Data about different ABS performances

[lui5]

I've just read in a magazine (motociclismo, weekly) the test of the Ducati ST4S ABS.

They say it's perfect even for sport riding. The ABS only kicks in when you really need it, and in an unobtrusive way.
The feeling of the brakes is totally conventional. It goes very well even on the track. It seems to give a lot of confidence and feedback. I wonder if it is much better than evo III ABS of the r1100s.

But when I looked at the data I was surprised:
Braking from 100 km/h to 0:
- distance (dry) 37,5 m
- distance (wet) 41,5 m
- max deceleration without ABS, professional rider 10,3 m/s2
- max deceleration using both brakes and ABS 9,7 m/s2
- max deceleration using only front brake and ABS 9,3 m/s2

I was surprised because I compared it with a test on the evo III ABS made by the same magazine (la moto, monthly):

Braking from 100 km/h to 0, non professional rider:
- r1150rt integral ABS 25,5 m
- k1200rs semi integral ABS 22,4 m
- r1150gs ABS II 26,3 m
- f650gs without ABS 36,9 m

(Just some data for those who still despice ABS)

So these two sets of measures can't be right. If the Ducati brakes are so good, why does it take them twice the distance as the BMWs? I guess in the first case they've taken into account the reaction time and not in the second? Track tarmac vs road tarmac? Mistakes when taking data? Stupid journalists? Any other explanation?

Has anybody any reliable data comparing stopping distances of r1100s, vfr and st4s (all ABS). Or at least some independent opinion about the feeling. I'm tired of journalists saying this or that is better instead of doing some basic research.

Thanks guys for any info!

[Rattus]

I'd suggest BMW's integral ABS is better since the dynamic braking allocation to both wheels would help a lot in braking also. They've also been in the ABS game a tad longer, not just the last five minutes. Furthermore I have a hunch telelever is a better platform for ABS than conventional forks. You dont lose time with the front forks diving on you.

[markjenn]

I don't know the reason for the discrepency, but it probably has to do with testing conditions. I certainly wouldn't bet on an ABS BMW outbraking an ABS Ducati under otherwise identical conditions.

Min braking distance is a red herring of a performance statistic anyway. Since most vehicle brake systems these days can lock a wheel at will, braking distance mostly tests tire grip. And this is something that is so variable with respect to pavement type, temperature, etc., that braking distance measurement is almost a random number. It generally has little to do with the overall performance of a braking system, particularly the feedback it gives you through the lever/pedal and how it responds to repeated braking.

- Mark

[Rattus]

Agreed. A side by side comparison would be a good idea. I'm not dismissing the ducati ABS (produced by Bosch) but assuming immediately that its superior to BMW isn't something I'd do.

[Joe]

Mark

Your so right what good is the biggest and baddest brakes without feel and progressive control.

Thats one reason I'm not fond of ABS or Newer ABS with power asist..............I guess thats why you can't have power brakes without ABS lot's of road rash

[jclark]

I still think the ABSII is a good middle ground ?_unobtrusive, quiet, able to be turned off easily ( anyone figgered how to disarm the EVO brakes yet? ), yet I'd be happy to try out a bike so equipped...any volunteers?

jeff

[remedy70]

My guess is that evo ABS can be disabled by pulling the sensor.

[smithmar]

Hmm ...
V2=u2-2as

so with v at 28ms-1, s at 25m ... a comes to 15.9ms-2
pretty good for a bike, actually I'd be happy with those figures if I was Frank Williams.

someone's porkying.

34m is par for a supercar ... giving 12ms-2 ie pushing just past the rolling friction theoretical limit.

[lui5]

Thanks smithmar for doing the phisics calculations I was too lazy to try to do. As I thought, this magazine journalists' are not too serious. The discrepancy was too big to be caused just by different test conditions.

Another data about the Ducati ST4S ABS: Jeronimo Vidal (professional rider) did the same excelent laptimes at the Calafat circuit (1:38) with or without the ABS. They could also do stoppies at will, with the ABS too. There was only one place in the circuit (braking+bend+bumps) where the ABS kicked in.

It seems that the feeling and control was as good as a conventional system. They say it feels better than BMW's but they don't state any facts. A comparo would be very interesting indeed.

BMW has smart dynamic braking allocation to the wheels, and telelever.
Honda do very well everything they do, and have combined braking.
Ducati seem to have the edge with this simple, powerful, non-intrusive system.
And the winner is... I want to know!!!!! I'll pay a pack of beers to whoever comes with the answer.

Do you think that (after the steps forward by Honda and Ducati) BMW will improve its system next year?
Now they are praised for braking power, but criticised for lack of feeling and control, specially on bumps or at low speed. What's your opinion? Is it as bad?

[Rattus]

No doubt in my mind ABSIII is more sophisticated and effective in emergencies, at the sacrifice of being "intrusive" in the opinion of some riders. Having an ABS system which allows stoppies is not my idea of an ideal emergency braking scenario. Furthermore praising a system for NOT kicking in during an evaluation... what is that? Lets get out on wet foggy roads and hammer the brake lever and see what happens... I know for a fact that ABSIII is supreme in this context. I know a Wallaby that can second that opinion hehehe

[Nitro]

Let us not forget the telelever factor. Telelevered BMWs don't dive as much during hard braking. This helps keeping the weight more evenly distributed. In the end the front brake is under less "stress" and there is more use of the rear brake.

I do agree that there is something "fishy" in eitherr or both reviews.

[MoDog]

I agree with Rattus about the ABS III. In my real world of riding where I routinely deal with deer, elk, herded cows, sanded mountain roads, wet canyon shady spots, and sudden snow and/or thunder storms (often all in the same day), I couldn't ask for a better braking system. After having ABS III for the fifteen months and 15,000+ miles, I can honestly say that I love it...the only downside is that the guys riding behind me often don't have it.

[Bails]

Good link this I would like to know which is better also. I don't currently have ABS but did on previous BM. I've always seen the Plus of ABS as not stopping the Gyros , not about short stopping distance. But I'm going for ABS next S I buy as I often think it will be just once when I have a lock up and that is it. I find it very easy to lock rear wheel in bumpy corners if riding hard, have had the rear step out quite serverly once, ABS would solve this and that's the plus for me. If it can stop me shorter than that is the bonus.

[Joe]

Originally posted by Bails
Go I find it very easy to lock rear wheel in bumpy corners if riding hard, have had the rear step out quite serverly once, ABS would solve this and that's the plus for me. If it can stop me shorter than that is the bonus.

This is were you don't want ABS leaned over in a bumpy corner......what kind of true feedback can you get from a pulsing brake system when you need feel the most.

[lui5]

An ABS system can be wrong in three ways: not acting when needed, acting too soon, or too much. Not acting is the worst posibility, we all agree. Too soon means acting when the blocking is not total or there are small bumps that could allow a momentary blocking without danger. Too much when it releases the brakes more than needed.

Personally I've often come into a bend too hot and blocked a bit the back wheel without danger. Then I would like the ABS to act softly, if at all. On the other hand, the two times I've blocked the front one in emergency stops I've crashed before I could even realize. There I would have paid anything for an ABS helping me a bit (not too much).

In favour of Ducati's system, I have to repeat that they did stoppies AT WILL. Not when they didn't intend it. And a stoppie doesn't imply blocking the wheel. Just braking hard and using your body.

And the prove that this system worked well is that it never allowed the wheels to block. The only place that it went off is where the wheels left off the ground (bumps) and blocked.

What's more important (and the problem in other systems) is that when the ABS decided to start, it did it in a good way. It didn't release totally the brakes (spooky when you're trying hard to brake) but only a bit, just enough to allow the tyre to recover contact, while still braking. No pulses, no panic, no overkilling. I just hope it is true and not some journalist fantasy...

By the way, I also thing that electronics and linked brakes will help do this and more, but it still lacks some speed or precision to convince the sportiest riders. Good enough for me now, though. Just wondering which system is the best now. :-)