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Discussion in '365 GT4 2+2/400/412' started by Longstone Tyres, Jan 27, 2021.

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  1. Longstone Tyres

    Longstone Tyres Formula 3
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    Dougal
  2. raemin

    raemin Formula 3

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    #2 raemin, Jan 27, 2021
    Last edited: Jan 27, 2021
    No comment on the fact that the guy is scared by the Dinoplex noise (6:39). He will have plenty of time to discover how temperamental these cars can be... I was not aware the injected boxers had center-lock wheels?

    My cylinder head failure occurred next to the very same building that can be seen at 17:37... (This road wants spirited driving).




    In case you wonder where he got this abstract: "The Italian Job" movie intro.

     
  3. bjwhite

    bjwhite F1 Rookie

    Mar 17, 2006
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    All BBs were center lock wheels and this continued with the Testarossa until they converted to 5-lugs in what, 1987?
     
  4. Longstone Tyres

    Longstone Tyres Formula 3
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    Is my fitment guide on my web page correct do you think?

    • The first of the 512 Berlinetta Boxer cars of 1976 fitted 7”X15” Wheels and 215/70VR15 Michelin XWX the front.
    • Unlike the earlier 365 GT/4 BB the 512BB had wider 9” rear wheels with 225/70VR15 Michelin XWX Until 1981.
    • Tyre pressure for the early Ferrari BB 512, we suggest 41psi in the front and 48psi in the rear.
    • In 1981 Ferrari added the fuel injection and 415mm Wheels and 240/55VR415 Michelin TRX Tyres to the BB512i.
    • The front Wheels of the 512BBi were 180mm and the rears 210mm. However the Ferrari BB 512i fitted 240/55VR415 TRX front and rear until 1984.
    • Ferrari Berlinetta Boxer 512i tyre pressures 45psi. front and rear are suggested.
     
  5. SouthJersey400i

    SouthJersey400i Formula 3

    Mar 14, 2007
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    I have seen a Boxer with the same TRX tires on the front and rear wheels that are significantly wider (2"?) at rear. It is a real stretch for the 245/55/415 tires. It almost looks rediculous on the car. MHO Ken
     
  6. raemin

    raemin Formula 3

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    Not everybody here is as hopeless as I am regarding the boxer, but that's not the forum we're you will find the BB crowd...


    As far as the Trx are concerned michelin does not list anymore tires larger than 245, so the boxers do have to make it do with our "narrow" tires on the rear.
     
  7. rovexienus

    rovexienus Formula Junior
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    Jun 10, 2010
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    Jean-Michel Savary
    The wheels of 365 GT4 BB and the front wheels of 512BB are 7.5" wide (not 7"), the same dimensions as the Daytona front wheels, the 365 GTC4 and the 365 GT4 2+2
     
  8. Longstone Tyres

    Longstone Tyres Formula 3
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    Oo well spotted thank you . I'll fix that.
     
  9. rovexienus

    rovexienus Formula Junior
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    Thanks Ken for your input, which raises a point about the wheels width for a 512BBi

    I took this picture of front and rear wheels side by side on the floor, the tyres are 240/55/415 for both wheels:
    Image Unavailable, Please Login

    They are subttle visual differences between the two (rear wheel with rim size 210mm is left, front wheel with rim size 180mm is right), I measured the overall width difference between the two wheels as 18mm (approximately). The face of the rear wheel rim appears to sit "deeper" with respect to the face of the wheel.

    According to the TRX specifications page on Classic Michelin (https://classic.michelin.com/en/Classic-Tyre-range/TRX), the rim size for the TRX 240/55/415 should be between 150mm and 195mm, which (unless I am mistaken) means that the above rear wheel rim size is outside of the range published by Michelin.

    I have sent an email to Classic Michelin asking to clarify this point.
     
  10. Longstone Tyres

    Longstone Tyres Formula 3
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    That is standard Ferrari. It is not uncomon for Ferrari to stretch a tyre onto a wider wheel. It started with the Daytona having the 9" Borrani RW 4300 option on the rear https://www.borrani.com/ferrari-wheels/365-gtb-4-daytona.html to fit 225/70VR15 XWX. The receomended ETRTO rim recomendation for a 225/70R15 tyre is 6" - 8". Howevere a 225 section tyre is of course slightly over 9" wide on an optimum rim, but that tall side wall does allow it to be somewhat stretched so 9" is not a ploblem.

    225/70 wasn't OE on Daytona they were 215/70VR15 XWX as standard.

    The first 512BB fitted 9" wheels on the back with 225/70VR15 XWX. It is a funny thing Michelin print in their books that 6"-8" rim is recomended for 225/70Vr15 XWX yet here it is in a 1980 Michelin fitment guide telling us that Ferrari are fitting 225/70VR15 onto a 9" rim against the ETRTO recomendations.

    It is my understanding that the reason for wanting to have a good half an inch of tyre overhanging your rim is to protect your wheel rims from curbs etc.

    in a Michelin book, granted under another section not the XWX, it states "For competition use, one inch wider is possible"

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    The reason you might want a wider rim on the back is to give the rear tyre more stability. which will help keep the handling progressive and predictable.
     
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  11. raemin

    raemin Formula 3

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    I would assume that Michelin would not recommend these narrow tires unless it is safe. But let's be clear: there used to be a perfect 280mm tire up until 2017 which does not appear on the catalog anymore! So BB owners have no choice but to "make it do" with 240 tires stretched on the wide rear rim.

    The fact that they dropped the 280mm tire is no good news: it may also happen to the 240mm tire.

     
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  12. Longstone Tyres

    Longstone Tyres Formula 3
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    Hi

    They did make a 280/45VR415 TRX, but i think it is more like 10 years that hey haven't actually made any for. And in all fairness i don't blame them that tyre was about as popular a leprosy I think the most we ever sold in a year was 10. I think some years i didn't sell any, but average would be 2 or maybe 4. That tyre only fitted the rear of the Testarossa https://www.longstonetyres.co.uk/classic-car-tyres/ferrari/testarossa.html and even then it was only for a few years

    I don't think the 280 tyre was relavent to the 512BBi was it? Or am i mistaken. Ferrari fitted 240/55VR415 TRX front and rear on the BB512i. That is right isn't it? I don't think the 280 ever fitted anything else that is why it was such a pain in the bum of a tyre.

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  13. rovexienus

    rovexienus Formula Junior
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    Thanks Douglas, I agree with you, as far as I recall the 280/45/415 was only for the rear wheel of the first Testarossa's. In that configuration, the Testarossa rear wheel rim size was 240mm wide.
     
  14. Newman

    Newman F1 World Champ
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    Dec 26, 2001
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    I didn't read the thread as throughly as I should but the lettering on the BBi rims is the rim width not the tire width. Interesting they chose the the 240 tire on all 4 corners compared to the carb'd car that had a wider tire on the wider rear rim. The 240 tire on the BBi also made the steering very heavy compared to the BB. Im happy with my 215/225 factory combo on my BB512 and it looks very 70's.
     

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