Danilo Petrucci: changing tyre brands can be harder than changing bikes

Then you have the area where you are going into the corner, with a lot of lean angle and a lot of front brake pressure. The Michelin and Dunlop aren’t strong in this point, because they’re really hard.

The front Pirelli’s construction isn’t hard, so you cannot push a lot in straight braking, but you can stop the bike with some lean angle. The carcass is soft, so it moves around, but it’s really grippy and you need to adapt yourself to this movement, but the bike stays on line so you can really stop the bike in this area.

You can’t do this with the Michelin or Dunlop fronts because they have a stronger construction, so you need to stop the bike before in straight braking, then you need to release the brake.

Moving onto corner entry, front tyre feedback at this point is maybe the most important feature of a race bike, because you need to feel the limit…

At the beginning of the Michelin time in 2016 we still had bikes with a Bridgestone set-up, so we started to lose the front at the apex, when we opened the throttle in the middle of the corner, so we crashed a lot in this area. This is where Marc Márquez always saved crashes with his elbows. Other guys like me could do that sometimes but not all the time.

“If you lose grip for a moment you just lose the front”

Then we started modifying the bikes. With the Michelin front you can’t really push on the tyre when you have a lot of front brake pressure and a lot of lean angle.

To stop the bike in this area, with Michelin and Dunlop you need to let the rear of the bike slide to try to unload the front. You can only use a lot of front brake pressure when the bike is leant over if you start to lose rear traction, so you have to go sideways to unload the front when the bike is starting to go into the apex. If you don’t do this the rear tyre pushes the front tyre and you lose the front immediately, without any warning.

The Pirelli front starts to move and it moves a lot, so you think you are going to crash, but in fact you need to really lock the front to crash. This tyre gives you good warning before you completely lose grip.

Toprak [Razgatlıoğlu] and Alvaro [Bautista] are so good in this area. They make the difference in the last part of corner entry, which is the riskiest area, because if you lose grip for a moment you just lose the front, because you have a lot of lean angle and a lot of front brake pressure.

Brad Binder is sideways on the brakes more than anyone and he says the same thing – he kicks the rear sideways on the brakes, so the sideslip takes some load off the front, which gives him more margin with the front tyre…

When I did MotoGP at Le Mans this year [replacing injured factory Ducati rider Enea Bastianini] I was making a lot of rear slides to help me stop the bike. In fact most MotoGP riders now slide in corner entry like they did many years ago.

The master of doing this is Binder – it seems like he only brakes with the rear tyre but as you can see it’s a f**king fast way, because he doesn’t load the front when the bike is leant over, so the bike is completely sliding into the corner. Its impressive! If you see Brad from behind you think he will lose the bike at any moment, but this is how he rides. It’s unbelievable, unbelievable! Hats off to Brad, really!

I used the Dunlops on American circuits where the asphalt is generally very old and bad, so usually you need to carry speed through the corner with the Dunlop front, which moves a lot and chatters a lot if you don’t load the tyre. Some riders say the Dunlop is more like a GP tyre, because it’s stiff, but I was riding a production bike on bad tarmac, so the lean angle with this tyre wasn’t really good.

At the apex, where you reach maximum lean angle, the Michelin is really good so you can carry a lot of speed in that area.

So, more corner speed than with the Pirelli and Dunlop?

Yes, but the Pirelli is also quite good in this area. But the more you unload the front tyre when you’re approaching the corner the more the rear comes into action.

The rear tyre also affects braking. When MotoGP used Bridgestones the front tyre was very powerful, so there were a lot of stoppies, but the Michelin isn’t really good in this area, so you need a lot of help from the rear in braking, where usually you think the rear isn’t really useful.

This is why the factories now make their MotoGP bikes with more load on the rear, especially in braking. For this reason all the bikes get longer and lower every year.

Now you’re at the corner apex and you’re getting ready to pick up the bike, find some traction and accelerate…

In this area with big bikes there is no neutral moment, hardly a fraction of a second between when you completely release the front brake and start opening the throttle. This is when you really start to feel the rear tyre because the weight goes to the back of the bike.

In this area the Michelin is great. You can carry a lot of speed through the corner, then like with all tyres, you need to pick up the bike as soon as possible, to put more weight on top of the tyre, instead of losing energy on the side of the tyre. This is the important thing – you don’t want to lose too much energy on the side of the tyre through side loads.

Both the Michelin and the Dunlop rears are really strong in this area, so you don’t have to push too much with the throttle.

The Pirelli is also very good, very grippy. You can push on the tyre in acceleration and the tyre deforms [deflects] to make a big contact patch, which helps you pick up the bike and accelerate.

But this is where I am suffering at the moment [this part of the interview was conducted before Petrucci scored his first WSB podiums] because I think I put too much load into the tyre, so I go a bit sideways and I lose time in acceleration, because I’m losing energy going sideways.

The Dunlop rear is very hard, so you need to carry your momentum, not using too much throttle, then pick up the bike and open the throttle when the bike is quite upright, already far from the apex.

With the Michelin the carcass is quite soft, so you need to be really smooth, both in the trick of picking up the bike and opening the throttle. You mustn’t be too aggressive.

So the Michelin and Pirelli are better on the exit, while the Dunlop is hard so you can’t use all the power you’ve got?

Yeah, in MotoAmerica we used very soft compounds, because the construction of the Dunlop is very, very hard compared to the Pirelli, and because the tarmac isn’t very grippy.

If you visit a motorcycle dealer or a tyre shop you can take a Dunlop and you can sit on the tyre. You can’t do that with a Pirelli because you can easily bend the tyre with your hands! These tyres use very different pressures because their construction is completely different.

How do the different tyres compare when you’re trying to control wheelspin out of corners?

This is very difficult to compare, because in MotoGP everyone uses the same electronics system, whereas in superbikes you have better electronics, because every manufacturer makes its own electronics.

So in MotoGP you can’t make so many modifications. In superbikes Ducati use their own system, although the two systems are from the same mother, because they both come from Magneti Marelli.

“Sometimes you do one run and the next run the tyre is 1sec slower. It’s something that the engineers still can’t calculate”

Let’s say it’s more complicated to perfectly adapt a MotoGP bike’s spec software, because you can modify more things with the private software in WSBK. You can do whatever you want and try many, many different things and control many different things, so in this way it’s easier to ride a superbike, because you need less throttle control in acceleration and you can modify the engine brake more.

In MotoGP the engineers can’t always make what the rider asks for, so the rider needs to adapt himself more to the bike and to different corners and conditions.

Also, in races the Pirellis usually make quite a big drop, which you don’t usually get with the Michelins.

Some years ago each season used to end with a combined MotoGP/WSB test at Jerez, where Jonathan Rea would often end up fastest on his Kawasaki superbike. He told me he could attack corners more aggressively with the Pirelli front, because the tyre would squish and give him a big footprint, while MotoGP riders took long sweeping lines, trying not to overload the stiffer Michelin front.

Yeah, I remember that test so well. I think it was one of the first times we used Michelins in cold weather, and at a track where we usually race in hot conditions. This is another thing: Michelin tries to bring you the perfect tyre for every race and during that test it was very, very cold, maybe too cold for the compounds they had there.

On the other hand the Pirellis are so good with cold temperatures because they are commercial tyres, so you can use them in all kinds of different conditions. With a GP tyre you have a window of temperature in which you can use that compound, although Michelin’s tyres have improved since then.

Tyres are a chemical thing. Still in the MotoGP paddock no team really has control of this with the Michelins. Sometimes you can use the same tyre for two sessions and it’s still good, sometimes you do one run and the next run the tyre is one second slower, because the tyres have been heated, cooled and heated again, so they lose performance. It’s the same with pre-heated tyres and, because it’s a chemical thing, it’s something that the engineers still can’t calculate.

Tell us about switching back to a MotoGP bike at Le Mans, after riding a Panigale superbike for more than a year.

At the beginning at Le Mans the MotoGP bike was like riding a wooden table because the bike is really, really stiff and this is also the main characteristic that’s transferred to the tyres.

Because the bike is so stiff you really need to push on the bike and the tyres, which is what I’m still doing with the superbike. I always want to really push the bike with the brakes and with the throttle and in the middle of the corner, because everything with a MotoGP bike is quicker, so you need to be quick and strong, even if from the outside the riders look so smooth.

Also because everything is stiffer the bike is very precise, so to make every movement you need more power and you need to be so precise.

With a superbike every movement needs to be softer. Of course, a superbike is a lot stiffer than a normal production bike, so compared to a MotoGP bike it’s in the middle.

For example at Le Mans [riding Bastianini’s GP23] I needed to adapt in the changes of direction. I was always a bit late in changing direction, because I’d adapted myself to be smoother with the superbike, so at Le Mans I needed to be quicker to change direction.

This interview was conducted in May, before Petrucci scored his first WSB podiums at Donington and Most, so after those results I asked him where he had improved.

Finally I’ve been on the podium but I’m still missing that one step – I still need to work on the details.

I’ve got more used to the Pirelli front tyre, improving in trail braking, where you are still braking a lot, with the bike leant over, when you’re entering the corner. This manoeuvre is really difficult to do when the rear tyre isn’t sliding a bit. If you can’t slide the rear at this point, this is when the rider says, “The rear is pushing the front in braking”.

Also, although the rear tyre is also very important in braking, it can make it more difficult to stop the bike if the tyre is rebounding off the ground all the time when you are braking.

In acceleration traction I’ve made no significant improvements. I don’t have good grip when the rear tyre is new, which makes the early laps of races more difficult for me.