Random Pulls When Driving In A Straight Line

[bashdem]

Hi everyone

Getting used to driving my Lexus now but I have noticed something that I'm not sure is a problem or not.

When driving in a straight line at say above 50mph I notice very slight but firm pulls in the steering wheel causing me to sway within my lane. It has been windy lately but no gale force winds. The steering is heavier than my previous car when cornering but when these slight pulls occur the steering feels very light.

Any ideas what this could be?

Cheers!

Greg

[kam05]

Do a search on the IS forums for 'geometry' and 'Wheels-in-Motion'

You will be answered.

Are the tyres over/underflated? Could be something simple as this?

[Spoony]

Hi everyone

Getting used to driving my Lexus now but I have noticed something that I'm not sure is a problem or not.

When driving in a straight line at say above 50mph I notice very slight but firm pulls in the steering wheel causing me to sway within my lane. It has been windy lately but no gale force winds. The steering is heavier than my previous car when cornering but when these slight pulls occur the steering feels very light.

Any ideas what this could be?

Cheers!

Greg

Is it definately the front end that shifts and not the back end when going over grooves in the road or thick line paintings?

I had this issue and it ended up being a set of Dunlops on the back. They were close to needing replacement so I purchased a new set of dunlops, only to have the same problem. Put the Pirellis from the front on the back (and vice-versa) and the problem vanished. I will not be buying any more dunlops.

[bashdem]

Already read about WIM - thanks though kam05!

The dealer I bought the car from said he had to replace the front tyres before selling it due to uneven wear - I knew I'd be visiting WIM before I even bought the car :winky:

As for the tyres...yep, Dunlops all round (not sure the exact type - will check later)...and I suspect one of the rear tyres has a slow puncture. I'll try the spare and see how I get on.

Although, this is not really limited to driving over lines or bumps. On a smooth motorway staying in lane I still get the swerve/drift.

Thanks for your reponse Spoony - if I need new tyres I'll steer away from the Dunnys.

[Hando]

Hi everyone

Getting used to driving my Lexus now but I have noticed something that I'm not sure is a problem or not.

When driving in a straight line at say above 50mph I notice very slight but firm pulls in the steering wheel causing me to sway within my lane. It has been windy lately but no gale force winds. The steering is heavier than my previous car when cornering but when these slight pulls occur the steering feels very light.

Any ideas what this could be?

Cheers!

Greg

Tramlining?

[c4shr]

I would definitely think it is the tyres, my car was doing the same and then the judder came in at high speed.

Having changed all four tyres, the problem is resolved. Ive had Bridgestone Potenzas and Dunlop SP's - I dont rate them at all. Opted for Falken FK452's from Camskill.co.uk (£60 a piece), they are absolutely brilliant on both wet and dry conditions. They look the business too!

Check you front tyres, inner tread wearing quicker than outer will mean that your geometry needs to be set.

[bashdem]

Do a search on the IS forums for 'geometry' and 'Wheels-in-Motion'

You will be answered.

Are the tyres over/underflated? Could be something simple as this?

Topped them all up to 33psi and still the same.

[kam05]

try 35psi

[Spoony]

Already read about WIM - thanks though kam05!

The dealer I bought the car from said he had to replace the front tyres before selling it due to uneven wear - I knew I'd be visiting WIM before I even bought the car :winky:

As for the tyres...yep, Dunlops all round (not sure the exact type - will check later)...and I suspect one of the rear tyres has a slow puncture. I'll try the spare and see how I get on.

Although, this is not really limited to driving over lines or bumps. On a smooth motorway staying in lane I still get the swerve/drift.

Thanks for your reponse Spoony - if I need new tyres I'll steer away from the Dunnys.

The Dunlop 9000 SP (I think) were the recommened tyre by Lexus, which is why I bought another set. I would have put money on a brand new pair of tyres not being the problem but tried it anyway and it worked!

I had my problem when driving straight, like you said. Felt like a big gust of wind as the car suddendly lurched a foot to the left or right. Very unnerving too - I thought I had massisve suspension problems or similar! The problem was a lot more noticable/predictable when traversing ruts/grooves and thick painted lines.

Pirelli's did the job good. Not cheap tho.

[kam05]

Already read about WIM - thanks though kam05!

The dealer I bought the car from said he had to replace the front tyres before selling it due to uneven wear - I knew I'd be visiting WIM before I even bought the car :winky:

As for the tyres...yep, Dunlops all round (not sure the exact type - will check later)...and I suspect one of the rear tyres has a slow puncture. I'll try the spare and see how I get on.

Although, this is not really limited to driving over lines or bumps. On a smooth motorway staying in lane I still get the swerve/drift.

Thanks for your reponse Spoony - if I need new tyres I'll steer away from the Dunnys.

The Dunlop 9000 SP (I think) were the recommened tyre by Lexus, which is why I bought another set. I would have put money on a brand new pair of tyres not being the problem but tried it anyway and it worked!

I had my problem when driving straight, like you said. Felt like a big gust of wind as the car suddendly lurched a foot to the left or right. Very unnerving too - I thought I had massisve suspension problems or similar! The problem was a lot more noticable/predictable when traversing ruts/grooves and thick painted lines.

Pirelli's did the job good. Not cheap tho.

There were/are two different versions of the Dunlop SP9000 tyre, the ones made in Japan (they are called SP9000L) are designed for the IS200/300, where as the normal SP9000's are made in Germany and not designed for the IS200/300. I read this on LOC when I first joined.

[bashdem]

Just checked the tyres...

Bridgestone Potenza RE050 on the front

Dunlop SP9000 on the back

Any recommendations if I am to replace these? I think one of the Dunlops may have a slow puncture and they dont seem to be recommended so should the Bridgestones go on the back with new ones on the front or vice versa?

Cheers