Different speed rated tyres - problems with traction control

[EllzJ]

Hello all,

So my traction control kicks in when driving on the motorway (generally over 50 mph) and when taking hard right turn bends. At times the ABS light also comes on but not so often.

I tried to resolve the problem by spacing the offside rear ABS sensor from the ABS ring using a 1mm washer last weekend, however that has not sorted the problem.

I've now found that the 'problem corner' has an odd tyre in that the speed rating is rated 'V' whereas the other 3 corners are all rated 'W'.

For context, I have 2 x Bridgestone Potenza run flat tyres (205 / 50 / R / 17 W) on the front.

& Goodyear tyres on the back - again 205 / 50 / R / 17 W (on the nearside rear) and V (on the offside rear).

Question is, could having two different speed rated tyres on the back be causing my traction control and ABS problems?

[RUSSELLM]

Very doubtful.

With the correct diagnostic equipment, get the car in the air, put it in drive, and read the speed sensor outputs.

Is my advice

[Dave.]

Granted this is a different car, but....

My Discovery 3 did the same after having an alignment done, something to do with the steering angle sensor calibration.

[Andy70]

Different rolling rotations of wheels could make a difference surely? for example if certain wheels are turning faster than other because the outer diameter differs from brand to brand then could that not mess up sensors? For example, I bought some new wheels for my old compact years ago, I took the old wheel off and chucked it next to the new one (all with tyres on of course), I noticed that the new wheels tyres were about half inch higher looking at them than the old ones... The tyres were EXACTLY the same profile, but I suppose different manufactures meant that there were differences, I was a bit stumped to be honest because half inch is a lot I would have thought. So basically are all of your wheels turning at different rates? just a stupid opinion.. The golden rule is always buy tyres in pairs so at least on each axle the tyres have the same treat etc, plus grip and braking predictability etc etc...

[gizlaroc]

It is not the fact you have different speed ratings, it is different tyres.


This has been discussed ad infinitum on the BMW forums over the last 20 years, no one will believe mismatched tyres can cause such issues, they change all sorts from suspension parts to abs sensors, and finally when all else fails they put matching tyres front and rear and.....BINGO!

Get matching tyres on the front and rear asap, as you have found out the car is constantly trying to correct itself, the issue is, as you may find out, you actually have very little grip. Not good.

[Ninja59]

As per above seen the same not just on BMW's but on MX5's different tyre tread patterns can cause all sorts of strange issues with handling and grip levels.

And similar to the above many owners changed multiple items, before thinking of the basics.

[EllzJ]

gizlaroc said:

It is not the fact you have different speed ratings, it is different tyres.


This has been discussed ad infinitum on the BMW forums over the last 20 years, no one will believe mismatched tyres can cause such issues, they change all sorts from suspension parts to abs sensors, and finally when all else fails they put matching tyres front and rear and.....BINGO!

Get matching tyres on the front and rear asap, as you have found out the car is constantly trying to correct itself, the issue is, as you may find out, you actually have very little grip. Not good.

Thanks for your response on this. I'm hoping it is my tyres that are causing the problem. However the issue only developed a week or so later, so this could be purely co-incidental.

I'm going to replace the tyres this weekend and hopefully that gives me some luck! Just to clarify, I should have matching tyres on the front and back i.e. all 4 corners should be the same?

[EllzJ]

Thank you all for your responses on this - it has been very helpful

[gizlaroc]

EllzJ said:

Thanks for your response on this. I'm hoping it is my tyres that are causing the problem. However the issue only developed a week or so later, so this could be purely co-incidental.

I'm going to replace the tyres this weekend and hopefully that gives me some luck! Just to clarify, I should have matching tyres on the front and back i.e. all 4 corners should be the same?

Yeah, all 4 the same.

BMWs seem to be the worst for it.


It should be really hard to get the traction light to flash on BMWs, even when it is damp, one of the easiest ways to tell if having different tyres front and rear axle is causing issues with overall handling and grip is if you see the traction light come on pulling out of fast junctions, damp roundabouts etc.
Traction light should be a very, very rare thing to see flash. Of course with an M5/6 or mapped 440i you may see it a bit as standard but not on most cars. My mapped 530d (320hp) struggles to get the traction light on, even when trying to provoke it in the wet.

Some different tyres front and rear can be fine and work together, but more often than not it is degrading the handling, sometimes in an extraordinary manner.

[gizlaroc]

Having said all that.

Not sure if it is that in your case.


Is it definitely happening at 50mph?

Or is it happing when going straight for a certain time?


What if you are doing 50mph on a sweeping corner?

Steering angle/yaw sensors are known to fail on certain BMWs which would cause your issues.




You have checked all abs sensors and rings?



I would first try going 50mpg on a long sweeping corner, sweeping left and right and see what happens.




Have you got two different Goodyear tyres on the rear axle?

[EllzJ]

gizlaroc said:

Having said all that.

Not sure if it is that in your case.


Is it definitely happening at 50mph?

Or is it happing when going straight for a certain time?


What if you are doing 50mph on a sweeping corner?

Steering angle/yaw sensors are known to fail on certain BMWs which would cause your issues.




You have checked all abs sensors and rings?



I would first try going 50mpg on a long sweeping corner, sweeping left and right and see what happens.




Have you got two different Goodyear tyres on the rear axle?

It seems to happen when doing over 50 mph on the motorway, going around hard right bends and sometimes when there is an incline on a road/motorway.

The code reader indicates that the offside rear seems to be the problem, which coincidentally, or not, is the tyre that is the 'odd one out' from the other three.

& Yup two different speed rated Goodyear tyres on the rear axle.

I'll need to get that sorted anyway, as I don't want to invalidate my insurance. Failng that I will replace the ABS sensor and rings. What are the YAW sensors you refer to?

Again appreciate you taking the time to respond to this!

[gizlaroc]

EllzJ said:

It seems to happen when doing over 50 mph on the motorway, going around hard right bends and sometimes when there is an incline on a road/motorway.

The code reader indicates that the offside rear seems to be the problem, which coincidentally, or not, is the tyre that is the 'odd one out' from the other three.

& Yup two different speed rated Goodyear tyres on the rear axle.

I'll need to get that sorted anyway, as I don't want to invalidate my insurance. Failng that I will replace the ABS sensor and rings. What are the YAW sensors you refer to?

Again appreciate you taking the time to respond to this!

You keep saying different speed rating.

Is it the same model tyre? Not brand, but model?



Look up yaw sensor on google, and steering angle sensor.


Also, what car have you got? That would help.


Have you had any work done recently?
Some work requires the steering angle sensor, yaw sensor, and transverse acceleration sensors need to be calibrated afterwards. This would also cause the issue you are seeing.

It is worth getting the codes read. It could be the steering wheel has been off or control arms been replaced and the sensor is not reading straight ahead and just need resetting.

Edited by gizlaroc on Thursday 19th November 12:17

[Locknut]

Andy70 said:

... I took the old wheel off and chucked it next to the new one (all with tyres on of course), I noticed that the new wheels tyres were about half inch higher looking at them than the old ones... The tyres were EXACTLY the same profile...

Were there new tyres on the new wheels and worn tyres on the old wheels? A half inch is about 12mm which is what I would expect should be the difference between the worn and new tyres, that is 6mm worn off the tyre top and bottom.

(Hope I have not strayed too far from the main subject of the thread.)

Edited by Locknut on Thursday 19th November 22:58

[mckeann]

20 Years ago I fitted a different speed rating tyre when I was a poor apprentice and didn’t know the difference except one was cheaper. The car was FWD and the tyre was on the front. It would pull to one side when I accelerated hard, the only difference was the speed rating.

[MajorBeef]

EllzJ said:

Thanks for your response on this. I'm hoping it is my tyres that are causing the problem. However the issue only developed a week or so later, so this could be purely co-incidental.

I'm going to replace the tyres this weekend and hopefully that gives me some luck! Just to clarify, I should have matching tyres on the front and back i.e. all 4 corners should be the same?

If I have read your initial post right, you don’t have run flats on the rear correct?
I had this issue when phasing out my Michelin pilot super sport. I put PS4 on the rear but the fronts were still half worn so I left them. That meant, soft side walled, road orientated rears with very stiff side walled fronts, a bit like your set up unless I’m mistaken.

This sent the TC all over the place, the handling was awful and the car was unpredictable. As soon as I matched all 4 to PS4 it was perfect again.

[Andy70]

Locknut said:

Andy70 said:

... I took the old wheel off and chucked it next to the new one (all with tyres on of course), I noticed that the new wheels tyres were about half inch higher looking at them than the old ones... The tyres were EXACTLY the same profile...

Were there new tyres on the new wheels and worn tyres on the old wheels? A half inch is about 12mm which is what I would expect should be the difference between the worn and new tyres, that is 6mm worn off the tyre top and bottom.

(Hope I have not strayed too far from the main subject of the thread.)

Edited by Locknut on Thursday 19th November 22:58

both had used tyres on but tread depth was the same give or take a mm ish, I just put it down to different tolerances between manufactures, I was staggered because that means the diff would be under stress all the time as 1 wheel is spinning faster than the other. I wish I took a picture now