Advice: What makes a good tyre?

Sometimes a simple change in colour can define one motorcycle model from the next. But when it comes to tyres it’s a different story – which what makes motorcycle tyre manufacturing such a black art.

If you gave me a choice of a bike with all the latest safety gizmos fitted with less than ideal tyres or a bare-bones machine with a good set of hoops, my choice would be simple. The latter.

Tyres are the most critical part of any rider’s safety arsenal, and can mean the difference between a great weekend or weeks of pain in recovery mode – not to mention the damage done to one’s bike. I’ve been lucky to work with tyre giants such as Pirelli and Michelin developing many different variants, from slicks to road tyres and have a pretty good understanding of how a tyre makes progress from a piece of paper to fruition.

Boardroom to bitumen
The truth is that most people scan the net, take counsel from mates or have had a good run with a particular tyre and that’s why they choose it. There’s nothing wrong with that approach per se, but it means people go with their hearts and what they believe because the facts are generally a deep, hidden secret.

All manufacturers have the ability to build top-shelf tyres, but there is one critical fact to consider in mass production: price. Although we don’t want to believe it, sometimes cheaper materials get used to meet a particular retail point at the expense of grip, durability, warm-up characteristics and/or handling, which are the four important aspects of any tyre.

The Pirelli Diablo Rosso Corsa II (DRC II) launch in South Africa not only let me test the new tyre to its limits on the road and track, but it also gave me an opportunity to find out the philosophy behind the new hoop.

Like any new tyre, the DRC II concept started in the boardroom with the marketing department considering the needs of its customers and identifying areas of improvement. Then when a target was reached – which in the case of this tyre is a broader working spectrum on and off the track – the R&D and test team identified the technologies and processes able to achieve those goals.

It took two years for a 20-person team to finalise the tyre, which is different in every way from the original with varying compounds and a brand new carcass.

Balancing act
It sounds easy to manufacture a new compound and add it on, but making tyres is a demanding business. Companies like Pirelli are continually changing the mix of the polymer compound to meet stringent environmental pollution targets. Trying to arrive at an ideal balance of grip and durability is always an ongoing battle – but with time and effort it’s a winnable one.

The DRC II’s a sports tyre, so handling was also a paramount concern. A lot of time and development went into making sure the profile design of the tyre would meet expectations insofar as lean angle and sharper feel were concerned.

Designing and changing moulds is a very costly affair, so a major focus went into making sure the right shape was manufactured from the get go.

Strong body
This is where experience comes into play, and Pirelli has a lot of it when it comes to developing hypersport tyres. It’s already done the hard yards of development as the sole tyre supplier in the Superbike World Championship since 2004, giving the company a wealth of experience to draw on.

The carcass is the most expensive part of any tyre to construct, and it really needs to be done right. The radial strands that make the carcass up are generally made from rayon, which is a fairly standard material used in tyre construction. It does a good job at keeping the conformity of the tyre intact, but at the same time it’s cheap which helps to keep the final price down.

The juggling act with the radial fibre material is one of stability over cost, and if you use the wrong product the first thing you will notice is loss of stability – not in a straight line but when exiting a corner. The radial strands stretch and the carcass loses its tension, which leads to movement.

Pirelli has just started using a product called lyocell instead of rayon for its radial strands because the purpose-designed and patented material offers less stretching but at affordable prices. This new wood-based wonder product is not so new, though, and was first used back in 1972; it’s taken until now to get it right.

Having a stable carcass is the basis of all tyres because it affects the compound mixture, which in turn controls the warm-up and grip levels. A more stable tyre can use a softer compound for the same durability. It’s not as simple as that, but you get the picture.

Of course, you can’t discuss about a tyre without touching on its wet-weather properties. Silica has been used as a compound filler for years, with the main advantage of less rolling resistance and therefore better fuel economy and wear.

The problem with just silica is that with the extra mileage comes a lack of grip. This time, Pirelli has worked a little magic with a secret mix which gives the end user better wear and much more wet-weather grip – and confidence.

So how good is this new tyre?

On the road
I chose the BMW S 1000 R naked for two reasons: it’s powerful and I just love riding the bike! In a normal world, I would always leave all the safety devices like traction control and ABS on, but it’s a bit hard to really feel what the tyre is doing when they are muted. So off they went.

The roads in South Africa are rough and bumpy, with no real discernible road rules. This gave me the opportunity to really get up the Beemeer without fear and boy, how much fun did I have.

The first thing I noticed was that how solid the front tyre is. It’s always ‘there’ and gave me a lot of confidence, taking the full force of the BMW’s amazing brakes without so much as a hiccup.

The rear is really amazing, though. It’s got plenty of grip, but the biggest thing is its outstanding composure. It never felt like it was dipping or moving, even with copious amounts of S 1000 force thrown at it. The warm-up is also first class, which is a major positive for any tyre.

On the track
Kyalami is one of the world’s most historical circuits, so to get the chance to ride it on Ducati’s new Panigale V4 was a pleasure. The Panigale must be the new king of grunt with its big-bore engine, but I was very interested to see how the tyres went on the track – not just the bike…

Tyre warmers weren’t used, so to go out and get the knee down on the first lap showed me that these hoops are nothing like race tyres at all. Do that on a slick and you would end up in hospital; they need warming.

However, the grip sensation was like a race tyre, and I was flabbergasted by the amount of feel available and the inch-perfect precision the Panigale exuded with the DRC IIs fitted.

The biggest takeout for me was the stability and composure the rear took lap after lap. It didn’t wallow or tear, held its line, and simply produced a nice little spin that was very controllable.

The front was just as good on the track as it was on the road, capable of more than most riders will feel confident to feed it.

Summing up
Riding the best bikes in the best places is always a fun part of my job, but one thing I need to keep in context is whether the tyre is better or just different.

This time, clearly it’s better: Pirelli has made improvements across the board, and it shows in the DRC II’s superiority over the original DRC. There’s no real weakness – at least one that I can find.

The Diablo defines Pirelli’s sporty product offering, while the name Corsa has become synonymous for riders looking for top performance both on and off the track. The hypersport segment is definitely an important one for Pirelli, as it has been best in class since the introduction of the Diablo Rosso Corsa in 2010. With the new Diablo Rosso Corsa II, Pirelli is confident it can maintain leadership in a segment so relevant to the Australian market.

Sizes
The DRC II will be sold in the following sizes:

Front
120/70 ZR 17 M/C (58W) TL

Rear
160/60 ZR 17 M/C (69W) TL
180/55 ZR 17 M/C (73W) TL
180/60 ZR 17 M/C (75W) TL
190/50 ZR 17 M/C (73W) TL
190/55 ZR 17 M/C (75W) TL
200/55 ZR 17 M/C (78W) TL

This article was originally published on March 15, 2018.