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What's the pick of the 1b/1c tyre list?

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Tue Nov 03, 2015 8:10 am PostPost subject: What's the pick of the 1b/1c tyre list?
nefarious
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The Westie needs new boots. I've run 888s the last couple of times (med/GG compound), and would be very happy to go with that again, but have half a thought about running the odd round of SLS next year, so am now considering other tyres on the 1b/1c list.
There seems quite a lot of love among some of you S&S boys for the Kumho V70s. Are they any better than the 888s in either wet or dry? What about the new Advan AD08s? Wear rates?
I should mention that the 888s are right on the margin compound-wise - even with a wee bit of extra toe, you need to be in 100% attack mode to get them up to temperature (not that that's a problem!). The car is only 560kg wet.
Oh, and final consideration - any reports/feedback on the new 888Rs? They look sticky but potentially iffy in the wet.
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Tue Nov 03, 2015 8:15 am PostPost subject:
AK
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SLS Regs are not confirmed, or a draft version published yet.

Tyre regs are not fully clear yet.
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Tue Nov 03, 2015 9:17 am PostPost subject:
HummuH
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Kumho V70's best 1b/1c tyres I've used in dry and damp but downside is less rubber than other tyres so wear quicker. Useless in full wet conditions but available in Super-soft, Soft and Medium in a wide range of sizes, if you can find stock.

R888R are very good, asymetric too which helps preserve the life of the tyre. Never used them in the wet but their wet rating isn't great.

David Long swears by the Kumho's on his R400 so no doubt he'll comment too.
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Tue Nov 03, 2015 11:12 am PostPost subject:
David Long
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Yes, all the Caterham sprint guys seem to use Kuhmo V70. I use 235/45 13 in K12 compound on the rear, and 175/60 13 K22 on the front.

The K12 compund (supersoft) works really well for 2-3 laps then goes off a bit. On my car they last well (600 Kg) and, from a wear point of view, I'm getting two seasons, but they peak after about 3-4 short track sessions (heat cycles?). I've done longer session to see what happens, and an 11 lap race would be possible, but they would probably not do more than two of those before they would be scrap. Next year I'm thinking of going for the K22 (soft) compound all round if qually is an open session. Grip level is similar but it takes just a little longer (half a lap maybe) to get them working. Wet running is OK and they are excellent in the damp.

On the down side, they are heavy and quite rigid. That is noticeable on a light car and you may find yourself look at stronger spring rates (if you can), or going for smoother bits of track and taking less kerb in an effort to keep them on the ground. I need to run much lower pressures than with other tyres, and that has it's own problems.

But ultimately traction is so good they are the only tyre I found that deals with my power levels from cold. Ideal for the SLS, but I'd maybe use something else for trackdays.
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Tue Nov 03, 2015 11:22 am PostPost subject:
nefarious
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Not sure my pockets are deep enough to be replacing tyres every 22 laps!

I know your Caterham is considerably higher spec than my Westie, but what sort of times are you running on the Soft/supersoft mix?
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Tue Nov 03, 2015 11:40 am PostPost subject:
David Long
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PB this year was 54.9, but typically I'm in the 55-56 from cold.

https://www.youtube.com/watch?v=YUHszoU6hOg

With the right driver, there's probably a 53 but, as you know, light cars are so sensitive it needs conditions, and the car, to be 100% to get it.
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Tue Nov 03, 2015 12:53 pm PostPost subject:
nefarious
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David Long wrote:
PB this year was 54.9, but typically I'm in the 55-56 from cold.

https://www.youtube.com/watch?v=YUHszoU6hOg

With the right driver, there's probably a 53 but, as you know, light cars are so sensitive it needs conditions, and the car, to be 100% to get it.


I was expecting the difference to be bigger - you're about 1.25-1.5s up the road from me (pb 56.2). How much power is that thing putting out? From the vid you're about 10mph quicker at the end of the main straight than me.
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Tue Nov 03, 2015 1:11 pm PostPost subject:
David Long
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The SLS dyno gave 210 at the wheels, but I think it is more. Probably somewhere between 210-240 at the wheels. The Kumho has the advantage in traction - I can get the power down, but the apex speeds are similar to other tyres I've tried. They give you good confidence but maybe get a bit squirmy at the limit. As said earlier, the construction is quite heavy and it's swings and roundabouts with traction and the cornering. But overall I would guess they are worth a second over the ZZR I used before. On a lower powered car, that may not be the case.
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Tue Nov 03, 2015 1:41 pm PostPost subject:
nefarious
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I guess the power difference isn't as big as I'd suspected - mine was measured at 185 at the wheels when it was mapped at Track'n'Road, so maybe you're running at 35-40bhp advantage based on your estimates. That said, you've got a fancy-pants gearbox that's probably worth a bit of time.

Your comments re: lateral grip seem borne out by your vid - I'm usually pretty much flat through the bottom of Dufus (so long as I get the entry right!) and between the apex of McIntires and the entry to the chicane. That's on boggo Avo dampers too.
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