TT 2017: How hard are tyres worked on the mountain course?

Published: 02 June 2017

He might not be racing this year, but nobody knows the Isle of Man mountain course better than 23x TT winner John McGuinness. After riding the TT for 20 years, McGuinness knows what it takes to lap the mountain course at speed. 

Of course, one crucial part of putting together a fast lap is what’s underneath you, and it’s not just all about the bike. The tyres that connect the machine and rider to the road ahead are of vital importance. Arguably, the tyres are the one component that takes the most stress around the TT course as they cope with the vast amount of challenges posed by the different road surfaces and they have to withstand that over 75.46miles of speeds in excess of 200mph. We sat down with McGuinness and Dunlop’s Stephen Bickley to see just what stresses the tyres go through during that time.  

Bray Hill – force under braking

“One of my favourite points of the Isle of Man TT course is down Bray Hill right from the start probably because it’s so scary and unbelievably insane to go down there from no sighting lap, no warm up lap, boof, bang, you’re gone. 

“I go from being on the warmer to being unbelievably hot straight away then where the tyres deflect somewhere like, I mean, straight from the word go, the first 10, 15 seconds you go down Bray Hill and it hits the bottom and you know the tyres squash really, really flat. Those Dunlop stickers they put on the side, the yellow ones, you can see where the rims have been touching that. I mean the force they go through there, it’s just uncomprehendable to me. I can’t believe that patch of rubber’s the only bit that’s connecting you to the road. 

“There’s loads of places where they’re spinning 130mph, 140mph, 150mph and they’re off the ground sometimes, lots of jumps so they’re off-loaded and you’ve still got the throttle open so they’re probably spinning fastest when it lands and it has to catch up with itself as well.”

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “We have three main objectives when designing the tyre; safety, consistency/stability and grip all of which lead to performance. Our tyres have something called Heat Control Technology (HCT) this technology helps to keep the tyre thermally stable which leads to better stability and controlled temperatures. This year we have also increased the speed of our machine testing, we’ve really been pushing the tyres at higher speeds (15% higher to be precise) and this helps to increase rider confidence as they know the tyre can cope at the top end of the speedometer.”

Ago’s Leap and Crosby – jumps and wheelies

“Some of the bits over the jumps where like over Ago’s Leap, somewhere over Crosby where you’re on… a lot of places where you do like wheelies where it’s something like 150, 160mph wheelies, and you probably do 200 yards on the back wheel, so the front wheel slows down and when it lands, it’s got to catch up with itself. It’s like an airplane landing, that type of thing.

“Somewhere like through over Crosby jump, some of the bumpy sections as well from Ginger Hall to Ramsay they’re working really hard them tyres and moving, spinning, bouncing off the ground. You can hear the engine up and down with the rpm and like, I don’t know, the mountain section’s quite smooth compared to lots of the track.” 

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “The revolutionary NTEC system, which allows pressure tuning for optimum track performance is the key to what John feels here. He works closely with his Dunlop engineers to make sure he is optimising his pressures; you’ll see the guys in the yellow shirts swamping the pit lane and there’s a reason – ensuring safe usage and optimised pressure to get the most out of the rubber.”


Over the Mountain – temperature changes

“Yeah, it’s beautiful there. It’s like you, the road… it’s quite difficult when you’re learning up there because there are no walls or trees or lampposts, so it all looks the same. A lot of the track looks the same, so it’s quite difficult.

“It’s quite smooth up there too, quite a lot of grip, but it can be dodgy because conditions can come down as well. It might be 20 degrees on the bottom part of the section and you go up there on a night practice when you’re losing the daylight and all of a sudden the temperature’s dropping like mad as well. I don’t know how they work it out or what, the Dunlop technical boys would let you know but it’s definitely a different feeling. You’ve got to have the confidence that everything’s there for you in the colder conditions and the hot conditions. They’ve got to work in all conditions.” 

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “All tyres are designed with different temperature operating windows. For some races or tracks you can keep it quite tight as you know what you’re going to be facing, but on courses like the TT the temperature can be very changeable. We do a lot of testing in endurance racing at circuits like Le Mans and you can get a real advantage if you have a wide operating window where the tyre can cope across the full course." 

Ballacraine to Cronk-y-Voddy – kerbs and white lines

“Kerbs? No, you get close to one or two but you definitely don’t use them. No, I definitely try to be away from them. Some of the white lines are a bit sketchy, you know, you’re crossing the white lines sometimes and you don’t really know what to expect until you’re actually on the track on the first night, and you think, oh you just get a bit of a feel from Ballacraine to Cronk-y-Voddy they sort of repainted them and they’re quite proud of the tarmac and it was a bit messy for a bit and they actually had, in between on Sunday after first night’s practice, to grind all the paint off as well so it was all the better for us.” 

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “All tyres have to be able to deal with different surfaces, unless you’re on a professional race circuit you can’t get more than a mile without the surface changing. Some areas of the TT course are quite abrasive, then you have areas where it’s dewy from the trees, the compound needs to be able to cope with different scenarios and continue to be consistent and stable. By ensuring the right compound and right pressure we can provide consistency and stability no matter what the surface. Stability gives confidence which then equals performance.” 


Kirk Michael – manhole covers

“Yeah, there’s manhole covers you cross. There’s one or two on the track you can’t help it no matter where you are on the line, you have to go beyond the line, you cross a few manholes coming out of Kirk Michael, you cross them but you go over them that fast, they’re only two foot and God knows how many milliseconds it takes to cross them, but it’s always a little bit of ‘hold your breath’ type of thing for a millisecond as you go over them.

“But I think they’ve got it quite good now, the track, you know. It’s actually a manhole but they put like a material on it, shell grip I think they call it and they put it in there and you whizz over there that quick you don’t really feel it. As well as the manholes sometimes there are bits of road where a gas main might have bust over the winter so they’ve put a trench in, a new gas main or electric main or the water board’s been, or pikeys have been in and bloody done something! Always something, but once you’ve done a lap or two you get a feel for the place and it’s down to business really.”

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “Riders like John know the course so well that they are aware of each and every manhole cover, bump and groove. Unfortunately, tyres don’t have a magic ingredient that enables riders to go over manhole covers without noticing something’s different but with good compound and the right pressure you can manage the impact such things have on handling.” 

McGuinness’ – tyres well loaded

“I think another bit where the tyres are really well loaded up between fifth and sixth gear is McGuinness’. I’m super proud to have my own corner, it’s just amazing you know. You normally get your own corner when you’re not with us anymore but to be still doing a bit and have your own corner… 

“It’s a fifth gear left hand downhill blind corner that you’d think was impossible to go round at the speed I go round it or we go round it at, and I think it was when I won my first TT I passed a real top rider called Laurie McNelly through there. He’s not with us anymore, bless him, I just got a little run on him through there and it always give me a real big buzz to have passed him through there, I don’t know why, I’ve just always liked it. It gives me good memories. I passed Adrian Archibald coming out of there when I won my first Superbike TT on ’04 as well.” 

Dunlop’s Tyre Designer, Stephen Bickley, explains why:We really enjoy working with McGuinness, he provides us with some fantastic feedback. Sometimes it’s good to push him too, one year he wanted to stay on the old product rather than try the new. That year Michael Dunlop broke the lap record using our new product. The following year, John asked us to push him, so, we only brought the new product for him to use. He moaned to begin with but then he pushed it and broke the lap record once again.”

Quarry Bends

“I like these real high speed committed corners really. Quarry Bends is quite special. Coming through Quarry Bends is dead natural, smooth, left, right, left, right and back on the Sulby Straight. It’s one of those corners where when you get it right, it’s a real special corner. Yeah a good run down Sulby Straight.”

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “Recently we’ve been working on lighter handling/steering. Riding through corners like Quarry Bends needs to nice and easy to reduce rider fatigue. By offering a lighter feel it makes it less work for the rider, allowing them to concentrate on keeping the speed and what’s coming up next.” 


Trees and the issues from the first lap of practice

“Yeah, trees, a bit of sap can be a little bit damp and not so much in the race, depends as well, sunlight – not affecting the tyres - but like strobing through under the trees is quite difficult as well. It’s quite hard to judge where you are. It’s funny, it’s quite green sometimes. The track the first few nights, the tyres and that look quite scruffy and you think, they’re not going to last very long. Then they come to you and you will learn how to set the bike up better, then you’re not as aggressive on the throttle, you’re a bit more smooth and you learn to ride the track and the lines and everything. And then the track gets rubbered in a little bit, the racing line gets a lot cleaner, then actually the tyres get better and come back to you as well. The first night they’re quite scruffy but that’s just what can be expected really at the TT.”

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “What John notices here is exactly right. To begin with the tyres are picking up a lot of additional debris off the road which has culminated over the previous year. Once we’re into racing the tyres are nice and smooth. We often notice this at the start line of the races, this is the time that we want the tyres to retain the heat they have accumulated in the tyre warmers who cares if they’re scruffy, we just want them to keep the temperature which is where the HCT comes in for us.”

TOP STORIES

Start – slow lap?

“No, it used to be, it never used to be like it as it is nowadays. Everybody nowadays goes full gas straight away. You can see them off setting up a line and you’re like, there’s no easing yourself into it. It just seems to be full on, full on, which is good. Sometimes you get the bad weather or you might break down at first night and it’s raining on the second night so you haven’t really got much choice, you know, you’ve got to get stuck in and if you don’t you get left behind and then you’ve no chance then.” 

Dunlop’s Tyre Designer, Stephen Bickley, explains why: “This is why it’s so important for tyres to be able to perform from the off. They get no casual break-in nowadays, it’s straight on the throttle. As the TT is such an individual race there isn’t always the opportunity to get the warmers on so we make sure to carry out testing with and without. We have to make a compound and construction that can generate and retain heat straight away, that’s HCT, getting the pressure right helps with stability and consistency, all of which leads to better grip and performance overall.”

Pick up a copy of our special edition McGuinness: Ordinary bloke. Extraordinary Racer. This special from MCN, celebrates the career of one of the sport's best-loved road racers. Affectionately known as McPint, John's career has wowed and entertained bike racing fans for more than 20 years. Buy it here. 

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