# 17" vs 18" tires for winter



## ggs (Mar 3, 2004)

I have asked a few people this question, but don't seem to have a good answer. I notice that most people who change their tires for the winter change to 17". Why do people do this? - I would imagine larger tires give you more grip.

Tirerack does not even sell 18" winter tires for the M3 - wondering if someone know a source where I can buy 18" tires so that I do not have to change wheels.

Thanks


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## daihard (Feb 15, 2004)

rumratt said:


> another is that narrower tires generally do better in snow because they cut through, rather than skiing on top.


I agree. Wider tires grip better on a high-traction surface. That's not the case with snowy/icy roads...


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## batmanm3 (Jan 28, 2004)

18" Winter tires are available for the M3... I'm running 245's on 18...can't remember if its 245/40/18 or 245/35/18...I'd go look but car's in parkade right now...too far away to just pop out for a look

Anyhow, they are Goodyear Ultragrip (GW3 ?) unidirectional, grippy in wet weather, about 90% as good as the stock Contis in dry, and work great in snow up to 10-15 cm (which was about the deepest we have ever gotten here in Van) Can't say about really deep snow.

No question though, if it is ultimate winter grip you want, narrower tire with higher sidewalls are better...cuts through snow, better weight distribution on the contact patch, and dedicated snow tire rubber works better in the cold.

Depends on how much snow you get where you live. Pricewise 18s will be more expensive but you won't have to buy new wheels.

Also learn to drive in snow...all wheel drive is mostly of benefit when starting, under braking its all the same...the key is to be smooth and gentle with your inputs. I used to drive my 93 RX-7 and now my M3, up the local mountains when lots of other cars and trucks would be stuck spinning their tires


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## rruiter (Feb 10, 2004)

*narrow*

You would want to have narrow tires. Diameter doesn't really matter. Since 17 inch wheels are usually cheaper I am guessing that is why people use them. 
Most optimal is to have narrow tires with high profile to prevent damage from holes.
Just watch World Rally races in the snow.. they use narrow tires.


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## daihard (Feb 15, 2004)

rruiter said:


> Just World Rally races in the snow.. they use narrow tires.


Very good example! Too bad the WRC isn't all that popular in the U.S....


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## JPinTO (Dec 20, 2001)

I've got 225/45-18 fronts and 255/40/18 rear Dunlop Winter Sport M3's. They came from Tire Rack but I got them early in the winter. The Winter Sports are such a soft sidewall that even with 18" wheels, they are very compliant on poor roads... nothing like the summer Pilot Sports.


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## daihard (Feb 15, 2004)

JPinTO said:


> I've got 225/45-18 fronts and 255/40/18 rear Dunlop Winter Sport M3's. They came from Tire Rack but I got them early in the winter. The Winter Sports are such a soft sidewall that even with 18" wheels, they are very compliant on poor roads... nothing like the summer Pilot Sports.


My fear is that too wide tires may not get enough traction on the snowy surface. Did you simply put the snow tires on the factory rims?


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## JPinTO (Dec 20, 2001)

daihard said:


> My fear is that too wide tires may not get enough traction on the snowy surface. Did you simply put the snow tires on the factory rims?


Yes. I wouldn't drive in more than a few inches of snow with such a powerful motor, which easily overpowers the traction of these tires. Fortunately, we get only a few really bad days of snow, and I don't want to be driving at all on those days.


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## daihard (Feb 15, 2004)

JPinTO said:


> Yes. I wouldn't drive in more than a few inches of snow with such a powerful motor, which easily overpowers the traction of these tires. Fortunately, we get only a few really bad days of snow, and I don't want to be driving at all on those days.


I hear you... It doesn't snow much in Seattle, but when it does the whole city gets into the panic mode. The fact that we've got lots and lots of hills doesn't help either.


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## HUMMM 3 (May 10, 2003)

daihard said:


> I hear you... It doesn't snow much in Seattle, but when it does the whole city gets into the panic mode. The fact that we've got lots and lots of hills doesn't help either.


One reason perhaps for a 17 inch tire is you could put on chains if they are required. I don't think chains will fit in the wheel well with a 18 inch tire. My strategy is to park it if it's going to snow. I'm not concerned with my ability to drive in snow, it's the other idiots with 4X4's who think they're invincible until they end upside down in the ditch.

BTW with the weather we've been enjoying in Seattle why in God's name are you concerned about snow tires now?


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## JPinTO (Dec 20, 2001)

daihard said:


> I hear you... It doesn't snow much in Seattle, but when it does the whole city gets into the panic mode. The fact that we've got lots and lots of hills doesn't help either.


The reason I run snow tires, is because I hate getting caught at work with a dusting of snow and being virtually immobilized with Pilot Sports. It's not fun wondering if you will die on the commute home because of non-dry pavement. Also, snow tire compounds become advantageous over summer compounds when pavement temperatures drops below 7C.


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