Dunlop z1 vs Kumho 36

dbr · Postby **dbr** » Wed Apr 20, 2011 5:21 pm

Howdy,
I'm due for a new set of tyres. I finished off the Michelin Pilots at Winton and I am now considering weather to buy a sport tyre that will give decent grip at race tracks, or a second set of rims and race orintated tyres plus road tyres.

Looking through the many threads in this forum, the KU36 is cheep (thanks Randy) and the Dunlop z1 star is the favourate of the "standard" class in Victoria. My turbo takes me out of the standard class, so I am looking at the tyres on their absolute merits, not their class efectiveness.

Stucky says the Z1's are suitable for road use and track use, with reasonable road life and track grip. They will not say how much quicker the full on expensive DZ03g's are, but do say not to use them on the road.

The Kumho importer says the KU36's are intended for track use and recommend the KU39's for dual use, but they are not available under 17 inch diameter.

Has anybody know how much faster the KU36's are than the Z1's ?
If they are similiar, I can save a bit of money by not buying a second set of everything.

bensale · Postby **bensale** » Wed Apr 20, 2011 5:32 pm

It's the other way around... The Z1's are the faster tyre... They're a bit more expensive but are better on the track, better on the road and better when it's wet. I'm a big fan of the z1's in every aspect except cost when compared to tyres like the ku36 and the R1R. Tyre life is not exceptional, but not terrible... I guess it depends on how hard you drive them... They are quite a soft tyre after all

The only negative I've found with them where a dedicated semi slick such as a Toyo 888 would be better is that they go off reasonably quickly at Winton if you're pushing hard... At the end of the last day there I was struggling to get a single lap out of them before the grip levels dropped off. They come back to you if you do a slower lap or by the next session. At tracks like Phillip Island this isn't as much of a problem as they can have some breathing time on the straights.

Guran · Postby **Guran** » Wed Apr 20, 2011 6:47 pm

Good response there from Ben. I'd add that although R-specs (D03G, R888, RE55, V70A, etc) are street legal, you should never plan to use them for daily driving. They're noisy as hell, wear quickly and have less grip because they don't get up to optimal temperature on public roads. Plus they're bloody expensive so why waste them on daily driving? It makes much more sense to buy a second set of wheels and fit the right tyre for each job. And in that scenario, I highly recommend the RE55s for track use (SR2 compound). They work brilliantly and last the full season.

manga_blue · Postby **manga_blue** » Wed Apr 20, 2011 7:22 pm

I've mixed it a few times around Winton, Phillip Is and Wakefield with guys on the Dunlop Z1s when I'm using Dunlop DZ03G or Toyo R888 r-specs. To me there's no apparent difference in grip between Z1s and r-specs although the Z1s do seem to go off quicker than true r-specs.

KU36 shod cars don't seem to have anything like the same grip and I think that's reflected in their lap times in Vic versus the Dunlops.

I'm now contemplating giving up r-specs completely in favour of z1s. Remember that this is for a lightly modded NA8 running in CAMS 2B and Vic club MOD classes. With your turbo setup I'd be much more inclined to have a dedicated track set of r-specs. I prefer R888s over Dunlop D03Gss basically on the grounds of toughness and user friendliness. The Dunlops are potentially quicker but are much too fussy about temps and it's much too easy to permanently overcook them. I can destroy the Dunlops in 2 laps while the R888s last me 12 to 15 meetings

rascal · Postby **rascal** » Wed Apr 20, 2011 7:31 pm

I also agree with having two sets of rims/tyres each dedicated to the required job, rather than trying to get one tyre to do both jobs which is a compromise on both counts.

If you opted for eg Star Specs then you'd be paying more than you'd normally pay for road tyres, and they still wouldnt be as good as a R spec on track, and they'd get chewed out by the track work so you'd be buying new sets more regularly.
Buying good road tyres and using them just for road work is cheaper than Star Specs and would last considerably longer with no track work.
Then buy the R specs to do the best job on track where you really want the extra grip.

I ran the DZ03Gs on my car and they were definitely quicker than the R888s that I now run, (back to back they were 0.5secs better at PI) but only managed 7 meetings out of them which isn't enough for me.
So I sacrificed a smidgen of performance in the sake of cost saving and I've now gone back to R888s. I can get a whole Vic club season of 10 meetings out of one set. (In fact curr set has done 11meets and still will make one maybe two more )

dbr · Postby **dbr** » Thu Apr 21, 2011 2:06 pm

Thankyou for your input.

It is interesting that the Z1 is faster than the KU36 but lasts longer on the road.

I agree the smart move is to buy dedicated race wheels and tyres. It just requires more money.
I used to burn the slicks off a Forrmula 2 around Winton and that had a lot more rubber and less power than the MX5. So if Z1's are prone to overheating, I could wind up with another tyre bill and the same dilemma in very short time.

This brings up the next question, Does anybody know somewhere that sells Michelin Pilots cheep?

bensale · Postby **bensale** » Thu Apr 21, 2011 7:34 pm

I wouldn't say that the Z1's are prone to overheating and worse than the competitors, namely the KU36 and R1R. I would be surprised if they're worse than the Michelin Pilots too... I was pushing pretty hard (1.12s on the short track in a mildly mod'd NA6) and was faster than most of the guys with semis so was asking a bit of the tyres... That being said perhaps something like Toyo 888's could work out cheaper in the long run as I think they will last you longer...

manga_blue · Postby **manga_blue** » Thu Apr 21, 2011 8:53 pm

Maybe I need to make it clearer. I said the Dunlop DZ03G R-specs were prone to overheating (and permanent damage from it). They're good tyres if you're not the one paying for them.

The street Dunlop Z1s do go off faster than the average R-specs but I'd still say they last more laps than any other grippy street tyres I've seen. For dry laptimes they're in a class ahead of the KU36s, Hankooks and Michelins. For wet times they're also way, way ahead of R-specs.

dbr · Postby **dbr** » Wed Apr 27, 2011 12:58 pm

Sorry for the confusion, The Michelin's would be for road use while another set of wheels and tyres where purchased for track use.
The old Michelin's I used last time didn't overheat. They didn't stick either.
They are old enough that Adam could have used them to drive Eve to the Orchid.

jerrah · Postby **jerrah** » Thu Apr 28, 2011 10:39 am

What sort of prices are people paying for Z1's? KU36's are very (RE001) cheap.

mitch_f1 · Postby **mitch_f1** » Thu Apr 28, 2011 2:52 pm

I don't really have anything to compare to, but for what it's worth I love my Dunlop D01J's. I got them second hand off of a fellow MX5 owner, and since then they have lasted me 13 club days (and counting). On one WP speed off the streets day I rekon I did a bout 15 laps and they didn't go off. But they are expensive when new, very expensive.