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  1. 365man

    365man Rookie

    Sep 12, 2007
    13
    Northern California
    Full Name:
    Rick
    Moving this thread from the 308 discussion on XWX, and the modernization of current production XWX tires and how that compares to modern BF Goodrich tires (which are not rated for high speed).

    Question: when one says "keep in mind that today's technology and tire quality is 30-40 years better than what came on the car originally." are we suggesting that the XWX is still made with 30-40 year old technology? That is, has anyone asked Michelin if they are using the same old compounds and assembly methods, or are they (I would think so) using more modern compounds and processes? And that presupposes that the BFG is not >20+ years old itself. ??

    I'm in need of tires for both a 4-cam and Queen Mother, and am at a loss: XWX to look good but "firm" riding, versus the BFG which has a low speed rating.

    Curious if anyone has compared the ride of the XWX to the BF Goodrich on a vintage through C/4 model?
    Aloha.
     
  2. miurasv

    miurasv F1 Veteran

    Nov 19, 2008
    6,838
    Cardiff, UK
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    Steven Robertson
    I've said before that using the BF Goodrich tyres with the low speed rating is dangerous, as it is not just the speeds above 113 mph they are not capable of handling, but also the acceleration, deceleration, braking, lateral forces and otber factors introduced from a high performance car capable of speeds over 113 mph, whether you go over 113 mph or not. You may also void your insurance and are also placing other road users at risk by using tyres not up to the job. They are grossly inadequate. The QM and 275 GTB/4 are capable of speeds above 150 and 160 mph.
     
  3. Bluebottle

    Bluebottle F1 Rookie
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    Oct 15, 2012
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  4. miurasv

    miurasv F1 Veteran

    Nov 19, 2008
    6,838
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    Steven Robertson
    #4 miurasv, Jul 30, 2019
    Last edited: Jul 30, 2019
    365 GT 2+2 and 275 GTB/4 use full profile tyres, 205 x 15 and 205 x 14 so the 205/70 VR 14 are too small in total diameter for the 275 GTB/4. Even though a 15" tyre is referred to in the text, I could only find the 14" diameter tyre with full profile on the web site. https://www.blockleytyre.com/product/205vr14

    These are VR rated and ZR speed rated tyres may be required for these cars today. The speed ratings changed around the early 199os I believe.
     
  5. JCR

    JCR F1 Veteran
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    Mar 14, 2005
    5,920
    H-Town, Tejas
    This is nonsense.
     
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  6. 365man

    365man Rookie

    Sep 12, 2007
    13
    Northern California
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    Rick
    You’re saying “...the 205/70 VR 14 are too small in total diameter for the 275 GTB/4.“. I don’t think I understand. I have those now. They fit. They’re also in the spec book page in the manual. Please clarify.
     
  7. 365man

    365man Rookie

    Sep 12, 2007
    13
    Northern California
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    Rick
    I have not tried those. Thank you for the suggestion. In lieu of The 215-70 on a 365 GTC/4, I’ve seen the Avon 225/65 R15 99V CR6 ZZ Sport. Those are amazing tires. Expensive. Like rails. But incorrect.
     
  8. miurasv

    miurasv F1 Veteran

    Nov 19, 2008
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    Steven Robertson
    #8 miurasv, Jul 31, 2019
    Last edited: Jul 31, 2019
    Notice I had the aspect ratio in bold, which was the 70 of the 205/70 VR 14. They are low profile tyres. The 275 GTB and 275 GTB/4 use full 80 aspect ratio tyres, not low 70 aspect ratio tyres. Diameter and therefore the radius is smaller as the height of the sidewall is only 70% of the width of the tyre, whereas the correct full aspect ratio 205 VR14 has a sidewall height which is 80% (or 82%) of the width of the tyre. The car will sit too low with the 205/70 VR14 tyres and the manual does not specify this tyre.

    Anyway, listen to Dougal from Longstone Tyres in the video, who demonstrates it perfectly.

     
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  9. 365man

    365man Rookie

    Sep 12, 2007
    13
    Northern California
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    Rick
  10. Longstone Tyres

    Longstone Tyres Formula 3
    Sponsor

    Feb 2, 2006
    1,119
    Full Name:
    Dougal
    I would assume a BFG might give you a softer ride if that is what you are looking for.

    However a XWX will go round corners better and give you more directional stability at higher cruising speeds (and look cool). https://www.longstonetyres.co.uk/classic-car-tyres/ferrari/275-gtb.html

    As a road car I think you would only buy anything other than XWX if it was cheap. Cheaper tyres would come at the expence of handling. in the size 205VR14 it would XWX every day of the week. There is not another good tyre that i know of.

    If you go racing then you need the 15" Borranni https://www.borrani.com/ferrari-wheels/275-gtb-4.html

    Dunlop Racing Crossply tyres are great fun https://www.longstonetyres.co.uk/vintage-tyres/dunlop-racing.html crossply racing tyres are so gracefull.

    Then Avon CR6ZZ are great for the track too https://www.longstonetyres.co.uk/vintage-tyres/avon-cr6zz.html fantastic grip, Although they are not period and don't look very good on cars from this period, there is plenty of grip. What makes the CR6ZZ worth while as a historic race tyre is that they have a carcass designed with nice rounded shoulders developed to give lovely progressive handling. they are great but not for ride comfort or with racing rubber, longevity.

    If i to choose a car to drive, that i knew had got tyres that had been fitted 5 years ago. i would not choose the one with 5 year old racing rubber!
     
  11. 365man

    365man Rookie

    Sep 12, 2007
    13
    Northern California
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    Rick
    Longstone: What valve stems and tubes do you typically use on the XWX 205 VR14?
     

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