best road legal trackday tyres?

[Mars]

^^^ That would be extremely interesting. I love ACB10s, and I'm even prepared to use them in the wet (they are amazing if you drive hard enough to get them warm) but the tramlining is really tedious. The CR500s are very nearly as good as the ACB10s in the dry, slightly better in the wet and don't tramline. If they can basically mate a CR500 carcass with an ACB10 tread pattern, I might simply expire with happiness.

[sfaulds]

Hmm, while I'm a big fan of CR500's, they're not that close to an ACB10 in terms of feel or performance.

The ZZR has much the same level of grip as a Caterham compound ACB10 in the dry, but isn't as light as either the CR500 or ACB10. It's still a good tyre, with much better feedback than a 48R (evil things), and the limited testing we did on them suggests the wear rates will be very good.

[fergus]

sfaulds said:

Hmm, while I'm a big fan of CR500's, they're not that close to an ACB10 in terms of feel or performance.

The ZZR has much the same level of grip as a Caterham compound ACB10 in the dry, but isn't as light as either the CR500 or ACB10. It's still a good tyre, with much better feedback than a 48R (evil things), and the limited testing we did on them suggests the wear rates will be very good.

thks Stuart. Do you have any experience of the Kumhos?

[sfaulds]

We've never run them on a Caterham. We did run them on an E30 at one point, and that experience would suggest they'd be bloody heavy on a Caterham. Cast iron sidewalls though, which a lot of people seem to think is a mark of a good tyre.

[Shaun_E]

The Kumhos are heavy and stiff, no doubt about that, and that is quite noticeable through the steering wheel. My favourite road tyre is the CR500 mostly because it is so light and makes the steering and ride much nicer than with heavier tyres. I do prefer the Kumhos to the Yokohama A048R though. I am really only using the Kumhos as they are the softest tyre we can use for sprinting (crossplies are banned in our championship) and by running a second set in hard compound I don't need to change the car setup between sprint/hillclimb and trackdays. In terms of grip though they are very good and if you can live with the extra weight then I would recommend them. Most of us are running 215/50R13 front and 235/45R13 rear. Starting cold pressures are about 16 psi although in the cold and wet could be even lower.

[BertBert]

fergus said:

BertBert said:

I think that this is the only topic in the caterham world that Fergus and I actually agree on

I may need to take you up on your historical offer of borrowing your engine hoist if the option is still available?!

Yepyep, not in use at the mo Fergus, you are welcome! PM or email me if and when.
Bert

[BertBert]

JakeR said:

Mars said:

By the way, CR500s are radials but they just work differently to the other brands. Don't really know why.

phew... i thought they were, got well confuseded when someone said you can swap between them and acb10s!!

You can swap. Radials in general and certainly CR500s are nowhere near as sensitive to camber as ACB10s. Now if you were going to be racing, then it might be a different matter.

I had my caterham set up for ACB10s and used my CR500s as wets for trackdays and for when the ACB10s were bald! I had no problems at all running CR500s on ACB10 settings.

Bert

[JakeR]

BertBert said:

JakeR said:

Mars said:

By the way, CR500s are radials but they just work differently to the other brands. Don't really know why.

phew... i thought they were, got well confuseded when someone said you can swap between them and acb10s!!

You can swap. Radials in general and certainly CR500s are nowhere near as sensitive to camber as ACB10s. Now if you were going to be racing, then it might be a different matter.

I had my caterham set up for ACB10s and used my CR500s as wets for trackdays and for when the ACB10s were bald! I had no problems at all running CR500s on ACB10 settings.

Bert

Cheers Bert... just to complicate matters for my fuddled brain, my car is a Freestyle car: superwide pushrod job, so I'm not quite sure how much 'normal' Caterham knowledge I can transfer! I am currently using Michelin radial slicks in the dry and CR500s in the wet/on the road. The Michelins, though used, are things of complete and utter brilliance imho. Was just wondering what the alternatives were if I went back to having all my tyres road legal...

[fergus]

Shaun_E said:

Most of us are running 215/50R13 front and 235/45R13 rear. Starting cold pressures are about 16 psi although in the cold and wet could be even lower.

Thks Shaun. What rim sizes (& offsets) are you running to run those bad boys?

[Steve-B]

You lot may laugh, but I ran Yoko AO-21r's for years on our SV (so widetrack) and it was extremely capable on all conditions, snow on Stelvio, and more blats around Northants and Bucks and never had any issues. When we took the car to Oz, I went onto Yoko AO-48r's and frankly I think the 48's are WAY overrated tyres for a lot of reasons. Now us and the car are back in Blighty, I'm seriously considering the 888's as they have proven with a lot of folks to be a great intermediate, yet affordable tyre.

YMMV

[sam919]

I wasted a load of money on ACB's, ok there a tyre you can slide about on, but the kumhos gave far better grip at the all important 14 degree slip angle! I seem to remember the weight saving using aluminium lightweight wheel nuts was about 1.2 kilos per wheel for ACB over Kumho. The kumho does feel heavier no doubt about it, in the prementioned 235/R-215/F sizings, but ultimatly lap times were quicker and are quicker with the Kumho. I suppose you could go down the route of driving styles etc to determine what tyre suits what driver, but lap times in race conditions proved to be quikcer with kumho's. If your out to have sideways fun then any tyre could be considered, grip=kumho. I think MOG racing use them, not 100% sure though. Go against the grain of the usual caterham mullarky and you'll find the results to be favourable.

[fergus]

sam919 said:

I wasted a load of money on ACB's, ok there a tyre you can slide about on, but the kumhos gave far better grip at the all important 14 degree slip angle! I seem to remember the weight saving using aluminium lightweight wheel nuts was about 1.2 kilos per wheel for ACB over Kumho. The kumho does feel heavier no doubt about it, in the prementioned 235/R-215/F sizings, but ultimatly lap times were quicker and are quicker with the Kumho. I suppose you could go down the route of driving styles etc to determine what tyre suits what driver, but lap times in race conditions proved to be quikcer with kumho's. If your out to have sideways fun then any tyre could be considered, grip=kumho. I think MOG racing use them, not 100% sure though. Go against the grain of the usual caterham mullarky and you'll find the results to be favourable.

thks for the info. Where did you get the slip angle info for the Kumhos from? Is this not a function of both the tyre and the setup you're running?

Which rim sizes did you use for the 235 and 215 section V70/V700s?

[sfaulds]

Sam, have you got some laptimes for reference?

[sam919]

These are some results for the DDMC, probably not the best but the front R400 is on slicks. Same with the westfeild.They are a good representation of what the kumho can achieve though

http://www.darlington-motor-club.org.uk/datafiles/...

Same car with kumhos getting lap record


http://www.darlington-motor-club.org.uk/datafiles/...

Not an ACB10 in sight

[sfaulds]

Sorry, I was looking for some of your times on ACB10's vs. the Kumho.

Are you Phil? Did we speak about tonneau's earlier in the year?

[BertBert]

I'm interested in the kumho v ACB10 comparison too.
BErt

[sam919]

Sfaulds. No not Phil, Sam. Bought his last seasons car from him though. Funny you should mention the tonneau as i just got a DDMC newsletter stating blue book G102, it seems there not allowing them

I had a white R400 before that got a 1.29 with the kumho's in testing by previous owner, the best i cold muster was a 1.32. But racing with the ACB is as below.

http://www.darlington-motor-club.org.uk/datafiles/...

The Hoggarth car was another R400, think he was on yoko's. Dont know what Sharman was in. Marshall and Morris still using the Kumho, the rest on slicks untill position 14.

Raced a mag 7 this year at snetterton, and they all seemed to be using the Yoko. Some good hands there with the C400 getting 1.15's.

[sfaulds]

The tonneaus have always been a bone of contention with some scrutineers - it's a ridiculous rule from the MSA that needs to be sorted.

So was your 1:18.6 (http://www.tsl-timing.com/cscc/2009/91464.pdf) at Snett on Kumhos? Given that a 400 will do 1:15 on CR500's (we've had R300's in the 1:16's in testing), that's not particularly convincing.

[sam919]

The 1.17.7 was on the sunday, sports and saloons, page 151

http://www.classicsportscarclub.co.uk/Results/2009...

But my ability certainly isnt near the front runners. Yes on kumhos.Have you tried the kumhos on your 1.15 cars. The 1.15 cars were using CR500's then, not ACB's.

I just think the kumho offers better value for money and performance than the ACB.

[Murph7355]

Steve-B said:

You lot may laugh, but I ran Yoko AO-21r's for years ..

I wouldn't. I did too. Great tyres.