Conference oass::racers

    
      I have found that the A008R to have better cornering power and 
    braking grip than the A001R. The A001R tire felt more agile though,
    in quick transient manuevers. There is an A008RTU that offers more
    cornering grip and braking power than the A008R.

 Thanks for the info
do you know how these compare to the Avon Turbospeed CR28 ?

    
     I have not heard of the Avon Turbospeed CR28 in this country. The only
    familiarity I have with Avon is that some Formula cars have run sets
    of race slicks and were pleased with the performance, but the cost 
    was astronomically high and they had to bring them into this country
    themselves.
      Yokohama is rumored to be introducing a new high performance soft
    compound street tire for sedan racing in this country soon.I don't 
    know what it will be called but some major tire wharehouses have
    dropped their prices on A008R and RTU tires, so there looks like a
    replacement is coming.

What about the AVS series that Yoko had a few years ago.  Are they still
around?

Dave

>>What about the AVS series that Yoko had a few years ago.  Are they still
>>around?

I thought that the AVS tires were still around but never thought they were
real "performance" tires.

On the subject of tires, it looks like Hoosier cleaned up in Formula Ford
at the runnoffs. I've been running Goodyears. Am I on the wrong tires or
does Hoosier just have a tire that works well in Atlanta.

�I thought that the AVS tires were still around but never thought they were
�real "performance" tires.
    
    I use AVS tyres on my road car.
    
    I think that this is all that they are 'intended' for, whereas
    the A001/A008 range have definite competition use.
    
    J.R.

    Hi,
    
    Anyone knows where I can have my tires shaved around here?  I am in
    Nashua, NH, USA.  This is to get rid of a flat spot I got from my last
    outing at the track :-(.
    
    Also, anyone has any experience with the steaming new Yokohama A008RS? 
    Are they supposed to replace the A008RTU?
    
    -=Chong=-

    Chong,
    
    The Boston Chapter of the BMW CCA had Tom Mason from Yokohama as the
    speaker at our last meeting.  Tom said that the A008RS replaces the
    A008RTu.  The A008RTu replaced the A008R a couple of years ago. 
    The A008RTu had higher ultimate grip than the A008R but was peakier in its
    response, and, as a result, only the best drivers were quicker on the
    A008RTu.  The A008RTu had much more flexible sidewalls than the
    A008RTu, and all the 2002tii/2002/1600 IT drivers had problems with
    interference at the tie rod.  Tom said that the A008RS combines the
    ultimate grip of the A008RTu with the response of the A008R.  The
    A008RS should also last longer (but probably flatspots just as easily).
    
    Bjorn. 

    Thanks Bjorn.
    
    Do you know if the A008RS still have a recommended rotational
    direction?  And for a rear wheel drive car, is Yokohama still
    recommending mounting the front tires in such a way that it would
    rotate counter to that recommended direction, when the car is moving
    forward?
    
    By the way, it was a street tire that I had flat-spotted while on the
    track, hence the thought of getting some A008RS.  Any idea what the
    wear rating for this tire is?  Not that I am planning to replace my
    street tires with them, but I may want to leave them on the car between
    events.
    
    -=Chong=-

.8>    The A008RTu had much more flexible sidewalls than the
.8>    A008RTu, ...
    
    Through the magic of cut and paste I'm sure I copied that line
    verbatim.  Does anybody else share my problem interpreting it?
    
    Somehow I suspect there's a typo lurking there somewhere :-)

Hi, Chong:

I believe Motorsport Imports on Amherst St. does tire shaving. If 
not, Trisha Blethen at RST Performance can get tires shaved for 
you -- she can also order Yokies at a pretty good price and 
mount, shave, and balance 'em also pretty reasonably.

--Lil

Well I' cant use the AOO*R** at all since they  are not on the allowed list
for my  championship

    Chong,
    
    First, to correct the typo in my previous reply:
    
    The A008RS has stiffer sidewalls than the A008RTU.
    
    DOT tire information on the A008 series:
    
    Model	Wear Rating	Traction	Temperature
    
    A008R	50		A		C
    A008RTU	80		A		B
    A008RS	80		A		B
    
    So you can see that these tires are not 40,000 mile radials.  On the
    other hand, because the outside third of the tire tread has no tread
    blocks (and nowhere for water to go, either), the A008 series wears
    very well on the track.  By swapping the tires from front to rear a 
    couple of times during the season and by balancing my driving between 
    NHIS, Lime Rock, and Watkins Glen, I can usually get 50 to 60 15-min
    track sessions per set before I start seeing blisters.  My BMW 1600 is
    vey easy on tires due partly to its light weight, low power output, and 
    large amounts of negative camber at both the front and rear.
    
    Tom Mason of Yokohama said that the RS is being priced to retail for
    less than either the R or RTU did.
    
    Bjorn.

    Chong,
    
    Yokahama A008RSs come in "A" and "B" types to maintain the proper
    direction of rotation with the asymmetric tread pattern.  Whether the
    "arrows" point in or against the direction of tire rotation depends 
    upon both which wheels are driven and which end of the car the tire 
    is on; Tom Mason wasn't convinced that it was all that important 
    with present manufacturing technology; he said that the angle of 
    the bevel where the belts are joined is different for "A"s and "B"s, e.g.,
    
                          T R E A D
    		______________ _____________
                ______________/_____________
    
    			    vs.
    
    
                          T R E A D
    		______________ _____________
    		______________\_____________
    
     
    I hope this helps.
    
    Bjorn.

It's something to do with the stress of power application versus 
the stress of braking, isn't it?

All you have to remember is that the drive arrow points the way the 
driven wheels would spin under power. As I understand it, the little 
arrows labelled "DRIVE" on the sidewall should be pointing as follows 
when at the top of the wheel:


                 <---------------- driven wheels
                 ----------------> non-driven wheels

             <----------------------------- front of car


... in order to put the stresses in the proper direction for each 
set of tires. Still, isn't braking stress likely to be stronger, 
at least on many small-bore cars anyway?


--Lil

    re .15
    
    >>Still, isn't braking stress likely to be stronger,
    >>at least on many small-bore cars anyway?
    
    Lil,
    
    I asked Tom Mason the same question, because the braking g's are much
    higher than the acceleration g's (in any gear) on my car.  Tom didn't
    give a satifactory answer to this question.  My guess was that he was
    trying to say that due to weight transfer the rear tires are lightly 
    loaded during braking (eventhough the g's might be high for a short 
    time, 5-10% of time/lap) but are heavily loaded during acceleration
    (for rear drive) for the rest of the lap (eventhough the g's are low).
    Your guess is as good as mine.
    
    Bjorn.  

    Thanks, everybody, for all the information.  I ordered 4 of them (2 A's
    and 2 B's) from Tire Rack last Saturday and received them yesterday.  I
    got the 205/60HR15 for $94 each, plus $25.50 freight charge for all 4. 
    All the information like tread-wear and mounting as stated in .13 and
    .14 are correct.
    
    Can't wait to take them to the track.
    
    -=Chong=-

    Chong,
    
    You'll be amazed at how much grip the A008RSs will give you.  Break
    them in properly.  The first time out, if the format of your practice 
    sessions allow it, run about five laps at 7/10ths (I know it's hard 
    to do) and a couple of fast laps.  Then come in and park it until the 
    next session.  This will start to cure the rubber properly and will 
    improve both the grip and the tread life.  Chalking the edge of the 
    tread to determine the optimum tire pressure is of little use with 
    these tires since the sidewalls are so stiff. The pressure should be 
    adjusted to get each tire near 200�F.  The old technique of adding air 
    to the front or rear tires to increase grip at the front or rear is no 
    longer applicable.  A note of caution about flatspotting A008RSs: 
    soft compound tires flatspot in a HURRY when you lock up a wheel, so 
    SQUEEZE that brake pedal.  (The above info is courtesy of Tom Mason of
    Yokohama).
    
    Have fun!
    
    Bjorn.

    Re .18
    
    >You'll be amazed at how much grip the A008RSs will give you.
    
    Hey, sounds good to me.  I am really excited now.  8-D
    
    >Break them in properly.
    
    I will be using them on the street for about 300 miles before taking
    them to the track for the first time.  I shall see if I can drive them
    at 7/10 for a while.  :-)
    
    >The old technique of adding air to the front or rear tires to increase
    >grip at the front or rear is no longer applicable.
    
    Are you saying that there is no effect whatsoever?  Is the sidewall
    really so much stiffer than the regular tires?
    
    Thanks again for all the information, Bjorn
    
    -=Chong=-

    
Hmmm. Well, if even Yokohama doesn't know, then it must be 
important right?

And then there's my front-drive LOW-horsepower car ... wonder if I 
shouldn't run all my tires as if for non-driven wheels ... ;)

    Chong,
    
    >>I will be using them on the street for about 300 miles before taking
    >>them to the track for the first time.
    
    Street driving (in almost every case) won't do much to help you get the
    tires broken in.  You'll probably be able to get the mold release worn
    off.  However, the grid pattern on the tread will probably still
    remain, and the steering effort will remain light until that pattern 
    is worn away. (Tom Mason said not to push the tires until the pattern 
    is gone.)  
    
    >>Are you saying that there is no effect whatsoever?  Is the sidewall
    >>really so much stiffer than the regular tires?
    
    That's what Mason claims.  He also said that the tread cools off very
    rapidly once you get on a straight.  For example, at Lime Rock the
    tread will cool off 20-30�F between the end of Diving Turn and the time
    you can get the car stopped in the pits. (I assume that they're using
    infrared sensors in the wheel wells to measure this.)
    
    Bjorn.  

.21>    That's what Mason claims.  He also said that the tread cools off very
.21>    rapidly once you get on a straight.  For example, at Lime Rock the
.21>    tread will cool off 20-30�F between the end of Diving Turn and the time
.21>    you can get the car stopped in the pits. (I assume that they're using
.21>    infrared sensors in the wheel wells to measure this.)
    
    That tread cooling pattern could easily be based on time:temp curves
    measured once the car is in the pits.  That approach ignores the
    difference in cooling based on airflow, but then a 33% range (20 to 30
    degrees F) is a fair amount of imprecision.
    
    I wouldn't really be sure.  From my experience with trying to play
    around with IR sensing of tire temps, it's a tough problem.  I'm not
    sure it's amenable to a good solution.  One big problem is the variance
    in temps depending on airflow/ambient temps/speed/loadings.  Another is
    the mechanism of heat generation in tires, there are two seperate
    components and depending on the item of interest one or the other may
    be of interest or meaningless.  In general my impression was that IR
    temps would be useful only in limited situations, and in most of them
    the value might not be worth the effort.  (I'm still interested in
    playing around in this area, if somebody wants to justify it!)

    The A008RS worked very well.  When they were heated up, I could almost
    leave my fingerprints on them.  I have never used tires of this sort
    (street legal track tires) before so I can't really compare, but I am
    now a serious contender in my class.  I didn't win a trophy but I was
    only 0.13 seconds slower than the third place car (4"43.49 vs. 4"43.36,
    three laps).  If I had only pushed a little harder.
    
    Speaking of pushing, do these tires ever squeal?  I don't remember
    hearing anything all weekend.
    
    They also seems to hold up pretty well to wear.  The shoulder got
    chewed up quite a bit, though.
    
    I should really find a pyrometer to get the optimum tire pressures for
    my car.  Because it is time trial I am doing, I am still not sure of
    the best way of doing it, since the tires would go from cold in the
    first lap to hot in the last lap.
    
    Can't wait to get out there again.
    
    -=Chong=-

    Chong,
    
    >> 4"43.49 (approx. 1"34.5/lap)
    
    Which configuration did you run (both chikanes/south-end
    oval/north-end oval/other)?  Did you have a full lap to warm up,
    or did you get the 200 yard run at S/F like we used to get at Bryar?
    
    >> Speaking of pushing, do these tires ever squeal?  I don't remember
    >> hearing anything all weekend.
    
    A008RSs won't squeel like "normal" tires, but you should be able to
    hear them most of the time in a car with a street legal exhaust system.
    When you really hear them squeel, it's generally confirmation that 
    you've screwed up!
    
    >> The shoulder got chewed up quite a bit, though.
    
    How many laps did you get in over the weekend?  If it's the right front
    that's chewed up, you may need to the reduce the amount of understeer. 
    You can also swap the RR-->LF and LR-->RF to even out the wear.  After
    swapping, be aware that the tires have to re-grain before they get their
    old grip back; this should only take 3-4 laps, but the car will feel
    very strange at first.
    
    >> Because it is time trial I am doing, I am still not sure of
    >> the best way of doing it, since the tires would go from cold in the
    >> first lap to hot in the last lap.
    
    The tires are probably up to working temperature halfway through the
    first lap if you get no warm-up lap (what were your lap splits?).  I 
    would suggest optimizing your temperatures for the end of the run.
    
    Bjorn.

    I thought radial tires should maintain the same direction of rotation.
    By having the RR->LF swap, doesn't that screw up the tire?  Or are you
    saying to remount the tires?
    
    Jeff

    Bjorn,
    
    We used both chicanes this past weekend.  We had a 300 yard run from
    the beginning of the front straight to the start/finish line, where the
    timer would start.

    >How many laps did you get in over the weekend?  If it's the right front
    >that's chewed up, you may need to reduce the amount of understeer.

    I got in around 60 laps through the weekend.  Yes, I need to reduce the
    amount of understeer a little bit, especially for turn 3 and 10.
    Unfortunately, the front camber isn't adjustable (I did take up all the
    allowance possible from all the nuts and bolts), and the toe out in the
    rear is already at maximum allowed.  The only thing left seems to be
    tire pressure.  Hence the thought of using a pyrometer.  Last weekend I
    run 42/36 psi front/rear (highway 32/32).  I had run 32 in the rear
    before on street tires and the car seemed to be in good balance so I
    think I just have to go back to that.

    >(what were your lap splits?).

    Sorry, I don't have it as yet.

    Thanks, Bjorn, for your help.  What is your experience with this tire.

    -=Chong=-

    
    How does the A001R compare with the A008R? Are these tyres suitable for
    limited use on the road?
    
    Mark

    Mark,
    
    I have used A001Rs (175/70-13) --> A001Rs (205/60-13) --> A008Rs
    (205/60-13) --> A008RTUs (205/60-13) (and have A008RSs in size 
    205/60-13 ready for use) on my 1600.  I used to use a separate set of full
    tread depth A001Rs (175/70-13) for street and wet track driving.  The
    A001Rs were VERY good in the wet (narrower and better tread pattern
    than the A008s).  I probably could have gotten 10,000 miles of street
    wear on them in addition to the wet track miles.  However, I put about 4 
    hours of dry track time on them and that just about finished them up as
    wet tires.  I sold them to someone with a tii for driver's school use,
    and he loves them.  I leave the A008RTUs on the car all the time now. 
    They are reasonable even in the wet (as long as you stay away from
    puddles) because the tread compound is so soft.  To generalize, in a 
    given size, the A008R/RTU/RS has better dry grip and wear than the 
    A001R, but the A001R is a much better wet tire.
    
    Bjorn.
                                          

    
    Thanks Bjorn,
    
    That's just the kind of information I wanted. The Avons on my Marcos
    are still pretty fresh, but I might try A001Rs when they wear out.
    
    The car is only used on the road, but only does a couple of thousand
    miles a year at most.
    
    Mark

    re .24
    
    Chong,
    
    I checked the Drift results from May, and you've made a substantial
    improvement in your lap times.  The double chickane configuration is
    about 3 sec. slower than the "South end chickane / North end oval"
    configuration you ran in May (and about 6 sec. slower than the "South 
    end oval / North end chickane layout) in your type of car.  That means
    that your average lap time improved by almost 7 seconds!
    
    Bjorn.  

    Re .31
    
    Bjorn,
    
    You shouldn't really use my time from May.  I had one pair of very well
    worn RE71 and a pair of brand new D40M2 that weekend.  The car suffered
    from either extreme understeer or extreme oversteer, depending on which
    end the new tyres were on.  It was so frastrating that weekend, I
    decided that unless I get some decent tyres, I wouldn't want to go back
    in June.  So I got the A008RS.  :-)
    
    A better comparison would be my time from last October, when I had four
    well worn RE71s.  My best time than was 4:42.24, so if it is true that
    the double chicane configuration is about 3 sec. slower than the
    "South end chicane / North end oval" configuration, I had improved my
    average lap time by over 2 seconds.  I think I should do better than
    that once I figured out the correct tyre pressure and got used to the
    tyres.
    
    Hey, I didn't know you are a COMSCC member.  How come I never see you
    around?
    
    -=Chong=-

    These A008RSes really pick up everything, including nails.  :-(
    
    I have another one punctured (two nails) and is being fixed right now.
    This brought up a question.  Anyone foresees any problem if I continue
    to use these patched tyres (on the track, that is)?  Perhaps I should
    ask Yokohama.  Anyone has the number?  I bet they will want me to get
    new ones.
    
    Yeah, I am using them on the street.  I know that's not a good idea but
    I didn't have another set of wheels until recently.
    
    -=Chong=-

    	If the holes are just from nails, I wouldn't worry about it.  A
    patch or plug used to work for me.  The annoying thing was that the
    fibrous plugs used to always trickle air, so you had to keep blowing
    them up between sessions.  Think of it this way:  even if the patch
    failed completely how long would it take for you to lose enough
    pressure to have a problem, and wouldn't you notice something long
    before it got terminal?  A leak of any sort is far different from a
    sudden blowout.  
    						John
    

    Re .34
    
    I am worrying about structural damage or failure of the A008RS, which
    may be constructed differently from regular tires.
    
    Re .35
    
    The tire would loose all the air very, very quickly if the tubes is
    punctured, effectively becomes a blowout.
    
    -=Chong=-

    Chong,
    	The ones that I used to plug were slicks, so if anything were going
    to fail because of design differences it would be much more likely to
    than in a DOT approved tire like yours.  In many ways street driving is 
    more likely to show a problem because although there are fewer
    stressful events per mile there are a lot more miles and therefore a
    lot more stressful events.  
    	You aren't likely to have a sudden structural failure of a tire
    that has maintained proper pressure.  There really isn't anything that
    has been done to it to cause that.  The kind of things that cause
    massive failures are HEAT (from underinflation) and massive trauma
    (like whacking curbs hard).  From your description you haven't done
    anything like this.  A hole less than a quarter of an inch is going to
    let out some air and maybe break one or two cords or belts.  This isn't
    anything like the kind of damage that would be required to cause a
    massive failure.
    	Of course if you like to spend money, tire companies like to take
    it.
    						John
    

 >>I am worrying about structural damage or failure of the A008RS, which
 >>   may be constructed differently from regular tires.

Well I had a rear tyre fail ( A001HFR) @ about 100mph when someone plugged it

with the  mudguard/ suspension of another car. Had to do a "Mansell at
Adelaide " impression down the straight. He ripped a hold 2" by 2".
 Didnt really cause much of problem except having to stop.

    Quick question,  can anyone out there direct me to information on Avon
    Clubman tires - specs, US distributor, etc.  I've posted the same type
    note in the CARS_UK, but with no responses as of yet.  I think TRACER
    racing (SCCA CSR National champs) may be a/the US distributor but I'm
    not sure.  If anyone can supply info - perhaps TRACER's address or
    phone number, it would be appreciated.
    
    Thanks,
    
    	Barb
    

I am not sure about Avon Clubman tires but I do believe that Euro-Tire in 
Fairfield N.J. used to sell Avon tires.

The number I have for them is 201-575-0080. This is probably the service 
center but they can connect you with the mail-order department.

    Thanks Glenn.  I called them when I read your note, however, they
    denied ever having sold Avon.  Oh well, it was a nice lead.  Guess I'll
    have to wander thru the last issue of Sportscar and see if I can dig up
    the address for Tracer racing.  I'm pretty sure they're distributors,
    just don't know where they're located.  The season's over for the Elva
    anyway, so I guess this may turn out to be my winter project for next
    season is to hunt this info down.

Does anyone know a rough figure for shipping *mounted* tires via UPS?  I'm
looking at shipping 2 or 4 mounted tires from GA to NH and then back and
was wondering if it would be worth it.

Dave

    Dave,
    The limit is by weight and size. 75lbs. and something like 3 cubic
    feet. You may have to ship four seperate packages. 
    
    Jim
    
    
    ps...why round trip?

I will be making a trip up to NH in October and instead of sticking 
my 4 mounted P7s in the trunk for the 2400 mile round trip, I thought 
I'd look into shipping them up and back.

Dave

    Dave, you might also look into having them trucked up. Call a trucking
    co. in your area and see what they charge.
    
    Jim
    
    
    how about a roof rack?

I shipped 4 unmounted tires at a cost of about $16.  I would imagine it would
be about twice that with rims.  Might be a little more from GA.

On the sneaky side, why not call someone like Eurotire and ask how much is the
shipping as you are (ahem) pricing tires.

Jeff

	I bought 4 snow tires on steel wheels from Euro-Tire last year... 
	Shipping was about $25.00 for all 4. 

	They didn't bother with boxes,either. Just put some cardboard over 
	the wheel and slapped a shipping label on.

	/ken