Jump to content

Help me diagnose my tire


donkason
 Share

Recommended Posts

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

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

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
Link to comment
Share on other sites

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?

Link to comment
Share on other sites

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.

Link to comment
Share on other sites

  • 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

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...