Brakes Wheels 2nd Gen Tires Tire pressure, different sized tires from stock

Discussion in '2nd Generation: 2007+ R55 through R61' started by DneprDave, Mar 18, 2016.

  1. DneprDave

    DneprDave Well-Known Member
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    I've switched over from run flats to non-run flat tires and went up a size, from 205/45 17 to 215/45 17. My new wheels are 1/2" wider than stock also.

    Will I still use the same tire pressure as indicated on the door frame for stock tires and wheels?

    If not, how do you calculate the correct tire pressure? I looked around the web for a tire pressure calculator or a chart and didn't see one.
     
  2. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    Same pressure, more or less. Note that this is not an exact science....
     
  3. ZippyNH

    ZippyNH New Member

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    I started at the same psi you used before....and then adjust it by 2 or 3 psi to tweak your handling....I bet you might never adjust it.
    I used 3 diffent tires sizes....think my "ideal" psi was all within 5 psi....heck many don't even keep all 4 tires within 5 psi!!
     
  4. Firebro17

    Firebro17 Dazed, but not Confused
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    I've never paid any attention to what the tag says on the B post. I look at the recommended tire pressure on the sidewall and adjust it accordingly to suit the desired handling characteristic I feel is best suited for the set up and weather conditions. This may not be the best approach, but it works for me.
     
  5. TG.

    TG. Active Member

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    Hey I found this thread so I'll tag along :biggrin5:

    I don't know I mentioned it here but my last Michelin PSS got badly worn on the inside corner after only 16,000 miles with about 80-90% daily casual driving. And granted I forgot to rotate the tire this past summer and drove 8,000 miles straight without rotation.

    Here's the result after 2 rotations (winter swap) and 16,000miles:

    Rear (inside corner to the left):
    IMG_9118_zpsvawubs85.jpg


    Front (inside corner to the left):
    IMG_9117_zpsjpj2bnkd.jpg

    (inside corner to the right):
    IMG_9109_zpskkcqelms.jpg

    You can see both have a slanted wear right to left of the images.

    The car is going in for service next Monday and I'm going to have them check the alignment.

    Meanwhile I've been told that if the tires wear too much on the inside it could be because the tires aren't inflated enough. I thought I've kept up with the pressure :confused:

    So the manual calls for the R59 S says 205/45/17 @ 41psi.
    Should I inflate at 41 or higher with these tires?
     

    Attached Files:

  6. minirab

    minirab Well-Known Member

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    That would be for the factory runflats, I have Conti DW's on my R58 and run 36 psi in them. They are at 16k right now and show no uneven wear on them. They are not runflats.
     
  7. TG.

    TG. Active Member

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    So you're actually saying I should lower the pressure?
    I agree that run flat aren't the same type of tires.
    It doesn't tell me much what I should do with these specific tires :confused5:
     
  8. DneprDave

    DneprDave Well-Known Member
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    Your car has an alignment problem. If it were a tire pressure problem, too high tire pressure will cause wear in the middle of the tire, to low pressure will cause wear on the both edges of the tire.

    I had a car that wore the tires like that, it was bad ball joints. New ball joints and an alignment fixed it.
     
  9. whaap

    whaap New Member

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    ^^ this.
     
  10. TG.

    TG. Active Member

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    Although I forgot to mentioned both front tires have very similar wear, I'm hoping to get an alignment this Monday while taking the car for service.

    It's also interesting that there is an occasional faint but noticeable knock sound I've asked to have check as well. Maybe it's related!?
     
  11. Dave.0

    Dave.0 Helix & RMW Powered
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  12. TG.

    TG. Active Member

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  13. Dave.0

    Dave.0 Helix & RMW Powered
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    Then you need to go to a good shop to have it aligned correctly.

    Also my old Michelin SS did close to the same thing and I hate those tires.
     
  14. TG.

    TG. Active Member

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    Ah ah, I love those tires. I just don't like the wear on the MINI. I have them on my other car (granted they're a different size 225x45x18) and they haven't worn like that...

    Tires and cars need a good dating website :lol:
     
  15. TG.

    TG. Active Member

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    I'm not 100% sure I read this page correctly :crazy:
    I assume "after measurement" means the correction ?
    But it doesn't look like the alignment was the problem:

    MINI Alignement May3-2016_zpsgkhlikqb.jpg
     
  16. mrntd

    mrntd Well-Known Member
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    Tire pressure can be changed to suite your driving style and handling preference. Around town I have the DWs set at 38 on all 4. On fun roads 42 front 40 rear.

    There is an old auto cross trick to mark the shoulder for all 4 tires with chalk or a tire crayon then look where is worn after driving. That's where I came up with my higher pressures.

    The other variable is going to be tire construction, mainly sidewall. A softer sidewall will want higher pressures for more spirited driving.
     
  17. Qik

    Qik Well-Known Member

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    Next weekend will be my first real driving test with the MINI. I've driven her plenty on challenging roads and one track, but from what I've read and seen The Dragon is a whole different level. I usually keep all 4 of my tires the same PSI about 38-39. I have 215's on factory 17" wheels. Is it wise to leave a little less pressure in the rears than in the front? Being a muscle car guy originally, I'm used to leaving the rear's super low for launching in the 1/4, do the same sorta rules apply when looking for more grip in the rear for cornering?
     
  18. BlimeyCabrio

    BlimeyCabrio Oscar Goldman of MINIs
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    I usually run 32psi cold in the mountains. More grip.
    When up there, I run that as starting pressure front and rear. When hot, front pressure will be a bit higher (because they get hotter) which is what you want.

    What works best for you will depend on tire compound, alignment settings, and driving style.
     
  19. BruceK

    BruceK Active Member

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    Sorry in advance for the all caps.

    THERE IS NO RECOMMENDED TIRE PRESSURE MARKED ON THE SIDEWALL OF A PASSENGER CAR TIRE. THERE NEVER HAS BEEN.

    The values which tire manufactures list on the tire sidewall is the maximum tire pressure for that tire (just like they list the maximum load carrying weight of the tire). But tire makers have no idea (in almost all cases) what particular model vehicle the tire will be fitted to. They are just providing a threshold limit for tire pressures and load weight that is to not be exceeded.

    The recommended tire pressures are always set by the vehicle maker, (not the tire maker), after extensive testing with different loads, different vehicle options, etc. It's up to the vehicle owner to follow those, or modify them to suit individual driving style.
     
  20. TG.

    TG. Active Member

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    As I said before, tires and cars need a good dating website :lol:
     

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