stealthology

I have a 2005 545i Sport manual, purchased about a month ago. The tires which were on the car were Dunlop Sport SP 01's (they are summer performance tires). The rears were getting extremely low on tread, so I decided to just replace those. I replaced the rears with Bridgestone Potenza RE960's.

My car's handling is not very confident at all right now. Before, I could speed right through curves without second guessing the car. Now, I start getting a little nervous when doing so. It feels like the car is floating. I feel like the car is going to tip over taking a slight curve at around 70 or so. Is this mostly due to having 2 new brand new tires on there? Does this have to do with the break in period? Or could this have to do with summer tires up front and ultra high performance all season's in the back?

Thanks!

Dan

daveny87

check your tire pressure. sometimes when the tire is overinflated, you dont have a good contact patch when tire and road meet.

cleung

maybe the bridgestone has softer sidewalls

kscarrol

New tires take some time to break in as well, soften up the tread. Give them a couple of hundred miles and they should improve...

LJTX545I

I consider the RE960 a touring tire and will not offer the grip or the sidewall stiffness of Dunlop SP01's. You also imply that only the rears were changed, so you have grippy summer only tires up front and less grippy a/s on the rear. DCS will probably keep you in line, but I wouldn't be pushing too hard out of turns. What made you go with the 960?

As someone said earlier the grip will improve slightly with use, but take it easy..and either replace the fronts or rears to match as soon as you can.

juris335

Oooh. I'd never mix...

kscarrol

Agreed! I skimmed thru the post quickly and just assumed all four tires were changed...

sdg1871

Do not mix tires. You do not want front and rears with different rubber compounds and tread patterns as this will make the grip levels uneven and you do not want different sidewall stiffnesses as this can affect stability, ride, response, etc.

Mixing summer tires with all seasons is asking for trouble in the twisties.

My own practice is that I run 2 sets of wheels: summer performance tires in the spring, summer and fall and dedicated snows in the winter.

I do not like all seasons for the non Xi cars as they have neither the grip of summer performance tires or the snow traction of a dedicated snows.

stealthology

I think it makes much better sense to have two pairs of wheels like you do when you live somewhere where it snows quite a bit. Over here, it really doesn't snow much at all, and from my research, a good ultra high performance all season tire will perform basically just as good as a summer performance tire; you also get the protection for driving in colder temps, get better wet traction, and have a bearable ride in light snow (it really doesn't snow here like it does in NY).

kscarrol

Ultimately the choice of tires is yours. If you are happy with the Potenza tires, that is all that matters. I do think your issue is a combination of the mixed front sport/summer tires and the rear AS tires, along some breaking in required for the new tire treads...