200tw tires for Track use

[krs]

I've only shifted to 3rd once. Our clubs speeds seem to slowly go up in 3 year cycles, then we have an incident, and back to tight slaloms and lower speeds.

I get to third in a few events a month. Third gear, just to clarify.

 

[krs]

View attachment 253048

View attachment 253047

Picture of my 255/35/18 V730’s after one event, top tire is the front which has around -2.3 camber. Looks like I could use some more camber dailed into my plates.

The bottom tire is the rear, camber looks fine at around -2.2. I got some good heat into them and they still felt manageable.

They took about 1.5 laps before I felt confident to start pushing.

Initial testing seems to be around 1.5 - 2.0 seconds slower than the RE71R at Auto Club Speedway Roval though I would like to get some more use before full judgment. Faster lap times shifted to my 4/5th lap compared to my 2/3rd with the RE71R. The car tends to heat soak a bit more before getting up to speed for a hot lap.

I like the stiffness of the sidewalls, I think I can run less than 35 psi hot with the right camber up front for a bit more grip. Steering response wasn’t bad too.

Overall good price point and can handle the heat for a small sacrifice in lap times.

Dang those tread grooves look so much deeper than mine did. I wore the cross groves down to slicks after just a few runs, but mine were very shallow.

 

[krs]

Weird wear, seems like potential mfg defect.

Definitely a defect.

I've seen this in a LOT of 660s, consensus seems to be just send it and the mark will wear itself away. If TR will give you a new tire though, that's obviously preferable

Here's tire racks response:

Good afternoon, Thank you for your email.


What is shown in the photos is called “visible tread splice”. During the manufacturing phase, before the tire goes into the mold to cure and get its final shape, a wide sheet of uncured tread rubber is wrapped around the tire casing above the steel belts. There is a beveled junction where the ends of that sheet meet, which becomes invisible as the tire cures in the mold. Sometimes, braking force or torque and/or wheelspin from acceleration can put enough stress on this junction to cause it to become visible as a faint line that runs across part or all of the tread area. Proper tire rotation will prevent it from getting deeper, but if left in the same wheel position it will likely grow further, eventually tearing open to the point the tire must be replaced. Usually, after rotating away from the wheel position where the splice first became visible, the splice will eventually disappear as the tire continues to wear from use. With the splice is at the visible stage on at least one of the tires, the tire should be rotated to help hold the beveled splice closed. Rotate front to back on the same side of the vehicle, or side-to-side across the same axle to help hold the splice closed rather than continue to pull it open. If the splice is torn open far enough to see the flat under tread rubber that lies beneath the tread compound, then the tire should be removed from service.


See this Tech Center article for reference –
Should I Inspect My Tires Between Sessions?

 

[Will_]

Here's tire racks response:

Good afternoon, Thank you for your email.


What is shown in the photos is called “visible tread splice”. During the manufacturing phase, before the tire goes into the mold to cure and get its final shape, a wide sheet of uncured tread rubber is wrapped around the tire casing above the steel belts. There is a beveled junction where the ends of that sheet meet, which becomes invisible as the tire cures in the mold. Sometimes, braking force or torque and/or wheelspin from acceleration can put enough stress on this junction to cause it to become visible as a faint line that runs across part or all of the tread area. Proper tire rotation will prevent it from getting deeper, but if left in the same wheel position it will likely grow further, eventually tearing open to the point the tire must be replaced. Usually, after rotating away from the wheel position where the splice first became visible, the splice will eventually disappear as the tire continues to wear from use. With the splice is at the visible stage on at least one of the tires, the tire should be rotated to help hold the beveled splice closed. Rotate front to back on the same side of the vehicle, or side-to-side across the same axle to help hold the splice closed rather than continue to pull it open. If the splice is torn open far enough to see the flat under tread rubber that lies beneath the tread compound, then the tire should be removed from service.


See this Tech Center article for reference –
Should I Inspect My Tires Between Sessions?

I missed your original post but FWIW I had this exact same thing happen on my RT660s after their second track day. Unfortunately that was my last one so I can't comment on how they've help up since other than they've been fine for street driving.

 

[krs]

Dang those tread grooves look so much deeper than mine did. I wore the cross groves down to slicks after just a few runs, but mine were very shallow.

I found a pic, kind of. The middle wheel.

 

[Autobahn]

I found a pic, kind of. The middle wheel.
View attachment 253059

Yeah, you made the outer portion slick pretty quickly, inner doesn’t look to bad. The outer grooves are more shallow than the inners. How much camber do you have?

 

[GTIfan99]

Here's tire racks response:

Good afternoon, Thank you for your email.


What is shown in the photos is called “visible tread splice”. During the manufacturing phase, before the tire goes into the mold to cure and get its final shape, a wide sheet of uncured tread rubber is wrapped around the tire casing above the steel belts. There is a beveled junction where the ends of that sheet meet, which becomes invisible as the tire cures in the mold. Sometimes, braking force or torque and/or wheelspin from acceleration can put enough stress on this junction to cause it to become visible as a faint line that runs across part or all of the tread area. Proper tire rotation will prevent it from getting deeper, but if left in the same wheel position it will likely grow further, eventually tearing open to the point the tire must be replaced. Usually, after rotating away from the wheel position where the splice first became visible, the splice will eventually disappear as the tire continues to wear from use. With the splice is at the visible stage on at least one of the tires, the tire should be rotated to help hold the beveled splice closed. Rotate front to back on the same side of the vehicle, or side-to-side across the same axle to help hold the splice closed rather than continue to pull it open. If the splice is torn open far enough to see the flat under tread rubber that lies beneath the tread compound, then the tire should be removed from service.


See this Tech Center article for reference –
Should I Inspect My Tires Between Sessions?

So it's a defect, but F you? I've been autocrossing for 35 years and never seen that happen to a tire.

 

[SouthFL_Mk7.5]

So it's a defect, but F you? I've been autocrossing for 35 years and never seen that happen to a tire.

That’s how I read it.

 

[GTIfan99]

Yeah, you made the outer portion slick pretty quickly, inner doesn’t look to bad. The outer grooves are more shallow than the inners. How much camber do you have?

The outer groves are much more superficial.

 

[krs]

That’s how I read it.

Yeah me too. I replied asking for clarification that they just told me to remove it from service and buy another.

 

[GTIfan99]

I'd autocross on that, but wouldn't want to be headed into turn 1 at 140+ mph on that thing.

 

[SouthFL_Mk7.5]

I'd autocross on that, but wouldn't want to be headed into turn 1 at 140+ mph on that thing.

A few years ago I bought a set of 200tw V720’s (predecessor to the V730) only to find out that Kumho was advising to use them exclusively for autocross and not track them after having several delaminating issues with prolonged heat cycles. The warning was enough for me to keep them off the track -let alone a huge seam coming apart! I wouldn’t run a tire with a gash like the ones shown in the pics at Sebring or Homestead (my home tracks)!

 

[sibanez]

View attachment 253048

View attachment 253047

Picture of my 255/35/18 V730’s after one event, top tire is the front which has around -2.3 camber. Looks like I could use some more camber dailed into my plates.

The bottom tire is the rear, camber looks fine at around -2.2. I got some good heat into them and they still felt manageable.

They took about 1.5 laps before I felt confident to start pushing.

Initial testing seems to be around 1.5 - 2.0 seconds slower than the RE71R at Auto Club Speedway Roval though I would like to get some more use before full judgment. Faster lap times shifted to my 4/5th lap compared to my 2/3rd with the RE71R. The car tends to heat soak a bit more before getting up to speed for a hot lap.

I like the stiffness of the sidewalls, I think I can run less than 35 psi hot with the right camber up front for a bit more grip. Steering response wasn’t bad too.

Overall good price point and can handle the heat for a small sacrifice in lap times.

Did you get a heat cycle in on these before running them? The Kumho really needs a good heat cycle before it’s fully activated.

 

[GTIfan99]

V730 need a heat heat cycle. They also need more negative camber than RE71R's OR more pressure. Not both though.

 

[Autobahn]

Did you get a heat cycle in on these before running them? The Kumho really needs a good heat cycle before it’s fully activated.

I’ve yet to have tire rack heat cycle a set of tires for me and I don’t have an extra track set. I’ll give it a try next time