Am i being too fussy about proper tyre fitment on my 355 wheels? | FerrariChat
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Am i being too fussy about proper tyre fitment on my 355 wheels?

Discussion in '348/355' started by Blacksku11, Feb 21, 2013.

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  1. Blacksku11

    Blacksku11 Rookie

    Apr 12, 2012
    40
    #1 Blacksku11, Feb 21, 2013
    Ive gone and bought a set of 355 wheels for my 348, now i need a set of new tyres. I ve read so much about tyre fitment my heads spinning.
    Ive decided to go for Pirelli PZero as its the original fitment, but Direzionalis are so hard to find. Esp at the moment as Pirelli are out of stock themselves.
    Im leaning towards Directionalis front and Asimmetrico rear, some say Rossos front or extra load front Asimmetrico and rear but thats a no with Pirelli Technical!
    Even tho these are completely different to the 348 set up i want to fit the correct tyres to the wheels 355 wise!
    Im not taking the car to track days etc, just normal road use with the odd high speed blast every now and again lol.
    Past experiences both 355 and 348 with 355 wheels would be greatly appreciated!
    Thanks in advance
     
  2. BigTex

    BigTex Seven Time F1 World Champ
    Owner Rossa Subscribed

    Dec 6, 2002
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    Bubba
    #2 BigTex, Feb 21, 2013
    With a 348 I'd be VERY careful with mixing tire styles...

    No experience with 355 wheels, I'll defer to 348 owners..the car is kind of 'tail happy' reutation to start with, unless it's a late year or there's a rear stagger update of some sort...widens the track.

    Best wishes!
     
  3. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    9,732
    #3 Mitch Alsup, Feb 21, 2013
    Correct procedure:
    A) choose F355 tire sizes (225/40ZR18 F, 265/40ZR18 rear (or 275/40ZR18R))
    B) have them mounted and balanced.
    C) take the car with new tires and have it ride height adjusted to F355 ride heights
    D) then have the car corner weighted, finally aligned to F355 alignment specs (except leave the front caster at 348 specs (5 degrees) since caster on the F355 is for a power steering rack (7 degrees))

    It is the ride height adjustment prior to corner weighting that puts the chassis back where it is supposed to be. And at this point you can fine tune the oversteer/understeer relationship with minor tire pressure adjustments.

    ETA:: the tires on the front and rear wheels must be from the same manufacture, make, model and hopefully manufactured in the same month. Nothing less is acceptable for high performance vehicles.
     
  4. Kaivball

    Kaivball Three Time F1 World Champ
    Owner

    Jan 11, 2007
    35,997
    Kalifornia
    #4 Kaivball, Feb 21, 2013
    I am using challenge wheels and have 245 in the front and 295 in the rear.


    Kai
     
  5. SoCal1

    SoCal1 F1 Veteran
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    Tim Dee
    #5 SoCal1, Feb 22, 2013
    Any rubbing in the front? 245/40 ?
     
  6. Kaivball

    Kaivball Three Time F1 World Champ
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    Jan 11, 2007
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    #6 Kaivball, Feb 22, 2013
    Nope. Perfect fit.

    Kai
     
  7. SoCal1

    SoCal1 F1 Veteran
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    #7 SoCal1, Feb 22, 2013
    Thank you much, I am getting around to putting my challenge wheels on, want some meat on them.

    245/40
    295/35

    sound like a deal, just need to find 295/35's getting harder and harder
     
  8. Kaivball

    Kaivball Three Time F1 World Champ
    Owner

    Jan 11, 2007
    35,997
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    #8 Kaivball, Feb 22, 2013
    Stop!,

    My apologies.

    After your message I went out and checked.

    I am running 235, not 245!!!!


    235/40/18

    295/35/18


    Sorry for the mix up.



    Kai
     
  9. Kaivball

    Kaivball Three Time F1 World Champ
    Owner

    Jan 11, 2007
    35,997
    Kalifornia
    #9 Kaivball, Feb 22, 2013
    My stock is 215/50/17 and the 235/40/18 is the exact diameter equivalent.

    Same with 255/45/17 and 295/35/18.


    Running challenge wheels.


    Kai
     
  10. SoCal1

    SoCal1 F1 Veteran
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    #10 SoCal1, Feb 22, 2013
    Thanks Kav

    :)
     
  11. Blacksku11

    Blacksku11 Rookie

    Apr 12, 2012
    40
    #11 Blacksku11, Feb 22, 2013
    Thanks for your replies!
    Im sticking with 355 fitment 225/40/18 and 265/40/18
    I have an early 348 92 model so i have 15mm spacers front and 25mm rear, so i will be using these with the 355 wheels if need be.
    I ordered Direzionalis Asimetricos today should have them in approx 10 days, cant wait!
    The diameter difference between the 348 17" and the 355 18" are around 8mm greater with the 355 fitment, my tyre supplier worked it out. Never really took the ride height into consideration until now, thanks for that.
    Think i will leave ride height settings alone unless im not happy with the handling of the car, fingers crossed i will be!
    One of the reasons i created this thread was because ive read other threads with other members fitting Michelin's Goodyear Bridgestone etc. Reason being tyre wear on Pirellis being poor, handling and effecting the front end, not to mention car insurance.
    Saying all that for the sake of a couple of 100 pounds i think its best keeping it OEM, were have i heard that before!!!!!!!!!
     
  12. John Glen

    John Glen Formula Junior

    Dec 30, 2009
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    #12 John Glen, Feb 24, 2013
    I don't think you need the spacers with the 355 wheels as the offset difference will make up the difference.
     
  13. tazandjan

    tazandjan Three Time F1 World Champ
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    #13 tazandjan, Feb 24, 2013
    The best max performance tires out there right now are Michelin Pilot Super Sports. They will corner and brake better than the Pirellis and have a much longer life. Just looked and they have both the 225/40 18 and 265/40 18 sizes available.
     
  14. 348Jeff

    348Jeff Formula 3

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    #14 348Jeff, Feb 25, 2013
    Last edited by a moderator: Sep 7, 2017
  15. Extreme

    Extreme F1 Rookie

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    #15 Extreme, Feb 25, 2013
    Looks good although I must say in the last picture the rear wheel looks stange, it doesn't seem to fit in the wheel well right. It's probably just the angle of the picture.
     
  16. 348Jeff

    348Jeff Formula 3

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    #16 348Jeff, Feb 25, 2013
    Last edited by a moderator: Sep 7, 2017
  17. Extreme

    Extreme F1 Rookie

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    #17 Extreme, Feb 25, 2013
    I figured it was but had to wonder out loud.
     
  18. Blacksku11

    Blacksku11 Rookie

    Apr 12, 2012
    40
    #18 Blacksku11, Feb 26, 2013
    Didnt think id get away without using spacers, ah well at least i have them already!

    Ive been reading your 348 resto Jeff, just hadnt got as far as you changing your wheels. I read the start and now the end will have to do the middle sometime soon lol. Out of curiosity what tyres did you fit? Was trying to read the tyre walls but couldnt!
     
  19. 348Jeff

    348Jeff Formula 3

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    #19 348Jeff, Feb 27, 2013
    Hi I bought Falken FK-452 225/40 R18Y on the front but was struggling to find right size for back (which are supposed to be 265/40 so ended up getting 275/40 R18Y for the rears which are only 10mm wider.
     
  20. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    9,732
    #20 Mitch Alsup, Feb 27, 2013
    In another brand, this is what I run, just lower the rear by 1.5-2 turns and the rake returns to the same as with stock fitment.
     
  21. Blacksku11

    Blacksku11 Rookie

    Apr 12, 2012
    40
    #21 Blacksku11, Mar 2, 2013
    Last edited by a moderator: Sep 7, 2017
    Hi Jeff
    Those sizes are quite common on the rear, with 235 on the front .Went with 225 and 265 X 40 in the end. Got the tyres fitted after work yesterday and fitted wheels this morn. Am really pleased with the wheel tyre combo. (355 Spec) I used the same spec of spacers as yourself, was wondering Were Alloys Uk bolts more reasonably priced than Hill engineering? Thought Alloys UK website a tad confusing when pricing the bolts, maybe it was the wine lol! Anyway my bolts are a bit shabby, was thinking of some new shinny ones :-D
    Image Unavailable, Please Login
     
  22. 348Jeff

    348Jeff Formula 3

    Oct 25, 2011
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    #22 348Jeff, Mar 2, 2013
    Looks good! :)

    Yeah, bolts were cheaper - Id just ring them TBH as I found website confusing too I actually ordered wrong spacers which they kindly pointed out! DOH!

    This is what I ordered

    348 DIY "Restoration" - Page 94
     
  23. Blacksku11

    Blacksku11 Rookie

    Apr 12, 2012
    40
    #23 Blacksku11, Mar 7, 2013
    Ok so I've fitted the wheels with spacers and IMO looks great!
    Prob is I've loads of understeer. The car was fine with oem wheels with spacers.I've had the car read by laser 4 wheel alignment. It showed red in every corner.
    Before geting it done I thought I'd do some research first. Ie Shims toe setting etc. I'm a bit puzzled about the understeer bring so much. Has it to do with the off set difference between the front 348 and the 355?

    Cheers
     
  24. Mitch Alsup

    Mitch Alsup F1 Veteran

    Nov 4, 2003
    9,732
    #24 Mitch Alsup, Mar 7, 2013
    So, do you want it to look great (IYO) or to drive great?

    These cars are set up to be "lively" from the factory with minimal understeer. This effect can give the uninitiated a bit of concern for oversteer (348s more than F355s).

    Widening the front track increases oversteer. Widening the rear increases understeer.

    You can also raise the rear by a couple turns on the sprng perches to induce oversteer and tune the car back to normal.

    For minor amounts of understeer, you can try some tire pressure adjustments.
     
  25. Blacksku11

    Blacksku11 Rookie

    Apr 12, 2012
    40
    #25 Blacksku11, Mar 7, 2013
    Dont think there is any harm in wanting both LOL

    The problem is the lively which i loved has gone im afraid, just want it back. The front track has been reduced via the 355 offsets. You can visually tell. I noticed it immediately i fitted them.

    Front
    •348: 7.5Jx17, ET49mm
    •355: 7.5Jx18, ET46.15mm

    Rear
    •348: 9Jx17, ET68mm (early), ET43mm ('93 onwards - essentially integrated a 25mm 'spacer' into the wheel hub to improve handling)
    •355: 10Jx18, ET77.9mm

    I will reduce or remove the rear spacers to increase oversteer on the front. thanks for reminding me about the difference in handling by the rear being wider. When i 1st got the 348 i read the ultimate handling was 25mm rear front as is. I tried it and didnt like it until i fitted 15mm front spacers.

    Once im happy il get ride height and alignment sorted, thanks for the advice. Any more would be appreciated. ;-D
     
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