348 - My 18" wheel thread | FerrariChat

348 My 18" wheel thread

Discussion in '348/355' started by Ferrarium, Jun 7, 2020.

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  1. Ferrarium

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    #1 Ferrarium, Jun 7, 2020
    Last edited: Jun 7, 2020
    Taste is subjective there is no right and wrong here. I drive on street only as well.
    The 348 I always felt has too short a rear tire and too tall a front tire. I really wanted 18" wheels but a 7.5" front rim do that left most if not all after market wheels as a non option and 360 and 355 the main contenders. On the 348 I really like the 360 wheels in gun metal (have to refinish for that). My plan was 360 wheels and even found a machine shop to machine them locally. But I stumbled across 355 wheels 4 hours from my house so I drove down and picked them up, at under 2K it was hard to pass up, geez they are light! They are in good condition, not great, probably 8 out of 10.

    So now it comes to tires. Here is the 348 and 355 OEM sizes DIAMETER X WIDTH
    348 front 355 front
    25.5 X 8.5 R17 25.1 X 8.9 R18

    348 rear 355 rear
    26 X 10 R17 26.3 X 10.4 R18

    There are various tire options some even match the 348 size but a 295/35 for example is much wider and heavier and while it looks great I want to minimize weight and address the 348 size imbalance as I see it that I mentioned in the first sentence. It's actually 1mm taller than 348 so its in the right direction at least. 275/35 are also used but are 1/2" shorter making wheel more apparent and 285/35 is about the same size (wee shorter) but it also wider/heavier and again the whole size thing.

    The 360 rear wheel it too large btw I have seen it, it looks balloonish, the car is too small for it. The 355 got it right with 265 and 225 combo. The problem is as I see it is they should have done a 9.5" rear rim not a 10" rim. It can cause the tire stretched look. Its important to note that not all tires of a given size are the same width, some tires of 1 size are actually wider than another brand 1 size up. Get one narrow and it will look more stretched than another option. So clearly the option as I see it for me, was finding the widest 265 section width and the 225 is less a concern width wise but hey, if I can get a 255 that has section width close to 215 then great.


    Folks can start here for size and widths to do selection then you move to Tire Rack and dig in to each tire spec.
    Sizes -> https://tiresize.com/chart/
    Tire Rack -> https://www.tirerack.com/tires/TireSearchResults.jsp?tireIndex=0&autoMake=Ferrari&autoYear=1996&autoModel=F355&autoModClar=&frontWidth=225/&frontRatio=40&frontDiameter=18&frontSortCode=53650&rearWidth=265/&rearRatio=40&rearDiameter=18&rearSortCode=54350

    So I was after widest 265 to reduce the stretching look. I wound up selecting the Continental EXTREME CONTACT SPORT in 265/40 and 225/40 which is for example 1/4 wider than the Michelin 4S. But is actually has a tread width narrower than the Michelin so moire like the 348 so less rolling resistance on paper at least. So I get a high performance summer tires rated about the same as a Michelin PSS and should fit the overly wide rear rim (my opinion only) better.

    So Compared to OEM 348 tire sizes here is the basic height difference compared to a 355. Front to rear difference is 7 mm diameter (3.5 mm radius) higher ride height in the rear. Brands differ in width (some quite noticeably) not in height.
    • Front height difference - 4 mm (2 mm radius)
    • Rear height difference + 3 mm (1.5 mm radius)

    To maintain 348 balance one would need coil over adjustments, none in front all in rear adjustment for my preference. It will have a larger rear tire and lower the arch filling in the rear well better and it will have the factory balance. Win win win. The front will be 1/8 lower but that's fine. I hope it does not add to the scraping problems too much, the 348 front lip is lower than the 355. It looks better too. :)

    The rear coil over calculation is as follows to lower the rear and maintain 348 balance:
    1. Front suspension change 0 mm
    2. Rear suspension change -3.5 mm ( 3.5 * .85 = 2.975 / 1.5 = 1.98 turns down) (Round to 2 turns)
    I bought a few tools for the job, jack cross bar (thanks to Wade for pointing that option out), spanners and strut compressors. I had to cut the strut compressor threaded rods to clear the frame (you can see it in the picture, they did not fit before cutting them). I marked the spring perch so I can count 2 turns. Then I put the compressors on and used electric ratchet to spin the screw compressing them. The coil compressed and lifted from the perch. Easy peasy. I used the spanner to unlock the lower lock nut and tightened the perch 2 revolutions. For reference spanners were not needed, I could turn the perch by hand after unlocking the lock nut, I could have knocked that loose with a socket extension end and a mallet easily. No penetrating oil or grinding on threads compressing under spring tension or anything. Just stupid easy as you would imagine it should be.

    Tires get mounted Tuesday, let's hope it all works out and looks amazing.:cool:






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  2. ATLdoghouse

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    Great project. How much lighter are the 355 wheels compared to the oem 348 wheels ? Also, what floor jack are you using the the cross beam ?
     
  3. Ferrarium

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    The cross beam is Daytona, I got it from harbor freight, (I drove 10 hours for vacation to Mountains of NC, pulled over for gas and there was a harbor freight, I went in and they had 6, they are sold out everywhere can't you cant get them online) but they fit most jacks, I have a Pittsburgh floor jack from harbor freight and it fits.

    I do not have the 348 wheels off and I am keeping the tired on them so I am not sure but the 355 wheels are stupid light.
     
  4. nismodrifter

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    haha from your previous posts on the forum I can see you are really passionate about the short rear tire/tall front tire syndrome.

    Here is one owner that I felt corrected the situation very very nicely:
    https://www.ferrarichat.com/forum/threads/550-maranello-wheels-on-348.426685/
    ^see page 2 and 3 for pics after it is lowered along with ijvpets black 348 Spider with similar setup.
     
  5. Ferrarium

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    #5 Ferrarium, Jun 8, 2020
    Last edited: Jun 8, 2020
    HA HA and yes! I am passionate about everything on these cars. I phone nothing in. :)

    yep, I wanted those 550 wheels quite badly, found a few too, I think they are the best looking 348 wheel period. But have you see how wide they are? 8.5" and 10.5". Starts to get tires too wide and heavy for the power plant for my personal opinion, plus the manual steering thing. If the 348 had 375 HP it would be a no brainier I'd put electric steering in. Dang those 550 wheels do look good. The HRE P47s are also amazing, there are knock offs of them out there. I have scrolled though every wheel or tire thread out here going back to early 2000's several times. Seen them all.

    As stated there is no right or wrong here. Some folks stick 275's on and let it roll with no adjustments, that fine. It is all subjective some folks love that look some like 360 wheels sticking out, what ever its all good. I have a symmetry issue wit things in general, I walk down a hall and notice the ceiling is not level and the baseboards are not gaped correctly and that poster is .5 higher than the other one next to it and the one on the left is not plumb. :eek:

    BTW I think I am the only person on the planet who does not like challenge wheels. Can't put my finger on why either, my brain just flat rejects it but when I try and ask it why, I can't figure it out.

    It's not like I think the 355 wheel is the end all be all either, its like #4 on my list but at 2K why not I can always sell them for more. :)
     
  6. Ferrarium

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    My overall ride height is 1/8 lower, my rear fender gap is about 3/16 less, the rear rim extends 2.8mm out farther than the later 348, the front rim with 11mm spacers sticks out 4mm more than the 348 with 11mm spacers. I will take the spacers and have 6mm machined off. Good thing I fender rolled for now.
    This is as far as I got so far with work etc. I have to put then fender liners back in, ugh.
     

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  7. Ferrarium

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  8. KevZep

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    Great thread, and timely as I am about to do tyres on my car, I am using information from this to make some changes to my sizes...
     
  9. Ferrarium

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    Something did not look right, I went and measured the left side of my car is 8mm higher than the right so I need to adjust the coils, the drivers side is within spec, passenger side is high. And I paid mega dollars for mega expensive shop here in NJ to set the height and do the 4 wheel alignment. So I need to do the height myself then take it back in somewhere else for an alignment. I swear shops just suck. Everything they touch is wrong somehow.

    I am glad someone finds this useful I would have loved a detailed thread.
     
  10. Ferrarium

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    Look at that tire size in post #7, it is 1 size wider, imagine 3 or 4 sizes wider, good googly goo!
     
  11. KevZep

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    Setting ride heights can be tricky, its never as straight forward as it seems.
    I have to agree with you that "everything they touch is wrong", a lot of the time I don't believe its intentional, they are more concerned with achieving a particular amount of chargeable work per day....
    I was a mechanic as a Toyota dealer in the '80's/early '90s so I get it.

    This is why I decided to go ahead and do my engine out service myself, I knew I could take my time and make sure it was right...

    I trust you do have these Doo-Dads to adjust the coil platforms? If not definitely get some...
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  12. Ferrarium

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    Ohh you bet, Ferrari 348 specific ones actually. The ones you have work better I am certain.
    The WSM has the front and rear ride heights as well as the measuring points for front and rear in the suspension section btw.

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  13. QSA

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    Car looks great Eric. I think the 355 wheels look awesome and period-correct on the 348.

    Not sure if that is your final settings, but I would consider lowering the rear a half inch, or so.

    Have you used that cross beam yet? Been thinking of buying one from HF. Looks like it would be perfect for jacking up the rear cradle.
     
  14. Ferrarium

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    Yep you can see the cross beam in the first post, it's freaking great.

    Not sure about lowering the rear the spec is 125-130 mm for ground to chassis and driver side is 129 with no driver. The passenger side is 137. So I will fix that.

    I fear if I adjust the rear based on looks and go down 12mm in the rear the car would scrape and it would create understeer. 1-2 mm is alll it takes to change balance.

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  15. Ferrarium

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    I am going to reset the ride height to factory, then lower the rear 1/2" then get it realigned. What exactly did they do when I paid for an alignment cause they sure did not check height first.........
     
  16. Ferrarium

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    #16 Ferrarium, Jun 10, 2020
    Last edited: Jun 10, 2020
    It's just not right... I will lower the rear a tad but I looked and measured and looked and it turns out the 25mm spacers with the 355 wheels push the tire shoulder closer to the fender making the gap more prominent since it actually sticks out the front and rear where the body curves under. When tucked under its less apparent. I never really looked at my OEM 348 and said that rear gap is too much, but I find myself saying that with less of a gap now.

    I believe the solution is the Hill 15mm instead of 25mm used for the 348 with the narrower tire. The 25mm spacer pushes the wider rim and tire out too far, it starts to get that jacked up Camaro look. Lowering it will help yes but it needs to get back under the fender I think.
     
  17. Ferrarium

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    A 15mm spacer will push the wheel inboard 8.6mm more than the 348 wheel with 25mm spacers (or the later offset 348 wheel its the same). With the chunkier tire that should look right the 348 was on the edge outside distance for my eye.

    25mm spacers are not for me with 355 wheels.... Let me get those in and lower the rear 1/4" and see I'll post updated pics for others to see.
     

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  18. Ferrarium

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    Ok ride height is all jacked up, explains doggy steering at higher speeds. The front clearance is 4" so 1 inch too low just to get to minimum spec. I have to raise the car back to stock spec then lower the whole car 7mm. Have to adjust it, put it all back together, take a quick spin to settle it, then measure and do it all over again. I will do the alignment myself for toe and camber when I am done.

    How to adjust front ride height.
    1. Pull the trunk liner (I am so sick of doing that, hidden fuse, aux pump, flap motor etc etc all different maintenance)
    2. Pop off the sway bar and and rotate it down, pop off the tie rod end, pop off the lower ball joint (when it gives it goes off like a gun) , remove the 2 lower shock bolts and mind the caster shims (I taped and marked them)
    3. Use a jack to hold the hub up.
    4. Move the ABS unit out of the way and remove the top 4 shock nuts. (note the glass bullet AC fuse mod )
    5. Pull the shock out from the bottom.
    6. Put on spring compressors, compress, unlock lock nut, turn the seat. It turns quite freely with the spring compressed. Shorter spring raises the car, Longer spring lowers the car.


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  19. KevZep

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    Why are you pulling everything apart? Or did I miss something?
    Nothing needs to be disconnected or pulled apart for setting ride height.
    All you need to do is compress the spring, loosen the locking nut and simply adjust the platform. I did this last weekend, it’s really very straightforward. You can do this without pulling anything apart. All you need to do is take the wheels off.
    I use my vernier calipers preset to the amount I want to move the platform, and just wind it up to the desired height until I can get the inside jaws between the platforms and locking ring/nut, job done.
     
  20. Ferrarium

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    #20 Ferrarium, Jun 19, 2020
    Last edited: Jun 19, 2020
    This is the front, the rear is easy on the car you can compress the spring more than enough. On the front, to lower this is true what you say, its much easier, but to raise 11 turns its tough even if I take tension of the spring with compressors. I have 2 style different compressors even. Plus the lower shock bushing needs to be replaced. You can see the shiny zinc area which is how much I had to raise it. Now when I am done... if I have to lower a side I can do as you say.

    Takes little effort to remove btw. I replaced all the ball joints and tie rod ends, and steering rack etc awhile back.
     
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  21. Meister

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    I'm sure you have considered this but careful lowering the front too much. On my previous 348 the PO had lowered the front and installed 360 wheels. Well that was fine in the suburbs of Chicago, but I live in a hilly city and in no time at all the tires started catching the inner front fender lips and tearing them up. If you have things this far apart you may want to look into rolling th inner fender lip just as a precaution.
     
  22. Ferrarium

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    Good point but in this instance I am not lowering I am raising the front, it was over an inch below minimum spec. I am dead certain the shock is not even functional that low.

    BTW here is what the shock bushing should look like and what it does look like. I assure you this is not specific to me, its an age and gravity thing. Notice its all spooged and swollen out the sides. Now I need to mock up a press to press it out, polish the bung then press the new one in. I'll take pics and post it. Taking the shock out is very easy. 30 minutes.

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  23. KevZep

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    Oh I see, I thought there must have been some sort of logic I was missing. I am talking about the front though, the rear does have a lot more room to get the the spring compressors in for sure.
    I raised my car 12mm at the front so it was fairly easy.
    It’s easy to get one spring compressor in, the other was a bit tricky but still easier than ripping everything apart, however I will be having to do that when I replace all the suspension bushes at some stage....

    I do enjoy your threads, always good information.
     
  24. Ferrarium

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    The front shock bushing was the issue. Has to come out for that so 2 birds. It's causing sag and it will get worse and more uneven. I can't get the bushing out with sockets and grade 8 bolt, the bushing bung is so thin. I am going to a machine shop Saturday and have them turn some custom mandrels and then press in and out. So I will have some mandrels for others perhaps.

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  25. Ferrarium

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    Ok both front bushings are collapsed at different rates which explains difference in corner height. Fixing it with coild adjustment is just masking a symptom. I bet the rear are worse... One thing at a time. Should have done the shock when I did suspension ball joints etc. Ugh.

    I raised the front higher than j know it has to be so lowering with shocks in will be easier, you can use 1 compressor and just take tension off. Few turns here it there is no biggie on the car. All my measurig is out the window have to out it back together drive it to settle it then redo height. Then align old skool way.

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