking or TCS (Traction Control System) as both fitted now to Honda's top-of-the-range ST1100 Pan European, and Honda says the idea is "to give the rider an enhanced feeling of riding ease, controlled confidence".

What that means is Honda has reappraised the whole front brake lever/back brake pedal convention. In that sense, the CBR's system, though vastly more sophisticated, is very similar in principle to the Honda Gold Wing's or Moto Guzzi's age-old linked brakes where the front brake lever operates one of the twin front discs with the other disc brought into play by the rear brake pedal.

Guzzi's system is still very popular today, and rightly so: most of the day-to-day braking is taken care of by the foot pedal which reassuringly retards both wheels. And if that extra little bit of bite is needed the front brake lever could be used to squeeze the second disc. For lightweight sports bikes, of course, forget it. But with gentle, lumbering heavyweights it definitely makes life less fraught.

The same sort of thinking applies here, but with a great big chunk of extra engineering sophistication and complexity besides. Honda says it wanted to extend the benefits of Guzzi-style linked brakes to more sports-orientated bikes which require more frequent front brake operation. In other words, Honda aspired to the idea of the rider being able to operate both brakes with the foot pedal or hand lever whereas with the Guzzi system the back brake could only be operated by the foot pedal. And that's what they've produced.

Even more commendably, it's a system so refined that, at first, it's unnoticeable: you brake, the bike slows undramatically and, really, it's all very dull. The controls are firm, the operation is simple, there's no frantic diving of the forks and no kick-back when both lever and pedal are used at once. They seem to be idiot-proof...

Until, that is, you appreciate the complexity needed to make it work and realise, realistically, how few the real benefits are.

Technically, it's a nightmare. At the front and back both calipers are what Honda calls new Dual CBS three-piston calipers. Uniquely, these can each be operated by two wholly independent hydraulic systems. In short, the front calipers can be operated by either the brake lever or brake pedal, or both.

With each caliper, the front brake lever operates the two outer pistons with the centre piston being activated via the brake pedal. The rear caliper works in the same way, so that when the rear brake pedal is pressed, hydraulic pressure from the master cylinder is routed through two lines. One connects directly to the rear caliper and acts on the centre piston. The other brake line runs to the centre pistons of the two front calipers.

But the even more fiendishly clever bit is the pivoting, sliding caliper mount to the front left-hand caliper which enables braking forces to be balanced between front and rear. When braking force is applied through the hand lever, this allows the left-hand caliper to be pulled in the direction of wheel rotation around its lower linkage pivot. This movement then, through a linkage, acts upon another master cylinder which in turn activates the outer pistons of the rear brake caliper. Everything, meanwhile, is kept all fine and dandy by what Honda calls its proportional control valve. And if you want me to try to explain that, forgetit.

Net result? Grab the front lever and you get lots of front brake and more and more rear brake depending how hard you tug. Stomp on the brake pedal and you get a fair bit of back brake and quite a lot of front brake besides.

Meanwhile, everything squats something akin to a Yamaha's hub-centre GTS or Bimota's Tesi, rather than the dive and lurch most of us are used to. Meanwhile, about ten miles of brake hosing and gallons of brake fluid are here, there and everywhere.

Meanwhile, I'm beginning to wonder why Honda bothered. For me, it actually seemed to get weirder the more I rode it. The more miles I did, the more different it seemed to be to conventional set-ups. It's stable, it works, it's probably a boon to inexperienced riders. But it's not ABS, and that pivoting linkage will almost certainly need an inordinate amount of attention if it isn't going to seize up during a British winter; the phrase sledge-hammer to crack a walnut springs to mind.

As a complete package, however, the CBR1000 remains an almost incomparably polished performer. It's soft, heavy, but smooth; fantastically built and almost impossible to fault. Other changes for this year are few: the tailpiece is recontoured; the front mudguard is revamped; the inner console is tidied; the paint schemes are reworked and it remains a fantastically accomplished machine, even if it is a little bland next to the more brutal powerhouse Kawasaki ZZ-R1100.

But those brakes, well... Fantastic achievement Mr Honda; it works; But, for my money, like the Ronco banana peeler and the electric tin-opener, they are a massively complex solution to a problem that doesn't really exist. The question is, for God's sake why? O

Source Bike Magazine 1993