Nowadays MotoGP mechanics seem to spend half their time in their garages and even on the grid changing front wheels, brake discs and calipers. Why is this and how does it help?
Mechanics change Brad Binder’s front wheel on the grid at Losail, where riders need to save fuel on the sighting lap, so they don’t get enough heat into the tyre
Oxley
MotoGP is all about doing everything as fast as you can, whether you’re on track or in pit lane. Which begs the question – why do you see mechanics going to all the bother of changing brake discs and calipers every time they change a front wheel?
This even happens on the grid, when mechanics sometimes change the front wheel after the sighting lap, while their rider sits on the bike, getting into the zone before the warm-up lap. Which begs another question – why do they change the front wheel at this very stressful time?
Three reasons…
KTM has various clever tricks, saving seconds that can be spent on track.
First, at high fuel consumption tracks – like Losail, Red Bull Ring and Motegi – riders come very close to running out of fuel at the end of the race, so they ride the sighting lap as slowly as possible, to save fuel. This means they don’t get much heat into the tyres, so the sighting-lap tyres are swapped for fully heated tyres, straight out of their tyre warmers.
Second, at tracks where tyre life is an issue, changing the tyres on the grid reduces tyre use by one lap, which might not sound much, but at the end of a race it could save the rider a few tenths or a few seconds.
Third, if the rider gets a bad feeling from the front tyre during the sighting lap he will ask for a new front wheel and tyre, just to be sure.
And then there are the reasons why mechanics must change discs and calipers whenever they change a front wheel.
The start of the process: fender off, dry-brake lines disconnected, calipers attached to discs
Oxley
“During a session when you’re using one spec of front tyre and you want to change to a new tyre or a different spec, you’d think it’d save time having the new tyre already waiting with discs fitted, wouldn’t you?” says Mark Lloyd, who works on Brad Binder’s Red Bull KTM RC16s. “But we always move discs and calipers across to the new wheel because the brakes are hot, the calipers are hot and the rider’s got a feeling with those brakes.
“We feel that the few seconds you lose swapping them over in the garage you regain out on track, where the rider knows he can go straight on the gun because the brakes are still warm. Also, with the new [since 2020] finned Brembo calipers it takes a bit more time to get heat into them when they’re cold. Plus, of course, you always want to keep the discs and pads as matched sets, so you know you’re not going to get any vibration from the brakes.
“The other thing is that the 340mm discs we use nearly all the time are too big to get the wheel out with the calipers in situ, so we have to remove the calipers anyway. And the only time we use 320mm discs is at Phillip Island, because there’s hardly any braking there.”
Lloyd and Daniel Petak remove the discs/calipers from the ‘old’ wheel, in its wheel stand. Tyre warmer keeps the tyre hot in case it’s needed later
Oxley
Lloyd and his fellow mechanics have the operation down to a fine art and KTM has made various detail changes to the front-end to make front-wheel changes even quicker.
“It’s usually three of us doing it, so we can do it super-quick,” adds Lloyd, who used to work for the Castrol Honda and Repsol Honda WSB and MotoGP teams. “We do it once or twice most sessions, especially in FP3, when you really need to go for a time attack at the end to get into Q2. It’s easiest when we’re not running disc covers, because when we’ve got disc covers we have to remove the front fender, then the covers.”
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KTM has accelerated the process with various clever tricks, because every few seconds saved in the garage is another few seconds that can be spent on track.
It has reduced the number of pinch bolts on the front axle and halved the number of disc bolts, from six narrow-thread bolts to three wider-thread bolts. And each caliper stays attached to its disc via a little handle that mechanics clip into place as they remove the wheel. Then each disc/caliper set is placed in a specially moulded carbon-fibre tray.
KTM has also created a front-wheel stand, which holds the wheel vertical when it’s out of the bike, so two mechanics can remove or fit both discs simultaneously. Surprisingly, no other factory or team has copied the stand, unlike the rear wheel trollies which allow mechanics to spin the bike around from pit lane into the garage in a matter of seconds, rather than three-point-turning the bike into the garage. Suzuki was the first with this gadget and now everyone uses them.
The new wheel, with discs and calipers fitted, is put into the bike
Oxley
The whole process is assisted by power tools and non-spill, quick-release dry brake couplings, which allow calipers and hydraulic lines to be separated without disturbing the brake fluid.
So it goes like this… fender off, calipers attached to discs, disc covers off, dry brake couplings disconnected, axle out, wheel out and into tyre stand, discs/calipers removed and placed in tray, new wheel out of its tyre warmer and into stand, discs/calipers attached, wheel into the bike, axle fitted, dry brake couplings connected, disc covers fitted, fender fitted. About two minutes in all.
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Brakes are obviously very important on machines capable of exceeding 225mph (360km/h), so teams take great care to ensure everything is just right, including disc/caliper temperature.
Teams have a large permutation of disc-cover specs – full covers, half covers and slotted covers, with multiple slots that can be individually closed or open. They usually know, according to track layout and weather conditions, which covers to use, or not, as the case may be.
The idea is to have the discs running between 500 and 700 degrees Celsius, not exceeding 800 degrees. Above 900 or 1000 degrees the carbon will oxidise and the discs will literally disintegrate. This is why 340 or 355mm discs are compulsory at the heaviest-braking tracks – Buriram, Motegi and Red Bull Ring.
Disc covers attached, fender attached, calipers and everything else torqued up and ready to go
Oxley
Front calipers need to run at between 140 and 160C. Any cooler than that and the rider will get an inconsistent feeling from the brakes.
Obviously brake temperature is carefully monitored, with old-school temperature paint on the discs, an infra-red sensor aimed at each disc and temperature stickers on the calipers. And new for this year is Brembo’s latest front caliper which features a screw hole for a temperature sensor.
Each and every year MotoGP gets tighter and more competitive, which means each and every year teams must work harder to have everything 99.9% right 99.9% of the time or they won’t be competitive.
