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Help me diagnose my tire


donkason

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I have watched the Dave Moss videos but my lack of experience is keeping me from making a confident decision. I know two things so far, reduce rebound and increase compression given the wear patterns on the sipes. However, I think there may be more here than that. The Dunlop tech looked at it and said I'm throttling too hard out of left corners, but he's a tire guy and not a suspension guy.

What do you guys think. Left side of rear tire. My goal is to heal this so I can pull off another 1-2 track days on it. The Dunny D211 is expensive!

46c2063d-dcff-312e.jpg46c2063d-dd19-e02e.jpg

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I agree with it being a tear. Just need to know what pressures he started with and adjust accordingly. Those look like Q2's so I think I recall the cold pressures are like 30f/29-30r but someone with more time on them could chime in.

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They are the D211 Dunlops and it's a GSXR 750. I ran 21psi in the rear per dunlop specs for the track. When I got off the pressure had increased to 24.5psi. I backed it down to 23psi. The track was hot as hell, last Tuesday at Mid-Ohio. I hear a 10% increase from cold to hot pressure is optimal and that's what I was shooting for and thinking I was compensating for the intense heat.

After lunch the cold pressure said 19.5 so I bumped it back to 21 cold and didn't remeasure during the afternoon.

I was hammering the throttle in turn 1 right on that contact patch. I'm still working on entry speed and halfway through I'd realize I was way to low and roll on the throttle aggressively to make up time. I'm a quick novice guy if that helps.

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dave moss says 5-7lb increase. I'm no expert but I'd say you simply ran them way too low to start with. try starting at 24 maybe. I think he says in his video's if the tire doesn't come up 5-7lbs you get hot tear because the carcass of the tire is flexing so much it's getting too hot. something like that.

I did the same exact thing you did. I ran what everyone said they use and boy it about fried my tire in just a few laps. when my tires are looking good (to me anyway) they go from around 30 cold to 35-36 somewhere in there. I checked them as soon as I climbed off the bike. I didn't take my gloves or helmet off.

my tire looked exactly the same as yours does.

for reference I have a picture of it at the end of the day. I adjusted the psi before lunch and ran the rest of the day and you can still see the groove it cut into the tire.

3733230723_846c9a96c3_z.jpg?zz=1

Edited by serpentracer
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Well, you have 211s but for Dunlop Q2 i was told to run 28r/30f cold and those temps have worked out well for me so far.

http://dunlopracing.com/tires-products/d211gp/ does confirm the manf. specs for a low pressure tire.

It says GPA on the side. Would to Q2 say GPA or Q2?

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U need 22 HOT OFF TRACK and 34-35 Hot off track. HOT OFF WARMERS IS 19/34 Also have you messed with geometry at all. The GSXR needs it!

Flushed fork tubes with triple trees and shimmed up rear 5mm.

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  • 4 weeks later...

Update: it was a cold tear. I dropped the pressure to 19 in the rear and it cured up after a few rounds. I tracked pressure after each round and it bumped to 21.5-22 and held up fine.

Sent from my SCH-I510 using Tapatalk 2

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