tyres rubbing inner guard

Discussion in 'Technical' started by WazTTed, Mar 13, 2017.

  1. WazTTed

    WazTTed Grease Monkey

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    i have a rubbing issue with my front tyres under compression or sometimes turning..

    fronts are 245/40/R18 there is only a rubbing issue on the front edge, the passenger side has even slightly rubbed the coolant over flow bottle.

    would it be worth going to 235 with a 35 profile would this give me much more clearance ?
     
  2. MikeZ32

    MikeZ32 das Über member

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    Good question, I have the exact same issue but I suspect it has more to do with the wheel size and offset than tyre profile.

    What size front wheel?

    8.5 +25 here. I may test fit 9 +35 with a 235/40/18 tyre at a later stage.
     
    Last edited: Mar 13, 2017
  3. ProckyZ89

    ProckyZ89 Senior Member

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    What style tyre
    I didn't have any issues on my 245/40/18 until I went to a R compound tyre.
    Dropping to 245/35/18 will give you the few mm you need I'd wager
     
  4. QLDZDR

    QLDZDR ID=David

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    Caster settings/adjustment?:bash: can the wheels be moved back a couple of mm
     
  5. East Coast Z

    East Coast Z Well-Known Member

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    Tyre sizing

    Your 245/40/R18 tyres are:

    3.1% larger in diameter & circumference & 7.3% wider compared to the 225/50/16 tyres originally fitted to a TT.

    In addition, the OEM 7.5" wheel has a 45mm offset.
    The OEM 8.5" wheel has a 35mm offset (but different tyre size).
     
  6. WazTTed

    WazTTed Grease Monkey

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    That's interesting what size tyre would be the same size as a stock wheel ?
     
  7. lidz

    lidz Well-Known Member

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    Yeah tend to agree, your sidewalls too tall.

    1010 tires have a good tire size calculator tool for comparing tyre sizes (excellent wheel size one too).

    Stock size of 225/50/16 have an overall diameter of 631.4mm, your 245/40/18 tyres have an o.d. of 653mm. That's an extra 22mm, pretty big difference.

    A 245/35/18 has an o.d. of 628mm so 2.5mm smaller, that's the closest you'll get to stock in that sort of size.
    The 235/35/18 is 621mm so 10mm smaller than stock, too far the other way really but definitely no rubbing issues!
     
  8. ProckyZ89

    ProckyZ89 Senior Member

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    Could do what I did and just cut back the lining till only the rear fender portion remains -

    Give a bit of shielding to the wiring along underside of fender and if needed make a small curved shield to put against the front bar and overflow
     
  9. WazTTed

    WazTTed Grease Monkey

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    I have 2.5" intercooler piping sitting behind the guards aswell so not much room to spare
     
  10. East Coast Z

    East Coast Z Well-Known Member

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    What is the rim width & offset?
     
  11. WazTTed

    WazTTed Grease Monkey

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    There a +35 8.5" wide
     
  12. East Coast Z

    East Coast Z Well-Known Member

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    If those details are correct, the rim sizing is not your problem.
     
  13. QLDZDR

    QLDZDR ID=David

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    If you compare your Zed speedo with your GPS indicated speed (or use an app on your phone that is in a hands free mount) is your GPS speed over or under the Zed speedo?
     
  14. WazTTed

    WazTTed Grease Monkey

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    It's actually pretty accurate as far as I can tell . I do have a 320km speedo tho .
    Do you think dropping to a 235 40 or a 235 35 is worthwhile 235 35 is actually smaller then a stock setup so I may loose ground clearance
     
  15. lidz

    lidz Well-Known Member

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    see my post above, ideal size is 245/35/18 for your front wheels. It's within 2.5mm of stock outer diameter.

    The 235/40 is still 645mm o.d. which is still 15mm bigger than stock.
     
  16. zx299

    zx299 Well-Known Member

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    The problem may lie elsewhere ......

    That wheel/tyre combo should only be about a poofteenth (>10mm) taller and should only poke out about under 1" (25.4mm) more than the oem combo

    So unless your tyre manufacturer is known to turn out markedly 'oversize' tyres, I would be looking at wheel alignment issues (possibly caster, as mentioned elsewhere in this thread)
     
  17. QLDZDR

    QLDZDR ID=David

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    I hacked up the OEM caster bush in the radius rod because that is how you get them out without a bush press tool. Well I think it is an OEM.
    If the rubber outer completely fails, the solid cross shaped core would allow your wheel to shift 15mm closer to the front wheel liner.
    Wider tyres would also cut a wider arc in the wheel well.

    Does it rub harder if you are reversing out of a parking space with wheels turned fully to left or right.

    [​IMG]

    If your bushes are new/replaced...
    Do you have adjustable radius arms?
    Is the current length longer than stock?
     
  18. WazTTed

    WazTTed Grease Monkey

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    No adjustable arms at the front end I do have es poly bushings in the front tension rods .
     
  19. MikeZ32

    MikeZ32 das Über member

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    Running same size tyre and rim width on the front as yourself but with +25 offset, plenty of caster though with adjustable tension rods and it rubs on the front liner on hard lock and some times on compression. Suspect it's more in the tyre than anything else.

    Main issue is, 245/35/18 isn't a common size! Most of them are 40 profile and it's either downsize to a 235/40 or nothing at all. At the time of buying my tyres they didn't have 235/40 in stock which sucked too.
     
  20. QLDZDR

    QLDZDR ID=David

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    [​IMG]

    Well I think my wheel is more forward than it used to be. The wheel shift backeards when I use the brakes.
     

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