TRD pro unsteady under hard braking?

[GB-man]

My truck is pretty much stock and I've noticed the truck handles a bit sketchy under hard braking scenarios. For instance when a light changes late on you in a 45 or higher zone. The nose dives of course then the brakes seem to lock up the tires and if there's any moisture on the road the front will swerve side to side a bit.

I realize there are on road limitations with AT tires and suspension but is this something that I could fix with different tires? I'd really hate to put regular street tires on it because it would kill the look and off road chops for the few times I need it.

Has anyone else with a stock pro experienced this? Any suggestions for improvement?

Thanks :tea:

 

[snif6969]

With the heavy downpour we've been having here down south (AL) I have been in that situation as well.

I am so surprised with how quick the tires lock. It's unbelievably unsafe

 

[GB-man]

With the heavy downpour we've been having here down south (AL) I have been in that situation as well.

I am so surprised with how quick the tires lock. It's unbelievably unsafe

I like to think I'm fairly calm behind the wheel but this has happened to me a handful of times and these are not true emergency braking scenarios. I love everything else about this truck though so I'm hoping to find a solution if one exists.

 

[wfo9]

You purchased a vehicle designed to go offroad... it's not going to handle that well in extreme maneuvers on-road. It's got everything going against it on the road....

Can't have your cake and eat it too.

Bigger and wider tires do help.

I suggest learning to drive very defensively and cautious compared to a regular car. Also, put you phone down.... or buy a crossover.

As far as brakes locking up... I have not experienced this myself in many years of ownership. ABS seems to work fine. But I drive it very defensively... especially when the road is wet.

Only thing that has ever scared me is the anti roll over crap in corners... beside that it seems to be predictable. Just not planted like a car...but mine is far from stock. If the brakes are locking up... I would have it looked at and report to dealer

One thing to note.. And I don't think many people get this. If it just starts to rain (especially in the summer)... the road will become extremely slick near intersections. It can be just like ICE. The oils from tires.... If it is that.. any car will skid. It's scary enough that I will sometimes pull off the road and let all the accidents happen and slow everyone down before proceeding. Most people just don't get it. I can actually predict where the accidents will be in these scenarios. It's OK if it has been raining for a while....

 

[GB-man]

You purchased a vehicle designed to go offroad... it's not going to handle that well in extreme maneuvers on-road. It's got everything going against it on the road....

Can't have your cake and eat it too.

Bigger and wider tires do help.

I suggest learning to drive very defensively and cautious compared to a regular car. Also, put you phone down.... or buy a crossover.

As far as brakes locking up... I have not experienced this myself in many years of ownership. ABS seems to work fine. But I drive it very defensively... especially when the road is wet.

Only thing that has ever scared me is the anti roll over crap in corners... beside that it seems to be predictable. Just not planted like a car...but mine is far from stock. If the brakes are locking up... I would have it looked at and report to dealer

One thing to note.. And I don't think many people get this. If it just starts to rain (especially in the summer)... the road will become extremely slick near intersections. It can be just like ICE. The oils from tires.... If it is that.. any car will skid. It's scary enough that I will sometimes pull off the road and let all the accidents happen and slow everyone down before proceeding. Most people just don't get it. I can actually predict where the accidents will be in these scenarios. It's OK if it has been raining for a while....

I'm not driving while on the phone. I have no idea why you believe that is related.

Yes the brakes are locking up.

I'm not willing to pull over every time it begins to rain. Is that suppose to be a joke?

 

[Cymon]

If pushed down too hard too quickly the break will sense "emergency breaking" and activate the breaking assist, which is likely what you are noticing. Here is another thread on what you might be experiencing. The first time it happens and you're not ready for it, it can be surprising. In an emergency it is what can get these things stopped quick and save someone's life.

http://www.toyota-4runner.org/5th-gen-t4rs/196755-touchy-grabby-brakes.html

 

[wfo9]

I'm not driving while on the phone. I have no idea why you believe that is related.

Yes the brakes are locking up.

I'm not willing to pull over every time it begins to rain. Is that suppose to be a joke?

Half the people on the road these days... are on their phones.. That is why I brought it up. They suddenly have a need to stop and don't brake early enough.... Causes a chain reaction... I'm not saying you do this necessarily, but in general an attentive/defensive driver should rarely have the need to slam on the brakes. I'm not saying it does no happen.. just should be very rare.

When it first starts to rain in the summer.... intersections can become very slick until the oil and tire debris wash away. Even an F1 car with rain tires will slide at these intersetions. That is why I avoid some intersections in my area under those conditions. There is an accident every single time it happens. Very similar to ICE. If your 4r slid on ice you would not blame the vehicle, right?

After it has rained for while.. it is not usually an issue.

Just thought it might be relevant to your situation as what you described sounds a bit unusual under normal conditions. Some tires are just bad in the rain.... I would research that and also make sure your tires don't lock up easily on dry or normal wet pavement. If so... the ABS is malfunctioning.

 

[Saker]

.....under hard braking scenarios. For instance when a light changes late on you in a 45 or higher zone. The nose dives of course then the brakes seem to lock up the tires and if there's any moisture on the road the front will swerve side to side a bit..........

Sounds like [MENTION=120701]Cymon[/MENTION] described it perfectly.

I think there is some panic braking going on from your description.

I have felt the same thing at times depending on road conditions, but realize conditions change quickly when raining and so does the trucks' response....
And we get a lot of rain here!


If you feel they are oversensitive in response to your braking you should take it to a dealership and make them look at it....

 

[MissouriBreaks]

My FJ Cruiser was that way too. The first time the emergency brake assist kicked, I was not expecting it and it was very surprising. Not surprised that other Toyotas would have that feature.

 

[wfo9]

He described it as locking up the tires.. That is not what the brake assist should do. It should not mess with the ABS at all and should have nothing to do with wet pavement.

Everyone's perceptions are different.. after years of racing.. I know what the tires are doing. But I can see where some could think it was a skid when it was just hard braking with side to side abs pulsing.

I've also never felt this emergency assist, but I'm guessing I modulate and cover the brakes differently. I've been told you have to move from throttle input to braking quickly for it to kick in.

 

[GB-man]

If pushed down too hard too quickly the break will sense "emergency breaking" and activate the breaking assist, which is likely what you are noticing. Here is another thread on what you might be experiencing. The first time it happens and you're not ready for it, it can be surprising. In an emergency it is what can get these things stopped quick and save someone's life.

http://www.toyota-4runner.org/5th-gen-t4rs/196755-touchy-grabby-brakes.html

Thanks! I believe this explains what I'm experiencing. I feel somewhat better knowing the vehicle is functioning as expected.

I think I will take it out behind the mall and test the system some more to get a good feel for how it reacts that way I'm more prepared if I god forbid need to slam on the brakes in a highway accident scenario.

In a related note, how do you all feel about wet road performance of the stock Tera grapplers? Is there another AT option that's better? I realize I'm asking for pig that flies but I figured someone may have upgraded tires and found something with better on road performance while still maintaining some AT capabilities.

Thanks

 

[Spanky052]

... I've also never felt this emergency assist, but I'm guessing I modulate the and over the brakes differently. I've been told you have to move from throttle input to braking quickly for it to kick in.

That's exactly what triggers it. The one time it happened to me, I was accelerating away from a stoplight when some dingus stepped out into a crosswalk from behind a tree that I hadn't been able to see him through. I hit the brakes and had plenty of room to stop, but the truck decided that we should stop in half the distance.

No lockup though. Just standard ABS feeling.



Sent from my iPhone using Tapatalk Pro

 

[philsey]

I think that for all of you who are reporting that your brakes are "locking", you have posted misleading information. I hope you mean that the anti-lock feature has engaged.

If your brakes are really LOCKING something is wrong with your truck.

Please read [MENTION=120701]Cymon[/MENTION] 's post. The 4R has some logic which senses the time of transitioning from "off-accelerator" to "on the brake pedal", aka emergency brake assist (I think).

It is sensitive. We've all encountered it. Me twice. It does scare you. You just have to learn it, nothing is wrong. A few more milliseconds in the logic would be nice, but it is what it is.

Maybe don't follow so close.

eep:

 

[philsey]

In a related note, how do you all feel about wet road performance of the stock Tera grapplers? Is there another AT option that's better? I realize I'm asking for pig that flies but I figured someone may have upgraded tires and found something with better on road performance while still maintaining some AT capabilities.

Dude, AT means ALL terrain. Nothing does "all" well, meaning that everything is a compromise.

I recommend you visit your nearby Michelin dealer and inquire into the LTX.

 

[GB-man]

Dude, AT means ALL terrain. Nothing does "all" well, meaning that everything is a compromise.

I recommend you visit your nearby Michelin dealer and inquire into the LTX.

Thanks I was hoping to get feedback from someone who has run the stock pro tires and switched.

 

[S54MCoupe]

The first time the emergency brake assist came on I almost shit my pants. Never had a vehicle with that wonderful feature before. If you're "locking up" the brakes, I'm guessing you're activating that feature. I will say that I'm not very impressed with the stock terra grapplers in the rain. I haven't had an issue braking yet, but from a stop in the rain I've just sat there spinning tires before.

 

[GB-man]

The first time the emergency brake assist came on I almost shit my pants. Never had a vehicle with that wonderful feature before. If you're "locking up" the brakes, I'm guessing you're activating that feature. I will say that I'm not very impressed with the stock terra grapplers in the rain. I haven't had an issue braking yet, but from a stop in the rain I've just sat there spinning tires before.

Yeah I've also had some wheel spin on wet pavement. They were so bad in the snow I ordered blizzaks after sliding 20 feet past a stop sign! And before people flame me, I'm very experienced driving in the snow. I live in Buffalo for Christ sake!

 

[JSparky]

I think that for all of you who are reporting that your brakes are "locking", you have posted misleading information. I hope you mean that the anti-lock feature has engaged.

If your brakes are really LOCKING something is wrong with your truck.

Please read [MENTION=120701]Cymon[/MENTION] 's post. The 4R has some logic which senses the time of transitioning from "off-accelerator" to "on the brake pedal", aka emergency brake assist (I think).

It is sensitive. We've all encountered it. Me twice. It does scare you. You just have to learn it, nothing is wrong. A few more milliseconds in the logic would be nice, but it is what it is.

Maybe don't follow so close.

eep:

I second this, wheels should not be locking up. You're laying rubber down on the pavement frequently when braking? Take it to the dealer and have it investigated and consider performing a zero point calibration to ensure that the traction control system is set properly (easiest and cheapest starting point). I've wondered if Toyota calibrates the Pro's differently to compensate for the front lift or if they all roll off the assembly line the same.

 

[GB-man]

I second this, wheels should not be locking up. You're laying rubber down on the pavement frequently when braking? Take it to the dealer and have it investigated and consider performing a zero point calibration to ensure that the traction control system is set properly (easiest and cheapest starting point). I've wondered if Toyota calibrates the Pro's differently to compensate for the front lift or if they all roll off the assembly line the same.

For the record yes I believe the front tires have locked for a second or two but I'll have to test it in a controlled environment to confirm. If true, I'll ask my dealer to have a look.

Thanks

 

[philsey]

If pushed down too hard too quickly the break will sense "emergency breaking" and activate the breaking assist, which is likely what you are noticing......

Cymon, Cymon, Cymon.

:moony: