First question, many to follow about our new to us 05 S.

The run flats are gone, saved me the trouble.

On the car now are
Falken ZIEX ZE 215/45ZR17
On Drag Extreme alloys DR-44.

Somebody??? has put 28lbs in them.
I’ve looked in the owner’s manual and the door, looks like I need at least 30lbs?

Any thoughts on how much air I need would be appreciated.

ab

 

On the tire, there's a max pressure rating, what's that say?
Because you should base your settings of such, NOT the sticker inside the door as you're running non-OEM sized tires.

28psi isn't all that "low", especially if you like a greater flexing sidewall.

Example, if 44psi is the max, a 35psi (80% of max pressure) or so is a great starting point.

- Erik

 

Adjust your pressure to where you get the entire footprint across the width of your tread. You'll know when it it's too much, when there's non-contact gray at the edges of your tires. Max pressures are for max loads, doesn't take into account vehicle weight at each corner, etc. Myself...I'm on Kuhmo ASX 215/50-16s, and my optimum pressure is 33psi.

Credit card trick is a useful tool too. If you can slide more than a 1/4" of a credit card between your tire edge and the road surface, you have too much air. (use a smooth surface like a concrete garage floor or driveway).

Bluefox is right, 28 isn't all that low. All depends on vehicle weight, tire load rating, sidewall plies, on and on...

 

That's my problem, run flats are gone.

The door says MAX 38 = no longer valid
The book says the Mini Cooper S 205/45R-17 (the OEM size per the window sticker) should run 33 for two people no luggage
The Falkens say 51 MAX

I bumped it up to 32 from 28 and noticed a small increase in stiffness.
I'll go to 36 (40 sound high to me) tomorrow.

I don't want to run to much, wears the middle or to low wears the edges.

Thanks
ab

 

Looks like we’re all on the same page.
Too much air bad, too little not good.

These tires on this car show more wear on the edges than the center @ I assume 28lbs.

I’m going to go with 34 lbs for a couple k miles then re-evaluate.

Thanks everyone for your help
ab

 

abjb: My guess is that you're in the right ballpark between 32 and 35 psi, depending on how much firmness you like.

bluefox280: Where did you read/hear to run 80% of sidewall maximum pressure? I've never heard that one before, but at least it's not as extreme as 100% sidewall maximum psi, which I've also seen people recommend.

With his tires, that would be 51 max psi X .80 = about 41 psi; significantly higher than manufacturer's recommendation. Summer highway driving would probably get them up to around 46 psi or more, with the middle half of the tread constituting most of the contact patch.

 

7 years of Grease Monkey / Big-O Tires experience.
Had excellent results with tire wear, comfort and car response.

Who's the recommending manufacture? It isn't MINI anymore as the tire size and tire brand are different from OEM specs.
Sidewall construction and driver comfort come into play on how much you want your tire set at.
And 40psi is where we would have put 51psi maximum pressure tires based on driver comments / feedback.

I run my lower than 80%, more like 70%-75%, because I build tire pressure as tires heat up during my spirited commute.

- Erik

 

I have the same size tire, a 215/45/17 Nitto Neogen on my JCW. I have been running it at 35/36 psi for 2.5 years. That tire pressure has worked well for me. But I am open to comments and advice as well as the OP.

 

Erik: According to the Big-O Tires' explanation of tire sidewall info at their website, the maximum permissible inflation pressure indicated on the sidewall should not be used to set tire pressures. Instead, "The vehicle manufacturer's pressure recommendations must always be used when inflating your tires."

I don't always set pressures according to those recommendations myself, but that's probably a good pace to work from. MINI supplies wheels and tires in a relatively wide range of sizes, but their tire pressure recommendations don't vary by much.

 

I've been out of the quick-lube / tire business since 2003... wow, that's new.
And honestly, I had situtations in the past where that comment would be absurd... in fact:

So, here's a scenerio I've been in before, "if the tires max is LESS than the car tire sticker, then what?"
You're not about to over-inflate the tire just to match the car manufacture specs, you'll have a serious blow out.
That's one of the reasons why I personally set my air pressure based on the tire, not the car sticker.

- Erik

 

I think this would be a rarity. You would really have to have a huge difference in size for this to happen.