SCBS Saved my @ss!!

Kayger12

Member
:
'14 AWD GT w/Tech
My wife and I have been driving the CX-5 for about 2 years. Neither of us have had the SCBS kick in and always wondered if/how it would work. I've been driving for about 25 years now and have never had an accident so, to me, it was one of those nice-to-have-but-I'll-never-need-it things-- until...

We were driving to dinner last night. I'm driving on a surface street and trying to figure out where a parking lot is that I can use (tough town for parking). It's my first time there so (like an idiot) I'm looking at the GPS screen trying to figure out the route and read the street name that I want to turn onto. I'm driving maybe 30 mph. Unbeknownst to this idiot who is looking at the screen, the cars in front of me come to an abrupt stop in traffic. My wife, who is not a back seat driver, realizes that I'm not slowing and starts calling my name repeatedly to get my attention. I look up and see the car in front of me at a dead stop. I quickly realize one thing... There is no effing way I can stop in time.

I crush the brake pedal as hard as I can (my calf muscle actually felt a bit of charlie-horse like pain I was pushing so hard). We're braking hard but I can tell that I'm going to be about a foot or two short on stopping distance. There is absolutely no doubt in my mind that I'm going to hit the car.

With about 6-8 feet to go I feel the brake pedal give under my foot. Even though I was pushing as hard as I could it suddenly dropped what felt like another 2-3 inches and at the same time the CX's braking effort seemed to increase dramatically.

We came to a stop inches from the stopped car in front of us. No contact. I couldn't believe it. I looked down and saw the SCBS indicator illuminated on the dashboard.

I looked at my wife and said, "well-- tech package just paid for itself!" Seriously. Felt like the best money I ever spent.

So that's it. Before last night I could have taken or left SCBS and never really thought much about it. Now I can confidently say that it is the only reason that I didn't have my first accident and smash up my wife's favorite car.

So while I deserved to get in an accident for being an idiot and allowing myself to be distracted, it's great to know that the technology that has been quietly sitting there for 2 years worked exactly as designed when it was needed most. I'm now a believer.
 

CX5Alive

Member
:
Mazda CX-5 Touring
Hmm, we have SCBS too, but that's not how I thought it worked. I thought that it would just automatically apply the brakes if you were about to hit something between the speeds of 4-18 mph, and you hadn't yet touched the brakes yourself. I'm surprised to hear that you were applying the brake pedal with full force, yet it SCBS kicked in and somehow found extra stopping power at the last second. I mean it can't change the laws of physics, right?
 

CXVille

Member
:
2014 CX-5 GT & 3 i Touring
SCBS had nothing to do with not hitting the car in front of you, unless you were not pushing on the brake pedal hard enough. As mentioned, SCBS is for applying the brakes at lower speeds while you are watching the GPS or phone, not for "helping" you. I believe most brake systems take around 100 pounds of force to get maximum braking force. At that point ABS should start activating, and you may notice the pedal moving around a little. You should feel the kick back.

Take the car to a EMPTY lot in the wet or snow and slam on the brakes and feel the ABS. Then, when its dry, do the same thing. If you can't get the ABS to activate in the dry, on solid, dry, clean pavement, take it to the dealer to confirm that the brakes work. Any car sold in the past 30 years in the US, that I know of, can lock up the brakes from any speed, IF the brakes are working properly. May not be able to do it more than once or twice, depending on speed.

ABS and the other electronic nannies do a lot, sometimes not for the better, and this can create strange feelings and performance that is not anticipated. It is possible that you slammed the brakes hard enough to get them to lock up and what you felt was ABS reapplying them. I believe that the cars have a brake "anticipator" system that applies the brakes for you when you jump off the gas onto the brakes. Basically, when it feels you jump off the gas and onto the brakes, it JAMS the brakes on. You may have felt some of this action. But, I assure you, SCBS did not increase the braking capabilities of the car, unless you were not applying adequate force to the pedal.
 

socalcx-5

Member
I've had the SCBS kick in a couple times:

1) when inching into our garage, trying to get as close to the wall as possible (we have tandem parking so I have to leave room for the car behind me)
2) bumper to bumper traffic in LA, I'm fairly aggressive in terms of merging and changing lanes, so it kicked in once thinking I was going to hit the car in front of me.

Both times the car was essentially idling, no gas applied, just foot off the brake. It's a bit jarring when it kicks in (the first time I thought something seriously wrong had happened), and even though I didn't "need" it to save me either time, I was glad to know that it worked.
 

Dr_Watson

Member
:
2106 CX5 2.2D AWD MT 175PS, Tech pack, Sunroof, full LED
You didn't crash because you were lucky, nothing to do with SCBS. At least it wasn't a you child running across in front while you were map reading and driving.
 

Kayger12

Member
:
'14 AWD GT w/Tech
Hmm, we have SCBS too, but that's not how I thought it worked. I thought that it would just automatically apply the brakes if you were about to hit something between the speeds of 4-18 mph, and you hadn't yet touched the brakes yourself. I'm surprised to hear that you were applying the brake pedal with full force, yet it SCBS kicked in and somehow found extra stopping power at the last second. I mean it can't change the laws of physics, right?

What he said^^^!

I thought the same thing, but it definitely kicked in while I was already braking.

After looking into it I found out that the scbs system uses brake assist to provide additional braking force (page 4-76 of the owners manual). "when the driver depresses the brake pedal while the system is in the operating range the brakes are applied firmly and quickly to assist (Brake assist (SCBS brake assist))"

Mazda describes brake assist on their website as follows

"Sometimes, although drivers press the brake pedal as hard as they can, it may not be sufficient. Brake Assist measures the speed at which the brake pedal is pressed and the braking pressure and when the force is judged to be insufficient the system compensates by applying additional pressure."
 

Kayger12

Member
:
'14 AWD GT w/Tech
SCBS had nothing to do with not hitting the car in front of you, unless you were not pushing on the brake pedal hard enough. As mentioned, SCBS is for applying the brakes at lower speeds while you are watching the GPS or phone, not for "helping" you. I believe most brake systems take around 100 pounds of force to get maximum braking force. At that point ABS should start activating, and you may notice the pedal moving around a little. You should feel the kick back.

Take the car to a EMPTY lot in the wet or snow and slam on the brakes and feel the ABS. Then, when its dry, do the same thing. If you can't get the ABS to activate in the dry, on solid, dry, clean pavement, take it to the dealer to confirm that the brakes work. Any car sold in the past 30 years in the US, that I know of, can lock up the brakes from any speed, IF the brakes are working properly. May not be able to do it more than once or twice, depending on speed.

ABS and the other electronic nannies do a lot, sometimes not for the better, and this can create strange feelings and performance that is not anticipated. It is possible that you slammed the brakes hard enough to get them to lock up and what you felt was ABS reapplying them. I believe that the cars have a brake "anticipator" system that applies the brakes for you when you jump off the gas onto the brakes. Basically, when it feels you jump off the gas and onto the brakes, it JAMS the brakes on. You may have felt some of this action. But, I assure you, SCBS did not increase the braking capabilities of the car, unless you were not applying adequate force to the pedal.
See my post above. If I didn't experience it I would have thought the same as you... But in this case I think it had everything to do with not hitting the car and apparently did provide additional brake pressure through the brake assist integration.

I'm a driving instructor with plenty of track time. I'm very familiar with the pedal/vehicle feel of abs kicking in.
 
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CX5Alive

Member
:
Mazda CX-5 Touring
I thought the same thing, but it definitely kicked in while I was already braking.

After looking into it I found out that the scbs system uses brake assist to provide additional braking force (page 4-76 of the owners manual). "when the driver depresses the brake pedal while the system is in the operating range the brakes are applied firmly and quickly to assist (Brake assist (SCBS brake assist))"

Mazda describes brake assist on their website as follows

"Sometimes, although drivers press the brake pedal as hard as they can, it may not be sufficient. Brake Assist measures the speed at which the brake pedal is pressed and the braking pressure and when the force is judged to be insufficient the system compensates by applying additional pressure."

Hmm, very interesting! I will go back and re-read my owners manual. Still going to take the CX-5 down to the cul-de-sac with a big cardboard box and try to activate SCBS under controlled test conditions. I'll get my wife to video me.
 

Kayger12

Member
:
'14 AWD GT w/Tech
Hmm, very interesting! I will go back and re-read my owners manual. Still going to take the CX-5 down to the cul-de-sac with a big cardboard box and try to activate SCBS under controlled test conditions. I'll get my wife to video me.

Looking forward to results!!
 

Kedis82ZE8

'12 GX 460,'07 G35x / '15 CX-5 AWD GT w/Tech Pkg
Contributor
I haven't experienced it yet in my CX-5 and hope not too. One use would easily pay for the feature. The closest I have ever experienced with such a system is the Preview Braking system in my G35 that uses the radar cruise sensor to detect imminent collision and it will reportedly close the gap between pad & rotor and pre-pressurized brake system so a simple push on pedal is like a full compression panic stop. The older system in the G won't brake the car to a stop for you though. It requires driver intervention.
 

vroom

Member
:
CX-5 GS AWD 2014, Sky Blue Mika
I thought the same thing, but it definitely kicked in while I was already braking.

After looking into it I found out that the scbs system uses brake assist to provide additional braking force (page 4-76 of the owners manual). "when the driver depresses the brake pedal while the system is in the operating range the brakes are applied firmly and quickly to assist (Brake assist (SCBS brake assist))"

Mazda describes brake assist on their website as follows

"Sometimes, although drivers press the brake pedal as hard as they can, it may not be sufficient. Brake Assist measures the speed at which the brake pedal is pressed and the braking pressure and when the force is judged to be insufficient the system compensates by applying additional pressure."

I find it worrying that a normal driver is unable to get the full available braking power out of the car without some mechanical assistance that you have to pay extra for...
 

Kayger12

Member
:
'14 AWD GT w/Tech
I find it worrying that a normal driver is unable to get the full available braking power out of the car without some mechanical assistance that you have to pay extra for...

Yep-- crossed my mind as well. I was wondering why the brake assist didn't kick in right away.
 
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2013 CX-5 Touring FWD; 2013 BMW Z4 35i
Am I missing something here? If you were on the brakes hard enough to activate the ABS (and from your description, you had to have been) how would "additional braking force" provided by SCBS stopped the car any sooner given that ABS alone keeps the tires on the ragged edge of adhesion?
 

Kayger12

Member
:
'14 AWD GT w/Tech
Am I missing something here? If you were on the brakes hard enough to activate the ABS (and from your description, you had to have been) how would "additional braking force" provided by SCBS stopped the car any sooner given that ABS alone keeps the tires on the ragged edge of adhesion?

ABS was not activated. If I would have had the brake force that came in that last 6-8 feet right from application I would have had ABS activation.
 
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2013 CX-5 Touring FWD; 2013 BMW Z4 35i
So if you were standing on the brake to the point where your leg was hurting, why was ABS not activated? It certainly would have been in my 2013 without SCBS.
 

Dr_Watson

Member
:
2106 CX5 2.2D AWD MT 175PS, Tech pack, Sunroof, full LED
Take your car to the dealer, it sounds broken if your ABS only works at low speed.
 
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2013 CX-5 Touring FWD; 2013 BMW Z4 35i
Take your car to the dealer, it sounds broken if your ABS only works at low speed.
Is this addressed to me? I didn't say my ABS only works at low speeds. I said it would have worked at that low a speed (as well as any other speed)!