[billyedtimmy]

Ok, I've had 1 other ABS bike previously (SV650S), but this Honda is the first 'combined' ABS I've ridden, so the whole front activation when the rear locks is all new to me.

Anyway, yesterday I was pulling into my driveway and there was a bunch of wet grass on the pavement from mowing the other day, so I decided to slam the rear brake on it just to see how the combined part of the ABS works (I was in 1st gear, thus going pretty slow). Well, the rear definitely locked up, but so did the front, and as a result the front wheel began to turn (as they tend to do when sliding). Naturally, I immediately let off the brake and managed to recover, but the fact that I have 2 (rather than 1, or zero) skids marks in the grass on the driveway is a bit perplexing. Shouldn't the ABS have kicked in, or do I have to be going a certain speed for that? I know I've activated it before (and it worked) at a quick stop in the rain once, but wonder if this wet grass and/or slow speed condition is different or something. Anyone? Bueller?

 

[etiainen]

I think the manual says that it only turns on above a certain speed.

 

[billyedtimmy]

I think the manual says that it only turns on above a certain speed.

I guess the question then is, if that's the case, why does the 'combined' part apply (i.e., if the ABS itself doesn't kick in until a certain speed, why would the front activate when only the back is pressed at that low speed)? Seems like that 'combined' shouldn't happen if the anti-lock doesn't either.

 

[etiainen]

I think the combined happens anytime you hit rear brake only? At least that's what I thought.

 

[billyedtimmy]

I thought the 'combined' was only supposed to activate when the rear 'ABS' is activated. I don't see the point of the front being activated otherwise (and certainly not the locking if the ABS itself doesn't kick in at the rear).

Me-con-fus-ed.

 

[etiainen]

I thought the combined braking happened anytime you hit the rear?

I guess i haven't ridden one so I don't know for sure.

 

[CBR250R ABS]

ABS activates only above 6 MPH. Brake linkage from back to front always activates even at slow speeds. So it is possible that you were below the threshold of ABS activation and locked up both wheels.

 

[r100]

The combined function is hydraulic. It has no brain.
ABS is electronic. It observes and decides. If it is anything like my friend's VFR800 it does not engage at very low speed.

 

[billyedtimmy]

ABS activates only above 6 MPH. Brake linkage from back to front always activates even at slow speeds. So it is possible that you were below the threshold of ABS activation and locked up both wheels.

Hmm... thanks, that should make parking-lot cone practice more ...uh...interesting.

 

[Michael]

From the Owner's Manual:

Combined ABS 〈CBR250RA〉
This motorcycle is equipped with a Combi Brake. Operating the front brake lever applies the front brake. Operating the rear brake pedal applies the rear brake and a portion of the front brake. For full braking effectiveness, use both the lever and pedal simultaneously, as you would with a conventional motorcycle braking system.

As with a conventional motorcycle braking system, excessively hard application of the brake controls may cause wheel lock, reducing control of the motorcycle.

This model is also equipped with an Anti- lock Brake System (ABS) designed to help prevent wheel lock up during hard braking on uneven or other poor surfaces while running straight. Although the wheel may not lock up-if you are braking too hard in a turn the motorcycle can still lose traction, causing a loss of control.

In some situations, a motorcycle with ABS may require a longer stopping distance to stop on loose or uneven surfaces than an equivalent motorcycle without ABS.

ABS cannot make up for road conditions, bad judgment, or improper operation of the brakes. It is still your responsibility to ride at reasonable speeds for weather, road surface, and traffic conditions, and to leave a margin of safety.

ABS is self-checking and always on.

ABS may be activated by riding over a sharp drop or rise in the road level. It is important to follow the tyre recommendations (page 37 ).

The ABS computer works by comparing wheel speed. Non-recommended tyres can affect wheel speed and may confuse the ABS computer.

ABS does not function at low speeds (approximately 10 km/h (6 mph) or below).

ABS does not function if the battery is discharged.

 

[feliz]

I've noticed that during slow maneuvers using the rear brake cuases the front forks to squat (compress) indicating to me that the front brake is applied when the rear brake is used at slow speed. This has nothing to do with ABS of course which I believe only works over a certain speed, as others have suggested.

 

[TBC]

Wet grass = ice. not sure but i dont think motorcycle abs will work in extremely slippery surfaces. I doesnt work on my truck on extremely slippery surfaces

 

[Jme250RA]

I believe when the rear brake is applied the combined system activates the center piston of the front brakes 3 piston caliper. The other 2 pistons are controlled by the front brake.

 

[CBlackR]

I like the multi-linked brakes. In low speed tight maneuvering situations such as busy parking lots it leaves my hands free for clutching and throttle control. I can use the rear brake lever exclusively and still feel the front brake responding. Thumbs up to Honda's engineers, they're a pretty smart bunch.