[FieldingMellish]

I have noticed, on sections of motorways that have that rough surface texture, it's very hard to hold my new car straight, the steering wheel won't sit centred, I constantly have to make slight adjustments right and left. Don't remember my 320d doing that. Maybe a tyre issue? I'm assuming the wheels are aligned right, since I only got the car from the dealer 2 days ago?

[Boyd1963]

Originally Posted by FieldingMellish

I have noticed, on sections of motorways that have that rough surface texture, it's very hard to hold my new car straight, the steering wheel won't sit centred, I constantly have to make slight adjustments right and left. Don't remember my 320d doing that. Maybe a tyre issue? I'm assuming the wheels are aligned right, since I only got the car from the dealer 2 days ago?

You've bought a duffer mate. I would suggest that you drive it down to Bournemouth and I will swap it for my 320i no questions asked

It may just you being hyper sensitive as it's a new car.

[m1bjr]

Plenty of cars come from the factory badly aligned.
Get it looked at.

You said in another thread you might have a mix of brands on there.
For sure that can cause odd feelings on some cars, as they warm up at different rates (pressures vary)

[FieldingMellish]

Originally Posted by m1bjr

Plenty of cars come from the factory badly aligned.
Get it looked at.

You said in another thread you might have a mix of brands on there.
For sure that can cause odd feelings on some cars, as they warm up at different rates (pressures vary)

I'll need to check more closely. Certainly the dealer told me they had replaced a tyre as part of MOTing and refurbing the car. And I'm guessing it's the left rear as it looks new and seems to make more noise when running over road markings etc.

[parapaul]

I'll second both of those points: tyres - pressure, brand and wear AND alignment.

[SO8]

BMW's with RFT's and even with non RFT's are far twitchier at speed in my experience than any other car I have driven ....

That said - as has been mentioned all of the above need checking ... pressure, balance, makes, alignment, etc ...

[xenon]

tramlining

[FieldingMellish]

Originally Posted by xenon

tramlining

Doesn't feel like tramlining, tbh. I find tramlining produces more movement, but less force. This is as if the steering wheel is being forced a tiny bit left, then a tiny bit right, then a tiny bit left, then a tiny bit right, etc. Only seems to happen on those reddish rough motorway surfaces, at high speed. On normal roads the alignment feels fine.

[m1bjr]

You are lucky to reach such speeds.

I just crawled back to Somerset with all the other emmits (muryons).

[Dr Dave]

You sure you aren't driving in the ruts in lanes 1

[Em135eye]

Get it laser aligned, ditch RFTs if you have them.

A dealer won't align them unless you pay for it.

[chris_s1]

Do you still have the same width of tyre as before? Even a small change in tyre width can make tramlining much more pronounced

[FieldingMellish]

Yes I think I have pretty much the same tyres as before. Never noticed this phenomenon before - it's like I absolutely cannot hold the steering wheel still, it keeps going very slightly left then very slightly right etc...

[gIzzE]

That sounds exactly like a BMW with different tyres front and rear, constant corrections to the steering.
Does the back end feel as planted as the old car when pressing on??

[FieldingMellish]

Originally Posted by gIzzE

That sounds exactly like a BMW with different tyres front and rear, constant corrections to the steering.
Does the back end feel as planted as the old car when pressing on??

Very difficult to compare but yes I would say so. Tyres all seem to be same type tbf, and I have only encountered this problem on rough motorway surfaces at high-ish speeds.

If my alignment was off, or I had a steering problem, surely I would notice more symptoms?

Possible, as someone said, that I'm just being hyper sensitive.

[FieldingMellish]

Originally Posted by Dr Dave

You sure you aren't driving in the ruts in lanes 1

Pretty sure.

Will go for a run later and pay close attention.

[gIzzE]

Have a play with the pressures, make sure you set them when hot, and stick to the low end of the scale, so car unlaiden and under 210kmph.

The geometry could still be out and cause this, just that they could all be out equally so this is the only symptom, the M3 CSL used to feel a bit the same so many would use slightly more aggressive settings to make it feel a lot more planted, however it then wore the inside of the tyres a lot quicker.

[FieldingMellish]

Well, I checked my tyre pressures. Surprising results, to say the least.

I had decided to try them at 36 Front, 40 rear.

Here's where they were when I tested them:

Fronts were 41 and 39
Rears were 37 and 38

What's up with that? Random pressures. All different, and the fronts higher than teh rears???

Anyway adjusted them to 36/40 and tried a run on the roughest motorway surface. Didn't encounter the 'cannot steer straight' problem at all.

Bit odd that the dealer would have issued me a car with those weird pressure ratings, eh?

[SO8]

2 psi out in tyres can be down to the amount of air escaping as you put the hose on the tyre or take it off .... or just being checked too quickly .... but the back ones lower than the front - not clever on a 3 series..

To make you feel better I bought a 3 series a month ago where all four tyres were different by up to 8 psi .... from a BMW dealer !!

Glad it drives better now you have corrected it.

[parapaul]

Originally Posted by gIzzE

Have a play with the pressures, make sure you set them when hot, and stick to the low end of the scale, so car unlaiden and under 210kmph.

Out of interest, why? I get the impression from your other posts that you know what you're talking about, but the standard instruction is to check them when cold so I'm genuinely interested.

I know for track cars that they set the pressures when hot, but I'm not entirely sure why.

[gIzzE]

Because I have found that when cold sometimes the side that has been sat in sunlight can be up to 3psi more than the ones in the shade, so I would rather fill them up when you know all are hot.

Most door stickers will say +3 or 4psi if setting hot, so just add it on.

[FieldingMellish]

Originally Posted by gIzzE

Because I have found that when cold sometimes the side that has been sat in sunlight can be up to 3psi more than the ones in the shade, so I would rather fill them up when you know all are hot.

Most door stickers will say +3 or 4psi if setting hot, so just add it on.

Good tip.

What do you make of the dealer sending a car out the door with tyre pressures higher on the front than the back?