Warning light after new tyres

[Aparoon]

Fitted some Vredestein tyres to the fron of my car the other day, they are 235 40 18, since then the light has been on the dash (looks like a U with a ! mark in the middle)

Anybody know why this is? I thought maybe the different tyre size is tricking the sensor or whatever it is 

[NEWEY]

have you held down the tyre monitor button to reset them? as if there has been a change in tread depth etc it will cause it to come up!

[Phil Mcavity]

Fitted some Vredestein tyres to the fron of my car the other day, they are 235 40 18, since then the light has been on the dash (looks like a U with a ! mark in the middle)

Anybody know why this is? I thought maybe the different tyre size is tricking the sensor or whatever it is 

Any thoughts of the tyres thus far ??

[Aparoon]

Im finding them very good, im still getting a bit of spin when flooring it but it hasnt been dry since i fitted them... they do feel lots better in the bends 

I have pressed the button and the light goes off and then instantly comes back on? Is there a recommended tyre pressure for this size tyre?

[gillm]

pressures are on the fuel flap and you need to press and hold the button down , i think it will chime

[Aparoon]

Cheers 

Are the tyre pressures on the fuel cap not just for the 225's?

[bacillus]

If your rear tyres are 225/40/18 then your problem is the rolling circumference of the front and rear tyres are different and the ABS sensors will pick the difference up and light up your dash.

Only solution is to use tyres of similiar spec all round.

[Aparoon]

Ok, is there any other issue with running different front and rear other than the light??

[john_o]

there are no 'sensors' as such , its done by rotational differences detected thru the ABS setup..

have you pressed and held the button til it 'boings' ?

you are 2.5% out in rolling radius (2 on front versus 2 on back) which the car may detect as a low pressure .........
but its should be within tolerance not to trigger it.
Better to run the same size all round though.

try a few miles then reset again.

or in the process of fitting the tyres a sensors been damaged is an outside possibility too

John

edit : bacillus just posted the same thing 

[bacillus]

Ok, is there any other issue with running different front and rear other than the light??

I don't think so but I would wait for someone with more intimate knowledge give you a definitive answer.

[john_o]

im not more knowledgeable but I would expect it to effect your ESP trigger levels to some extent

[Aparoon]

Thanks for the replies, traction controlisnt a problem as i turn it off anyway, i will give it a few more miles and try and reset it 

[RedRobin]

Ok, is there any other issue with running different front and rear other than the light??

I don't think so but I would wait for someone with more intimate knowledge give you a definitive answer.

....No comment about me being intimate with black rubber, but yes, there is another potential issue:

According to what the front/rear axle tyre differences are, the ESP may randomly kick in as it thinks that the car is about to skid or similar and steps in to 'help' you. What initiates this is factors such as tyre wall differences in stiffness. Having directionals on the front and assymetrics on the rear is what gave me some scary moments until I learnt what it was and then I just ignored it and drove through it until I was ready for replacing the directional tyres.

So, Aparoon, your idea of "tricking the sensor" is correct.

HTH

[Aparoon]

Yes that help Robin thanks, I'll put up with it untill I can justify some more tyres  £££££