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[bellemastiff]

Hello gents, just had a few questions I am hoping more knowledgable forum members can help me with!

I just switched in my winter wheels & tires (I know, it's only October.... I live in Michigan)

Actually I'd never seen them before -- when I bought my M3 a few months ago, the seller 'threw them in' to seal the deal (as I was balking at their bottom line price)

They are 18" w/ blizzaks which seems perfect for bad roads / snowy winters. But I still had a few questions,



1) Anyone know what wheels these are? I don't see a manufacturer or trademark listed physically on them (At least anywhere I can see)

2) I checked what the bmw had inflated the tires to when I got home -- I read air pressure at 40 in the rear / 36 in the fronts. Granted I checked the pressure after 45 mins of spirited & highway driving -- AND it's 58 degrees outside -- so that's probably the high end of the range the pressure will normally be at over the winter as it gets colder (and when they haven't been driven hard).

E.g. I would guess they'd read 37 / 33 PSI when they cool down for rear/front, and maybe even lower pressure when outside temps get below freezing. Just wondering if this pressure seems right for winter tires on an e92 m3. (Not sure what the 'right' pressure is anyway -- the tire manufacturer's recommendation? Does BMW have a recommendation? etc)

3) At higher highway speeds, the tires felt a bit 'floaty' and frankly I felt less confident driving at speed with them. Also in the twisties (with no one else around), I safely take a turn at 25mph and floor it -- the rear seemed to swing out a bit, and the traction control came on much more strongly than usual. Basically it just seems these tires have less traction both at low and high speeds, compared to my OEM ZCP wheels + michelin all season tires, which is a little worrying?

I'm wondering if this seeming loss of traction & confidence is because I'm driving Blizzaks above a temperature they're not well suited for (again, its 58 degrees outside right now). Or maybe it's because the rears are skinnier now. (At least, it looks like they are, but I'm definitely not an expert, and I didn't compare the numbers on the side of the respective tires)

Any feedback would be much appreciated!

[dmppdx]

1. The wheels are : Sport Edition A7 wheels. Tire rack sells them.

2. I'm really sure what tire pressure they should be.

3. Since they are snow tires, particularly since you are using them in warm weather, they will be slippery and squirmy. They just don't have the traction or stability a summer tire has. "Performance Winter" tires are much better, but you give up a lot of traction in the snow.

[M3SQRD]

Above info is correct.

Are your Blizzaks the LM60 or WS60?

The LM60 is a winter performance tire and the WS60 is a winter snow/ice tire. Both have taller and softer tread blocks compared to your summer performance tires - WS60 are even taller and softer than the LM60. The winter tire sidewall also is softer than your summer performance tire sidewall. Finally, the winter tires have thinner tread blocks compared to wide summer tire tread blocks so winter tires have less rubber making contact with the road. Consequently, the feel and characteristics of winter tires are very different from your summer tires - you've already experienced the differences!

Give it some time to get used to how the winter tires perform. Ultimately, they're safe to use on the M3. I've been running LM60s for years without issue.

[MRV99]

I have 19" summers and 18" dunlops 3d winters. What I have observed is that the 18's are softer and a bit more squirrelly under exceleration. Plus the rule if thumb is winters are best when the temps are consistently in the 40's. When it gets warmer like you said 50's the tire will be even softer because they are made to be pliable in the lower temps. Another thing to think about is the tire will wear faster in warmer temps.

I swap out my summers when the temps when driving enters into the 40's consistently. If it is 50's during the day but is 30/40's in the night I don't worry.

[bellemastiff]

Gents, thanks for the responses so far.

What about tire pressure for winters?

On a warmer day (50 degrees), after being driven hard, what pressures should they top out at?

On a cold day (say 20 degrees), before being driven, roughly what PSI should they be?

[ben@tirerack]

Originally Posted by bellemastiff

Gents, thanks for the responses so far.

What about tire pressure for winters?

On a warmer day (50 degrees), after being driven hard, what pressures should they top out at?

On a cold day (say 20 degrees), before being driven, roughly what PSI should they be?

Recommendations for street tire pressures are always given cold. Don't even worry about what hot pressures you're seeing, that's for the track.

Cold in this case means tires sitting at ambient temperature with no residual heat from driving. That means that if the ambient temperature changes significantly, you have to adjust your air pressure if you want it to be 'perfect' all the time.

I usually just put an extra psi or two in if I'm setting the pressure on something other than the coldest day I expect to see before I next check the pressure. Every 10 degrees is roughly 1 psi change in pressure.

Start with the stock pressure recommendations of 36F 38R. You can adjust for handling preference, but don't go too much lower than the recommended rating.

[swartzentruber]

Originally Posted by ben@tirerack

Start with the stock pressure recommendations of 36F 38R. You can adjust for handling preference, but don't go too much lower than the recommended rating.

Is this really correct? Isn't there a special M/S tire 225/40/18 recommendation of 33/36 for a lightly loaded car not planning to exceed 100mph? I would assume that's what you'd use for a typical winter tire setup. I know you guys are the experts, but that's what's in the manual.

[ben@tirerack]

Originally Posted by swartzentruber

Is this really correct? Isn't there a special M/S tire 225/40/18 recommendation of 33/36 for a lightly loaded car not planning to exceed 100mph? I would assume that's what you'd use for a typical winter tire setup. I know you guys are the experts, but that's what's in the manual.

The 36/38 I pulled out of the tire industry guide, which doesn't give as many specific scenarios and tends to be conservative, listing the higher end of the scale. You can certainly use pressure settings that are in the manual as appropriate to your conditions, load, and tire size.

I'd still start with 36F 38R or thereabouts, and tune from there according to what feels best. A couple reasons I'd favor the slightly higher pressure:

Most people will want higher pressures to keep the handling from feeling quite so squishy with the winter tires.

As I mentioned above, every 10 degrees of temperature drop is ~1psi drop in pressure, so if you on the higher side, a cold snap will not leave you under-inflated.

Pressure escapes slowly over time. If you check your tire pressure every week, that doesn't matter. Some people do. Most people don't. I'm in the business and I probably check them once a month.