M/C Tires 2010

[Stainless1]

Yes, they had a shitpot load of ruined tires at the impound.... is it more than usual...yes, they usually don't get the bad tires....

One guy had 3 of them I think....

to the guy that is running 190... run the street zr, you are not affected by the tire rule until you run over 200.

I hope the scta got meaningful tire data and are able to make an informed and intellegent decision...

More changes to follow... just about guarentee it 

[DahMurf]

The reoccurring theme I heard on failures was lower tire pressures unfortunately as recommended by the tire rep present. (at least that's what I heard by talking to others directly affected & scrutinized. I didn't see the tire rep) I have many pictures of a few of the "bad" tires. I'll try to post some later. I believe one racer willingly did experiments with a variety of tire pressures for the benefit of tech(?) and the tire rep(?). It's his story to tell but essentially the lower pressures were problematic.

I do believe there are a few racers with throttle control issues that no matter what tire or pressure will continue to have issues until they overcome their throttle issues.

I finally had the pleassure of experiencing obvious wheel spin on the last day. It was apparent to me at the time & I did my best to compensate with throttle input but I'm sure the finesse of the proper amount is a learned skill I will need to master. The tire didn't suffer for my experience and was checked after each run.

I'm interested like everyone else to see how this rule may be tweaked with the new data. Hopefully we'll know sooner then later! I'm just happy that I was running a < 200 mph bike so we were able to stick with a proven tire setup. Being the guinea pig out there with tires while I'm trying to learn how to ride the salt makes me really nervous!

[1212FBGS]

most of the tire problems i saw were actually over inflated tires... some idiot was telling people to run 45psi.... thats what happens when people start believing all the internet experts
kents

[fredvance]

45 is what I always run. All of the people that I talked to that were running the "reccomeded" 30-36 lbs were having trouble.

[DahMurf]

most of the tire problems i saw were actually over inflated tires... some idiot was telling people to run 45psi.... thats what happens when people start believing all the internet experts
kents

What PSI do you consider over inflated?

What PSI do you run?

What PSI would you recommend?

[racergeo]

 I'm the idiot that ran 80lbs in the rear MC race tires on the back of my lakester. I trimmed all of the shoulder rubber and about 2/3 of the tread off. The real benefit for me was they were 3/4 inch narrower after I was finished. More aero. mine started life as a roadrace front tire with the soft compound. 275mph at about 875# static and maybe several times that at dynamic load. Go figure MC tires on a car and they worked good and you guys are having trouble. You know centrifugal force affects tires on a motorcycle same as on a car. LOL

[jeffb]

I will pipe back in being the "guy running 190".  I understand the rule.  However, here is my problem.

I am finishing a new bike that has never been on the salt.  Based the the spreadsheet I have developed using my 100" pushrod bike over the past 5 years of landspeed racing at Bonneville and Maxton, I estimate that this bike will go 192 as it sits.  Obviously that is a guess and yet to be proven, although I think it is a fairly well educated guess.  

My estimate could be low or it could be high.  

So what kind of tires would you show up with?  Play it safe and run the ZR's and hope I don't go over 200 or run race tires that are legal for anything I may do, but possibly more dangerous.  I will probably mount up the ZR's and worry about 200 later.  Just thought I would share my situation.

Jeff

[joea]

jeffb...imo...you will be PERFECTLY fine running either a zr dot spec or race spec....

EITHER ONE.....!!!!!

im being very serious giving you best advice i know to do...based on personal experience...

PLEASE be VERY CAREFUL listening to ANY banter....take it ALL with a grain of salt....

this whole thing of trying to call zr race spec more dangerous...is dangerous....

there are many pieces to the puzzle........case by case "individual" reports and
a more quantified report by the sanctioning bodie(s) who often gather significantly
more data than one or two individuals could....

ie simply contact the sanctioning body tech folks for a more global informed view, ie
scta gathered dozens of surveys on specifics related to tire usage, compound, psi, load,
data/ecm logging/management, etc......and also includes observations of runs, that can
be quite enlightening.......ie amt and duration of tire spin and ensuing results.....

please remember, for YEARS many folks had blistering/chunking on zr dot spec radials and
other tires, and they simply went to the pits and changed out tires and went back out,

this year ALL bikes were mandated/forced/monitored to return to inspection for followup
from fast runs...so all these tires were followed, and some (i think all) had blistering and chunking
limited to the very center .5 to 1 inch or so of tread.....

in years past, zr dot spec tires failed...often with baseball size chunks coming off much further away
from center tread, and or near complete delamination......

Van Butler has much more indepth data from numerous tire engineers with respect to tire construction
and tread failures...as well as emperical data from our meets....

i can emphatically tell you that if wheel spin controlled/minimized you will enjoy your zr radials regardless of choice...

do i think race spec zr's have perfect compounds for our use, probably not, do they have a safer failure mode..possibly...

im a huge proponent of zr dot spec tires, BUT my experience doesnt mean its the best conclusion given all available
data from all available assets...i have one defined data set from my own self consumed world...but dont for a minute think
that i have a better knowledge base about tires than engineers who design build, test etc tires...

ask stainless and the 6 different riders setting/qualifying for records on his bike or the many riders/racers including Jeannie P., Wagner, Porterfield and so many more that were basically hotlapping last week at Bonneville on race spec zr radials......that looked perfect.....

thankfully scta is employing a progressive-comprehensive tire evaluation process driven by decades of experience and
track record second to none.....additionally there are some darn good folks at BUB as well collaborating with SCTA and pooling data in the best interest of us all...

[BVCBR]

I have been using the same tire since 2008. It is a Dunlop D211GP 2779 Daytona compound.

After looking at my run logs from Bonneville (08,09,10), it looks like it has about 50 or so passes on it; all above 175mph and about 40% are above 190mph. It also has about 25 passes on it from El Mirage, ranging from 175 to 190, most in the mid 180s.
I run anywhere from 21 to 25 psi pressure with the tire hot. This is also with Nitrogen and a tire warmer that has been on for about an hour.

I use the tire warmer to stabilize the pressure. In 2008 and part of 2009 I did not use the tire warmer and would see a pressure rise of about 4-5psi after a pass at El Mirage (even with Nitrogen). With the tire warmer the pressure is the same before and after the run.

This year at Bonneville, Jeannie (rider) told me in 5th and 6th gear the tire was spinning through the last mile and the engine was on the rev limiter, which would make the rear wheel speed in the 220mph range based on the calculated ratios and tire size. With a 190mph front wheel speed, that make is a percentage of slip around 15%. We have never had any problem with the tire; in fact it still looks like new.

The bike has no weight added and has a weight bias of 220lbs on the front and 208lbs on the rear, without rider. That makes it 51.5% on the front, 49.5% on the rear.

I will never run any tire other than a DOT race tire or slick on my bikes.

I have seen a lot of race tires delaminate and chunk during my time working in the AMA Road Race series; it’s just part of racing in those conditions. But I have never seen a catastrophic failure (meaning the tire lost all air pressure).

Jamie Wagner
970B 1000cc P-P
977B 1000cc A-G

[John Noonan]

Joe thank you for your post, it is good to hear from a racer at the event that sees the big picture.

I was not at Bonneville however have spoken with racers and officials that were there regarding the tire situation that ensued.

I know that in the past years at Bonneville I have seen many racers blister tires from over spinning them on the salt building up heat and then the blistering starts, these racers have been known to simply return to the pits and install another rim/tire and then proceed to make further runs and motorcycle techs/officials never got a chance to see the damaged tires.

With the new policies the SCTA motorcycle officials have put in place the racers cannot make a pass, kill the tire and return to the pits without the SCTA motorcycle officials knowing about the situation.

This year I know of 6-8 tires that as Joe mentioned lost rubber in the center of the tire.

2-3 from one P-P bike, 2 from a turbo bike, one from a 1000 GSXR with a road race used throw-away tire (should have never been brought to the salt), heard a turbo 1000 started to blister one however kept the tread on...

Unless a racer over-spun his/her tire and then left the SCTA officials and motorcycle tire specialist were able to see all of the racers and take data from them regarding, HP, fuel management/traction control, type of tire/slick/compound etc.

The information is more than has ever been collected at an SCTA event and will go along way to making it safer for the racers, I have seen tires loose all of the rubber from over-spinning and yet still maintain air pressure however it seems that these race only tires are only losing the center section where the heat is being applied and none of the racers were even aware of the blistering until after the runs were over.

I am spending along time writing this in between company emails and see that Joe has already mentioned some things I either was going to or did mention, one thing that should be noted, the bike that lost the most tires was not a Turbo or Nitrous bike, it never hit 200mph or above yet due to lack of proper throttle control/modulation or traction control the rider as Joe mentioned spun the tire  for miles and even after blistering the slick and race tires was able to keep the bike upright as no air loss occurred.

I was not aware that a racer was able to install a non conforming tire after hurting a race tire, thank you for that information, it would be interesting to see the tires in person and compare them to what I have seen in the past...oh wait I am sure they are in the SCTA trailer and can be seen at El Mirage.. cheers

It was great feedback from Fred, Jamie, Racergeo ...lets continue to learn from this and make it safer as we go.

I don't feel that Bubs is going to allow riders to run 200+ on ZR tires however I would get that in writing before I trailered out there and found that I needed correct tires.

Has anyone got it in writing they are reversing the tire rules?  I have not heard that however my sources are just Tom and Van, I am sure there are more people on the internet that have better information/experience regarding this issue.

Be safe everyone...even you VeeTwin  cheers


John

[Randall Parker]

Well, I brought my heat cycled Bridgestone YCX race tires with little rubber left on them. I drug a knee for 5 sessions heat cycling these tires at Miller Motorsports Park. I believed they were the best choice I could make for a bike with lots of tire spin and still meeting the current 200mph tire rule.  They were put on a turbo Busa and only managed to make one run before blistering on a 210 mph pass I think. They were a 55 durometer rating as mounted for the busa. My heat cycled for one race Pirelli Super Bike Tire made 10+ passes at 196-201 mph with no visable affect.  The durometer rating went from 60 as mounted to 40 at the end of the week probably due to wearing off the heat cycled surface?  I could not hook up as well as I did using a Bridgestone BTO 15 ZR DOT tire or the Michellin HPX.  I was spinning for the last 1.5 miles every pass minimum on my best runs.  I tried several different lead combinations but could not stop the Pirelli racing slick from spinning and my speeds were consequently slower than my last Speed Week results using the same bike and the BTO 15. For what it is worth.

[1212FBGS]

deb,
my answer to your questions are
40 psi
36 to 38 in the front and 28 to 36 in the rear
as i run

Fred
45psi will pooch your tire out resulting in less contact (but you knew that)... the Busa wheel safety bead is not designed for those pressures due to contour, tolerances, and well location..... please rethink your approch

randall
 if you tested your tires with a durometer and recorded your information then im sure you recorded pressures.... what pressures did you have your failures at? And please amuse us as to why you think heat cycling is good for a tire

[Randall Parker]

I had a new sticker ZR DOT BTO 15 Bridgestone tire in the trailer.  It had a durometer rating of 70 new as tested by Tom Evans.

[John Noonan]

Randall,

Don't forget that the salt surface and weather conditions can also have a huge effect on speeds from previous years, heck the top speed for bikes last SCTA season to this speedweek was down nearly 40mph.

[k.h.]

I'll remove my "coffee house philosopher" tweed jacket with leather elbow patches, take off my "bar room intellectual" driving cap, un-pin my "chicken inspector" button, and go directly into "internet expert" mode, to scribble out that 6 years ago Marvin Rifchen told me (that) heat cycling LSR tires is a good thing as it "seasons" the tread attachment to the casing.  He also relayed that too high a pressure is not good.