ABS and lockup for the new guy

[deagle]

Have ridden for many years, 2nd FJR, first bike with ABS. Have gotten along just fine without.

So riding to parents farm on dirt road, decided to test. Locked up rear brake several times at slow speed. Seemed to kind of skip but not skid/ride out the back end. Did not test the front (falling down I remember hurts). The "kind of skipping" concerned me.

So, my question is, if the ground is wet, and I hit both brakes in a panic situation...for that split second that the brakes stop and release, am I going down? I understand that the braking is better than I can do, but is it safe to lock up the brakes in the rain?

sidenote: This question is in no way opening the "abs vs non abs" debate. Just questioning how rain affects how hard I can rely on abs.

Thanks all.

Don.

 

[wfooshee]

When you say locked up several times, are you describing chatter, like it locked, released, locked, released, or do you mean you were able to lock it several times, and have it stay locked?

The latter is not good, indicates a definite failure in the system.

The former is not quite right, either, if the wheel is actually stopping for a perceptable amount of time. But see the next question about 'how slow.'

Also, "slow speed." How slow? As you approach walking speed it will allow a lockup. It measures the difference between wheel speeds to detect that one is locking, and of course when riding slow, that difference will be rather a bit smaller than when boogeying right along.

 

[garyahouse]

Test it, Don.

Here's what I did. On a dirt road, @2 mph, I balanced it just right, handlebars dead straight, and clamped on the front brake. Then I tried it at say 3 or 4 mph. Then again at 6-8 mph. I worked my way up gradually to increase my confidence in the ABS. You'll find out in an easy, safe manner (as I did) that the ABS on an FJR works really well. You can even steer the bike fairly well while the ABS is doing its thing. You can do this same thing on a wet road. You'll have much more confidence in testing the system if you do it gradually. However, that doesn't mean that one should go looking for trouble, like testing the ABS while out grinding the pegs somewhere... Recently I had the unfortunate opportunity to test my ABS in normal traffic. I don't get into situations like this often, but it happens. I cranked on the brakes, and they worked perfectly, slowing me down in a hurry. And like you, I have some not so fond memories of my last bike that didn't have ABS. And I still have the scars to prove it. That was a huge factor in my decision to buy an FJR with ABS.

Gary

 

[ionbeam]

...On a dirt road, @2 mph, I balanced it just right, handlebars dead straight, and clamped on the front brake. Then I tried it at say 3 or 4 mph. Then again at 6-8 mph. I worked my way up gradually to increase my confidence in the ABS...

I'm glad that worked out for you. According to the FSM 5 mph (roughly) is the minimum speed at which the ABS will activate. Choose for yourself, but I wouldn't trust ABS to work until I was over 7-8 mph. Again, choose for yourself, but I see wet pavement as a more predictable and reliable surface for testing one end at a time.

 

[garyahouse]

IONBEAM, could you shed a little more light on function of the ABS system? I understand that though the ABS doesn't activate below a certain speed, however IF IT IS ACTIVATED above that speed, it will continue to function until the bike comes to a full stop... is that correct? In other words, it doesn't deactivate itself when crossing the 5 mph threshold during deceleration, right????

I would certainly agree with giving precedence to the wet pavement experiment. I don't get to see wet pavement much... especially since when it does get around to finally raining once in a while, the bike stays in the garage. I practice on a dirt road 'cause dirt's is what I got...

Gary

 

[ionbeam]

... could you shed a little more light on function of the ABS system?...IF IT IS ACTIVATED above that speed, it will continue to function until the bike comes to a full stop... is that correct? In other words, it doesn't deactivate itself when crossing the 5 mph threshold during deceleration, right????...

The ABS system monitors wheel speed and chassis speed then continuously performs a mathematical function that sees the relationship between the two as a percentage ratio referred to as either 'slip angle' or 'slip ratio'. When wheel speed and chassis speed are equal they are 100% proportional. When a wheel is braked to the point of slipping (lock-up) the ratio of wheel speed to chassis speed becomes out of balance. A skid or wheel lock-up is when the chassis has enough inertia to overcome the available tire traction when braking.

In automotive ABS applications the trigger point for ABS is typically defined as when the wheel slip angle becomes greater than 87%. This is the critical point between a rolling wheel and a skidding wheel. When chassis speed and wheel speed vary by more than 13% (impending lockup) ABS will engage until chassis and wheel speed come closer to balancing. With a slip angle of 86% the wheel is considered just over the threshold and actually beginning to lock-up and skid.

As to your question about ABS being applied down to a complete stop, it can be yes or no. ABS will be applied to the brake(s) until the slip angle becomes less than 87%. It depends on available traction and rate of deceleration (inversely, inertia) as to when the ABS will deactivate, if at all. At a steady 5 mph and under there is so little inertia in the chassis that it is unlikely that the slip ratio can exceed the 87% that is required to activate the system.

 

[SkooterG]

Ok, my opinion? This isn't that tough folks. Go out on DRY pavement and get up to 60 mph (going straight) and stomp on the rear brake. There will be no drama. (On a Gen II. On a Gen I you will feel the lever kicking and feel the rear wheel momentarily locking and releasing. Gen I abs system is not as sophisticated as Gen II) If for some freak of nature your ABS is not working and the rear locks up, well then, release the brake and continue on your way.

Next, get up to 60mph again and quickly and gradually squeeze the front brake. You'll have to do it quick as you will be bleeding off speed very quickly. Eventually you will feel the abs kick in for the front. Again, no drama, no big deal. Don't be afraid of this. If for some freak of nature your ABS is not working and the front locks up, well then, immediately release the brake and continue on your way.

I have tested both front and rear ABS on many FJRS. It's not a big deal. Don't make it into one. In my opinion, every owner of an ABS FJR SHOULD do this. You should know how your ABS 'feels' when it activates so that you are not surprised by it when the **** is actually hitting the fan. It's not magic, voodoo, or hocus-pocus. It is simply, a mechanical safety system on your motorcycle. Go out and see how it works!

A few days ago, I had the opportunity to test ride a Kawi C14 and the new BMW K1600GTL. I tested both of those bikes front and rear ABS systems just to see how they worked and felt. It's NOT A BIG DEAL.

 

[sylvester]

Have ridden for many years, 2nd FJR, first bike with ABS. Have gotten along just fine without.

So riding to parents farm on dirt road, decided to test. Locked up rear brake several times at slow speed. Seemed to kind of skip but not skid/ride out the back end. Did not test the front (falling down I remember hurts). The "kind of skipping" concerned me.

So, my question is, if the ground is wet, and I hit both brakes in a panic situation...for that split second that the brakes stop and release, am I going down? I understand that the braking is better than I can do, but is it safe to lock up the brakes in the rain?

sidenote: This question is in no way opening the "abs vs non abs" debate. Just questioning how rain affects how hard I can rely on abs.

Thanks all.

Don.

I did some training with a motorcycle instructor in Galway. We both have fjr's . In a industrial estate closed to public, we started at slow speeds 20mph and building speeds up to 60mph- 70 mph. A typical Irish day very wet. Tested the back brake abs first on it own, then did a bit on front brake abs on its own, checking braking distance. After that using both brakes slow speed work and building up to high speed testing.

First some straight line braking, get the speed up , full in with clutch, full on both brakes, come to full STOP. You should hear a clicking noise(click,click, click) that's the abs working.

Then we did it going around a corner first at slow speeds and later at high speeds. the more you practice it the more confident you get in your ability and of the bike.

Then we practiced braking for emergency going around a left hand corner at speed. (Say there is something on road you cannot avoid)

Going around the bend bike stopped no problem under very hard braking at high speeds but i by the time i stopped I had drifted close to centre line. (We drive on left hand side of road in Ireland & uk)

Instructor then told me to apply pressure(Push) on left bar while emergency braking and the bike will take the line of corner and you wont drift to wrong side off road. A bit of counter steering with braking.

Best to practice emergency braking before it happens to you a year down the road for some real event.

What's that smell , new brake pads Please!!!!

 

[deagle]

Thanks for the replies. I will practice and get more comfortable with the system.

Don.

 

[Denver_FJR]

So, my question is, if the ground is wet, and I hit both brakes in a panic situation...for that split second that the brakes stop and release, am I going down? I understand that the braking is better than I can do, but is it safe to lock up the brakes in the rain?

Maybe... but have a lot better chance of not going down with ABS. Lots of motorcycle abs videos on youtube too. Youtube ABS vids

 

[Spud]

I took a motorcycle safety course for an insurance discount when I got my Bandit 1200. Even though I'd though I've ridden a lot of dirt-bikes, I was always scared about what would happen if you broke loose on the street. In the course, they made us lock up the rear wheel at about 20 mph. I'll admit I was pretty intimidated to do it, but it really was pretty drama-free (and the cool squealing sound was fun). It taught me that locking up can be a controlled event.

On my ABS FJR now, whenever I change tires or put wheels back on after removal, I always test my abs by stomping the back brake on some sand on pavement or even a gravel road (going straight of course) at around 35mph. The system does a great job, and it's good to know what it's like when it kicks in.

 

[SkooterG]

I took a motorcycle safety course for an insurance discount when I got my Bandit 1200. Even though I'd though I've ridden a lot of dirt-bikes, I was always scared about what would happen if you broke loose on the street. In the course, they made us lock up the rear wheel at about 20 mph. I'll admit I was pretty intimidated to do it, but it really was pretty drama-free (and the cool squealing sound was fun). It taught me that locking up can be a controlled event.

On my ABS FJR now, whenever I change tires or put wheels back on after removal, I always test my abs by stomping the back brake on some sand on pavement or even a gravel road (going straight of course) at around 35mph. The system does a great job, and it's good to know what it's like when it kicks in.

Have you ever activated the FRONT abs?

 

[Spud]

I took a motorcycle safety course for an insurance discount when I got my Bandit 1200. Even though I'd though I've ridden a lot of dirt-bikes, I was always scared about what would happen if you broke loose on the street. In the course, they made us lock up the rear wheel at about 20 mph. I'll admit I was pretty intimidated to do it, but it really was pretty drama-free (and the cool squealing sound was fun). It taught me that locking up can be a controlled event.

On my ABS FJR now, whenever I change tires or put wheels back on after removal, I always test my abs by stomping the back brake on some sand on pavement or even a gravel road (going straight of course) at around 35mph. The system does a great job, and it's good to know what it's like when it kicks in.

Have you ever activated the FRONT abs?

Actually I have tried it, going pretty slow on some sandy pavement. But only because I know I also get some rear braking from the linked system. As I recall I wimped out and rolled to a stop once it kicked on

 

[not2shabby]

Actually, you're not gettting any rear brake unless you're applying it at the same time. The rear brake is linked to 1 set of front pads, but the front brakes are not linked to the rear.

 

[SkooterG]

I took a motorcycle safety course for an insurance discount when I got my Bandit 1200. Even though I'd though I've ridden a lot of dirt-bikes, I was always scared about what would happen if you broke loose on the street. In the course, they made us lock up the rear wheel at about 20 mph. I'll admit I was pretty intimidated to do it, but it really was pretty drama-free (and the cool squealing sound was fun). It taught me that locking up can be a controlled event.

On my ABS FJR now, whenever I change tires or put wheels back on after removal, I always test my abs by stomping the back brake on some sand on pavement or even a gravel road (going straight of course) at around 35mph. The system does a great job, and it's good to know what it's like when it kicks in.

Have you ever activated the FRONT abs?

Actually I have tried it, going pretty slow on some sandy pavement. But only because I know I also get some rear braking from the linked system. As I recall I wimped out and rolled to a stop once it kicked on

Don't be a wimp! This isn't rocket science!

Don't do it on sandy pavement. Why? Well my line of reasoning is if something does go wrong and you start losing traction, it's going to be a lot tougher to get it back on sandy, or maybe even wet pavement. Let's say something does go wrong on dry pavement, simply release the brake and the tire will easily gain traction again. Also, you can't be going slow. The FJR will bleed off speed too quickly to either get ABS activation, or activation that is not just a quick jerk. Ideally you want to progressively (and quickly) apply front brake pressure only so that you can 'feel' how much braking force you get before abs activation, and then what it feels like as it activates. So get up to 60+ mph on a straight road with good surface and no traffic and give it a whirl. DON'T BE AFRAID OF IT. Really, it's not that big a deal unless you make it into one.

 

[Harald]

It's like Scooter said, "don't be afraid of the abs!" I was playing with the FJR one rainy day and tried something you'd normally not try on a non abs bike. I grabbed front brake hard and quick while going 40 mph. The front end dived and at the point where the brake would have locked, the abs kicked in and released braking pressure, causing the front end to raise up some. Then it allowed braking pressure to apply again, which caused the front end to dive again. This pogo-ing continued with no brake lockup. Works like a charm, even if you brake like an *****! :crazy: :lol:

 

[mikatollah]

I had an opportunity to test the ABS (front and rear) at 70 mph yesterday when a Dalmatian ran out from behind a car and headed right for me. I got on both breaks hard and would have still hit him but he pulled up at the last second. I was probably doing 20 mph when I came off the brakes.

Everything worked just as advertised.