D21 Gp Racer Tire Wear

[khp]

In the quest for trying something new and possibly better, I switched from running Pirelli Diable Supercorsa's to Dunlop D211GP Racer this year.

For the Easter trackday/training camp at Autodrom Most, Czech Republic, I put on new tires front & rear for the event. On the recommendation from Steve and Bullet here in the forum, I went for the following combo for my 2008 model YZF-R6:

D211 GP Racer (DOT, ie not Slicks). Tires are marked with "MT", "JLB" and "NTec".

Front: 120/70 Medium compound

Rear: 190/55 Endurance compound (date code 10/week 35)

BTW: these tires are "Made in France" - I guess this makes them "UK spec" according to Steve.

 

I followed the advice from the Dunlop Racing webpage (repeated here by Steve): 33 psi front/23 psi rear, hot off the warmers (I used a laser/IR temp gun to verify that the temperature was OK). Tires were warmed for an hour in the morning, and for the last 20 min prior to each succeeding session as advised. Upon returning to the garage after a session, I measured around 65C on the rear and 50-55C (hazy memory here) on the front.

Air temperature was 20-25degrees C, all three days - no rain . I didn't check the track temperature though.

 

I experienced no or little traction problems during all three days - except a single very small slide exiting the hairpin when pinning it in 2nd when leaned way over (hey, gotta try find the traction limits, right? ). Combined over the 3 days, I rode approximately 4 hours according to the laptimer.

 

My laptimes dropped from 2:05's on the first day to 1:55:45 in the 3rd & final session of the 3rd day.

I must be catching up, 'cause I'm now less than 15 seconds behind the fastest 600cc guy (who's on a Supersport prepped Yamaha-Denmark backed bike, which is wickedly fast), who did 1:41:xx laps

 

The front tire looks excellent, with very little wear. The rear, however, is a different story that I'd like some input on.

 

As it turned out, I did an error on the morning of the first day when setting the pressure on the rear: instead of setting the pressure to 23psi, I set it to 25psi. When the tire started to show significant wear on the second day, we diagnosed it as over-inflation (confirmed first by a suspension/tire expert from one of the bigger race teams, later also confirmed by the pressure gauge). The pressure was then reset to 23psi on the morning of the third day.

On the third day, my laptimes continued to drop from 1:57 to 1:55, but the wear pattern did not change.

 

I've attached 3 pictures of the rear. On all three, a band on each side of the tire can be seen where the tire is much more worn (the wear is more easily seen on pics 2 & 3). Also, it seems that the tire likes to have an "edge" or ridge in the wear-band where the wear-pattern changes. In real life, the wear looks more dramatic than in the pictures and I'm wondering much much more life there is in the rear tire.

 

Another guy on a 2008 R6 was running 180/55 Medium GP Racers (yes Bullet, you can get them!) was underwhelmed by their grip and complained about wear, which looked similar to mine. He was running 1:46 laps though

 

The Pirelli Diablo Supercorsa SC1/SC2's run by other riders on R6'es did not exhibit any wear problems.

 

 

My questions are:

Is this wear to be expected? - is the wear "just normal" or caused by the 2psi over-inflation? Are the GP Racers really that sensitive to (incorrect) pressure? Should I be running a different compound?

What is that ridge in the wear - compound change?

 

I'm wondering whether a return to the Supercorsas would make good sense from a tire wear/expense point of view, if I'm able to get less/better wear on the Pirellis than on the Dunlops.

 

And a final bonus-question to Steve: a third racer told that she is getting 6+ days out of a Soft compound front tire, which apparently is quite normal for the GP Racer's. Any good reasons to choose or not choose the soft front, if it really lasts that long?

 

I still have a set of Pirelli's with reasonable amount of thread left, so I'm considering to mount them on my rain-wheels in order to do a back-to-back test during a future trackday.

 

Thanks for all and any input,

 

Kai

[Bullet]

So you ran the same rear tyre for 3 days?

 

I have to say, I ran the GP racers with a slightly higher pressure last year, after advice from Dunlop UK, though I cannot tell you what it went upto because it's all in my book I make notes in, and it's just got to Jerez for my 3 day blast over next weekend, so I'm sorry about that fella. I think it was more like 26-27 Hot, but I'd like to check to be sure.

 

I don't think the wear looks that bad, though of course it's hard to say from a picture. You also can't realistically say that just swapping to brand X would resolve it either because you've seen another rider doing that on them, it could depend a lot on your bike's setup and your technique, so you could only realistically asses that by doing your own back to back comparison really on your bike, with you riding.

 

I'll be able to tell you the pressure settings, next week mate, but until then, i'm guessing in the dark really.

 

You may actually find a softer tyre is better for higher temperatures than an endurance tire, which would be better when it's colder, as it won't cold tear as badly. Complex stuff this tyre stuff eh? Experimentation is the key I'm afraid. It's good that you've made comprehensive notes and measurements though, as this is key.

 

Bullet

[Bullet]

p.s. GP Racers are made in France, (and are machine made) and GP Motorsport N-Tec's (which are more expensive) and can only be bought in either a 190 or a 200, are made (handmade) in UK.

 

 

Bullet

[khp]

So you ran the same rear tyre for 3 days?

Yup, you got that right. Effectively 2½ days, since we cut the last day short (didn't want to wait out 4 hours during the races to get our final session + an hour of open pitlane).

 

I have to say, I ran the GP racers with a slightly higher pressure last year, after advice from Dunlop UK, though I cannot tell you what it went upto because it's all in my book I make notes in, and it's just got to Jerez for my 3 day blast over next weekend, so I'm sorry about that fella. I think it was more like 26-27 Hot, but I'd like to check to be sure.

Oh, isn't that that awful for you that you have to go the the hot GP-track of Jerez instead of coming playing with me on the rural Kinnekulle Ring in cold & wet Sweden?

 

I don't think the wear looks that bad, though of course it's hard to say from a picture. You also can't realistically say that just swapping to brand X would resolve it either because you've seen another rider doing that on them, it could depend a lot on your bike's setup and your technique, so you could only realistically asses that by doing your own back to back comparison really on your bike, with you riding.

The wear does look worse in real life. Fortunately the tears don't appear to dig deeply into the tire.

 

As for changing back to the Supercorsas, do remember that I've been running them quite happily for the last two seasons - so I do have some experience in them and how I wear them. I did get the Ohlins shock serviced this winter, however.

 

You may actually find a softer tyre is better for higher temperatures than an endurance tire, which would be better when it's colder, as it won't cold tear as badly.

I would have thought it's a Hot Tear from what Dave Moss is saying (tear line goes up into the center of the tire & you can't get a nail into the tears), but I could easily have mixed things up.

But I do take your point on the softer tire. Too bad I don't have a tire sponsorship so I could have just dived into the van and grabbed the right compound from my stack of tires

 

Have fun and ride safely on Jerez.

 

Kai (suitably envious)

[Bullet]

So you ran the same rear tyre for 3 days?

Yup, you got that right. Effectively 2½ days, since we cut the last day short (didn't want to wait out 4 hours during the races to get our final session + an hour of open pitlane).

 

I have to say, I ran the GP racers with a slightly higher pressure last year, after advice from Dunlop UK, though I cannot tell you what it went upto because it's all in my book I make notes in, and it's just got to Jerez for my 3 day blast over next weekend, so I'm sorry about that fella. I think it was more like 26-27 Hot, but I'd like to check to be sure.

Oh, isn't that that awful for you that you have to go the the hot GP-track of Jerez instead of coming playing with me on the rural Kinnekulle Ring in cold & wet Sweden?

 

I don't think the wear looks that bad, though of course it's hard to say from a picture. You also can't realistically say that just swapping to brand X would resolve it either because you've seen another rider doing that on them, it could depend a lot on your bike's setup and your technique, so you could only realistically asses that by doing your own back to back comparison really on your bike, with you riding.

The wear does look worse in real life. Fortunately the tears don't appear to dig deeply into the tire.

 

As for changing back to the Supercorsas, do remember that I've been running them quite happily for the last two seasons - so I do have some experience in them and how I wear them. I did get the Ohlins shock serviced this winter, however.

 

You may actually find a softer tyre is better for higher temperatures than an endurance tire, which would be better when it's colder, as it won't cold tear as badly.

I would have thought it's a Hot Tear from what Dave Moss is saying (tear line goes up into the center of the tire & you can't get a nail into the tears), but I could easily have mixed things up.

But I do take your point on the softer tire. Too bad I don't have a tire sponsorship so I could have just dived into the van and grabbed the right compound from my stack of tires

 

Have fun and ride safely on Jerez.

 

Kai (suitably envious)

 

Well, I can tell you've I have seen these similar marks before on GP Racers, that I can confirm, though 4 hours hard work (remember you say you're improving all the time), really isn't that bad. I'm taking 2 fronts, and 3 rears to Jerez for 3 days. Oh, did I mention I'm going to Jerez on Thursday? On my shiny, newly finished Ducati, that's been lavished with love and the finest suspension I could procure, new triple clamps, and rear linkages. (god it better be good). You might find the move to the Motorsport version an even better jump my friend, rather than the GP Racer? I'll let you know how they go.

 

Sorry I can't be with you fella, but I will dig out my notes on my return for you.

 

Bullet

[DUNLOP-RTS]

 

BTW: these tires are "Made in France" - I guess this makes them "UK spec" according to Steve.

 

 

Those are French made. They are not considered UK made.

 

I would not be too overly critical about the PSI. 1-2 lbs is not going to part the red sea.

 

There is a small amount of tearing on the side, but nothing to be overly concerned about. Maybe a little less rebound dampening might clean that up.

 

The UK and USA versions of that tire are higher performers. If you are happy with the level of performance on that tire, it will only get better if you use the other lines Dunlop offers.

 

All in all it sound like you had a good ride.

[khp]

Those are French made. They are not considered UK made.

I stand corrected.

I would not be too overly critical about the PSI. 1-2 lbs is not going to part the red sea.

 

There is a small amount of tearing on the side, but nothing to be overly concerned about. Maybe a little less rebound dampening might clean that up.

 

The UK and USA versions of that tire are higher performers. If you are happy with the level of performance on that tire, it will only get better if you use the other lines Dunlop offers.

 

All in all it sound like you had a good ride.

Thanks for the input. I actually did try to play with less rebound, but it was getting too quick so I was advised to go back 2 clicks. I can see that I forgot to mention that the Most track is really bumpy in the final two (right hand side) turns leading out onto the straight - I guess this could easily affect the wear pattern.

 

So all in all, I had a good & fun ride, and I have been satisfied with the Dunlops. Now I just need to find a couple of more trackdays to put on the bike

That, and maybe some "mid-grade" Dunlops (D211 GP).

 

Kai

[khp]

Here's the next installment of my tire wear story.

 

After putting the D211 GP Racer on fresh for Autodrom Most, and seeing some tearing on the right side after 4 hours of riding (as discussed above), I was a little concerned about how long they would last next time out.

 

I went to a trackday on Ring Knutstorp Thursday & Friday. Thursday we opted not to ride due to a slight drizzle (too little for rain tyres, too much...) but Friday was dry. We had about 1h30m of effective riding time and in that time, the rear tire healed up so well that it's a small miracle - it's hard to see that had been tearing previously. See the attached pics (all of the right side, which is the side getting punished at Knutstorp).

 

What was even more surprising to me and my friend is that his Pirelli Diablo Supercorsa rear, started to tear up quite a bit at the same time - and he had no tearing problems at Most!

We tried a couple of different changes to suspension, until we figured out that he was seeing a cold tear caused by over-inflation. We let out a bit of air, and his tire started to heal up again.

 

This caused us to wonder about what we had just witnessed: at Most, my GP Racers were tearing, while his Diablo Supercorsas were fine. On Ring Knutstorp, the situation was the opposite - his rear is tearing, mine isn't.

The only explanation that we could come up with is the difference of the tracks: Knutstorp is small and with a lot of esses, while Most is big with a lot of long high-speed turns - and this has an impact on what is demanded from the suspension and tires. Oh, and Most seems to be more bumpy than Knutstorp

 

Steve - what's your opinion/input on this theory?

[DUNLOP-RTS]

Here's the next installment of my tire wear story.

 

 

Steve - what's your opinion/input on this theory?

 

I think the tire looks reasonably good. I have observed this wear pattern many times and it is not an issue.

 

I think you are focusing to much on the idea that 1-2 PSI will make the difference in the tire tearing or not. When its more likely to be the suspension. There are many gains to be made via suspension changes. I would set the PSI at the recommended and not vary from that, Then work on the suspension to tune that out. Keeping in mind that it may never go away because the track is simply abrasive and makes that wear pattern. Its never going to look like a new tire. Only after you have a very good chassis setup and you are within 5 sec of the class record for lap times, would I vary 1-2 PSI.

 

Maybe a 1-2 PSI change would effect the wearing, but a chassis change in the right direction will make even more difference. (much like adding a cup of fuel will make your car go farther, but a good tuneup will resolve the real problem and the car will go farther every tank full.)

[Tasman]

is this normal? this was done in slow track (95km/h average) with lots of corners 2km long. People are finishing these in just 3 sessions of of total 30 laps.

[DUNLOP-RTS]

is this normal? this was done in slow track (95km/h average) with lots of corners 2km long. People are finishing these in just 3 sessions of of total 30 laps.

 

Tasman,

 

I am happy to help.

 

But I need you to give more information other than just 1 pic and "is this normal?" question.

 

Please proide some information such as; what bike, what track, what tire, what compound, how many laps are on the tire in the picture, what laps times/ how far off the top lap time, what PSI was used, is it a stock shock? and others

 

The more information you provide the more I can help.

 

Certainly this would not be "Normal" for 1 lap. But this would be what can be expected if its an abrasive track and its a softer compound. Understand that things are relative. It would be nice to get more than 30 laps, but if its a full on superbike race a full race pace, this is what a tire might look like.

[Tasman]

ok sorry. here are some more information and pic.

the bike is 675R. set up is the recomentaion from triumph for race minus 2 clicks from all.

tire pressure 21 psi cold.

this is a gp racer endurance 190/55 made in france.

the track is new and lockated in Cyprus. As i said is 2 km long with low average speed 95km/h. it has long slow (70km/h) corners. it is not that abrasive. there isnt a lot of camper on the corners.

the tire shown is after 25 laps.

I am running with the fasted.

a TT racer which was on the track was 3,5 seconds faster than me with his cbr1000.

The tire in the pic is half warn.

A friend with a cbr1000 the same day running, the same lap times, the same tire, with a bit higher pressures 25psi cold he finished it in less than 30 laps. His tire looked just like mine shown in the pic.

I would like to note that before the gp racer i had the sportsmart 180/55 24 psi. I have done over 90 laps in three days. It is still new and it does not have the wear patern shown in the pic and i was running the same lap times.

 

please help.

[DUNLOP-RTS]

ok sorry. here are some more information and pic.

the bike is 675R. set up is the recomentaion from triumph for race minus 2 clicks from all.

tire pressure 21 psi cold.

this is a gp racer endurance 190/55 made in france.

the track is new and lockated in Cyprus. As i said is 2 km long with low average speed 95km/h. it has long slow (70km/h) corners. it is not that abrasive. there isnt a lot of camper on the corners.

the tire shown is after 25 laps.

I am running with the fasted.

a TT racer which was on the track was 3,5 seconds faster than me with his cbr1000.

The tire in the pic is half warn.

A friend with a cbr1000 the same day running, the same lap times, the same tire, with a bit higher pressures 25psi cold he finished it in less than 30 laps. His tire looked just like mine shown in the pic.

I would like to note that before the gp racer i had the sportsmart 180/55 24 psi. I have done over 90 laps in three days. It is still new and it does not have the wear patern shown in the pic and i was running the same lap times.

 

please help.

 

It is likely that the compound is too soft for the track and suspension setting you are using. The tire looks to have "Cold Tear" or "Tearing". This is from a stock shock, or bad suspension setup or the track is very abrasive or its cold (less than 70 def F).

 

Since you note the SportSmarts work fine with the same lap times, I suspect you are not on a record breaking lap time. Thus I would point the finger to suspension and compound first.

 

Is there a harder compound available? (if so go harder on the compound)

Do you have stock suspension? (if so get better aftermarket shocks)

 

The PSi is fine.

[Tasman]

ok sorry. here are some more information and pic.

the bike is 675R. set up is the recomentaion from triumph for race minus 2 clicks from all.

tire pressure 21 psi cold.

this is a gp racer endurance 190/55 made in france.

the track is new and lockated in Cyprus. As i said is 2 km long with low average speed 95km/h. it has long slow (70km/h) corners. it is not that abrasive. there isnt a lot of camper on the corners.

the tire shown is after 25 laps.

I am running with the fasted.

a TT racer which was on the track was 3,5 seconds faster than me with his cbr1000.

The tire in the pic is half warn.

A friend with a cbr1000 the same day running, the same lap times, the same tire, with a bit higher pressures 25psi cold he finished it in less than 30 laps. His tire looked just like mine shown in the pic.

I would like to note that before the gp racer i had the sportsmart 180/55 24 psi. I have done over 90 laps in three days. It is still new and it does not have the wear patern shown in the pic and i was running the same lap times.

 

please help.

 

It is likely that the compound is too soft for the track and suspension setting you are using. The tire looks to have "Cold Tear" or "Tearing". This is from a stock shock, or bad suspension setup or the track is very abrasive or its cold (less than 70 def F).

 

Since you note the SportSmarts work fine with the same lap times, I suspect you are not on a record breaking lap time. Thus I would point the finger to suspension and compound first.

 

Is there a harder compound available? (if so go harder on the compound)

Do you have stock suspension? (if so get better aftermarket shocks)

 

The PSi is fine.

 

thanks for the input but as i said the bike is the 675r which has ohlins suspension and the tire is the D211 gb racer endurance which can not go any harder.

May be, because the track is slow i cannot put much heat on them. is there any way to solve this with tire pressures?

[DUNLOP-RTS]

ok sorry. here are some more information and pic.

the bike is 675R. set up is the recomentaion from triumph for race minus 2 clicks from all.

tire pressure 21 psi cold.

this is a gp racer endurance 190/55 made in france.

the track is new and lockated in Cyprus. As i said is 2 km long with low average speed 95km/h. it has long slow (70km/h) corners. it is not that abrasive. there isnt a lot of camper on the corners.

the tire shown is after 25 laps.

I am running with the fasted.

a TT racer which was on the track was 3,5 seconds faster than me with his cbr1000.

The tire in the pic is half warn.

A friend with a cbr1000 the same day running, the same lap times, the same tire, with a bit higher pressures 25psi cold he finished it in less than 30 laps. His tire looked just like mine shown in the pic.

I would like to note that before the gp racer i had the sportsmart 180/55 24 psi. I have done over 90 laps in three days. It is still new and it does not have the wear patern shown in the pic and i was running the same lap times.

 

please help.

 

It is likely that the compound is too soft for the track and suspension setting you are using. The tire looks to have "Cold Tear" or "Tearing". This is from a stock shock, or bad suspension setup or the track is very abrasive or its cold (less than 70 def F).

 

Since you note the SportSmarts work fine with the same lap times, I suspect you are not on a record breaking lap time. Thus I would point the finger to suspension and compound first.

 

Is there a harder compound available? (if so go harder on the compound)

Do you have stock suspension? (if so get better aftermarket shocks)

 

The PSi is fine.

 

thanks for the input but as i said the bike is the 675r which has ohlins suspension and the tire is the D211 gb racer endurance which can not go any harder.

May be, because the track is slow i cannot put much heat on them. is there any way to solve this with tire pressures?

 

There is not a magic tire pressure (unfortunately) that will fix all tire ills. Pressure might make a small change, you can try it.

 

If we exclude any suspension issues, the problem is the 'compound - track surface' relationship. either change to a different compound, or change the track surface. What works great on one track may not on another.

 

But always keep in mind that a bad suspension setup will also tear a tire.

 

Is it cold out? could temps will tear a tire, that would not normally tear. Is it below 70Deg F?

 

Are other riders have the same issue?

 

Is the issue related to grip? is the grip good and the issue is the fast wearing?

[tmrki]

Hello Steve,

 

How does this front tyre D211 GP Racer looks like to you? It is Medium component, on 86 degree Fahrenheit with pressure 28psi cold.

 

And is it the lowest pressure for rear tyre D211 GP Racer 17psi cold?

 

Thank you

[cmd]

exclusively for street what do you think of Dunlop D211 GP Racer Endurance Front and Rear?

 

the temperature must be in the air they breathe to work properly for each composition in hand? or how to choose the tires depending on the temperature outside?

 

tnx

[stylo]

exclusively for street what do you think of Dunlop D211 GP Racer Endurance Front and Rear?

 

the temperature must be in the air they breathe to work properly for each composition in hand? or how to choose the tires depending on the temperature outside?

 

tnx

 

Ambient temperature shouldnt be a factor on the road. Naturally early mornings or cold days bring their own issues of grip, dew, frst etc but thats common sense.

Youre better off with a Dunlop SportSmart/Q2 as the mileage will be better and you will be no where near the grip limits on the road.