Possible alternative to ABS?

[the_adam]

Hi all,

With all the winter riding I do I liked the idea of having ABS on the bike, seems it would probably be cheaper to get a different bike so that's not going to happen. But I found this interesting company, wondered if anyone has come across them before?

http://www.tcbbrakesystems.com/index.html

Got to say, the claims seem a little too good to be true, plus the layout seems a little too much like one of these "find out how to mayk $100000 A MONTH!!111!eleven!!!!!" sites. I liked the "nothing to lose" claim, not entirely sure that applies to bolting some random item into my brakes :chuckle: the fact that they're able to self-certify it is a little worrying too.

I've also looked at the description and not convinced that it could prevent the wheel locking up every time without dragging the brakes or reducing their performance, any thoughts would be appreciated. So I'm a bit suspicious, but it certainly looks like a useful add-on if it's all true :D

[jerry]

The ideas seems OK but it does seem to be made for HDs where the bikes use more rear brake than front to stop as most weight is on rear tyre .

[utopia]

It sounds a bit "mickey mouse" to me.
I can see how the addition of a little air in the brake line would give a softer feel at the lever (just like badly bled brake lines, though in this case isolated by the diaphragm/accumulator) and this may reduce the tendency for ham-fisted braking to cause a lock up. Maybe this is where any advantrage lies, and it may be of some help to the novice rider in a panic situation, or even allow a more useable degree of feel in the brakes for a more experienced rider. That is neither anti-lock, nor traction control though.
However, the claim that some sort of pulsing effect is gained seems to me to be a little unlikely. I'm certainly not comfortable with the notion that this occurs due to minor natural variations in the disc surface, although on the other hand I can't see what else could possibly cause such pulsation either, or indeed how this would relate specifically to a lock-up situation rather than just happening all the time.
While the disc surface may not be absolutely and utterly flat in all directions, the only irregularities which could be detected by running a finger over their surface would be due to the circumferencial scoring, and this would have a uniform effect on the brakes rather than the pulsating that might occur if the grooves ran in a radial direction. My discs run true within about 0.002 inch, and this small variation is gradual over each full rotation and is moderated by the fact that the discs are floating on their bobbins, so would be unlikely to generate such pulsing, in my opinion.
Some of the "technical" explainations seem a little less than scientific, tending to use technical terms which are inappropriate in the circumstances, but which sound like proper science, giving the unit a spurious credibility.
Having said all that, I would nevertheless be interested to try the unit as there is no better way of verifying a system than putting it to test in the real world. I wouldn't be expecting it to fully live up to its claims though.
Another way of looking at it might be to consider that at least this is a mechanical unit which operates on a direct feedback loop, rather than normal ABS which relies on a multi-link feedback through sensors and electronics, any of which could fail and cause the feedback loop to break down. As such, it would avoid my inherent distrust of conventional ABS for motorcycles (or indeed of traction control) due to the likelyhood of compete failure due to the malfunction of just one of its many component parts.

[Nickj]

Utopia the disk surface does chemically change to a slightly harder more abrasive surface so they can pulse a little even if perfectly flat. It's all in the surfce layers reaction to heat and why I bed in pads and new rotors in a series of stops which get the suckers hot
All I can see this doing is dropping the max puressure in the line a teensy bit.. so if you have the lever in at max then it might stop you locking, depends how much volume it can absorb and how many PSI it takes to expand the rubber bellows.
LOL Last time I tried a harley the brakes didn't do anything that I noticed, I'd have though using one of these on them would be very counter productive ;)

[the_adam]

At $79 for each caliper it could be an expensive test... My feeling is that it would probably help a little with panic braking (this would actually be quite useful for me, with all the commuting and engine braking I've become one of these stopping-without-brakes people so it's a bit of a shock when I have to use them :)) But in doing that it could reduce the amount of braking force you have available the rest of the time. And probably still not stop the wheel locking up if you hit a patch of ice/diesel etc, which is the main thing I'm bothered about. I also can't help thinking it's essentially not that different to letting a controlled amount of air into your brakes?

I noticed most of the bikes pictured weren't exactly Monster-like, this is what it says about using them on sports bikes -
These low center of gravity motorcycles are made to corner at higher speeds compared to any other motor sports vehicle. During these maneuvers the amount of tire on the ground/“footprint” is most important and any wheel lock could end up with less than favorable results. As the TCB helps modulate the fluid pressures additional wheel rotation during aggressive braking is imperative.
Can't quite get that last sentence to make sense... :scratch:

Would quite like to give one a try to see what it's like, it should be easy to test since the back brake locks so easily! But then that's not the sort of money I could afford to just throw at something that is otherwise just a shiny banjo bolt...might have to think about this :)

[Dookbob]

Cant see it myself to be quite honest. All the rubber diaphram is doing is acting like the original equipment rubber brake hoses by flexing. You would get the same effect by dumping your stainless braided hoses and going back to rubber /textile hoses.

[gary tompkins]

Sounds like a con

It would never be pukka ABS unless linked electronically to wheel rotation

[utopia]

Dook has a good point, though maybe the effect would be even softer with the device ?

Nick...I know only too well, having had consequetive mot advisories on my pulsing brakes, but thanks to earlier posts of yours I have a better idea now of how to cure them.....ta.
I even wonder whether this device might be some sort of cure for the pulsing brake syndrome, but I can't see the mot man buying it.
Also, I think it unlikely that the device would rely on something so variable and unpredictable (from bike to bike) as badly tempered discs.

I don't mean to dismiss the device out of hand, but if it looks like snake oil and sounds like snake oil.......its probably snake oil.
The manufacturers certainly don't seem to understand how it works any more than I do.

[the_adam]

I'm thinking the same really, would have liked to try it just because I'm a curious-Adam rather than actually expecting it to work. I'm just going to have to have a sensible moment and not waste the money on it :D

I've done quite a bit of searching and turned up a mixture of brilliant reviews and snake oil claims (which the website definitely backs up)...don't think I really want something like that attached to my brakes. Apparently a similar sort of accumulator device was sold for cars in the 90s to do the same cheap aftermarket ABS job, although it was somehow bypassed except under heavy braking, haven't found any details on it yet. Presumably if it was any use it'd either still be around or fitted to every new BMW by now though! I guess in time you'd just get used to the extra lever travel and end up with the same wheel locking problem

There's also a rumour that KTM were testing this but we'll have to see if any results actually appear :)

[Nickj]

Playing with the front brake on the way home I'd be thinking that the expansion part is pretty 'stiff' and as far as I can see it would just take the edge off of a hard tug on the lever.
Just pulling the lever gently in gives you a relatively linear increase in effect until a certain point when the braking effect goes a little non-linear. That's got to be when the pads are firmly against the rotor and are just being pushed hard against it so at that point the pressure in the lines probably rises quite quickly. Absorbing a bit of that would intuitively thinking stop or moderate locking.
I usually ride with two fingers draped over the lever, that's more than enough to get the rear end really light.