Focus Fanatics Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
198 Posts
Discussion Starter #1
My Titanium came with Michelin PS3 235/40/18 tires.

For the winter I wanted narrower tires and went down 2 sizes in width only.

To keep the overall dia. the same and correct a 1% speedo error I went with 215/45/18 Michelin ice-x2 tires.

Now I know the 235 width required 39psi, however being that I now have 215 width do I need 39 psi or should I use the 35psi that the other models use, that are equipped with the 215 width tire.


[dunno]
 

·
Registered
Joined
·
257 Posts
Whats the maximum inflation rating on the side of the tire?
 

·
Registered
Joined
·
4,475 Posts
Well, if your winter tires have the pressure sensors, they are going to need at least 37psi to not be setting off the alarm of low pressure, I would guess.
Also, the reason for the 39psi is the short sidewall. The lower profile tires need a higgher psi to be safe.
Since your Winter tires are 45 series, i would say the compromise of 37psi would be ideal as far as the tire profile goes.
The stock tires are 50 series with the 17" wheels, and use 35psi.
Also usually snow tires are run a little lower pressure that all season tires.
You can try 35psi, but like I mentioned, you may set off your low tire pressure indicator.
 

·
Registered
Joined
·
198 Posts
Discussion Starter #4
I now have 2 sets of identical rims with summer or winter tires.

The factory required psi for the summer 235/40/18 tires is 39 psi.

The winters are narrower being 215/45/18 but still mounted on the identical 18" by 8.5" rims, which pushes out the sidewall further and theoretically increasing its width.

I started with 35 psi front and rear, and had a smooth ride, I then went to 39 front and 37 rear, and get a choppy ride with rear wheel apparent hopping. Finally I went with 37 psi front and 35 psi rear, smooth in the city on really bad roads then off to the highway and increased gas mileage about 1-2 mpg.

I stuck with this combination and then reset my sensors to trigger them so they will be learned by the Ford computer.

I am quite impressed with these michelin x-ice/ice-2 tires, the new 2 series is supposedly able to increase tire wear upwards of 30,000 miles.
 

·
Registered
Joined
·
4,475 Posts
I run 44 psi front and 36psi rear.
IMO it really is only the rear tires which give the 'choppyness' to the ride.
The extra weight of the front keeps the ride fine even with 44psi. (which also gives better turn in with fast cornering)
 

·
Registered
Joined
·
4,328 Posts
I am quite impressed with these michelin x-ice/ice-2 tires, the new 2 series is supposedly able to increase tire wear upwards of 30,000 miles.
Yay! I intend to buy a pair of these this month. I was kind of torn between these and the Blizzaks or maybe the General Altimax Arctics, but my commute is so far (and mostly highway), that these might be best for me. Plus, they're LRR tires.
 

·
Registered
Joined
·
788 Posts
Just a reminder to check your spare for winter tire pressure. I just check my tires and adjusted for an ambient temperature of 56 degrees, the average here now, and my mini-spare was down to 44 lbs. The last time I checked and adjusted the spare was in summer and inflated it to 58 lbs. when it was around 85 degrees.
 
1 - 7 of 7 Posts
Top