Strange bumping noise on full lock!

[MeLex]

Hi all. This problem just started out of the blue.... full service history well maintained lexus rx450h. On full steering lock, either direction, a very lumpy bumping coming from the passenger side front wheel. And I mean BUMP!. Felt like I was going over a pothole, yet no potholes.... Its one big bump per revolution. I tested it driving around, and I was absolutely certain I had a flat tire if I had never felt one before. Got out, looked, tire is fine. Cant see anything wrong from the outside. I did clump a kerb with that wheel about a week ago, not at high speed. But I checked it out, and its been fine since then. The steering is otherwise responsive and fine. Anybody help? Thanks!

[aterribleusername]

Usually a CV joint when it knocks on full lock.

[Mineral1]

Just as likely to be one of the control arm bushes.

[fiesta_STage3]

sounds daft but check your wheel nuts (on top of whatever good advice these forum lovelies give you). Hard earned experience…

[MeLex]

thanks for those suggestions.

[JohnnyUK]

Sure it's not the tyre skipping because of the castor and geometry on full lock?

Very common, esp. in the cold weather.

There's name for it, which escapes me, but I read about it on PH somewhere

[MeLex]

Thanks. I think a 'skipping' tire would feel different though? Like this is a real bump, precisely like going over a pot hole or a small brick. Only on absolute full lock (either way, same wheel), only once per revolution... so strange.

[GranpaB]

Cold hard tyres.

[Panamax]

Yup, don't let a bit of tyre scrub make you think there's anything wrong with the car. It's often just high speed stability vs low speed manoevering.

[trashbat]

JohnnyUK said:

Sure it's not the tyre skipping because of the castor and geometry on full lock?

Very common, esp. in the cold weather.

There's name for it, which escapes me, but I read about it on PH somewhere

Ackermann angles.

[Caddyshack]

trashbat said:

JohnnyUK said:

Sure it's not the tyre skipping because of the castor and geometry on full lock?

Very common, esp. in the cold weather.

There's name for it, which escapes me, but I read about it on PH somewhere

Ackermann angles.

I did wonder if it is this. My boxster does it but changing tyres seemed to help.

[JohnnyUK]

trashbat said:

JohnnyUK said:

Sure it's not the tyre skipping because of the castor and geometry on full lock?

Very common, esp. in the cold weather.

There's name for it, which escapes me, but I read about it on PH somewhere

Ackermann angles.

That's it!