D209GPA wear?

[needknees]

Yesterday was my first time to the track with actual track tires!

Something isn't quite right.


Info:
Bike - CBR1000RR
Tire - Dunlop D209GPA. Med/soft rear, Med front (Trackday Store super combo special)
Track - MidAmerica Motorplex. 2.2 miles, 14 turns, clockwise.
Rider - intermediate noob.
Weather - ~80F and mostly sunny
Pressures - Started the day 31F/21R cold per Dunlop's suggestion. Hot off the track I was at 35f/27r. I dropped the front down to 34 and rear to 25 hot. After that I had more or less consistent hot pressures of 34f/26r. IIRC Dunlop suggests hot pressures of 34F/24R but don't quote me on that.

This was after only one day at the track, put 104 miles or 47ish laps on them. The front looks pretty good (might want to go down a psi or two???) but the rear isn't looking too hot... what the hell do I need to change?

Right side of rear

Edit: Won't let me post all the pics. Will follow up with the rest.

It doesn't look quite as bad as I thought it did at the track, but :damn:. Is this some kind of hot or cold tear? Rebound issue? I need to watch that OTT Dave Moss video again.

Edit. Watched part of the dave moss video. Sounds like it was a cold tear. Then I found this: http://www.dunlopracing.com/Pressures.pdf . That kinda backs it up. I was running way too high of pressures.

Thoughts or suggestions?

 

[needknees]

Rest of the pics.


Left side of rear

Right side of front

front left

 

[stow]

One the rear is a soft rear so it is going to wear more quickly than a medium rear. This is the reason you are getting two rears to one front in the mega-deal. Second the tire pressures should be 33f and 22/23 rear hot off the track. You are getting cold tearing due to not running warmers.

 

[needknees]

Thanks for the prompt reply .

In asking around I would definitely agree with you on the pressures. But, I'm not so sure about the warmers. I was taking it easy the first two laps of a session then progressively picking up the pace. Hard braking and hard acceleration while upright, not driving hard out of corners or carrying a ton of corner speed, trying to get the tires up to temp. If not running warmers was the only thing that was causing cold tearing wouldn't that clear up once the tire got up to temp? It seems like I just wasn't getting enough heat in the tire due to too high of pressures.

I'm definitely not saying warmers *wouldn't* be a good idea if only to help out on those first couple laps if I get a little heavy on the throttle on corner exits, and generally reducing the heat cycles of the tires. But wouldn't a cold tear from the first lap or two get cleaned off by the end of a good session?

 

[stow]

The tires are not going to come up to temp until you start pushing them. During the process of coming up to temp they will cold tear. Add in the fact it is a soft rear and you get exactly what you are seeing. Using warmers will help, but the soft rear is going to wear worse than a medium rear.

 

[ronhix]

+1 on the increase speed to increase heat in the tire comments above. Without warmers, you can get into a "chicken or egg, which comes first thing".

Also, MAM is a pretty abrasive track. The track is a little too abrasive for a soft compound tire to last very long there. Very good for races, not so good for lasting 2 or 3 track days.

BUT, if you keep the tire in the operating temp range, the grip should be outstanding until all the rubber is burned off and the tire can no longer hold heat cause it gets too thin.

The Mega-deal makes them cheaper, you get two for the price of one. Just enjoy them while they last, it is a soft race tire and soft race tires are made to be destroyed. Feel them with the throttle more than examining them with your eyes. They will give great grip but not longevity.

 

[needknees]

So that wear patterning is a cold tear? Or is it just... wear, from an abrasive track and a soft compound? I know the middle of the tire isn't what you want to tune for but the wear on the center compound looks good to me. I was hoping the rear would be good for at least two days, maybe three. At this rate would you say maybe one more day out of it? I wasn't feeling anything strange even at the end of the day.

I was not aware MAM was so abrasive -- I've only run there and Autobahn (when it was wet, to boot) so I don't have much to compare it to. What kind of pace at MAM is enough to get the tires up to temp? I did not rent a transponder yesterday but previous times on street tires were in the 1:51s. If I had to guess I would say I was hovering around the 1:47-48 range, give or take. I guess if I didn't have the pressures right it wouldn't matter what kind of pace I was running...

Sounds like I might be better off running a med or hard rear even though they're not part of the mega-deal. And ponying up for warmers, I guess. Live and learn! It was an awesome feeling to go from street tires to these sticky bastards though

 

[ronhix]

needknees;132363 wrote: Sounds like I might be better off running a med or hard rear even though they're not part of the mega-deal. And ponying up for warmers, I guess. Live and learn! It was an awesome feeling to go from street tires to these sticky bastards though

Nothing wrong with your tire purchase, just adjust your expectations a bit.

The key to making a race tire work well and last longer is to match the abrasion level of the track to the comound of the race tire. In addition, the tire needs to always be used within it's designed operating temperature range. The discussion of how to accomplish this given all the various factors involved would be like writing a novel.

At Autobahn, the soft may work better than a med or hard compound because Autobahn is not very abrasive. No one thing works well everywhere. Tap the available resources of this forum. You are surrounded by guys/gals with years and years of experience and hard-bought knowledge.

 

[Casper]

I get the exact same wear pattern and I'm running warmers. On a litre bike, the 209s are only good for 2/3 TDs, and that's if you're slow like me.

 

[stow]

You can continue to use that tire until it starts to slide around on you. I have ran the 209GPA all the way down to the cords with no issues. It was sliding around on corner exit, but it was very predictable. You can also flip the rear tire to even out wear from left to right side in order to get more life out of the tire.

 

[needknees]

I appreciate all the info, everyone

My next day is also going to be at MAM -- would I be best served to continue running those tires, buy warmers and run the same tires, or get a different compound (and warmers... seems to be a common theme here). Any issues mixing a med 211GPA rear with a med 209gpa front, or are the med 209s still available?

 

[Casper]

I don't think you can run a 211 and a 209 due to variances in the profile. I run a Pirelli Superbike Slick up front and a 209 (medium) in the rear. It's the best bang per buck that I've found.

 

[ronhix]

needknees;132427 wrote: I appreciate all the info, everyone

My next day is also going to be at MAM -- would I be best served to continue running those tires, buy warmers and run the same tires, or get a different compound (and warmers... seems to be a common theme here). Any issues mixing a med 211GPA rear with a med 209gpa front, or are the med 209s still available?

I think a harder compound rear in either the 209GPA or 211GPA will serve you better at MAM. No issues with running the 209GPA front with either rear tire.

Been hearing some good things about the new 211GPA's, they cost a little more but I think they are probably worth it.

Either is available at the Trackday Store:
Dunlop Race Tires

 

[stow]

The slicks are the bomb. If it never rained at the track and I was slightly wealthy, I would only run the Dunlop slicks. Of course the way they wore at Road Atlanta they may last forever.

I have heard only great feedback in regards to the 211GPA. The only people that are going to be able to tell the difference between the 211GPA and 211GP are the AMA/WERA/CCS front runners.

 

[ronhix]

stow;132460 wrote: The slicks are the bomb. If it never rained at the track and I was slightly wealthy, I would only run the Dunlop slicks. Of course the way they wore at Road Atlanta they may last forever.

I have heard only great feedback in regards to the 211GPA. The only people that are going to be able to tell the difference between the 211GPA and 211GP are the AMA/WERA/CCS front runners.

:agree:

The slicks offer unsurpassable grip AND longevity. We did a cost analysis and found that it was actually cheaper for the race team to buy the slicks. We could run several races on them (less tire changes during a race weekend), then we could use them to test / CR on and still sell them as good solid takeoffs to friends that are NESBA B / I group riders.

 

[BigBird]

ronhix;132662 wrote: :agree:

The slicks offer unsurpassable grip AND longevity. We did a cost analysis and found that it was actually cheaper for the race team to buy the slicks. We could run several races on them (less tire changes during a race weekend), then we could use them to test / CR on and still sell them as good solid takeoffs to friends that are NESBA B / I group riders.

very interesting. since i don't really run in the rain, this could be a good idea, but I would feel kind of weird out there on slicks in B group

 

[JGardy_781]

ronhix;132662 wrote: The slicks offer unsurpassable grip AND longevity. We did a cost analysis and found that it was actually cheaper for the race team to buy the slicks. We could run several races on them (less tire changes during a race weekend), then we could use them to test / CR on and still sell them as good solid takeoffs to friends that are NESBA B / I group riders.

At a way, way slower pace than Ron, I'd second his observation. Using warmers, and a rear-pack A pace, I've gotten from 4-6 days (depending upon conditions, specific track, etc.) out of the hardest compound rear slick available (med-hard, I think), with a flip midway through their life, and I've had no problem using one of the hardest-compound available front tires to two rears, putting a front tire's life at between 8 and 12 days depending upon conditions.

I did have a nightmare day at Summit JC last year where I totally shredded both sides of a new rear slick over the course of a day (including a flip of the tire at lunch), but it was a softer compound than I normally run, in very hot weather, so I don't consider the experience typical (but I will say that the wife was real pissed off over the $300 tire bill for a single JC day)

Anyway, even using the hardest compounds available for the longest practical life, grip on Dunlop's slicks is nothing short of astounding, even for a slower guy like myself, and though the initial price of entry is considerably higher than the 209s at their current pricing (which I've also run), the longer life of the slicks, in my experience, has made them more cost effective over a greater number of days.

 

[erick1670]

I was going to add something to the topic but everything is being cover, I hade the same problem with my rear and at first I though that I may have mist adjust my rear suspention but for what I have seen on other guys rears is that the tire is too soft. I was planning to but a 211GPA med next on the rear but reading the above tread maybe I will run slicks on my RC51.... Just a question can I run slicks on the RC?

 

[pearsonm]

Well crap, I mounted my 209’s for MAM next weekend. Guess I’ll have to research what other tracks I’ll be riding this season that are non-abrasive. Anyone know which is the least abrasive between Hallett, Heartland and Barber? I may be doing Hastings, Putnam and (hopefully) Iowa as well.

 

[JGardy_781]

pearsonm;132932 wrote: Anyone know which is the least abrasive between Hallett, Heartland and Barber? I may be doing Hastings, Putnam and (hopefully) Iowa as well.

RTS' new website and the NESBA Trackday store both have the same posted suggestions for which compounds to run at various tracks on the product pages for the specific tires. For instance, see here:

http://www.racetireservice.com/DETAIL-SLICKS.html

or here:

http://www.trackdaystore.com/Dunlop-Race-Tire-NTEC-KR108-Slick-Rear-195_p_115.html

FWIW, I've also found the RTS staff to be exceptionally helpful when talking to them over the phone if I have specific compound selection issues; if the tracks you run aren't listed, they probably have some experience with the surface and can suggest a compound.

/j