Kumho V70A Ecsta tyres.

[OliS]

So Oliie's post about trackday rims and tyres got me thinking that I should probably do the same thing and get a set of trackday tyres to stop me killing a set of road tyres every other trackday. The tyres that I have read the most about on this forum are the Kumho V70A's, and I just want to see who knows what about these tyres.

Firstly, what compound do people advise for trackday use? The tyres are available in hard, medium and soft, and if I want the tyres to last for at least five trackdays which compound would be best? I'm kinda thinking that hard would be the best option as they will last the longest, but if I go for hard will they still offer more grip than std road tyres?

Secondly, I know they are road legal tyres, but just how safe/appropriate are they for road use? I was planning to have them fitted a day before each trackday, and drive to the track on the Kumho's, will the heat cycles generated on the road ruin the tyres, or reduce their life?

Appreciate that this may not be the best forum for questions like these, but I know there is one other person on this forum thinking about using these tyres (George), and another who is already using them (sm wrc), so your input would be greatly appreciated gents!

 

[oliie]

Oli... it may be better to go for a 15" set of rims and then go for the Yoko A048s.. I have heard nothing but good news about them.

This way you also don't have to drive to the track in the track tyres and risk wearing them down quickly and getting a puncture etc.

I am still searching for a cheap 15" ET45 rim... not as easy as I thought it was going to be!!

O.

 

[sm_wrc]

Hi mate,

I've just done my first track day on the Kuhmos, and i think they are pretty awesome.

I'm running medium compounds, front and back. Means you can swap them front to back. They are a directional tyre, as they have some tread. Abbeyville was very abrasive, so I have removed a little already.

They should be good for around 3-4 more days. It really depends how aggressive you drive on them. And what surface you drive them on. The thing you have to do with them is constantly check their pressures. Cos if you have too much or to little, you will knacker them.

Although they are road legal, i wouldn't recommend doing a lot of road miles on them, as they are quite soft, compared to your exaltos. But you could certainly drive to a track on them. They work in the wet as well, but best to avoid standing water, puddles etc, as you will aquaplane. I know. :wink:

 

[OliS]

Thanks for the replies guys!

Oli... it may be better to go for a 15" set of rims and then go for the Yoko A048s.. I have heard nothing but good news about them.

Don't know why, but I would only consider running a second set of 16" Turini's as trackday wheels - keep the same handling characteristics, looks etc - and I can't afford a second set right now, which is why I am thinking of having a set of tyres to change to for each trackday...Agree with your comments on the Yoko's, but I have also only heard good things about these Kumho's, in a test in German Auto Bild magazine, they rated the Kumho better than Michelin, Pirelli and Yoko trackday tyres. I've also got a mate who competes in the Kumho sponsored BMW Challenge, and these are the control tyres that they use, he rates them very highly and reckons they would make an ideal trackday tyre, and this is from guy who is used to racing on slicks!

The thing you have to do with them is constantly check their pressures. Cos if you have too much or to little, you will knacker them.

How does this work, what's the range that you have to keep the pressure within? How does it knacker the tyres if you run the wrong pressure?

How much did you pay for your tyres mate? Found them for £105 a corner from Peter Lloyd rallying, is that about as cheap as I will find them?

 

[George K]

As some of you will already know, I am also caught up in the Kumho debate as they are the only 16" tyre with proper track compounds (the Hankook RS2 has track construction with road compound - treadwear index200 versus 40 - 100). Kumho recommend medium front and soft rear and quite low starting pressures (28/26) - I wonder if this could aggravate the understeer?
I had also thought of running medium compound at the front and road tyres at the rear to help the balance

The choice of compound will also depend on how much running you do - obviously you will get a lot more heat into the tyres on a multi lap track day than a short hillclimb or sprint (maximum of one mile at a time).

Very few people use them, so a value judgement versus A048 is difficult. A048 were certainly quite good in the wet at Wiscombe - the only Kumhos were on an R5 turbo (the rear engined version) and that is a handful in the wet, so hard to assess.

The German report was a bit strange as in fact the Kumhos were not very good in the wet.

One last comment, I am warned that track day tyres can get very hot on long motorway runs on hot summer days, which is not good for them - whether that is an issue I have no way of judging.

 

[sm_wrc]

That's a good price if you are getting them for £105. Is that with VAT?

Running the correct pressures, keep the maximum amount of rubber in contact with the track at all times. Think of it like a balloon, if you inflate it more, you will have less contact area.

The kuhmos in the wet are ok, similar levels of grip to the Exaltos, but this does depend on the amount of tread on them. They do not work on standinging water, or heavy rain. As I found out. Hehe

On a track with a dry line, they work extremely well.

I wouldn't run them on the road for any great distance, as they are reasonably soft.

 

[fazedesign]

George K & other Kumho users - please take a look at my tyre spreadsheet in this post: http://cliotrophy.co.uk/forum/viewtopic.php?t=1508

Can you let me know the ratings of the Kumho and I'll add them to the sheet.

 

[OliS]

Can't really add much info to your spredsheet myself, I am pretty sure they are Z speed rated, and there is loads of other techinical info on the Kumho website but no data that you have headers for on the spreadsheet.

That's a good price if you are getting them for £105. Is that with VAT?

It says on the Peter Lloyd Rallying website that this price does include VAT, but I have not checked yet as I am still trying to make up my mind about what to do!

 

[fazedesign]

Cheers Oli - I haven't had a proper look through the manufacturer sites yet.

The treadwear/traction etc ratings can normally be found on the sidewall of most tyres - as I understand it there are different grades of the Kumho's so this will probably also vary!

 

[George K]

I have the Kumho catalogue - will check at the w/end. Suggest you add a column to show that they are track tyres. For us competitors you may also want to consider a cross reference to the MSA Blue Book, which defines what tyres are list 1A (Production) or 1B (Modified class) - confusingly a lot of regional club events apply different rules.