News

512tr wheels / 355 wheels what are differences?

Discussion in 'Technical Q&A' started by davey_jones, Feb 10, 2004.

  1. davey_jones

    davey_jones Formula Junior

    Sep 28, 2002
    781
    wherever it's sunny
    Full Name:
    Dave
    I'm considering new wheels for the 348. I was leaning towards the 18" 355 wheels but noticed another f-chatter had 18" 512tr wheels... Needless to say, they looked pretty nice!

    Besides appearrence, what else is different?
    Weight, offset, width, etc..
    thanks!

    dave
    indy
     
  2. To remove this ad click here.

  3. Mule

    Mule F1 Rookie
    Rossa Subscribed Owner

    Jun 25, 2003
    3,511
    Alaska
    Full Name:
    Mule
    I think the 328 with the TR wheels has all fronts on his car, so they are the same width front and back.

    Ferrari NA website should give you the diameter and widths, but not the offsets.
     
  4. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Davey, it would be easier to get and install 355 rims, and they look very similar to the 512TRs.

    The offsets are notablely different between 348 and 512. Trust me I spent way to much time dealing with modern Ferrari offsets.
     
  5. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,366
    Texas
    Full Name:
    Steve Magnusson
  6. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
  7. To remove this ad click here.

  8. Steve Magnusson

    Steve Magnusson F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    19,366
    Texas
    Full Name:
    Steve Magnusson
    Omar -- Thanks for getting that F wheel data together, but I'm puzzled by your pessimism regarding dave getting the 512TR wheels to fit on a 348. I know that the wider 512TR wheel widths can add general clearance complications, but since 348s typically take +25mm spacers on the stock rear 348 wheels (and the 512TR wheel positive offset is larger than the 348 positive offset), dave wouldn't be adding that much width in the inboard direction (if he moves the outboard sidewall out the 25mm) and would need a ~38.75 mm adapter so it seems quasi-possible to me at the rear (whereas your previous case of putting a wheel set with less positive offset than the stock wheels on a chassis is basically undoable as you presented) -- am I missing something?

    dave -- Have you tried contacting Sponsor Paul Hill at Hill Engineering for information?
     
  9. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Yea me and Paul are in frequent talks and he helped me alot with everything, in fact, he is the one who is the source for most of the offset values!

    Why I dont think 512TR will work? Here is my logic, and if I get bored enough I will calculate it out:

    360 Rims bolt on to a 348 straight with no spacers, no problems (I asked Paul, and provide you with a link to that effect also stating that). 360 Rims DO NOT fit on a ABS 328s without major spacing effects.

    Now, 512TR DO work near perfect on ABS 328s, implying their offsets are similar. Thus by a semi-sucessful application of the transitive property (512~328ABS which do NOT equal 360; and 360~348. Thus, 328ABS does not equal 348 and thus 512 does not equal 348...Transitive)

    I would have to work it out on paper first, and if you really want Davey I will do it for you, complete with diagram.

    355 rims are just easier since I am almost positive they bolt straight on.
     
  10. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Ok so if you dont like the transitive semi-BS ;), here is it mathmaticly:

    Ok, taking into account that the rears are very narrow on 348s and all the math,

    The difference is a -5.3mm in the Rears. Or that they would stick out 5.3 mm more then the OEM 348. Problem is that the 512 width is 10.5 while the OEM is 9...

    SO.... if you wanted to make them work, I suggest 20mm spacers. Since that way the 20mm spacer + the ~5.4 mm (that you get from the wheel itself) will compensate each other and you will get a track closer to the length as the stock (hopefully saving on clearence problems with what otherwise might pop up with a shorter track)

    But here is the cool thing, even though you have your wheels spaced out ~25mm, the actual contact patch location would be wider and coverng a larger net area then your current setup, and would overall be wider then the OEM track. In other words, the track taken from the face side of one wheel to the face of the other would be much longer then OEM, even though the track taken from the inside of the wheels will be slightly smaller.....I think.

    Nutshell, yes they work, but to make it work right, you really will need spacers or you will have major issues with your car (my guess if you have no clearence issues and do a straight bolt up: it will be that you will increase natural oversteer since the net track is on a smaller then the OEM 348, even though the wheels are wider and stick out slightly.)

    Understand what I mean?

    If I could get a hold of front 348 values I could do the front. If you are really interested I can talk to Paul about measuring my (hopefully) new coming 512 wheels to determine their actual offset....
     
  11. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    When comparing wheel cross fits, what range of difference have folks found workable, especially with respect to front wheel offsts that folks have tried? ( e.g., can pre ABS 328 wheels be used on an ABS 328?)
    I know I have seen 348 wheels used often on ABS 328 and Mondial ts
    In Europe at the dealer, MANY 348 owners were using 355 wheels.
    many thanks
    russ
     
  12. To remove this ad click here.

  13. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Depends what 2 cars. ABS to non ABS wheels on a 328, no; while teh other way around works well.

    What 2 cars did you have in mind?
     
  14. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner
    Many thanks! Your expertise in cross fitting is becoming a real resource.
    Looking at putting non-ABS wheels on an 88 ABS car. I had some concerns about scrub radius when decreasing offset discussed in another thread with a picture (http://ferrarichat.com/forum/showthread.php?t=8075)
    Had found a German picture of a Mondial 3.2 (with ABS as a late 328) running qv wheels, which would be the same as putting qvs on an ABS 328. It's my info that the ABS 328 and Mondial 3.2/t shared the same wheels. Any particular comments on drivability from what you have found?
    Again, many thanks - extremely helpful!
     
  15. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO

    308/328 PRE ABS: +11 (Front is 7" and Rear is 8" I believe)

    328 ABS: 7" with +38mm Front; 8" +63.5mm Rear.

    Since the widths are the same the centerlines will be the same, so the difference is simply the difference in offsets and is 27mm the front, and 52.5mm on the rear. It is the same as adding very very wide spacers. to the car, since the old wheels are really "deep" in comparison the later ones, so when they bolt on the longer 328 ABS hub, they stick out more.
     
  16. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Using all fronts from a 308 (7") would give you a +39.8 rear, still way to much.

    I believe that Mondials use a completely different offsets....
     
  17. snj5

    snj5 F1 World Champ

    Feb 22, 2003
    10,213
    San Antonio
    Full Name:
    Russ Turner

    Many thanks for the reply. The ABS suspension and wheels for the Mondial 3.2 and 328 are intersting to compare. While the wheels carry different part numbers, for example, the front stub axle, bearing and hub part numbers on both the 328 and Mondial 3.2 are the same, suggesting the same offset requirement. As an aside, the previous Mondial qvs have the same front suspension parts as the 3.2 and also share wheel part numbers with the earlier 8, suggesting all Mondial series wheels are interchangeable. When I bought my Speedline wheels, they listed the same wheels for the 328 with ABS and the Mondial 3.2. I think there are acceptable tolerences and overlap possibilities as you are finding.
    If I run the qv 16x7s all the way around with 11 mm offset, that would place the wheel centerline approx. 1" outboard of the stock, and the wheel rims 1/2 inch outboard, a tolerable quantity. The one thing I am unsure of right now is the effect of 1 inch more positive offset on steering geometry. The photo in the link clearly shows qv wheels on a 3.2, appearing like both 7 and 8 inch widths. I just don't know if the ~1" offset difference is a little or a lot - if the stock wheel centerline is inboard of the steering axis, 1 inch offset difference of the qv would actually help a bit for my purposes.
    Barring some revelation by someone smarter than me, looks like will have to start measuring relation to wheel centerlines and steering axis.
    Many thanks for posting such great information!!
    best
    rt
     
  18. 348paul

    348paul Formula 3

    Dec 27, 2002
    1,098
    Kent - UK
    Full Name:
    Paul Hill
    Omar

    348
    Front 7.5 x 17" (+49mm)
    Rear 9J x 17" (+68mm)


    Paul
     
  19. ernie

    ernie Two Time F1 World Champ
    Lifetime Rossa Owner

    Nov 19, 2001
    22,030
    The Brickyard
    Full Name:
    The Bad Guy
    The 512tr and 355 rims can both fit on a 348. You don't need spacers, the factory took care of this. The 348 gt competizione is the reason for this. The competizione used a split rim wheel that was made by speedline. The rims look very similar too those on a 512tr. The front rim of the competizione measured 8"x18". The same figure for the 512tr rim in the front. The rears of the competizione measured 10"x18". The same figures as for the 355. You don't need spacers because the factory took care of that. The earlier cars had a handling problem at high speeds. What they did to fix it was add more material to the inside of the mounting area of the rim. By doing this it moved the rim out further. As a result of the wider offset the handling problem was fixxed. So if you use the early 348 rims that is why people put spacers on them. If you have the later ones you don't need them. So the competizione shows that you can use either rims from the 512tr or the 355. Yes the 512 rims are .5" wider in the back, yes there is room for them in the rear of the 348. It is a tight fit, but they fit. Also I have seen three 348's with the 512tr rims on them.
     
  20. davey_jones

    davey_jones Formula Junior

    Sep 28, 2002
    781
    wherever it's sunny
    Full Name:
    Dave
    excellent info!

    The "tight fit" issue brings up another question..
    Should I have my fenders rolled?

    Not sure who posted this pic, but is a 348 with 512tr wheels - it certainly looks tight! I briefly thought about lowering the car but that option may be ruled out with the new wheels...
     
  21. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Cool picture as it semi confirms what I thought, The wheels indeed do look like they are stuck out a bit further then normal. When I said "way too much" I meant that the rim sticks out the side of the wheel well...something I don't like astheticly, and will kick up way too much debree onto the sides for me to even think of.

    What effect does this have on handling? Depends. If the overall front track is wider then the rear, you get oversteer and vice versa. If both are equally wide then your suspension will be less stiff, but your grip is higher.

    How does it "feel?" I cant say since I havn't yet tried...
     
  22. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    You completely glossed over the offset differences...
     
  23. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    No you will be fine if you get the right rubber for the car. If you do go this way I will help you with that.

    The tight fit is due to how far back the 512 rear will go INTO the wheel well, not how high it will be. I know this can be confusing how I am writing this, if you really want, I can make diagrams too to show what will happen. I am not saying they dont work at all, I am just saying it easier with 355 rims.

    Tell me what you definately want (512 Front and rear? just front? 355?) and I will help from there as much as I can.
     
  24. Auraraptor

    Auraraptor F1 World Champ
    Lifetime Rossa Owner

    Sep 25, 2002
    11,442
    MO
    Thanks Paul!

    If you can can you post the offsets you know in the other thread so we have all of them in one place? Thanks!

    Also, just wondering, how far are you from FoUK's warehouse?
     

Share This Page