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Yamaha Blue in any color
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Discussion Starter · #1 ·
Recently we had a track day at VIR, and Forum member Plimmer showed me some tire damage that he encountered after having his Dunlop D211s "flipped" to ease tire wear on the track he was previously on.

The following pictures were the result:








Since I don't claim to know much about tires, I emailed Dave Moss, the Founder of Catalyst Reaction Suspension, and here is his reply to me:

Dan,

211's CANNOT be flipped. They are a V belt tire and directional and will come apart. No one wants to seem to listen but I keep putting it out there! There are many tires that can be flipped safely for extra wear. That list is short but known and this 211 US GP-A tire is the first tire that Dunlop has created that is directional.


Dave Moss
So... DO NOT FLIP the D211. Please pass the word and be sure to credit Dave Moss as the source of this information.
 

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Re: Tire flipping - Dunlop D211 - DO NOT DO IT

I think he might have got a bad set of tires...I race with WMRRA here in washington and the vast majority of racers run the 211 spec or uk tires and everyone flips them.
 

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Yamaha Blue in any color
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Discussion Starter · #3 ·
Re: Tire flipping - Dunlop D211 - DO NOT DO IT

I think he might have got a bad set of tires...I race with WMRRA here in washington and the vast majority of racers run the 211 spec or uk tires and everyone flips them.
I saw the same tearing on two sets of flipped tires. But I'll continue the conversation with Dave including your input.
 

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I Race my R6
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Re: Tire flipping - Dunlop D211 - DO NOT DO IT

I've heard the US D211 (made in buffalo) are directional so you shouldn't flip them. The UK D211 use a different carcus which can be flipped with no issues. Correct me if I'm wrong but this is what I've heard.
 

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Moderator Narcissist
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Re: Tire flipping - Dunlop D211 - DO NOT DO IT

Wow, I'm guessing the peeling of the tread was caused by overheating of the carcass due to 'backwards' mounting (I know...'duh'). If Dave's info is any indication, deforming the belt backwards will simply cause the whole tire to begin to melt. I'm no tire expert, I simply calibrate the machines that make them (and car tires at that...unfortunately Toyo doesn't make bike rubber :(), but I'd never run a directional tire backwards. As far as the US/UK spec tires being different...that'd be nice to know for sure.

But thanks for the heads up, Dan! Plimmer didn't have any get-offs because of that did he?
 

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Yamaha Blue in any color
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Discussion Starter · #9 ·
Re: Tire flipping - Dunlop D211 - DO NOT DO IT

Wow, I'm guessing the peeling of the tread was caused by overheating of the carcass due to 'backwards' mounting (I know...'duh'). If Dave's info is any indication, deforming the belt backwards will simply cause the whole tire to begin to melt. I'm no tire expert, I simply calibrate the machines that make them (and car tires at that...unfortunately Toyo doesn't make bike rubber :(), but I'd never run a directional tire backwards. As far as the US/UK spec tires being different...that'd be nice to know for sure.

But thanks for the heads up, Dan! Plimmer didn't have any get-offs because of that did he?
I'll share what else I hear in this thread and the one on the R1 Forum.

As far as Plimmer... nah he caught it and changed tires. He's too in tune with what he does on the track. The man is good :fact
 

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Re: Tire flipping - Dunlop D211 - DO NOT DO IT

I'll send a link of this thread to Barry the local tire guy. He's the go to Dunlop guy.
 

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Rebuilding Track-Whore
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After another forum (altogether) member pointed out to me...those tires could possibly be mounted the right direction according to the way the rear tread points and the location of the sprocket?
 

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Took me a while but here is what Barry Wressell our local Dunlop guy told me:

"We personally have not had any issues flipping tires. The 211GP-A, the AMA spec tire, is JLB, Joint Less Belt. We've also flipped the 211GP NTEC tires with no issues. Many factors could have contributed to this gentleman's issue with the tire flip, it's really hard to say specifically what caused the tire to tear like it did. We always recommend working with your local tire supplier and suspension expert at the track, this is the best way to figure out what's going on."
 

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Moderator Narcissist
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Took me a while but here is what Barry Wressell our local Dunlop guy told me:

"We personally have not had any issues flipping tires. The 211GP-A, the AMA spec tire, is JLB, Joint Less Belt. We've also flipped the 211GP NTEC tires with no issues. Many factors could have contributed to this gentleman's issue with the tire flip, it's really hard to say specifically what caused the tire to tear like it did. We always recommend working with your local tire supplier and suspension expert at the track, this is the best way to figure out what's going on."
Hmmm...so basically what he's saying is you CAN flip the D211? I mean, it's a somewhat contradictory and ambiguous statement... :confused:
 

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Yamaha Blue in any color
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Discussion Starter · #15 ·
After another forum (altogether) member pointed out to me...those tires could possibly be mounted the right direction according to the way the rear tread points and the location of the sprocket?
They were flipped, and then flipped back. We ran Jennings GP on them, and if you are control riding for a couple days there it will wear the left side of the tire out quickly.
 

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Yamaha Blue in any color
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Discussion Starter · #18 ·
I'm gonna be the newb to step up and ask what exactly "flipping" is?
Race tracks, in general, have more turns in one direction than the other.



Because of this, you may wear the tire unevenly. At tracks like that, it's a common practice to "flip" the tire to wear the other side and extend the life of the tire.

We were doing a two day event at Jennings GP (above) which is left hand biased. So he flipped the tire to wear it evenly. When he flipped it again to run a different track, it began to tear.
 

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I'm gonna be the newb to step up and ask what exactly "flipping" is?
If you ever notice most motorcycle tires are now directional. You will notice small arrows pointing the way for forward rotation. Flipping just means you are turning the tire backwards and not running it in the direction of the arrows.

This is not good for street riding especially in wet conditions since the tread pattern is now working backwards and not displacing water as intended. On the track many riders {including me} wear the left or right side down faster and will just have the tire flipped to the other side where there is more rubber. This saves the track rider money which can be used on other things or delaying the purchase of new tires.
 
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