New tyres Fitted - Steering feels vague on the straight ahead.

[rickyclean]

Hello all

I have had all the tyres now replaced and since this the steering has been rather vague. Last week I replaced the front tyres and the car seemed totally fine and steering as normal. Yesterday I drove the car to the tyre specialist near my offices in Guildford (an hours drive across B and A roads as well as the M25) and the car felt fine. Dropped the car off and asked the technician to also do a full wheel alignment check and make the appropriate adjustments if needed. When I picked up the car and was told that only a very minor adjustment was needed on the front near side wheel so did the adjustment and did not charge me for it. The drive back to my office is only a mile so not really conducive to a thorough test, but later that evening I drove the car home and noticed on the motorway at 80 mph the steering was vague on the straight ahead with a bit of play in the wheel. Could the alignment have been done badly or is it the new tyres are causing the effect. I have done a like for like tyre replacement so a little flummoxed by this one... Any thoughts Peeps

Tyres are Continental Cross Contact UPH SSR (Fun flats) and are 255/50R19 V111 fronts and 285/45R19 W111 rears.

Thanks

RC

[sid10]

are they different speed ratings front to back could be different tread patterns ?

[X5Sport]

Certainly reads like that.  Not a good idea.

Are the tyre pressures correct?

[Graeme]

It certainly sounds strange.  I've never seen 255x50x19 rated at 111 - they're usually weight rated at 103 and 107 -and speed rated at H, V or W.  Mine requires 255 x 50 x19 107 V or W for the fronts.

Are the tyres the same pattern front and rear - for example on Campskill's site they offer Continental  conti-cross-contact, conti-cross-contact LX sport (H rated only) and Conti-sport-contact.

If you're unhappy check the pressures given on the plate on the drivers door pillar (mine are 2.1 bar front and 2.3 bar rear for 2-4 passengers) and if still not right best go back to the tyre supplier ASAP.

Graeme

[Pete]

Daft question but, they've not done something wacky like fitted the wider alloys with the 255 50 19 tyres and put them on the front have they?

[Mpower]

[quote="Pete"]
Daft question but, they've not done something wacky like fitted the wider alloys with the 255 50 19 tyres and put them on the front have they?
[/quote]

Wouldn't surprise me nowadays with so called "techs"[emoji851]

[celica]

Are they directional or assymetric put on the wrong way?

[rickyclean]

Morning all

Many thanks for all the replies, I'll try and answer them in order.

• Just to confirm the tyres are Continental Cross Contact UPH SSR (Fun flats) and are 255/50R19 V107 fronts and 285/45R19 W111 rears and BMW specific. Graeme as always well spotted I made a mistake with the fronts! 
• The fronts were fitted last week and the rear this week so I don't think the tyres would have been swapped round
• I need to look and make sure the rears were put in the right direction as the behaviour of the car changed once the rears were put on so good call Celica
• I haven't checked if the tread patterns match exactly, but on a previous post of mine the advice was that having W speed rating at the back and V rating at the front should not affect the car as I am not fitting a different tyre type
• I will also look at the tyre pressure tonight as well

I'll keep you posted and thanks again for all the advice

RC

[rickyclean]

[quote="rickyclean"]
Morning all

Many thanks for all the replies, I'll try and answer them in order.

• Just to confirm the tyres are Continental Cross Contact UPH SSR (Fun flats) and are 255/50R19 V107 fronts and 285/45R19 W111 rears and BMW specific. Graeme as always well spotted I made a mistake with the fronts! 
• The fronts were fitted last week and the rear this week so I don't think the tyres would have been swapped round
• I need to look and make sure the rears were put in the right direction as the behaviour of the car changed once the rears were put on so good call Celica
• I haven't checked if the tread patterns match exactly, but on a previous post of mine the advice was that having W speed rating at the back and V rating at the front should not affect the car as I am not fitting a different tyre type
• I will also look at the tyre pressure tonight as well

I'll keep you posted and thanks again for all the advice

RC
[/quote]

So I checked the tyre pressures on Friday using my tyre gauge. The car should be se to 2.1 bar at the front and 2.3 Bar at the rear.

The front nearside was set to 2.5 and the front off side 2.6 and the rears were both 2.7... To be sure I went to a petrol station to use their pump and got the same readings. I reset the tyres to the correct pressures, but yet to be able to go on the motorway to check if this has made the difference. Would this over inflation caused such a drastic change in the steering?

Thanks all

RC

[X5Sport]

It certainly won't help as the contact patches will be different and uneven pressures across axles.

[graemeX5]

Hi

I am pretty sur you have hit on the answer with having over inflated tyres would give you a floating and vague feeling on the road which is odd given the tyre place only recently fitted both sets to your car.

Also it's worth bearing in mind as the tyres warm up the air pressure increasesso you need to check them when cold and that is why racing teams use nitrogen to keep a constant pressure.

I know some tyre garages use nitrogen as well and that could help keep them more consistent.

[X5Sport]

The key bit with Nitrogen is it must be dry.  Tests run by 5th gear recently showed no difference or improvement using Nitrogen unless it is dried first.  Air is something like 78% Nitrogen after all.