285 40 rear tyre profiles and clearance?

Discussion in 'Technical' started by WazTTed, Aug 11, 2016.

  1. WazTTed

    WazTTed Grease Monkey

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    anyone running a 40 profile tyre on the rears.
    ive currently got a 265 35 r18 on a 11" rim that looks stretched

    285 is probably the next best size .. is there going to be clearance issues with a 40 profile tyre? my zed is a fraction lower then stock height

    front tyre is a 245 40 r18 thought it may be better to have a bit more rubber in the rear for comfort !

    rims in question are a 11" +42 from memory
     
  2. ProckyZ89

    ProckyZ89 Senior Member

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    Are yours rears rolled and rear bar tab altered? You'll contact strongly if not
     
  3. WazTTed

    WazTTed Grease Monkey

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    Rear bar tabs ??? No nothing rolled at all . Looks like plenty of clearance at moment with the 265 fitted
     
  4. lidz

    lidz Well-Known Member

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    The "rear bar tab" is literally the tab where the rear bar bolts to the arch. If you look inside the wheel arch its at the back.

    That said a 285/40/18 will be way too tall, compared to your current 265/35/18 the sidewall will be 20mm taller & rolling diameter will increase by 40mm. It's also a whopping 55mm increase over stock rolling diameter.
    You actually would want a 285/30/18. Keep in mind the sidewall value (ie. the 40 or 30) isn't a set size but a percentage of the tread width so a 285/40 has a sidewall 16mm taller than the 245/40.

    Your fronts also a touch tall, a 245/35/18 would be a better choice when they need replacing
     
  5. MagicMike

    MagicMike Moderator Staff Member

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    11+42 is a bit of an effort, how sure are you?
     
  6. AndyMac

    AndyMac Better than you

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    285/40 is an SUV tyre...literally.
     
  7. WazTTed

    WazTTed Grease Monkey

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    Not 100 % at all all the stickers have blown off long ago , rim measures 280mm roughly lip to lip . Is there a way to measure offset ?
     
  8. MagicMike

    MagicMike Moderator Staff Member

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    Find the centerline of the rim, and then measure distance from there to the mounting face.

    As for width, I am fairly sure it is usually measured from bead to bead. So if your 280mm is from outside to outside, you are likely on an 18x10, and if you have untouched guards, a +42 offset is very likely.
     
  9. ZDUCTIV

    ZDUCTIV Active Member

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    Wheel width is measured inside bead flange to inside bead flange, not outside to outside just in case you're measuring outside. Think you had a picture up of it at some point but couldn't find it on quick search to check.

    As lidz said, 285/30 is the better profile for that width.

    Measuring wheel offset: here
     
  10. WazTTed

    WazTTed Grease Monkey

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    Never mind turns out wheel is 10" wide got some 265 35s for now
     
  11. pmac

    pmac Z,, IT'S COMPLICATED!!!!!

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    Just get your local tyre garage to try a few different options for you.
     

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