Husqvarna adapts S1000RR ABS for off-road use

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Could the next big development in antilock brakes come off-road? Husqvarna thinks so, BMW’s Italian-by-way-of-Sweden dirt bike brand has adapted the S1000RR’s dual-channel ABS for off-road applications. Undergoing validation testing on Husky’s flagship TE449, the system is claimed to make threshold braking the front wheel easier and safer, while leaving the rear free to lock up, thereby facilitating slides and stops on loose surfaces.

ABS has traditionally been shunned on off-road motorcycles because existing street systems lack the ability to deal with loose surfaces and low traction. In such conditions, a rider must modulate the front wheel on the verge of locking up to achieve maximum braking, but ABS brakes developed for high-grip street use simply detect slide and don’t apply enough braking force, increasing stopping distances.

To overcome that, Husqvarna looked at the sophisticated, switchable ABS fitted to the BMW S1000RR. On that bike, selecting “Slick” mode disables rear wheel ABS to allow for brake slides, while continuing to compare front and rear wheel speeds to inform operation of the front brakes.

Antilock brakes work as the name suggests, wheel speed sensors are capable of determining when a wheel is locked or on the verge of locking and momentarily release brake pressure to prevent that happening. A visual demonstration of this effect can be seen in the dotted skid marks that now cover roadways. The tire marks are where the brakes lock, the clear spaces are where they’re released.

Maximum braking power is achieved just on the threshold of locking a wheel, but modulating lever force to maintain that exact threshold as speeds, surface and irregularities vary is a skill beyond most mortals. ABS has brought massive benefits to safety in both cars and bikes on the street, allowing operators to simply apply the desired amount of lever pressure while letting the computers sort out the safest, fastest way to slow down.

Husqvarna’s off-road system still uses sensor rings on both the front and rear wheels, but doesn’t apply ABS to the rear wheel. Instead, rear wheel data is used to inform the determination of when the front wheel is locked or on the verge of locking.

Interestingly, Husqvarna has found it necessary to build back in some of the lever pulsation of early road ABS systems, saying this is necessary to, “provide clear, transparent feedback on the braking manoeuvre.”

Husqvarna shies away from claiming improved outright braking performance, instead implying that dirt-biased ABS will make off-road riding safer and maximum braking forces more accessible to real world riders. The top picture is a good example, applying that much front brake descending such a steep hill is challenging, yet critical if you need to slow or stop on such terrain; the rear wheel is virtually unweighted. The system adds only 1.5kg to the TE449.

As ABS becomes mandatory on all street bikes in the EU in 2017 (dual sports can retain “off” switches) and as its advancing technology makes it more acceptable to the majority of riders, expect to see more bikes in more categories adopt the technology. Tellingly, Husqvarna suggests that the next development may be a mode switch, enabling dual-channel ABS to be optimized for either off- or on-road use at the push of a button.

  • http://www.muthalovin.com the_doctor

    That is pretty freaking trick.

    I would love to see a video of it in action.

  • markbvt

    Interesting stuff. Odd that BMW hasn’t already worked on this for their GS bikes, which have a reputation of having rather inflexible ABS that lets the bike freewheel far too easily. Seems not all ABS systems are alike, because I’ve found the one on my Tiger 800 XC to actually work surprisingly well on dirt/gravel. I’d turn it off for hilly offroad riding, but don’t bother for dirt/gravel roads.

    • http://worldof2.com/ jpenney

      The ABS on my G650GS was a little sketchy on gravel and dirt. It had a tendency to release pressure on the rear more than I would like.

      On the road, I loved it especially when it kept me from eating the rear of a van.

  • FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

    Do aftermarket ABS solutions exist? They should.

    • Sean Smith

      Like stainless lines and EBC HH sintered pads?

      On a more serious note, it would be pretty neat if you could plug in something similar to a power commander to dial in your ABS. I think the only thing preventing that right now is processing power (which leads to low cycle speeds) and lack of interest from hard-man carburetor loving off-road riders.

      • FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

        I guess I already knew the answer.

        Processing power bottleneck sounds like a good reason, but so many bikes already have ABS, traction control, etc. The tech to make bolt on ABS exists, but there isn’t any interest in spinning it down to consumer form. The bike accessory market is full of hard men across all genres. Why buy something to make you safer? What are you, some kind of pussy?

        Note the lack of comments on this post.

        • t-pod

          Actually, processing power isn’t the hold up. It’s the integration that makes it difficult. An ABS system is specifically tuned for every model it is installed on and hardware is rigorously checked to ensure compatibility.

          The legal environment surrounding safety systems on a motorcycle is a challenging one, and putting those concerns in the hands of a layman doesn’t absolve the manufacturer from liability concerns (at least in the US, anyway).

          • FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

            Specific tuning could be accomplished by a power commander-like unit. like Sean suggested, and the unit manufacturer could produce model specific braking maps. Indemnify the company if the end user tries to mess with the mapping.

            Viable ABS systems exist on some bikes already, so a generic option for mainstream bikes could be available if there was enough interest. Are there any studies about m/c ABS crash statistics?

            • t-pod

              There have been roughly a boatload of studies performed at least once by just about every agency that investigates such things.

              One of the better ones was the GIDAS study that the Germans did from 2001-2004. The results were that ABS could’ve reduced the motorcycle accidents they studied by something like 26%. Tried to find a link for you, but I don’t think they hand that information out freely.

              The IIHS performed a study in the states, too. The results were posted on HFL a while back.

              • FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFF

                Thanks for googling that for me. (:
                ABS is looks like it’s catching on, but I guess “safe motorcycle” will always seem to be a contradiction in terms.