Chad headed to the incredible Kyalami circuit in South Africa to check out the latest rubber from Bridgestone – the S23
The all-new Bridgestone Battlax Hypersport S23 builds on the highly acclaimed all-around sportsbike tyre, the S22. The S23 is designed to excel on both road and track and in all conditions. Although we tested the new S23 on the sun-kissed Kyalami race track in South Africa, Bridgestone claims it will be equally at home on the normal (and sometimes wet) roads we encounter each day.
The Bridgestone S22 is still on sale and is an excellent tyre, but Bridgestone has made some big claims for the S23: 5% increased corner speed; lap times reduced by 2.4% (on average during testing); 7% drainage resistance in the wet; 3% shorter braking distance in the wet and lap time reduced by 4% in wet conditions. All this and a claimed 8% increase in mileage.
Leaving pit lane, it was immediately apparent that the new S23 works from the get-go. Within a few corners, I felt comfortable enough to touch my knee down, and in less than a full lap, I was up to pace. In fact, by the end of lap one, I had settled into a comfortable, fast track-day rhythm. Both feel and feedback were excellent, especially from the front. On the first lap, I wasn’t guessing where the grip was, but feeling it. And this was on the MT-09, a highly accomplished all-round road bike, but certainly no race machine, complete with high-end performance forks.
This was a track-only test held in warm conditions of around 19-20°C with a rain shower thrown in, which I will come to later. We didn’t use tyre warmers, but the bikes were parked in the pitlane in the sun. Pressures were set to 2.3 bar front and rear.
Aboard the MT-09 and, later, the XSR900 and KTM’s fun 890 R, I was pushing hard, trying to reach the limits of the S23 rubber. The rear tyre coped without any issues and the front continued to give confidence-inspiring feedback. Ground clearance on both Yamahas, and a lack of control from the MT-09’s rear shock, were the limiting factors, not the performance of the rubber. When the MT’s rear shock started to give up the fight, I could feel the rear tyre working, doing the work of the suspension, its tenacious new edge grip coming to the fore.
KTM’s 890 R proved almost the perfect tool for the track and tyres, its gutsy, linear power delivery power and unequalled agility enabling anyone who rode it to push the boundaries in safety while seriously attacking Kyalami’s apexes and carrying dizzying corner speed. Some of the corners at Kyalami are taken at 160-190km/h with your knee pushed into the deck, and that is a lot to ask from road legal everyday tyre – but I had the confidence to roll in fully committed, and the KTM stayed planted, carrying extreme lean and speed. The new, racy edge grip is impressive for this type of tyre; on occasions, I had to remind myself this was a road-legal tyre designed to deliver decent mileage as well as decent lap times. Of course, it’s hard to compare the S23 to other tyres as the new Bridgestone was ridden in isolation, but I can say the edge grip is impressive for a tyre that can be used all year on the road, with improved longevity and wet performance.
Middleweight fun over, I assumed that moving to BMW’s M 1000 R would expose the limits of the S23’s track capabilities, but again, the new Bridgestone performed above expectations. Front-end stability, hard braking, and the roll into the corner were faultless for a road tyre. Sure, you can’t throw the bike onto its side to elbow-down levels of lean – no proper road tyre will happily let you do that – but it’s hard to fault, and I can say that the 23’s side grip mid-corner is truly excellent and probably the most impressive aspect of the new tyre and the biggest improvement over the old S22. Road-legal rubber shouldn’t be this good mid-corner.
Dialling in big power did give the rear tyre a hard workout, but on the BMW, the S23 coped especially well, thanks, in part, to the BMW’s smooth power delivery and class-leading electronics and chassis working well with the tyre. Later, on the more aggressive Yamaha R1 and KTM 1290, I could feel the tyre start to move around on the exit, especially as the contact patch moved from the edge of the tyre to the shoulder. Towards the end of a pacy 25-minute session, however, some movement is to be expected, and when the tyre did move there was still feedback, making it fun rather than a shock.
I also had a few moments on the KTM 1290 when releasing the brakes and turning in, as the front wasn’t perfectly set up to my weight and riding style. On the odd occasion, I’d feel a momentary tuck, but again, the feeling from the S23s was there, which meant I knew what was happening and what to expect – and changed my line and riding style accordingly.
ROAD USE? We can only guess
This was a track-only test so we could fully test the edge grip on powerful superbikes in relative safety. We didn’t use tyre warms and the South African track’s surface was much like a road with undulations, bumps and cambers.
But Bridgestone hasn’t just focused on edge grip. This is a new tyre, designed for road use and a direct development of the highly rated S22, so we can confidently expect similar performance and feedback on the road.
WET WEATHER? Yes, we did get a shower!
Unusually for a track-only test, we did, fortunately or unfortunately, have a brief rain shower mid-session. Normally, on track, I’d immediately head for the pitlane as soon as rain starts rolling across my visor, but Bridgestone has made some bold wet weather claims – a 4% faster lap time than the S22 in the wet, thanks in part to the new ‘Pulse Grooves’ in the rear tread – therefore I opted to stay out.
I could see the rain falling, see the tell-tale rain stripe on the rear tyre of other riders, but it wasn’t enough to send a rooster of spray – it was just damp. On Yamaha’s easy-going, relatively soft XSR900, I was able to maintain a decent pace, feeling for the grip which changed every lap, even every corner, as the rain shower passed over our heads.
With so much feel coming from the new S23, I could maintain a decent pace, which I assume kept some heat in the rubber. I couldn’t fault the S23 in the damp: I still had my knee down on occasions, could brake heavily (whilst perfectly upright), and they didn’t send the ABS into overtime. So long as I was smooth with the throttle, the rear tyre remained unfazed.
Despite the dampness, the ride was still enjoyable, and that only comes from a tyre that is working and giving feedback and confidence. I didn’t have a moment all session.
BUT HOW LONG WILL THEY LAST?
It’s hard to quantify longevity on a track-only test of a tyre. Bridgestone claims an 8% improvement in mileage over the S22, and the technicians on the launch appeared to have an easy job as there wasn’t any rapid tyre changing at lunch or at the end of the day. Furthermore, some of the bikes we tested were not on new tyres but worn rubber (I attended on day three of the three-day test). Bridgestone was confident enough to send riders out on worn rubber.
The big bikes on test – KTM 1290, GSX-R1000, M 1000 R and R1 – remained on the same rubber all day and, after a long day, both front and rear tyres looked worn but not shredded. Some trackday rubber is ruined after a full day, especially on a 200bhp plus superbike, but the Bridgestones kept their shape and looked like they could take another day of punishment without any issues.
Former MotoGP star and current AMA Bagger racer Jeremy McWilliams was on hand to comment: “Mileage hasn’t been a problem,” he said. “We have had three full days on track, and the front tyre lasted for the full three days on most of the bikes, in fact, nearly all of them. On the rear, some bikes needed a change after two days, but some bikes had the same front and rear for three days. And the riding has been hard; this is a fast track with fast riders.”
It was a big ask for Bridgestone to significantly improve the excellent S22, but on first impression, it appears they have done that. Side (or edge) grip at extreme lean angles and on the tyre shoulder appears to be the biggest improvement – an improvement made, Bridgestone say, without sacrificing tyre life. The feel and feedback you get while on the side of the tyre are excellent, especially on mid-capacity bikes.
We did have a small rain shower, which highlighted excellent damp performance, but for a full review, we need to try the S23 on the road and in varied conditions. However, if you’re looking for a genuine road tyre that can occasionally be used on the track in varied conditions, then the new S23 comes highly recommended. Grip and feedback are excellent, while mileage also appears to be good. Tyres are a little like mobile phones, with manufacturers constantly making tweaks to improve the next model. This is what Bridgestone has done: made an improvement over an already good tyre.
The new front tyre uses two compounds (three sections), with the outer shoulders sections of the tyre featuring an all-new compound. The rear, meanwhile, has three compounds (five sections), with the new compound deployed on the tyre edge (and only likely to be used on track). The S23 retains the S22’s MS-Belt construction.
The rear tread pattern design features Bridgestone’s Pulse Groove Technology for better wet performance, while both front and rear tread patterns are claimed to optimise both the land/sea ratio in the important shoulder area of the tyres as well as pattern stiffness.
In testing at the demanding Autopolis racetrack in Japan, Bridgestone says the corner speed of a test Yamaha YZF-R1 increased by 5% over the S22, which resulted in a 2.4% faster lap time. Furthermore, in the wet, there’s now a 3% shorter braking distance and a 4% faster wet lap time.
In terms of the Bridgestone range, the S23 sits alongside the S22, below the racy RS11 in terms of outright track performance as a fast, all-weather road tyre that can do a job on track days, too. Luckily, we had a mixed bag of bikes and conditions on the launch of the S23 in Kyalami in South Africa to test Bridgestone’s claims.
Bridgestone offers sportsbike owners plenty of choices. For those who only ride on the track and transport their bikes in vans, there is the V02 race slick and W02 race wet. The CR11 and R11 are not full slicks but are dedicated race and track day tyres. The R11 is road-legal but recommended for track use only with tyre warmers.
Moving away from track-only rubber, the RS11 is the most track-biased road offering, followed by the new S23, which sits as an all-round Hypersport tyre that will be sold alongside the current S22.
The Battlax Hypersport S23 is designed to work on a wide variety of sporty machinery, from naked, sub-100bhp street bikes, which may occasionally get the odd track day outing (think Honda Hornet CB750) to superbikes like the Yamaha YZF-R1, which Bridgestone used as a test mule during S22 and S23 comparison-testing in Japan. Sizes start at 160/60 ZR 17 on the rear and include the most popular large sizes 190/50 ZR 17, 190/55 ZR 17 and 200/55 ZR 17.
Words: Adam Child Pics: Bridgestone