Just a random friendly reminder to check your tire pressure! Especially if you have run flats! My tires looked fine, I thought my car handled like crap because I have the stock run flats still. WRONG. All 4 corners had under 20 PSI of air. Night and day difference. I still break lose in first, but cornering is amazing, and I can actually accelerate when turning instead of having to coast around the corner for fear of breaking my tires loose .

 

yep, you should check your tires once a week, at least once every 2 weeks.
my runflats are noisy because the dealer let it sit until it was 25psi!
I think it now has some memory.


Fall and Spring are very tricky times when nitrogen becomes more
appealing.....but i only have regular air so need to check at least once
a week. oh well.

90F today, 70F next week.... 2psi difference already.

 

first the report...

current psi in my 2005 MCS measured cold

Left Front 28 psi
Right Front 26.5 psi

Left Rear 27.5 psi
Right Rear 27.5 psi

Now... I dont know for sure but I think they were under inflated when I had Nitrogen put in about 3000 miles ago...

The tire shop that did I have been using is not the best. I am now going to get the tires inflated very next time I drive it - we (car and I) are going to the new tire store...

Here is a question for the brainiacs at NAM....

according to calculations raised by this post (read Post #3),

https://www.northamericanmotoring.co...ad.php?t=50149

If I have 1 driver weighing 200 pounds

I should have;

42 psi in the fronts and 25 in the rears

Why does the sticker on the door sill state I should have 38 psi in all four tires when I know the fronts have a lot more weight on them...

I have the Pirelli Eufori stock run-flats with max wieght per tire spec of 1102 @ 52 psi....

(the F/R weight bias for the 05 mcs is 63/37 if you get into the math from the other post...)

Why the difference between 38 psi in all four wheels and the calculated 42 psi in the front and 25 psi in the rears ?

Is 38 all four wheels for 4 people with a not to exceed weight of 816

Thank you for any help in understanding this.....


btw...

Why it Pays to Watch Tire Pressure
1. One fifth of all tires are up to 40 % under their correct pressure.
2. A 10 % drop in pressure cuts a tire's service-life by 15 %.
3. For each fall of 0.21 bars under correct tire pressure, fuel consumption increases by 1.5 %.
4. 75 % of all flat tires are the result of insufficient pressure or a gradual loss of tire pressure due to a leak.
5. Tire problems are the third most common cause of vehicle breakdowns.
6. In the U.S., around 250,000 accidents a year can be traced to insufficient tire pressure.

Source: Schrader-Bridgeport International

 

Thanks for the reminder. Bumble was good but the Sorento was low in one corner.

 

i also have these runflats, and was curious of the same thing. the other day my warning light went off and i checked pressure in all the tires, 3 were at 35, one at 25

but i noticed the max load on the tire is 51 psi, so i upped all 4 to 45 psi, i was wondering if this is a good idea. the car feel more nimble, and the wheel is a little lighter, but im not sure if thats cause the tires are overinflated.

any input is appreciated, thanks
marco

 

Nitrogen makes me laugh more

 

What is thiis "break loose" of which you speak? I just changed over from a 04 MC to a 06 MCS and I feel so much less control with the MCS. I feel like I am "breaking loose" all the time. What is this all about? Difference in wheel/tire size? Can tire pressure help or hurt? I am currently running Pirelli Snowsports in 205/45/17, pressure 35 psi all around. I don't think it's because I have snow tire on, however, as I had the same experience with the stock tires before I changed them over. Can anyone help/explain? Thanks.

 

42 front, 25 in the rears. Are you trying to kill yourself? Assuming you have the 17" wheels, you should have 33 psi for all corners (30 psi for 16" wheels). Fully loaded psi is 36~38. If traveling at sustained speeds over 100 mph, you can add 1 psi for every additional 6 mph. You may like the "feel" of the steering with the tires that overinflated, but all you're doing is making the suspension work harder. I'd imagine the overinflation is exacerbating the understeer too. Both MINI and the OEM tire companies agreed on the psi recommendations in your owner's manual. MINI engineered the suspension around runflats and those psi figures. I'd say experiment a little, but keep within 20% of the recommended. For me, I live in Germany so my car sees a fair amount of 100+ mph driving. My compromise is to keep psi around 35 all around. I also have my own air compressor and check my tires (dead cold) at least 2 time per month. I find my Dunlop SP Sport 9000s DSST lose at least a psi over that time. My winter Goodyear 16" runflats hold their 30 psi quite well. I haven't had to add any air since early November.

 

I initially had 32 all the way around. When I was doing an oil change in my shop at 5000 miles, I decided to rotate my tires. I saw the sticker and decided to up the pressure to 38 psi. After another 5000 miles, I had SEVERE wear in the middle area of my front tires. I dropped the pressure back to 32 and left it there. Anyway, the fronts were worn out at 17,000 miles.

Since then, I have decided not to rotate my tires at 5K intervals anymore. I drive until the fronts are worn out, move the rear tires to the front, and put the new ones on the rear. That way, I don't have ancient tires on the back, yet I don't have to cough up the cash for 4 tires at one time.

Rawhyde

PS I drive enough miles that this little ritual gets done twice per year.

 

How many miles do you get out of the fronts doing it this way, and how many total miles out of the tires that were on the rear and moved to the front?

 

so far on my GS-D3's i got about 18k miles with lincoln's head barely
clearing the tread on the front... i don't usually drive this car in the
wet so will go down to the wear bars which will probably take
another 8k miles. I drove my car in the rain a few weeks ago
and the car still handled beautifully in the wet.

the rears look pretty good. i can probably go another 15k miles
on them before they need to be replaced. im impressed how well
these GSD3's lasted considering they are high perf summer tires.

im probably going to swap out just the front's late season this year
or early spring next year.

 

Anytime you get tread worn out in the middle of the tires you have over inflated them given the weight of the car and your load in it- people plus goods.

It's best to use about 33 to 35 psi unless you know you are having four people in which case you can use 37 psi all around.

More than 38 psi I don't recommend for daily use. Under 32 you'd need to watch for.

51 max psi is for the tire's design limits and the recommended tire pressure comes from the car manufactorer based on weight of the car and it's use.

You cannot always see low pressure. You need to check for it.

If you had 20 psi in your runflats you just did a test of the runflats and I guess they survived.

 

I'm in the process of switching the 16" original runflats (195/55-16) on my 2005 MC for BFG g-Force Sports in 205/50-16 using the factory wheels. What pressure(s) should I use if I usually travel on the highway (at speeds up to 75mph)? It's usually just me and maybe one passenger?

Thanks.

 

I can tell right away if a front tire goes under 30psi from the massive wheelhop that results.
Generally, pressure adjustment formulas based on weight bias are for creating the same sized contact patches front and rear. Why exactly would you want to do this here? Front-drive cars often behave erratically with super-low rear tire pressures so the usual solution (when rules do not allow rear spring/bar rate adjustments) is to increase the rear pressures far above that which is optimal for grip in order to promote rotation. The same pressure specs front and rear tells us the MINI was designed to handle as the engineers intended with a larger contact patch in front even in stock form.
What's wrong with following the car manufacturer's recommendation when the car is obviously being used as they intended?

On a lesser car it is often worthwhile to sacrifice grip for improved turn-in using high tire pressures, but this seems a poor trade-off for the MINI as many consider it twitchy already. However some here have missed the sharp turn-in response of the runflats, so are happier with a little more air in their non-runflats.

 

For a MINI on the street with two people just use 32-33 psi all the time and check your pressure. Some will use 34-35 so that if some air leaks out it's still OK.

Doesn't matter which wheels and tires you have and anything on the street is going to be fine for this pressure as recommended by MINI and found on your driver's side door jam.

Psi does go up with four people but not too high. Read your owner's manual or equivalent. for the newest R56 I think I did see slightly higher psi for a fully loaded MCS.

 

BFG9000 & minihune,

Thanks to each of you for your response. I guess I didn't know if the pressure recommendation would change with tire size - the door jamb panel seems to be specific to the original size tires.

 

I have Toyo [FONT=Arial]Proxes 4 215/35R18.[/FONT]
[FONT=Arial][/FONT]
[FONT=Arial]I thought who better to ask what pressure I should be running than the tire manufacturer. But the answer I get from them was 36PSI in the front tires and 41PSI in the rear. Does this sound a little strange to anyone else? [/FONT]

 

The best source for tire pressures is your MINIUSA owners manual or pdf.

From the 2007 R56 coupe pdf manual
(applies to older MINIs and for all tire and wheel sizes except the emergency spare)

For speeds up to 100 mph
33 psi cold front and rear no matter what the load from 2 to 4 people

For speeds in excess of 100 mph
33 psi cold front and rear for load up to 2 people
36 psi cold front and rear for load up to 4 people and luggage

For the compact spare (115/70-15)
61 psi front and rear for load up to 4 people and luggage

It doesn't make sense to put more pressure in the rear for a front wheel drive MINI. 36 psi front and rear would be ok for you.

 

Those are actually not unusual cold pressures for track use on a FWD car, because the fronts will heat up a whole lot more making the hot pressures fairly similar. This is why it's easier to think in terms of hot pressures for racing, and also shows why it's important to also specify what the tire will be used for when asking.

Auto-X or street use will usually not heat the front tires differently enough to require adjusting pressures in this way.