Kumho vs ZZR opinions

[Dave Wilson]

I know I don't run in the Club Speed Series but I've seen a few of you at Loton and have a few years experience of competition under my belt. I run a 2.0VX, it's the pink one, in the Midland and selected British Championship events and followed the L7Club Class 5 trend this year and switched to Kumho 215 fronts and 235 rears (previously 175 and 215's) It's fair to say I could not get on with this setup, the back was fine, but I could not get any heat into the front's and the car felt very vague. It was so bad I switched back to 175 fronts halfway through an event at Loton and set my best time of the weekend on the 1st run!? Halfway through the year I need a new set of tyres so bought a set of Avon ZZR's, reset the ride heights etc and awaited the 1st run with eager anticipation. To begin with I was very impressed with the grip and feel of the ZZR's but found when I pushed really hard, especially on turn in, the back of the car would become very loose and was difficult to catch. Under breaking or on the throttle it was ok, but grip during turn in was very poor. The front of the car was superb, just this unnerving transition period as you committed to a corner. I changed all the things you should, ride heights, tyre pressures, toe in, camber, anti roll bar full soft to full hard, but nothing really made it better. Despite some good weather I only beat my previous year's time at one event, Prescott, every where else was close but no cigar...I have some video I could post if any one wants.

 

So my question to other competitors is, has anyone else tried the ZZR's and if so what are their opinions and what are the benfits of 215 Kumho's on the front for hillclimbs (I'm guessing with sprints tyre temps are not a problem)

 

Oh, by the way the ZZR's are fine in the wet.

 

Cheers

 

 

Dave

[Racing Snake]

Dave - very interested in seeing the video as i want to run at Prescott in 2011

Kumho super softs are

 

---

Mad Hatter The Dura Mentalist 😬 Carl @ Penn 7's Caution - May Contain Nuts !

[Simon.Rogers1]

Hi Dave

 

Like you have watched us we have watched some of your times 😶‍🌫️

 

I can not comment on the Avon's as I have not used them.

 

My thoughts on the Kumho's.

 

Unlike some others I had a perfect balance on 175/215 set up in Class 5. It has to be said that my current competitors were not in class 5 at that time.

 

We subsequently changed to 215/235 set up just to increase contact patch. (I'm not really sure about the amount of heat you can truly get into the tyre over such a short run although I understand the thinking of smaller contact = more heat faster).

 

I think we all thought that greater front end grip particularly when cornering would be achieved with 215 front. Remember I did not suffer this but I went along with the theory as (If I think back) it was predominantly those running standard Nitron set up that had the balance issue. Anyway I was increasing contact patch all around.

 

I think it became clear quite soon that although there was a small increase in cornering performance it was not as much as thought. I believe it improved things for those running Nitron's. I can not say it improved things whilst cornering for myself.

 

What it did do for me undoubtedly (backed up by data logging) is improve breaking performance. At both Curborough and Llandow G force has increased from around 1.5g to 1.75g.

 

As far as yur comments regarding the way the Avon breaks away I'm afraid that re enforces my thoughts and dislikes about the ACB10 (Although I found it whilst under power predominantly). The Kumho certainly breaks away sooner but far far more progressively than the ACB10. I have no doubt the ACB has more grip to a point but once its soft sidewalls have flexed as far as the can they snap loose and its all over. I find the Kumho far more predictive if not ultimately as sticky.

 

I do find the Kumho far more susceptible to temperature. To date I think I have only driven at 3 meetings where we have truly seen the Kumho's come alive. (Yes the weather has been that poor)!

 

Ultimately due to "MY" confidence in the tyre the Kumho has been faster for me. I can drive it loose or if I try really hard straight and smooth. Thats always the plan.

 

The Kumho is 2kg per tyre heavier. Thats just about 30% more than the Avon ACB10.

 

 

 

Competition Sec

Management Team Member

 

If in doubt.......Flat out!

 

[Dave Wilson]

Mad Hatter, I've put video of June's Prescott on the club site. The quality is not so special but you can see which way the course goes. Time was 44.56...good luck!

 

Simon, I think we are of the same opinion, I agree the braking was measurably better with the 215's on the front, but that was the only benefit I found. I really am quite sure now I don't like the balance of the car on ZZR's and almost certainly will change back to Kumho next year. At the moment I think I'll go with 175 on the front and 235 on the rear. I run standard VX Race spec Bilsteins, they're about 12yrears old now but I think they are spot on and it's one less thing to worry about adjusting!

 

We're thinking about entering the Club Championship next year, we can't do all the rounds as they clash with some of the BHC events, but it would be good fun for some head to head competition at some events.

 

Thanks for your views

 

 

Dave

[Simon.Rogers1]

Give me a ring if you want Dave.

 

Simon

07920 843146

01558 668708