Just put the s03's on - definitely different - The Unofficial BMW M5 Messageboard (m5board.com)

MikeNJ · 9th November 2003, 16:53

I had 19k on my dunlop 8080's.. fronts were worn to the wear bars with some excessive wear on the outer edges. Rears still had a couple of miles to go according to the wear bars. These things were really slippery now... at the track spinning thru second and some of third was too easy.

I had the s03's on my audi and loved them. Read many, many posts here about the s03's. About the only negative comments I could find (besides quick wear) was a couple of folks that felt they might not have that stiff of a sidewall, also possible issues over 100mph in terms of stiffness. This does matter to me, but I decided to roll the dice, as I really want to maximize grip as well as wet weather performance.

First off let me say that putting these tires on the M5 stock rims is no joke! First rear took like 45 minutes, even getting the dunlop off was a nightmare!! Needless to say I tipped the mechanic very well

The fronts were a little easier.. but not much.

Now the road test.. I thought that they would be greasy so I was taking it easy at first. Right off the bat I couldn't break them with a first gear rolling stomp.. an easy feat with the dunlops. They felt like they were tracking more than the dunlops around town, but were very neutral and felt balanced. Brought it out to the highway, late morning and very light traffic

I didn't want to get too exaggerated, but wanted to feel them with some speed on. At 70+ some lane changes felt really weird. At 90+ they felt bad. Felt like I had the mushy issues... really felt more like I had blizzaks on – the sensation was like the tires would cut over to the next lane quickly, then the body would catch up. My first thoughts were that they were either under inflated – or I just made a $1k mistake.

So I went home and the first thing that I was able to determine - the tires were over inflated. Once they were cold I measured them at 48 all around. So I lowered to 39 all around and went back out - voila - 90% improved. Still get the same sensations, but no where as much as before. Now I am thinking what I perceived as mushy was really the suspension. My working theory is that these tires stick way more than the dunlops, and have pushed the "weak link" back towards the suspension. In other words, where the dunnies were probably "giving" and sliding somewhat, the s03's are sticking and now there is a bigger force or weight transfer for the suspension to deal with.

I will continue to play with and dial in the air pressures. I would appreciate any comments or thoughts on my experience and theory.

M5 Meeyatch · 9th November 2003, 20:11

Hello...yes, the S-03 tires are very sticky, and take a little getting used to when going from almost any other tire. I have run them on various cars of mine, and the only other tires that seem to get close in terms of grip were the Michelin Pilot Sport tires that my M3 had. All in all you will like the S-03 tires....especially when it rains.

Need4Spd · 10th November 2003, 00:42

Yes, I noticed that S03s like lower pressures, too. I used to run my Pilot Sports at 43 ft/rr, but have my S03s now at 37 fr/35 rr. and it seems to stick better, with some of the understeer dialed back a bit.