Last weekend, for the sixth round of the Thundersport GP1 championship, I tested Pirelli Diablo Superbike slicks for the first time on my Prime Factors BMW S1000RR.
I’ve been racing on Dunlop’s superb KR106/108 Ntec slicks for the past four seasons on various S1000RRs and an HP4. They’re among the stickiest over-the-counter race tyres money can buy. But after years of being developed in WSB and BSB, have the Pirellis finally caught up?
The 17” SC1 Pirelli Diablo Superbike slick has a different construction to the Dunlop. The front has a slightly smaller diameter and the rear carcass is much softer. That might not sound like a big deal, but the bike needs to be set-up differently.
We had to adjust the traction control and alter the front ride height to take the new tyre sizes into account and remove some shock preload for the softer rear tyre.
Friday testing at the Northamptonshire circuit was a wash-out, so we guessed at a setting for Saturday dry qualifying, which wasn’t quite right and lined up 8th on the grid. But for the race we made some more adjustments and finished second behind BSB regular Joe Burns, who was out on an Aprilia superstocker for the first time. My lap time in the race was good enough for pole for the Sunday races.
But the race should have been won by Kawasaki ZX-10R-mounted Adam Shelton. He was miles ahead and a good chunk faster than the rest of us, but he had a nasty crash exiting the first chicane on the seventh lap. Given the speed of the crash he was lucky to come away with just a broken leg. Get well soon, Adam…
Compared to the Dunlops the rear Pirelli doesn’t have the same amount of unflappable edge grip, but it has excellent drive grip once you’re off the edge of the tyre and up on the main shoulder. The front Pirelli is very impressive and offers lots of grip, feel and excellent durability.
For Sunday’s main races we scored a win in changeable conditions and a disappointing 13th in the wet. It was bad enough riding in the torrential rain, let alone standing out in it, so thanks to all the Thundersport staff and marshals for braving the conditions.
This has been my best race meeting of the year, after evolving my 2015 S1000RR from running on electronic DDC suspension and Dunlops, to K-Tech and Pirellis. It’s good timing to have done well, too, as the main Prime Factors racing team is now managed by Steve Plater - it’s always good to impress the new boss.
My next round is Anglesey on the last weekend of August. The main team will be competing in the second round of the World Endurance Superstock championship at the Oschersleben on 22 August with riders Gary Mason, Barry Burrell and Steph Capella.
120/70 x 17 (£130)
200/60 x 17 (£190)
£7.50 fitting per loose wheel at Thundersport meeting
Holbeach Motorcycle Tyres LTD, www.racerubber.co.uk