Car pulls way left all the time?

mikey72

GolfBravo wrote: »

Unfortunately there are not many knowledgable tyre places. I got a new set of tyres last month, and it was the first time ever that the garage took particular attention to tyre runout lines and weight mark dots, and spot on balance - the end result is a super smooth ride.

First thing you should definitely check the tyre runout lines on your tyres - if both front tyres have runout lines to one side the car will definitely pull to that side. Also, if they are directional tyres, make sure they are facing the right way. Obviously, any OUTSIDE signs should be facing the outside.

Runout is a good suggestion.

Explanation here, and on the link they quote.

http://www.wheels-inmotion.co.uk/forum/index.php?showtopic=165

Tetley_the_Cat

This is known as Ply Residual Angle Torque (PRAT as it happens) and is extreamley rare. More common is conicity imbalance however the fact it has been lowered will be a massive factor, hence my last post.

mikey72

Tetley_the_Cat wrote: »

This is known as Ply Residual Angle Torque (PRAT as it happens) and is extreamley rare. More common is conicity imbalance however the fact it has been lowered will be a massive factor, hence my last post.

Conicity imbalance, and ply residual angle torque will change with the tyres, and as the op has said it happened since he changed the tyres, and as swapping them around is an easy test, it's better than trying to work out the suspension geometry which the op hasn't said when was changed, and could have been fine on the last set.

edit - We need more information on if it ever ran straight, and what's been changed when,and when it started pulling, as we've both read this thread differently.

Tetley_the_Cat

mikey72 wrote: »

Conicity imbalance, and ply residual angle torque will change with the tyres, and as the op has said it happened since he changed the tyres, and as swapping them around is an easy test,

Which I believe I said earlier. There is a set process which few garages and or tyre places carry out. They all believe front axle toe causes pull drift issues and this is fundamentaly wrong. To cause pull/drift by the front axle means setting the individual toe values to such extremes that the tyes would wear out in dozens of miles and make the car uncontrollable.

We don't know the car but I can catagorically state that if the ride height is changed outside of the manufactuers specs then it will affect the camber angles and thus the toe settings. This in turn affects the directional force placed on the car from the rear and thus means the toe needs correcting let alone the correction factor for the front toe and camber.

Tyres can play a part but tolerances today mean it is rare. Conicity issues are common where and because of the sensitivity of cars now to pull drift issues, tyres should be banded into ranges so that two tyres are fitted onto the same axle within the same tolerance band.

PRAT is getting into the very fine details of pull drift issues and will probably only come into play in place like the USA with very long, relatively flat straight roads.

mikey72

Let's keep it simple then.

If it was ok on the previous tyres, and isn't now, swap the tyres around, and check the colour bands.

If it was ok lowered before, it still is now.
If it's just been lowered, it may have changed.

I've a shortened, lightened, raised car, the back wheels have a positive camber you wouldn't believe. The Ackermann geometry is way off. It doesn't pull or drift, on standard toe settings.

Joe_Horner

It's been mentioned early on but then seems to have been forgotten as things start getting (possibly over-) technical. Brakes are one of the most common reasons for a pull - a partially seized caliper, wheel cylinder or handbrake linkage will all produce a pull, often without giving any other obvious symptom.

Seeing as the OP suggests that this happened since a tyre change it's unlikely (though not impossible) that it's a suspension or alignment problem but start with the easy and free checks first:

Tyre pressures

Tyre direction (if they're directional)

Swap front - rear on one side. Very occasionally you'll find tyres that simply don't like being on the same axle as each other. No idea why, but it does happen. By swapping one side only you create two new "pairings".

While it's jacked up, spin each wheel to check for brake drag. If it's pulling left then you're looking for a tight brake on one of the left wheels. If the steering wheel turns sharply left when you let go of it look especially at the FRONT left wheel. If the car swerves left but the steering wheel doesn't move, or only moves a little, look closely at the rear left.

If none of the above identify the problem then start looking at alignment. As Tetley says, it won't be a front toe problem because that will tend to make the car either very heavy to steer or stupidly twitchy / wandering long before it creates a pull. Similarly, steering linkage or bearing problems will normally make the car wander rather than a definite pull in one direction.

Rear alignment WILL cause a pull but is unlikely to have changed as a result of a tyre change!

Tetley_the_Cat

mikey72 wrote: »

Let's keep it simple then.

If it was ok on the previous tyres, and isn't now, swap the tyres around, and check the colour bands.

If it was ok lowered before, it still is now.
If it's just been lowered, it may have changed.

I've a shortened, lightened, raised car, the back wheels have a positive camber you wouldn't believe. The Ackermann geometry is way off. It doesn't pull or drift, on standard toe settings.

That because root cause of pull drift is driven from rear!

mikey72

Tetley_the_Cat wrote: »

That because root cause of pull drift is driven from rear!

That's why I said back wheels to suit your scenario.

You haven't mentioned caster on the front.

Tetley_the_Cat

Joe_Horner wrote: »

It's been mentioned early on but then seems to have been forgotten as things start getting (possibly over-) technical. Brakes are one of the most common reasons for a pull - a partially seized caliper, wheel cylinder or handbrake linkage will all produce a pull, often without giving any other obvious symptom.

Seeing as the OP suggests that this happened since a tyre change it's unlikely (though not impossible) that it's a suspension or alignment problem but start with the easy and free checks first:

Tyre pressures

Tyre direction (if they're directional)

Swap front - rear on one side. Very occasionally you'll find tyres that simply don't like being on the same axle as each other. No idea why, but it does happen. By swapping one side only you create two new "pairings".

While it's jacked up, spin each wheel to check for brake drag. If it's pulling left then you're looking for a tight brake on one of the left wheels. If the steering wheel turns sharply left when you let go of it look especially at the FRONT left wheel. If the car swerves left but the steering wheel doesn't move, or only moves a little, look closely at the rear left.

If none of the above identify the problem then start looking at alignment. As Tetley says, it won't be a front toe problem because that will tend to make the car either very heavy to steer or stupidly twitchy / wandering long before it creates a pull. Similarly, steering linkage or bearing problems will normally make the car wander rather than a definite pull in one direction.

Rear alignment WILL cause a pull but is unlikely to have changed as a result of a tyre change!

This is what I have been getting at. One needs to go through a set process to get to the root cause. What frustrates this issue is that the car has been moved away from spec by being lowered. Now whilst front toe has no effect on pull drift the mear fact that the car has been lowered and I think I pointed this out very easrly on will have or could have a major effect.
Whilst it has been said it is only since new tyres were fitted this is irrelevant as it does not matter when or what was fitted, you still have to go through the same process to determine what the cause is!

You can lighten, shorten, raise heights have extreame Ackermann angles and positive camber on the rear, it does not mean it is right or that the car will handle corrctly or as designed to do so.

The clue as is said, is with new tyres but I interpreted the post as always being there.

Frankly get rid of the reduced ride height, set the car and if you still feel it needs a revised height let me know. You can get the same effect as regards handling by optimising the spring and damper ratios etc without having to rely on lowering kits.

mikey72

Tetley_the_Cat wrote: »

You can lighten, shorten, raise heights have extreame Ackermann angles and positive camber on the rear, it does not mean it is right or that the car will handle corrctly or as designed to do so.

The clue as is said, is with new tyres but I interpreted the post as always being there.

Frankly get rid of the reduced ride height, set the car and if you still feel it needs a revised height let me know. You can get the same effect as regards handling by optimising the spring and damper ratios etc without having to rely on lowering kits.

No one has said it's the right thing to do, it's just odd that doing exactly the same to both sides, changing the height and altering the camber equally, will cause an unequal difference to toe that will cause pull enough to be noticable and consistent in one direction, on a car that was originally correct.
And may not have any adjustment on the back wheels.


Pull/push drift would be more noticable on acceleration/deceleration as well, and the op hasn't siad that.