Michelin Pilot Sport 4s

BraveSirRobin · Post by **BraveSirRobin** » Sat Oct 20, 2018 12:12 pm

Hi all, first time poster, long time lurker

Yesterday I put a pair of new Michelin PS4s tyres on the rear of my D4 to replace the Super Sports ...and immediately the car feels terrible! Really vague at the rear like itâ€™s not gripping properly and this is confirmed by the traction light flashing on the dash as I gently cruise around bends!! I thought initially that this might be because the tyres require a little running in but phoned the supplier and they said this is not the case. So I am thinking that the pressure is too high... theyâ€™re at 50psi (265 30 R20) which is a very small amount over the recommended 3.4 bar... but then I was running probably about 44psi with the older tyres. So has anyone else experienced this and what pressures are people running? Thanks! Paul

PhillV8S · Post by **PhillV8S** » Sat Oct 20, 2018 12:41 pm

Have a look at the recommended tyre pressures for your car. Itâ€™s on a sticker on the drivers side lower part of the B pillar on mine. 3.0bar for me with similar tyre size.
What model do you have? Nice to see a local owner (to me) on here.

BraveSirRobin · Post by **BraveSirRobin** » Sat Oct 20, 2018 1:46 pm

Hi, yes the recommended pressure is 3.4 bar which is 49 psi; thatâ€™s fully loaded though so probably need to drop a few psi as itâ€™s usually just me in the car. The Alpina manual supplement does recommend pressures for driver only (lightly loaded) but they are for the 19 inch wheels only not the 20s I have on the car. The car is a D4 no.44 Estoril Blue, which Iâ€™ve had since about April... how about you? ...will keep my eyes peeled

D3orbust · Post by **D3orbust** » Sat Oct 20, 2018 4:13 pm

From experience I would lower the tyre pressure, and I don't what it's like down your way but the temp up here in the NE was 7c yesterday which made my D5 a little skittish as well.

rc944 · Post by **rc944** » Sat Oct 20, 2018 5:40 pm

regardless of what the supplier says all tyres need to be scrubbed and michelin would confirm the same. i would say its a combination of weather, newness and, to a lesser extent, pressure.

my ps4s felt pants at first but now with a few hundred miles under them they feel fine

Express Andy · Post by **Express Andy** » Sat Oct 20, 2018 7:48 pm

Hi I agree with whatâ€™s been said tyres have relase agent and oils in them which comeâ€™s out over the life of the tyre. They need running to clear initial excess.
Tyre pressures make a big difference and climatic conditionâ€™s. I spoke to toyo uk in the past as I had a 205 gti but had the mi16 engine in which is heavier than the 1.6. They got me to weigh the car then gave me optimum tyre pressures for the weight and different pressures for different temperature range.
I also do trips to NÃ¼rburg ring and know if I forget to change tyre pressures as I get to the end of lap the car gets awfully twitchy and feels like its on marbles. Hope this helps

BraveSirRobin · Post by **BraveSirRobin** » Sat Oct 20, 2018 9:45 pm

Thanks for all your replies. I dropped the pressure by 5psi (now 46psi) this afternoon and went for a drive. It didnâ€™t really make any difference; the back end of the car still feels very vague and wayward! The traction control light seems to flash on particularly when coasting round downhill bends. Iâ€™m reassured that this will be fixed after the tyres have been scrubbed in ...also reassured by the fact that the Michelin.com site mentions a 30 day satisfaction guarantee (no mention of that on the .co.uk site though!). Anyway Iâ€™ll put some more miles on them and report back. Thanks again!

Express Andy · Post by **Express Andy** » Sat Oct 20, 2018 9:55 pm

Hi it concerns me that traction light flashes when coasting down hill that sounds very strange. So it doesnâ€™t flash when on power just coasting ?

BraveSirRobin · Post by **BraveSirRobin** » Sat Oct 20, 2018 10:55 pm

It doesnâ€™t flash in a straight line under power, although I havenâ€™t used full throttle. Iâ€™ve been driving quite tentatively round corners although giving it some power on the exit on the way home this evening and didnâ€™t flash on most corners... but it seems particularly bad on downhill bends where it will flash even when coasting and not going particularly quickly ...perhaps because the rear end is lighter and the wheels not under load? ...and also on smooth tarmac. It was even lighting up when going in a straight line over some bumpy tarmac this morning with very little throttle. Iâ€™m really surprised how bad it is and overall how bad the car is handling... night and day different compared to when it had the old worn tyres on!

Post by **Charles** » Sun Oct 21, 2018 2:16 am

Left field thought - have you reset the tyre pressure monitoring system since fitting the new tyres?

If it works on a rolling radius then new tyres will be different to worn ones and this might be throwing out the traction control system.

Express Andy · Post by **Express Andy** » Sun Oct 21, 2018 7:14 am

Charles has good point reset the tyre pressures monitoring system, itâ€™s always worth starting with the basics. You could even try turning all the systems off and back on you know ctrl alt delete (pull plug out of the wall)

Just to try nail things down is it the dtc light or dsc
I have read some were on line that bmw dsc can be sensitive to tyres ie new rears and worn front, and mixing run flats and non run flats. The system is so sensitive to permitted parmiters it can make its head spin.
Keep us up to date with what happens
Cheers Andy

BraveSirRobin · Post by **BraveSirRobin** » Sun Oct 21, 2018 9:10 am

Thanks Andy and Charles... the tyre pressure warning system was reset as soon as I drove away from the tyre fitting. Also the pressures reported on the iDrive do match the pressure readings from my pressure gauge. I wasnâ€™t aware that DSC and DTC had different warning lights on the dash... anyway it is the same light that comes on when you select Sport+ which is DTC I think. Is it possible to do a reset of all the systems yourself or is that a dealer job?

Metrics · Post by **Metrics** » Sun Oct 21, 2018 9:21 am

Sounds very odd, I must say. Have the tyres been put on the right way?
As they are directionals.

BraveSirRobin · Post by **BraveSirRobin** » Sun Oct 21, 2018 12:18 pm

Yes, just checked and they are on the right way... was looking for the directional arrow at first but they are marked OUTSIDE on these tyres... good call though!

PhillV8S · Post by **PhillV8S** » Sun Oct 21, 2018 11:36 pm

Hi Robin, I donâ€™t have any other suggestions to help you iâ€™m afraid but I live just outside Bromsgrove and go to Shelsley Walsh Breakfast Meets quite often locally in my black B6s convertible. If I spot an estoril D3 around iâ€™ll give you a flash (of headlights).😎