"ABS" almost sent me through an intersection By yoster (Read 773 times)

[yoster]

I was always happy with the brakes on my scooter, until yesterday when I had to get on them hard for the first time. It was a situation we've all come across before.. driving down a road, light turns yellow and you're right between the "stop" point and the "try to beat it" mode. Not quite close enough to easily beat it, but, not quite far enough to stop easily. And of course I was going bit over the speed limit.

So decision time came, and knowing my scooter doesn't have much "umph" above 60mph (and therefore no way in the world I was going to beat this light), I decided to stop... or try to. It started braking well (both brakes applied hard), but as I applied more pressure... the braking force did not increase.. in fact it almost felt like it decreased! Front brake lever would go do down more, but no change in braking. I'm rapidly approaching the intersection thinking... I'm not going to stop! I grabbed my rear brake and squeezed (still keeping the front brake down) until I was about blue in the face, and I stop just past the double yellow crosswalk lines (good thing no pedestrians were crossing). Then I just walked it back behind the lines.

Frustrating thing was, I know I wasn't even CLOSE to locking up. In fact I've stopped MUCH quicker before when I applied LESS force to the front brake. It seems like once this "ABS" thing kicks in, it releases a too much of the braking force. It was braking hard though regardless... I could smell the brakes once I had finally stopped.. they were definitely hot. I'd say this was just brake fade, but it felt different than that.

[Bashan]

By putting ABS in quotes it's obvious you know already that it's nothing more than a pressure relief valve. I took the one off of my Peace 150 and felt it actually helped the feel of the front brake, that could be just psychological however. I've had to hit them hard several times after I took it off and never locked the front brake up so it doesn't seem that I lost a safety factor. I can only speak for my one scooter though and certainly can't make a blanket statement for everyone's bike. Since your brake smelled hot it does sound like a lot of squeeze was put on the pads. Do you think the pads could be glazed? Rich

[Cruiser]

Hi Matt. I can lock the rear brake with a good pull. The front brake would take a lot more effort to lock and I think that is part of the ABS system. It sounds like your rear brake isn't up to snuff. Possibly glazed pads or worn pads. I only have about 1500 miles on my scoot and tend to brake gently until I was faced with the same situation you described. In my case, the braking was better than I expected with plenty of brake to spare. I also noticed that the rear brake which used to pulse slightly was now smooth. I decided to do some hard stops on purpose and noted that the rear could be locked up, but I don't think I can do a stoppie with the front. The brakes are now smooth and linear. I don't mind being able to modulate the front brake a little more in order to avoid lockup. It is simple enough to remove the ABS valve. I feel in our case, we would be able to lock up the front brake without the valve and maybe even with the valve? Further testing required.

[yoster]

Yeah I may consider eliminating the valve.. if it's easy. Cruiser, there definitely must be something up with my rear brake.. no way I can lock it up. I never thought much about it though.. on all the mountain bikes I've had (with disk brakes), the rear brake lever was always harder to press than the front.. I always just thought it was the nature of rear brakes. Next time I'm out I'll actually try to lock it up.. I thought I was on it pretty darn hard when this happened but who knows.. it all happened so fast! Definitely need to get it sorted out though.. it was not at all a good feeling and kinda caught me off guard. Don't think it would be a glazing issue (my scoot only has 1300 miles on it), but who knows.

[Cruiser]

My rear brake does feel "harder" to squeeze than the front, but it does produce results. I would imagine the front brake would feel a lot firmer without the "ABS" valve.

[yoster]

So a quick update on this. Was riding to work this morning and experimented with my back brake. Apparently this whole time I haven't been grabbing the end of the bar.. so I didn't have the same leverage as I could have had this whole time. I think it's because the back lever is "harder" so I naturally "choked up" on it more (with it being "harder" the end of the bar was a stretch for my hand. Now I force myself to just reach further and use the end of the lever).

Anyway, lesson learned.

[Cruiser]

I agree, Matt. You definitely have to grab near the end of the brake lever in order to get maximum mechanical advantage. I wish that someone offered dogleg levers which have a bend like on some motorcycles. That was the first mod I did on my GS1000 when it was offered on a newer model.

[shakeyjake]

It's been a while but on my 150 Roketa, I didn't have to remove the valve. If I remember right, to bypass or disable it I removed the cap on the bottom and screwed the hex nut all the way in to bottom it out.