CBR250R brake test with ABS On & Off

Redline said:

Looks better without it.

Also note the rear tire lifting (close to) off the ground in the second clip.

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Well, in the first clip you don't see the bike at the time the rear is lifting in the second. A man enters the frame and obscures the bike at that point. It is normal for the rear to lift under breaking, as momentum shifts the weight forward.

With a fully focused expert rider there would be little difference in braking distance between bike with and without C-ABS. However, how many of us are truly expert and fully focused all the time?

In both clips the rider is focused and keeps the bike under control. He knows what to expect. In the first clip you hear the chattering skidding sound as the rear wheel locks, though I don't think completely. If it did you would hear a more continuous sound. On the road, in traffic, with so much else going on you cannot be so focused just on braking. In wet or slippery conditions under an emergency situation you might slam on the brakes, lock a wheel...... and down you are likely to go.

ABS does not reduce braking distance per se. It prevents the wheel from locking up under braking, which can result in the rider losing control of the vehicle and crashing. Also vehicle with the wheels locked takes longer to stop as the adhesion to the road surface is broken. ABS is a back up to help the operator keep control of a vehicle.

In the case of the C-ABS for riding generally on sealed roads the C is more important. On the C-ABS model the brakes are partially linked. Hit the rear brake and one of the three pairs of brake pads on the front will operate in addition to the rear. Braking will occur simultaneously on both wheels. Pull the front brake and there will be increased braking power on the front.

Ideally, under normal circumstances on sealed roads, the brakes should be applied at the same time, or the front a moment before the rear. At medium to high speed most of the braking is done by the front wheel, with the rear brake being used to balance the bike. It is a hard skill to master, requiring a lot of coordination. The combined aspect of the C-ABS ensures that braking is simultaneous on both wheels.

Off sealed roads it can be a bit different. For that reason on some of those heavy weight ABS equipped "adventure bikes" (that I would not want to take far off sealed roads) the rider has the option of switching the ABS off.

I have never used any vehicle with ABS (the most modern car I have driven was a 1992 Honda Civic), but for a motorcycle such as the CBR250R, which is designed primarily for sealed roads, I would say the C-ABS model would be the way to go. The partially combined aspect of the brakes is applicable to day to day riding. The ABS is a back up, which ideally should never be called on to kick in, but could help in an emergency or panic situation.

kim said:

Heres a real test with abs on/off

YouTube - Antilocks significantly reduce motorcycle crashes

No doubt here that abs reduces braking distances

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As I noted in my previous post, once a wheel is locked (and therefore skidding) it loses adhesion to the road surface (traction) and it takes longer to stop.

Once a bike is sliding along on its side it can go quite a long way. Heavier bikes and higher speeds create more momentum, so the bike takes longer to come to a halt. Unless it hits something solid; obviously that can do a lot of damage to bike and rider.

You see it in motorcycle races, where bikes are often dropped at high speed. They do not slow down much until they reach the gravel trap, on a track designed with safety in mind. Often a rider (protected by leathers etc) simply gets up, picks the bike up and continues racing. Hit something solid, as is more likely on the road, and it is a different story.

The advantage of the ABS is that it prevents wheels locking, so the brakes can be fully effective under the prevailing conditions. It also means that the rider has a better chance of remaining in control of the bike.

On a dry road, ridden by a reasonably competent rider, an ABS bike and a non ABS bike will stop in about the same distance. On a wet road a highly skilled rider on a non ABS bike could match an ABS bike, but for the average Joe or Jill (i.e. most of us) or a novice it would be difficult to do.

The ABS itself does not reduce the distance it takes to stop. It is an aid that ensures that riders get maximum braking performance whatever the conditions.

Two of my friends purchased motorcycles last year and are new riders. Last summer, both had to make quick stops - one braked hard to stop in the wet while approaching a yellow light (a cop was sitting at the intersection), and the other was cut off by a young cager turning left in front of him. Both locked up their front tires. Both went down. The yellow light victim injured his collarbone - lost some range of motion, but is still riding. The other friend broke his collarbone (a common injury when going down on a bike) in two places, was off work for three months, and has not ridden since - though he still plans to ride again. BTW - he slid on the road but thankfully didn't hit the left turning car. If these new riders were riding a bike equipped with ABS brakes - I suspect they would be fine now.

Mike

ABS - worthwhile, but not a panacea

kim said:

So we better tell carproducers/bikes/trucks etc. that they dont need to make abs - its the same brakedistance on dry road; thats way it was banned in formula one ;-)
What a useless piece of sh** ey?

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That is not what I suggested at all, Kim.

I know it is a common fallacy that ABS reduces braking distances. Simply put, it does not.

ABS is an aid that stops wheels from locking up, which is more likely in a panic situation on slippery roads. Because of that, riders of all abilities are able to use their brakes to better effect under most on road conditions.

Once a wheel locks up on any vehicle:

1 - The brakes are no longer effective at slowing the vehicle down because the wheels no longer have traction. It takes longer to skid to a halt than to come to a halt under controlled braking.

2 - It becomes more difficult for a rider/driver to control the vehicle.

For the average Joe or Jill on the road ABS must be of great benefit, especially in less than ideal conditions. Seeing it available at reasonable cost on the CBR250R is a big step forward, which I hope other manufacturers follow.

That being said, ABS is a back up. Ideally, it should never be put to test. In reality, it will be, and it will save life and limb, and damage to precious bike and other property.

For day to day riding the C (combined) aspect of Honda's C-ABS will be the most beneficial aspect, in that it is less critical to coordinate front and rear braking.

ABS is not a panacea. It should not be seen as a substitute for proper roadcraft; reading the traffic, and adjusting to road conditions. Mike (CBR250) in his post describes two situations where ABS may have resulted in a better outcome. However as he describes them, the situations could have been avoided.

In the yellow light crash, the guy should have been slowing down to stop for the yellow light, not speeding to get through, then deciding to stop because he saw a cop.

Where I have lived for the past 8 years, in Phuket that is a tricky one, because drivers habitually run yellow and even red lights. No one bothers to stop because they see a cop, who will do nothing. In traffic you risk getting rear ended if you do stop. My solution is to keep a close eye on my rear view mirrors, and adjust my position on the road to minimise the risk.

For guy that got cut off by the car, it is a bit more difficult, especially in a place where you expect traffic to be quite disciplined. It sounds like the motorcyclist was not at fault..... but..... you do need to be well aware of road conditions, what is going on around you, and anticipate what people might do.

Again here in Phuket, getting cut off is a several times a ride occurrence. Traffic is completely indisciplined, but I have come to learn some patterns of behaviour and take a lot more into account when anticipating than I would in more road code abiding places.

So far, so good; I have not had a moving accident here, but my motorcycle has been struck while stationary a couple of times. My formative years of using a motorcycle on farms to muster livestock, including mobs of a hundred or more stroppy 4 year old bulls, probably did more for my survival on Phuket roads than anything!

But back to the ABS. It is not the be all and end all, and it will not make a bike stop quicker. It will increase the chances of all levels of rider maintaining control of their bike, especially under less than ideal conditions.

I feel ABS is well worthwhile.

Michael said:

Mike (CBR250) in his post describes two situations where ABS may have resulted in a better outcome. However as he describes them, the situations could have been avoided.

In the yellow light crash, the guy should have been slowing down to stop for the yellow light, not speeding to get through, then deciding to stop because he saw a cop.

For guy that got cut off by the car, it is a bit more difficult, especially in a place where you expect traffic to be quite disciplined. It sounds like the motorcyclist was not at fault..... but..... you do need to be well aware of road conditions, what is going on around you, and anticipate what people might do.

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Michael is right. In both situations my friends panicked. However, the yellow light rider wasn't actually trying to speed through the light. In fact, he wasn't speeding at all. The light changed to yellow just before he reached the point-of-no-return marker so he decided to apply the brakes hard and try to stop. The irony is that even though he slid on the road with the bike, both man and bike still stopped in front of the crosswalk and not into the intersection!!! He concedes now that he would have been fine to just continue through the yellow. And he said the police officers were the nicest he had ever met. They helped him bring the bike to the side of the road, and even later pushed him to try to bump start the bike!!! They were both riders themselves!! An ambulance was also called to assess for injuries.

What I was trying to communicate is that my friends are NEW RIDERS. All new riders WILL make mistakes (many seasoned riders make mistakes too). The nice thing about ABS is that it is more forgiving of such mistakes. If you apply the brakes with enough force to lock the front tire (because of a lack of experience) in situations like I've described you are much less likely to lose control of the bike and go down. I wonder how many new riders go down (and perhaps get injured) and then decide to never ride again? The addition of ABS on the CBR250R may introduce riding to more people, give them more confidence, and may keep new riders riding longer allowing them to develop more experience and grow into the sport.

Mike