I'm new to the forum. Just bought a mint 15K mile 2011 Countryman S All4 with very option but Nav. 18" Pirelli RF's, etc. The car has what I would call an unacceptable "clunk" even over a manhole cover with a 1-1.5 inch recess even at low speeds. Almost feels as though the shock nut is loose in the shock tower of the right rear. Took it to the shop and they inspected it and performed a few warranty/recall items. They say everything is perfect. If the Countryman that ANY magazines tested drove like this car it would get the failing grade. I know that a lot of people are getting away from runflats but it's hard to believe a car with a list of $36,250 would drive so poorly. Any suggestions? I'll bail on the RF's but I find it hard to believe that regular tires would mask all of the harsh ride and clunking sounds. Thanks for your help.

 

i have the 225/45-18" pirelli p7 runflats on my 2012 cms all4

i found the ride extremely harsh until i upped the tire pressure

i used a tire pyrometer and finally settled on 42 psi front / 36 psi rear

much better ride, the harshness is gone, and improved handling too

the tires now have about 7k miles and the tires are wearing evenly, both across the tread of each tire and front to rear, at this rate i expect all 4 to wear out at the same time

i did a front to rear rotation at 5k miles

scott

 

Thank you Scott. I'll check tire pressures tomorrow.
Best, Sean

 

Is it just one clunk, or a series of clunks? Mine has a VERY overactive ABS system. Every little bump will give me a series of clunks/rattles!

 

i hate itso much,,, i drive alot in the NYC so everytime i am stoping my brake pedal will have a earthquake............

 

I doubt the lack of air pressure is causing a clunk. Yes the ride is overly pounding, but a true clunk needs to be resolved. Plus, raising air pressure MAY help the ride, but the car will tramline more too. It tramlines alot as it is..

 

mine tramlines much less with the increased pressure, it was terrible at the stock pressure but now it tracks straight thru grooved sections of pavement and over roads in poor condition

i had a distinct clunk in the rear with the stock pressure ... tracked it down to the bag under the floor in the boot that holds the jack and other accessories, now each piece is wrapped in a rag and put back in the storage sack

raising the pressure has also resulted in the same wear rate on all 4 tires and also across each tires tread, something i had understood was not how minis typically wear the tires

all my comments regarding increasing tire pressures only apply to the oem pirelli p7 225/45-18 summer runflat tires that came on my cms all4 and my dad's cms all4 that has 205/55-17 pirelli p7 all-season runflats, i have no experience with other brands on mini coopers

when i get my winter tires mounted i will borrow my buddies tire pyrometer and start again

same goes for the michelin super sports that will be replacing the p7 runflats when they wearout, borrow the pyrometer and find the correct tire pressure

scott

 

Bmw606, what were your pyrometer readings for the tires?

 

i don't even remember the actual temps but the tires were very warm to the touch, the pyrometer is setup to record 4 temps across each tire in 2 places, in a specfic order, outside to inside,front of tire, back of tire, LF, RF, RR, LR

we also chalked the outside shoulders of all 4 tires to see how much the tires were "rolling over" in corners

the program then averages the 2 readings (front of tire, rear of tire) from each tire and displays the differences + or - across each tire and between the tires

it is a custom program running on an acer one mini pc running windows xp, it also is used to adjust my friend's engine manegment system on his racecars

the temp probe plugs into a "black box" that is plugged into a usb port

the object is to get the temp difference as small as possible between all the tires and across each tire, the target being less than 5C

i was +/- 3C

we ran a 5 mile stretch of twisty road, out and back, then read the tires, adjust the pressures and go again

my buddy ran the pc, i ran the probe

he was impressed by how quickly we were able to dial in the pressures and by how even the temps were on the cms all4, we made 5 loops, starting at 38 psi all the way around and the speed was 55mph to 90 mph and driving aggressively ... no pressure changes were made between runs 4 and 5

the last thing to note is that the pressures we arrived at were "hot" pressures and i read the pressures "cold" the next AM to find out where the pressures ended up

the final "cold" pressures were LF 42, RF 43, RR 36, LR 37 and i then adjusted them to 42 front / 36 rear ... i also tried 43F/37R and could tell no difference

this was done at 500 miles on the car and at 5000 miles i was seeing a little feathering on the outside edge of both front tires, so i did a front to rear rotation, at 5k miles, all 4 tires tread depth measured 6/32" measured in each of the 4 circumferential tread grooves, the tires started new at 10/32", so i am 1/2 worn, assuming i run them down to 2/32"

i was very surprised that the rears had worn evenly across the tires given the amount of negative camber the cms all4 has

when i get my michelin pilot super sports in the spring, i am going to go to the race track for an open day to set my pressures while my buddy is setting up his fleet of race cars

i am hoping to do 2 sets of runs, first a road setup, 55 mph to 90 mph and street cornering speeds and then a WFO race setup

scott

 

Why do you need to do this for a countryman?

I run pyrometers for my track r-comp tires after each session. And we usually run three readings per tire, outside, middle and inside. That is to test tire pressure, toe and camber settings. As well as driving style. Too much push is bad for the fronts.

Interpreting pyro readings is a real art.

 

it started because i found the oem runflats to be horrid riding tires

in reading the OM i noted the optional tire pressure of 38psi for running high speeds,up from the 32psi

i figured i had nothing to lose so raised the pressure and was amazed at the difference

i mentioned it to my friend and he grabbed his pyrometer and said "lets go"

i am very happy with the results, much better ride, much better handling and even tire wear, both front to rear and across all 4 tires

i was going to ditch the oem tires, but am now running them til they wear out

scott

 

On the MCS, we normally reduce the tire pressure from factory recommended to achieve better ride quality. Usually even a 1-2 psi can change the ride quality enough.

Of course changing out the run flats usually helps as well as choosing the right replacement tires with more compliant sidewalls. But you do loose some crispness with too soft sidewalls so it is a tradeoff.

 

i don't know why it works on the CMS All4, but my dealer really tried to talk me out of the 18" wheel option based on complaints from others who ordered the optional size

i went back and both the salesmanager and service manager drove my car with the raised pressure and they now deliver and reccomend 38 psi f/r to anyone with 18" wheels on a countryman

they would not go with my 42/38 because it is not on the doorpost, but the 38/38 is

scott

 

I would point out that at least several people (including ourselves) have not had same result at all after trying Scott's suggestion. We have an All 4 with 18" Bridgestone RFT's and standard suspension, the ride deteriorated substantially when we tried it, and we immediately went back to factory spec pressures. I had thought the different result might be due to different brand tires, but someone else tried it with 18" Pirellis (also standard suspension) and had the same reaction we did. Seems to be a real mystery.

 

i have the sport suspension

using my car, at the dealer, SA driving, he tried both 32/32 and 38/38 and he could not believe the difference it made using the 38/38

since i have settled on 42f/36r useing the tire pyometer

how are your tires wearing? mine are wearing evenly across all 4 tires treads and equal wear front to back, 6/32" left on all 4 tires when rotated at 5k miles

also, i see that pirelli now has both summer and all-season versions of the p7 cinturato runflats, i have the summer version

scott

 

Generally, the sports suspension will make the ride even harsher at high tire pressures.

You should check your front tire wear after a couple of thousand miles. You may be wearing the middle down.

Also from your pyrometer methodology, it is difficult to determine if tire pressure is incorrect because you don't take the middle measure along the width of the tire. With pyrometer measures, the readings have a tendency to be very inconsistent but you are looking more for temperature trends across the width of the tire (not even linearity) hence the three measurements.

 

reread my post ....

the ride is much smoother at the higher pressures than at the stock pressure, it no longer feels like hitting a pothole when i run over a tar strip and the loud banging noise is gone

we took 4 readings across the tread at two different positions on each tire (about 180 degrees from each other), the 2 readings at each point across each tire were averaged giving 4 averaged temp readings across each tire each time

as to wear, after 5000 miles, all 4 tires have wore from the original 10/32" to 6/32" (50% worn) measured in each of the 4 circumferential tread grooves across the tread, that is, all 4 tires are wearing evenly across the tread as well as evenly front to rear, there is no more wear in the middle than at the edges .... most surprising is the rears are worn evenly across the tread, given the amount of negative camber in the rear, i was expecting the inside rear to be more worn than the middle or outer edge, but that is not the case

i think that alone says i nailed the tire pressures

scott

 

Just trying to understand what you have done and I not sure I could. Something still feels off and I am not exactly sure what it could be.

 

Scott, I checked our tires this evening.

We have a bit more than 5k miles on the car, and the tires have not been rotated. Each tire is barely worn from the original 9/32nd depth across the face of the tire, so we are getting far better tread life than you are. But my guess is that has much more to do with driving style (we rarely drive the car hard at all) than tire pressure.

The person who tried your inflation pressures with the Pirellis has the exact same tires you do, but has the standard suspension.

So the obvious difference is that you have the sport suspension, although like Slinger said, one would not expect that to produce the results you are seeing.

When I read your original post about this I was eager to try what you said, and was very disappointed when it did not work. I really scratch my head on this one...

 

i drive very aggressively in corners, DSC always off, and if out playing, DTC off too, i like drifting the car and find it very controllable using the throttle to kick the rear end out

i also brake very hard, often kicking the ABS in

it is almost as much fun as a 2 wheel drift on my motorcycle

i accept the tire wear penalty for my driving technique, but a tire with a treadwear rating of 260 is not going to last very long no matter how it is driven

scott

 

with lower pressure in the rear, and stock hp, All4, I hardly believe you are able to get the rear to kick out much with throttle input.

 

after riding in my cms all4, my 91 year old dad decided he had to have one too

he bought a used demo 09/2011 build 2012 cms all4 automatic with standard suspension and standard wheels with pirelli p7 cinturato 205/55-17 all-season rfs and 2600 miles

https://www.northamericanmotoring.co.../ppuser/114554

i "borrowed" his car and went out with my friend and did the same tire pyrometer run as my car

ended up at 38f / 34r

no discernable change in the ride (which is much softer than my car), but the handling is much crisper, especially the turnin

my dad noticed the difference and asked what i had done

scott

 

trust me, it is not a problem with the DSC and DTC off the cms all4 drives like a proper sports car

enter a corner with a lot os speed, throttle wide open and a good yank on the steering wheel and the rear end comes out

i spun the car a couple times in a parking lot while in learning mode, but am now confident enough to slide it around on the street

i have taken many car driving schools, starting in 1976 with a rally school to learn how to drive my then new 1976 FWD vw rabbit and including dirt tracking in modified type cars, i have also taken many driving schools on motorcycles

i have managed a land speed record motorcycle team that holds 2 world records, 1000cc turbo and 1200cc turbo, both over 200 mph

nothing beats the thrill of a wheelie going down the hill after the corkscrew at laguna seca!

scott

 

Agree...turning DSC off works great...on the base model too

 

I agree; I ran a practice autocross in my All4 a few months ago and was occasionally able to get the rear wheels loose (with all traction aids off). I used 40 psi front, 34 rear as a start. Probably will up the fronts to 43 the next time I try it. Also may try 52 psi rear; that sometimes helps with some tires. I have the 17" Conti all-season with Sport Suspension.

I also need to get used to the slight turbo lag when getting on the gas mid-corner, something I'm not used to coming from an R53. Probably I need to get the throttle down a bit earlier than in the R53. Still I surprised a few STR Miatas I was running with...