Bridgestone BT-45 for Vintage Racing?

Discussion in 'WERA Vintage' started by boxerotto, Sep 10, 2010.

  1. boxerotto

    boxerotto Member

    I heard good things about using a Bridgestone BT-45 on the race track.
    Does anyone have experiences with the 120/80H18 vs 120/90V18. My BMW R75/5 barely passes 110 MPH at Barber so the H speed rating is OK. I wonder if the V rated tire has more grip?
     
  2. footwork

    footwork Honda Research Analyst

    I think this is the tire all the cb 160/ 175 guys use out west. It would be interesting to see how they worked on a bigger bike- but compromising on your tires can be risky. I would think it would be a good track day test to try them out when you are not going for it in a race. I once tried some Dunlop TT-100 tires on my race bike in practice session and was glad it was not the race. Turning into turn 3 in Savannah the rear would slide and dirt track for the first 50 feet of the corner- good tires but not for racing!
     
  3. toecutter418

    toecutter418 Flat Rat Racing

    I'm with Buff, don't skimp on tires. Minimum rim width is 2.50 for a 120/80-18 I think. Best bet is go to Barber Vintage fest in October and mooch up to the beemer guys and see what they run.
     
  4. boxerotto

    boxerotto Member

    Thanks for the advice. I ran Avon race tires last year at Barber and they worked fine for me.
    I’m still interested to find out if the bt-45 V rated tire has a softer durometer than the H rated version.
     
  5. footwork

    footwork Honda Research Analyst

    bring it over to my shop and I will let you use my durometer......
     
  6. stickboy274

    stickboy274 Stick-a-licious Tire Dude

    As the SE/MC/N.FL Bridgestone guy, go Avon or Dunlop. I think they will work better for racing.
     
  7. boxerotto

    boxerotto Member

    Here some feedback on my experience after I posted the question. After consulting with the Bridgestone Tech representative here in the US I learned that the H rated BT-45 tires are softer than the V rated. The H speed rating is enough for my setup so I decided for the softer tire of course. I did race a 120/80/18 t-45 in the rear at Barber last October and it worked great for me. (placed 1st in AHRMA heavy weight production). The tire stuck through the corners and like most BMW’s the cylinder clearance was the limiting factor. For more powerful bikes this tire may not be sufficient.
     
    Last edited: Jan 23, 2011
  8. VintageRacerRoy

    VintageRacerRoy Well-Known Member

    Boxer,

    Check this website http://www.motorradavl.com/. The owner is Ivan Messina. He is very fast on his beemers with loads of experience building BMW racers. He recently started running a race tire from Germany, Heidenau (spelling?) and winning against the fastest in AHRMA Sportsman 750. He has comitted to selling the tires which should be on the website.

    Roy Chapman
    AHRMA & WERA 778
     
  9. NYCNorton

    NYCNorton Holmeslice

    White bike, looking very stock? If so, well done.
     
  10. boxerotto

    boxerotto Member

    Last edited: Jan 24, 2011
  11. turboguzzi

    turboguzzi Active Member

    Interesting topic for very selfish reasons. I am moving into the open class this year (called TT1 here in italy) aboard a big bore '83 GPZ750/810, so i expect to start going through rears at a much faster rate than i did on my CB500/4.

    So something slightly more affordable than the AM23 130/650-18 rears would be nice.

    Now, the bridgestone site claims that:

    "Compound (BT-45)

    Battlax BT-45 rear contains Dual Tread Compound (DTC). The center compound secures long mileage and durability, while the tread edge compound secures grip and traction in corners. Also, Battlax BT-45 compound contains Silica for additional wet performance."

    http://www.bridgestone.com/products/motorcycle_tires/products/battlax/bt45.html

    Nice, very nice.

    now the question to boxerotto is, can your bridgestone guy tell if BOTH the H and V rated have dual compound rears? and if yes, then which one would be stickier?
    the H rated 130/70-18M/C (63H) or the the V rated 130/80-18M/C (66V).

    Not so concerned with rating per se as we have only one track with a really long +150mph straight (Vallelunga), in the rest we rarely hit 130mph or more (V). Most of our vintage series are run in the smaller, second tier tracks. Mugello, Monza or Imola are just to expensive!!!

    BTW, Heidenau's are quite common here, good grip, a bit heavier than Avon AM's/Dunlop KR's, 30%-40% cheaper, but at the end of the day none of the really top guys use them...

    TG

    PS - just in case you want to see the GPZ build....

    http://kzrider.com/index.php?option=com_kunena&Itemid=116&func=view&catid=2&id=410994
     
  12. BMWIVAN

    BMWIVAN Stick wanna-be

    Kenny, that was Peter Homan from Bavarian Motors West in Colorado. His Website He has been at it for a while, very quick on a mostly stock R80/7. He is an independent shop, making a go of it, my Colorado non-evil Doppelganger.

    Roy, thanks for the mention, yes the Heidenau are great tires, and true race tires, not street compounds. First container is on the way now from Germany.
     
  13. NYCNorton

    NYCNorton Holmeslice

    I came up on him many times, but he was always smooth - smoother than most with green plates. I was impressed.
     
  14. boxerotto

    boxerotto Member

    Turbo Guzzi,

    The Bridgestone website has a link for a technical contact for your specific question. The answer to me was that the H rated tire is softer than the V rated tire.

    My production BMW has 35-40 HP on the rear wheel at most and drum brakes in the front. It is hard for that bike to outperform a modern street tire like the Batlax.
    For a bike with more performance or a race bike I would definitely use race tires like Heidenau, Avon etc.

    Even the Batlax worked for me the safety margin on race tires for emergency situation etc is much broader.
     
    Last edited: Jan 26, 2011
  15. turboguzzi

    turboguzzi Active Member

    thanks boxer

    I think that those double compound bt45 might be worth checking, even on my (hope to have..) 90hp GPZ750/810. In any case was thinking about it for the rear end only. right now have a KR164 there but might try to do some sessions on the 45's.

    Check this guy who seems to have done pretty well on them :)

    http://kzrider.com/index.php?option=com_kunena&Itemid=116&func=view&catid=11&id=166519


    Sounds like you are riding a 500cc beemer? This year such a bike took the outrgiht 500 championship in dutch vintage racing , beating CB500/4's, Duc singles, Goldstars, Manxes and what not, pretty amazing and bike looks finger lickin good too

    http://www.deraceheldenvanweleer.nl/index.php?action=dlattach;topic=42.0;attach=7763;image

    TG
     

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