nicros01

Hoping someone here has some insight into this one...

Every once in a while, I will go over a speed bump or some other type of kind of sharp bump and experience a very odd issue.

It feels as if the brakes have caught for a few seconds... just enough to slow the car down a bit and make the ride feel odd and a bit rough. I dont hear anything, but there is definitely something happening, and it doesnt feel good.

I suspect this happens at higher speeds as well, but it just makes the car feel a bit odd again, like the brake is lightly engaged.

It's not consistent at all... I have to drive over a speed bump on my way to work, and it happens then once out of every 5 or 10 times.

Totally vague I know, but in the off chance someone has experienced something like this in their q5 or has an idea I thought I would at least ask.

Thanks!

MP4.2+6.0

The old tire chirp off the speed bump, whether intended or not. If so, could be a momentary activation of ESP, which would kick in the brake on the relevant wheel to try to pull down the perceived wheel spin. Alternately maybe a wheel sensor is getting jarred and not reading correctly, though I would kind of expect a trouble light for that, and stored codes the dealer could read (or you if you have VAG COM).

Haven't seen it on the Q5 in any case.

nicros01

Not much of a chirp, more of a grinding

Doesnt sound good in any case... anyone else have any ideas?

stash64

I think the ESP suggestion makes a lot of sense. I've had this happen going over some big bumps with my A3, anywhere between 10-25 mph. As the front wheels lost grip coming off the ground, the brakes grabbed suddenly and created quite a thump and front end shudder. Freaked me out a little the first time it happened.

nicros01

Hmm, interesting... but when it happens with me it is more of a gentle grinding feel- I can feel it in the brakes, and when Im doing about 5mph. Nothing as drastic as what you describe, but still it might be that.

Next time I go to the mechanic I will let him know and see if he can track it down.

serranot

It sounds as though the ABS is engaging. Is it similar to the "grinding" or vibration when the ABS pump self-tests when you first drive off or when the ABS engages on ice or snow?

nicros01

Hmm, maybe... hard to say, I live in southern california... dont get much snow here

But I think I have felt it on trips to the snow and you may be right- Ill point that out to a mechanic.

Cheers!

Wunsch

Wait, is your foot *on* the brake pedal while going over the speed bump? That could definitely be a bit of ABS engagement, then, if the bump is enough that your tire is briefly not making solid contact with the ground. I've noticed that behaviour now and then. It feels odd, but it's perfectly normal and explainable.

nicros01

Yep sorry I think I wasnt clear- when I go over the bumps its quite slow, so there's not enough speed to get a chirp- and the grinding is much more subtle than that... I actually cant really feel the car slow down much, if at all.

When I said I feel it on the brake, Im not pushing down on the brake, just touching the pedal- and I can also feel it if Im on the gas pedal- again, not pushing down but just with my foot resting on it as I coast over the bump.

Dunno what it is.