18" Tire Sizes to fit CMS All4
 

Can someone list the 18" non run flat tire sizes that will fit without rubbing or spacers?
Im thinking either the 225/50 18" OR 215/50 18"

Stock tires would be 225/45-18, 25.9" tire diameter
Stock wheels are 18x7.5"

225/50-18 would be 26.9" tire diameter, while 1" taller than stock it will fit the Countryman (see discussion later in this thread) for street use.

215/50-18 does not bring up any tires at tirerack

Your option on tire size for a non runflat tire would be the stock size
225/45-18 (Edited: or try the 225/50-18 if you want more sidewall for comfort)

But since you have 18x7.5" wheels you can use tires that are meant to fit 8" wide wheels although that is adding more weight and not really good for the tire since the sidewalls will be flexed differently than how they were designed. For normal street driving you can get away with it. Best is stock sized.

The following are possible without rubbing or spacers using stock suspension and stock wheels-
215/45-18 fits rims 7-8" wide, tire diameter 25.6", slightly less than stock, OK
225/40-18 fits rims 7.5-9" wide, tire diameter small at 25.1", increases wheel gap
235/40-18 fits rims 8-9.5" wide, tire diameter 25.4", slightly less than stock, OK
245/40-18 fits rims 8-9.5" wide, tire diameter 25.7", near stock, OK

Note that 40 series tires would be stiffer in sidewall and less comfortable for use on rough roads.

Thxs Minihumne,
ill probably play it safe and just go for the stock size in Non runflat. I just got the car 10 days ago and 4 days ago i got a ballon the size of a ping pong ball on the side of the tyre, after hitting a pothole.
I decided to change all 4 tyres to run flat for 2 main reasons 1) more comfortable ride 2) avoid more expenses with the risk of hitting another pot hole with a run flat and having to buy a new tyre. With non runflat u can fix them but with non run flats u have to buy new.

Thxs for your reply & sunny wishes from Egypt :)

not true ... if you hit a pothole that damages the sidewall, neither a rf or non-rf is repairable

the non-rf will be less costly than a rf to replace

as for flats from a nail etc ... if it is in the tread area, not the sidewall, both rf and non-rf can be repaired, the catch with the rf being that you do not run it with little or no air pressure before the repair

while a rf will allow you to run with no air, doing so does cause unrepairable damage to the tire due to excessive heat generated while running without air

if you search the forums, you will find many people are running 225/50R18 tires with no issues on the cms all4, specifically the michelin pilot super sport, it is designed for a 6"-8" rim and is 26.9" diameter

i will be running 215/65R16 winter tires, michelin x-ice xi3, designed for 6"-7.5" rim, on oem mini 6.5"x16 alloy rims, these have a 27" diameter

have already test fit the tires with no issues

scott

It is possible to fit taller than stock tires on a MINI but you will reduce clearance and the tires may look oversized. If MINI had intended that you use tires that large then they would have given you tires that large.

I do not recommend using any tire of 27" diameter for a MINI even if it is possible. Stock tire diameter is 24.3" so you raise your center of gravity and reduce your tire clearance under passenger or cargo load or on rough surfaces.

Also for any snow use you want tires that are more narrow not more wide to cut through the snow better. Less wheel clearance in the winter doesn't give the snow anywhere to go although tall tires will give you more ground clearance.

last time i checked 215 was narrower than 225, my stock 225/45R18 tires measure 26" diameter (spec sheet says 25.9", but i measure 26") now so i am only adding 1/2" (half of 1" diameter is 1/2" radius) into the wheel well, there is still lots of clearance above the tire, in front of the tire, behind the tire and the same applies at full lock and with the 215/65R16 winter tires, there is more clearance to the strut than with the oem tire

i have always (since my first car in 1970) put the largest snow tire i could fit in the wheel well on a second set of rims

so i guess we will have to agree to disagree, i will be running 225/50R18s (26.9" diameter) when the oem rfs wear out and 215/65R16 (27" diameter) winter tires on my cms all4

scott

The Countryman comes with either 205/55-17 or 225/45-18.

In 17" stock sized tires owners have a few runflat Grand touring All Season tires and a few non runflat winter tires to choose from:
http://www.tirerack.com/tires/TireSe...ting=S&tab=All

In 18" stock sized tires owners have several choices for snow tires both runflat and non runflats-
http://www.tirerack.com/tires/TireSe...ting=S&tab=All

Yes, 215mm wide tires are more narrow than 225, but I was thinking more of using 17" winter tires and wheels rather than stay with 18" although there are some good winter tires in both stock sizes.

Yes the wheel gap on the Countryman is big enough to have some extra space but that would be for suspension travel with rough roads and when/if loaded down. If you have only smooth and flat roads, only drive the speed limit and never have much more than yourself then you'd probably be OK.

205/55-17 = 25.9" od (my dad's cms all4 has these with stock suspension) i measured them at 26"
225/45-18 = 26.1 od (my cms all4 has these with sport suspension) i measured them at 26"

both cars have pirelli p7s, dad's in all-season, mine in summer

when we tested the tire/wheel fit of the 215/65R16 on my cms all4 at the tire dealer, we put 4 200 pound employees in the seats, 2 more 170 pounders sitting in/on the hatch and the gas tank was full (all lights lit, about 30 miles on the tank), ... total weight of 1140 pounds plus the fuel, way over the mini stated max load of 860 pounds ... the rear suspension was bottomed and the front was also bottomed, but the tires were not hitting the body, even with the front wheels turned to both right and left lock ... if there had been any contact, i would have dropped back to 205/65 or 215/60 and tried again ... guessing/talking/pontificating about which tires fit is pointless, just go to your tire dealer of choice and try them on

i KNOW that 215/65R16 tires fit my cms all4 with sport suspension because i tried them

once i put them on for the winter, i will go out with my gps and make an indicated vs true speed chart and tape it on the lid of the mirror on the sunvisor

instead of 17" rims, get some mini oem 16" alloy rims ... they are available from ecstuning

http://www.ecstuning.com/Mini-2011-C...oys/ES2159816/

these are factory oem alloys and work with the tpms system

dropping to 16" allows a taller sideway for even more pothole rim protection and a wider choice of winter tires ... tirerack is a good source of info ... i am going with the michelin x-ice x3i in 16" size 215/65 only 1" larger than my stock 225/45R18s, but a huge amount of sidwall

if i am not happy with the michelin, i will change them out for yokahama geolander a/t-s on/off road all terrain truck tires in size 215/65R16 (27" od)

i have used these on my sonoma p/u in size 235/75R15 and they are great in deep snow (on my 2nd set)

my favorite tire on the sonoma is the bfgoodrich All-Terrain T/A KO, but it is not available in a size for the cms all4, 28" od is as small as they go, however, there is a 2" lift kit available for the cms all4 from coopercrap dot com ... hmmmm

http://coopercrap.com/countryman-lift/

wow just saw they now have a 2" lift kit for the R55/R56 minis too

http://coopercrap.com/r5655-lift-kit/


scott

Thank you scott for your careful explanation.

Well it sounds like you have done your homework and should share it with MINI.
Have you?

The countryman has apparently a well engineered stock suspension to handle what you have done.
Probably it's over engineered, given they might have thought of doing precisely what you tried.

I can't say that holds true for the other earlier MINIs, hence my experience with tires on the MINI have limited the use of tires larger than stock to about 25" when using stock suspension.

Interesting that when I look up MINI base countryman I do not see any option for 16" wheels and the R123 16x6.5 et46 which I assume is available but not in the USA from dealerships. Too bad, as it seems a good option if it fits over the brake calipers, which it does.

When I went to the site in your link they had two styles of 16" rims for the Countryman, R123 and R124, the vendor suggested 205/60-16 winter and summer tires. They had 16" steel wheels too. Perhaps useful for a spare tire.

So the next question should be does a 15" wheel fit the Countryman? If so then you can put a set of Rally tires on it for some offroad fun. I only saw wheels as small as 16" in your link. Doesn't mean that some aftermarket wheel with clearance could not work. Mostly a brake caliper clearance limitation.

So now the question becomes why did MINI choose those tire sizes when they could have gone with a larger tire. The answer might be related to the size of runflat tire that was practical or used for more than one car.

thanks for all the information guys

in the uk, the base countryman comes with 16x6.5 steel rims, check it out

http://www.mini.co.uk/

there are 2 different 16x6.5 alloy rims avaiable, but i could only find 1 style available here in the us without paying huge freight to get them here

i really wanted to get the steel rims for winter use, but have been told by tirerack, my local tire store and a mini dealer that the tpms system modules won't mount on the steel rims ... i have a buddy that is a machinist and may still order a steel rim + tpms sender and see what can be done

there are many confirmed fittings of 16" alloy rims available in the us, but they require the use of a hub adapter ring, sometimes called a centering ring

i did not want to use a centering ring so began the search for a source of 16" oem rims

also, the wheel offset of the aftermarket wheels differed from the oem mini wheels, only a matter of +/- 10 mm or so ... is this a problem? i don't know, but given the centering rings and different offset, oems seemed the way to go

the final factor was availability in the future, per the mini dealer, the oem wheels will be available into the future, period

a buddy of mine bought aftermarket rims 4 years ago for his bmw winter tires, last winter he had an off road excursion to avoid an out of control vehicle, he avoided the vehicle, but one tire/wheel was damaged

he was unable to buy a matching rim, NLA, he ended up buying a set of 4 oem rims for his winter tires

as for a 15" rim, maybe a 15" steel rim would clear the brakes, but as of now, no tpms senders so you would have a warning light all the time (i am told ncs expert cannot turn it off)

i wanted the extra large diameter winter tires because in my 40+ years of winter driving, i have found that bigger is better

for my summer tires, going from 225/45 to 225/50 is a financial decision

michelin pilot super sport 225/45R18 is $223 each, $892/set
michelin pilot super sport 225/50R18 is $172 each, $688/set

the difference of $204 is like buying 3 and getting 1 free

also, $200 covers mounting/balancing

scott

Thanks for the info on the other OEM 16" wheels. It's good to look at various possible options. Everything is a compromise with tires, there are some benefits and some downsides one should consider.

Centering rings are not bad and needed for aftermarket wheels that have a hubbore larger than the MINI. As long as the ring is hubcentric and fits it is fine to use. Usually the wheel vendor provides the rings to fit your car. There is no downside for wear or handling. If the rings are made out of alloy metal they will withstand heat if you do performance driving. On the street hard plastic or metal rings are fine.

Wheel offset is also workable, the 16" OEM wheels have an offset of 46mm, if another wheel of the same 16x6.5" width has a 40mm offset then it will move the wheel 6mm more to the outside. Typically 10mm offset difference is fine, that less than 1/2". Since the 16" wheel is so narrow the wheel can be moved outward more than a wider rim and still be fine for the wheel well, not poking out.

Yes, there are some values in the Michelin Pilot Super sport sizes, same thing for 205/45-17 and 215/45-17, it might be due to overstocking by Tirerack.com or perhaps from the manufacturer. Michelin sometimes has a $50 or so discount from time to time for a set of four tires.

I get my mounting and balancing done much cheaper due to using a shop that handles SCCA members who often change tires for autocross. The price is negotiable at a small shop. If you do have SCCA in your area ask the members where they go.

As for using taller tires for your All4. Some things to keep in mind.

There are some downsides that we did not mention-
A larger tire diameter will throw off speedometer and odometer, about 2-3 mph at 60 mph and about 300-400 miles per 10,000 miles assuming your speedometer is accurate to begin with.
A larger tire will also tend to weigh more and the added weight will be require more work to accelerate and to slow down, this can be a factor in working the brakes harder.
A taller tire raises the center of gravity of the car (and can affect suspension geometry), in an ALL4 you already have a higher center of gravity.
A taller tire with a taller sidewall will flex more putting more stress on the tire given the weight of the car. Handling in corners can be reduced or affected.
A taller tire will affect your perceived gearing under acceleration, it will feel like acceleration is slower.

More reading-
http://www.tuneruniversity.com/blog/...n-performance/

Typically in the older/other MINIs when we want better performance a light wheel and tire setup helps handling, braking and change of speed.


And in the snow- narrow tires cut through the snow better. Wider tires tend to float on the surface. Narrow tires allow more weight (from your car) touching the ground per square inch which helps traction in snow.

http://www.insightcentral.net/forums...ger-tires.html
http://ask.cars.com/2007/09/large-tire-and-.html
http://www.mdxers.org/forums/2-gener...y-does-go.html

For more insight on tire sizing you might email or contact Alex@tirerack.com, I usually find discussions with him enlightening.

I have talked to many retail tire shops. Some will not mount tires that are so far off from the OEM tire size. They do this because of liability risk. If anything were to go wrong and they mounted a non standard tire, they could be responsible for any outcome. Why would they second guess the OEM specs.

Lawyers or investigators would see the non standard tire size and think, did this tire contribute to a change in handling which resulted in an incident.

Why does tirerack recommend tires that are OEM tire diameter, even for winter use?
http://www.tirerack.com/winter/tech/...jsp?techid=126

In the end, as long as you drive on the street with care I think you will do OK, if you have teenagers or family that also drive the ALL4 I'd ask them to respect the changes you have made.

And yes, I have experience driving in the snow, four winters in Colorado and 5 winters in Chicago. That's why I live in Hawaii.

Off Topic
 

Just have to say that the last several posts are some of the most articulate, informative, and civil posts between 2 contributors that obviously see things a bit different but are willing to share their knowledge and experience to the benefit of the rest of us.

:thumbsup:

I'm glad you could benefit from our lively discussion.

It's obvious there are more ways than one to solve this problem.

You can be very creative but think things out and know what compromises may be needed when it comes to tires.

Safety is always a priority for any tire used on the street or in bad weather.

Scott, would you recommend the Geolanders for daily, year round use?
-bg8

yes, i have had a 2 sets on my 1997 gmc sonoma p/u truck

scott

here is my final winter tire setup

205/70R-16 Dunlop Grandtrek SJ winter studless snow/ice tires

on

mini OEM R123 Alloy 5 Hole Circular Spoke Wheel, 16" (5x120) offset 46 Silver color

the tires are 27.3" OD and fit with no rubbing, even at full steering lock

testing speed with my aviation GPS, 1/10 mph speed resolution, i found the speedo is .6 MPH under my actual speed from 20 mph to 100 mph, which is more accurate than the stock 225/45-18 tires which are 1.9 mph over actual speed from 20 mph to 100 mph

i think they fill the wheelwells nicely

i wish they were white, but i could not bring myself to paint them as the finish is so nice

they grip amazingly well on dry pavement, have not had a chance to try them on wet or in the snow yet

scott

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