New design Kumho V710

Chuck Branscomb · **Posted:** Sun Feb 24, 2008 8:43 pm

I've been looking for more information on when the new V710 will be out, and it appears to be fairly close from what I've found on the net. For anyone that went to the Dixie National Tour event this weekend, did you happen to see any new V710s or hear anything about them?

I have found a couple of pictures on the net of the new design, and it appears that the tread-to-sidewall interface is extremely square. I'm totally conflicted on how this will fare on a camber-challenged stock class car (i.e. 330i). I have trouble with thoughts of the stress concentration that shoulder will see and the corresponding elevated local tread temperatures.

Here are some links to the pictures:

http://www.imagebam.com/image/4bd1b9719131/

http://webpages.charter.net/mitchlewis/kumho/edge.jpg

Arthur McDonald · **Joined:** Fri Aug 29, 2003 1:54 am **Posts:** 2052

I'm sure it won't take long for that square edge to wear down to a nice rounded shoulder.

Chuck Branscomb · **Posted:** Mon Feb 25, 2008 8:34 am

Yep, I would think so. My question though is more targeted toward the longevity of the tire's top performance. I was wondering whether Kumho desinged them like this to function REALLY well on a camber challenged car when the tires are fresh (i.e. top dogs running fresh tires at each event) without much regard for how many useful runs a local hack like myself will get out of them for $275/each.

Les Davis · **Joined:** Fri Aug 29, 2003 2:04 pm **Posts:** 2059

This was my exact concern as well Chuck when I heard about the design changes. I can't see how this tire will be as friendly to camber challenged cars.

Aaron Buckley · **Posted:** Mon Feb 25, 2008 1:02 pm

I didn't see any in person at Dixie, but from what I've been told, only one side is square and the other is still rounded, thus limiting the ability to flip it, but the overall should design is the same. I am guessing that it will further enhance the turn in for camber challenged cars, similar to the cantilever design of the original BFG R1. (I can't see the pictures in the links due to the filter at work) - AB

Chuck Branscomb · **Posted:** Mon Feb 25, 2008 2:28 pm

Aaron,

In this thread on sccaforums, http://sccaforums.com/forums/2/284703/ShowThread.aspx#284703, the last post is from a guy who has them, and his post indicates that both sides are sharp edged. Here's what he posted:

Quote:

Yep! That's how my 225/45/17's looked when they were new. But now after 3 events the outside shoulder has begun to round off and look like a normal V710. I think that with this new design the camber challenged cars will have reduced shoulder wear for even longer tire life before cording. But what I'm interested in is whether the tire behaves differently with a square shoulder compared to a rounded shoulder. We're running winter events here so there hasn't been much grip available for consistent testing.

How the tire behaves new versus once you round that edge is the question.

One thing is pretty certain -- people who had tight clearance issues before may run into rub or fender lip issues, etc, now that the tire looks to be "section-width-wide" out to the tread face. This is actually similar to the way the new BFG R1 is designed. Perhaps we'll see all new "hot" designs come with a shoulder like this...

Aaron Buckley · **Posted:** Mon Feb 25, 2008 3:05 pm

I have some good information on them now. I called Chris Harvey who works at the Tire Rack. Chris finished 4th at Nationals in an RX-8 in BS '07 and was in the top 10 in a CS Solstice in '06.

He basically told me that Rudy at Kumho has little or no information on the tire, but the change was designed more towards road racers. Only the "new" '08 sizes will be of this construction. The reason you have seen pictures of the 225/45/17 is due to this being the spec tire for the '07 Pro Spec Miata series and when Vilven didn't sell out of them in the series, sold them off to other companies (including the Tire Rack).

Chris said that all of the existing styles will be the "old" build styles, but said that Kumho does not think that mixing the styles would be good. There are no plans to rename the new tire yet in order to have them be legal for autocross in '08. Otherwise, they would need to meet the April 30th date, which they won't have 6 sizes by then. My guess is that they will likely rename it in '09 and make the existing tire the "710A" and the other the "710R", similar to Hoosiers A6 & R6.

In regards to Kumho build dates, the dates in 2005 and 2006 are different compounds, but after a lot of testing at the Tire Rack, there have been no differences in times they could achieve on the test autocross course.

Likely, you won't see anything in the new style until mid summer according to Chris (other than the leftover 225/45/17's). - AB

Chuck Branscomb · **Posted:** Mon Feb 25, 2008 3:15 pm

Outstanding information Aaron! Thanks very much. This really helps with planning for tires for this season.

Chuck

Aaron Buckley · **Posted:** Mon Feb 25, 2008 3:35 pm

Chuck Branscomb wrote:

Outstanding information Aaron! Thanks very much. This really helps with planning for tires for this season.

Chuck

No problem

I'm glad all this racing stuff has provided connections

- AB

michaelsmiller · **Posted:** Wed Mar 05, 2008 6:35 pm

I picked up a set and will be running them on my MX5. The edges are sharp on both sides. Mine is a camber challenged car in front. Luckly, I wear the insides on the back and the outsides on the front. Laurenberg will be my first time using R compound tires. The car pulls 1G with Azenis, I'm hoping for lots of grip with the V710's.

Wes Eargle · **Joined:** Mon Oct 27, 2003 9:47 am **Posts:** 3683

michaelsmiller wrote:

I picked up a set and will be running them on my MX5. The edges are sharp on both sides. Mine is a camber challenged car in front. Luckly, I wear the insides on the back and the outsides on the front. Laurenberg will be my first time using R compound tires. The car pulls 1G with Azenis, I'm hoping for lots of grip with the V710's.

How much camber are you running in the front?

JamesFeinberg · **Posted:** Wed Mar 05, 2008 6:51 pm

Wes Eargle wrote:

michaelsmiller wrote:

I picked up a set and will be running them on my MX5. The edges are sharp on both sides. Mine is a camber challenged car in front. Luckly, I wear the insides on the back and the outsides on the front. Laurenberg will be my first time using R compound tires. The car pulls 1G with Azenis, I'm hoping for lots of grip with the V710's.

How much camber are you running in the front?

And which size did you get? Is it one of the newly announced sizes? Born-on date?

Jim

steve remchak · **Posted:** Wed Mar 05, 2008 8:37 pm

1 G on Azenis? damn. seriously sprung?

michaelsmiller · **Posted:** Wed Mar 05, 2008 9:01 pm

The MX5 allignment is 1.2 deg front and 1.5 deg rear. The rear gets a lot of camber gain less some toe when cornering. The tire size is 225 / 45/ 17. The springs are soft and stock. The car has adjustable Koni's and an MS front bar. The shocks are adjusted full soft on front and full hard in the rear. The born on date I think is 2807 or July 07. I had to wait for Tire Rack to get the V710's in stock. They look just like the tires in the picture link above. That's why I have assumed that they are the new style. I really don't know what the old style looked like. Herb Adams of GM fame has a theory that softer springs with heavy sways provides more grip than relying on very stiff springs.

MikeWhitney · **Joined:** Wed Aug 20, 2003 9:15 pm **Posts:** 4724

michaelsmiller wrote:

Herb Adams of GM fame has a theory that softer springs with heavy sways provides more grip than relying on very stiff springs.

Can you point me to some more info on this?

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New design Kumho V710

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