Throttle Glitch Cause Of Pedrosa's Motegi Crash

Anyone seeing the crash by Dani Pedrosa at Motegi knew immediately that there was something very strange about the accident. The only footage of the crash is from the onboard camera, but the way the bike twitched as Pedrosa braked for Turn 9, the V Corner, was a sign that something was not right with the bike.

The problem, HRC revealed today, was a problem with the throttle. A malfunction with the fly-by-wire throttle caused the gas to stay open as Pedrosa braked, instead of shutting off, upsetting the balance of the bike under braking and causing Pedrosa to crash, fracturing his left collarbone in the process.

Fly-by-wire throttles - where the throttle grip operates an electrical sensor, which sends data to the engine ECU, which then calculates and controls the amount to actually open the butterfly valves in the injection bodies - have come under increasing criticism from the riders, commentators and fans who are opposed to electronics, and are likely to be one of the first targets for banning when the Grand Prix Commission turns its attention to limiting the electronics. However, the malfunction suffered by Pedrosa is both rare, and not limited to fly-by-wire throttles. Directly connected throttle cables have also been known to malfunction, either getting stuck open or snapping and shutting the throttle, causing several crashes in the past.

Below is the Repsol Honda team press release, containing details of the incident:


Repsol Honda rider Andrea Dovizioso finished in second place in the first free practice session for this weekend's Grand Prix of Japan. The 24-year-old Italian was quickly into his stride at the Twin Ring Motegi and rapidly established a promising machine set-up for his Honda RC212V. Steadily improving his pace throughout the hour, Dovizioso was in first position in the closing minutes until Valentino Rossi pipped him for top spot with his final lap. Dovizioso is confident of further improvements in tomorrow's practice and qualifying session, should the dry weather hold at Motegi.

For Dovizioso's team-mate, it was a much less happy day, Pedrosa falling early in the session and suffering a double fracture of the left collarbone which means the Spaniard is unfortunately out of the Grand Prix of Japan. The crash happened only five minutes into the session when the 25-year-old was still getting up to speed. As he began braking for tur n nine, he lost control and fell, with his left leg at first remaining under the bike as he slid into the gravel. The unlucky fall, just three laps into the session, was caused when a small problem with the throttle cable didn't allow Pedrosa to close the throttle when he came to brake, an issue which has already been investigated and resolved. Pedrosa will return home to Spain tonight, with an operation scheduled for tomorrow to plate the fractured collarbone.

Dovizioso will be back on track tomorrow morning for practice, with qualifying taking place at 13.55.

ANDREA DOVIZIOSO – 2nd – 1m 48.387s +0.213s
"I'm happy with today's session and especially with the lap time - today we started from a good base. In fact I think that we have a margin to improve further so I'm confident for the rest of the weekend. This is a track with particular characteristics; it has sections of strong acceleration and also parts where you brake aggressively, that's why it's important to find a good compromise to control the bike wheeling and get the best acceleration. I'm also very confident that we can improve because today we used the same tyres throughout the session and I didn't test the front hard tyre that seems to give an advantage. I'm really sorry for Dani. It's always very bad for a rider when there are injuries. I was behind him and it was a bad crash. He fell quite hard and stayed under the bike when he slid. I hope he can recover soon."

"Obviously this has been a really bad day for us. It was a strange crash in only my second full lap, in a slow section of the track. I tried to stop the bike as usual but I knew something was wrong and couldn't avoid going down. After the crash I knew immediately that I was injured because it was very painful. I had a big impact in my left ankle and also my collarbone was broken as I hit the track - so obviously it feels very unlucky because recently we have had really good results. I've been very healthy through the pre-season and through the year and we had been working a lot to get to and stay at the maximum level. Another injury to contend with is really not what I needed - I don't feel as though I deserve it. Anyway, once the doctors had checked everything here, we decided it was best to go back to Spain for the operation. I hope it goes as well as possible and t hat I can return to racing soon."

"Andrea did a good job today and he has the potential to improve his pace still further. He and his team worked will today and he's looking on course for a strong race. For Dani it's obviously very disappointing that he has suffered this injury. At any time this wouldn't be good, but Dani was in excellent form and so the timing - at the start of three races in close succession - is very unfortunate. We have looked closely into the reasons for the crash and hope that Dani can return to fitness and to racing quickly."

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That's kinda scary. Can't be good for Dovis confidence if your team mate has crashed from a stuck throttle... but like you say it's rare and can happen to any other part. Only a month or so ago I was riding into work and the clutch cable snapped on my K6 GSX-R1000. Thankfully it was as I was coming to a stop anyway, could have been worse! But it's not something that I even think about now. Hopefully the riders can do the same and Pedrosa can be back on form ASAP!

Speaking as someone who's suffered this a couple of times. You can even keep on riding and do clutchless shifts (takes a little throttle control: upshifts are easy obviously, but it needs planning when slowing down if you want to minimise stress on the gear box). Just remember to slow down well in advance of red lights and crawl toward them - bump starting gets very tiring, particularly with heavy leathers and bigger bikes. ;)

Ban a technology that's in use by production bikes? Ride by Wire isn't new and I doubt whether it's the cause of any of Motogp's issues.

Disappointing for Dani, I hope he makes a speedy recovery.

this is a proven technology, i bet cables give more trouble the world over jamming open and closed. when you boil it down it is a machine and machines can and do break no matter how rigorous the testing. it is real bad luck on dani's part and ruin's any slim hope of the title fight getting interesting. jorge champ in sepang.

Dani, when the throttle sticks you're supposed to pull in the clutch bro.

Fly by wire is probably more trustworthy than cables but should be banned anyway because of the electronics associated with them. These controls are overriding the riders inputs and making the racing steril.

This has to be corrected in my opinion or we will never know who is the best rider - only who has the best programmers back at the home office.

Sorry for the loss of Dani. He was just finally showing his profuse talents. Bummer.

at a street pace maybe, at the pace these guys are riding any unexpected event like an electronic throttle blip or even funky behaviour from the slipper clutch while tipping the bike into a corner... is going to upset the bike and cause a crash before the rider can even blink.

I'm sure neither one of us has ridden "at the pace these guys are riding..." but my experience in that exact situation was to pull in the clutch and hit the kill switch - worked for me.

It also works when your motor blows and locks the real wheel - again I'm speaking from experience, on the track, during a race.

It may look to fans like it all happens in an instant but to a racer, many times it happens in slow motion.

Poor Dani. I still am pulling for Lorenzo but I like Dani and hate to see something like this happen.

It also sucks to see championships decided like this.

Really sad for Dani and I wish him all the best.Dovi is a racer and the technical incident won't affect him one iota.
Cable,fly by wire,is merely part and parcel of racing and technological edge.
Just a real pity about the timing of this technological glitch.Mind you,some geological glitch in Iceland also had a hand in this year's play viz a viz Motegi.
It will be a sad day for racing,should anyone from manufacturer down to technician,to safety consultants be held accountable.
Old story,'If you can't stand the heat...get out of the kitchen'.
Dani will be the first to accept the situation.Great racer,great personality.
Tough as nails.Look forward to his return.
What will Motegi 2010 throw up next ???

The problem with throttle-by-wire is the nature of the mathematical functions, imo. As it stands right now, twisting the throttle to 100% can deliver unlimited variation of specific throttle output b/c TC, wheelie control, GPS, fuel computers, and lean angle sensors all modify the riders throttle movement to optimize efficiency and speed. I guess technically, this means the software is not technically a function since one input in the domain has multiple relationships in the range, but you understand what I'm saying. The software is extraordinarily complex and borderline dangerous in it's current form.

Throttle-by-cable is a 1:1 function. If the rider twists 25%, he gets 25% throttle. If throttle-by-wire were a simple 1:1 function without interference from electronic rider aids, I think it would actually be safer and more reliable than throttle by cable, but I have no idea how such and arrangement could be enforced without a spec ECU.

With apologies for the digression :)

If any given combination of inputs always result in the same output, it's still a function (the domain is just the cross-product of the inputs, or subset thereof). Note that while the cable operated one is indeed surjective for carburetted engines (if we ignore play and stretch in the cable) - there's a direct 1:1 relationship between the position of the grip and the slides. Even so, there obviously need not be a direct relationship between the throttle position and the response of the engine. The current state of the engine obv matters (e.g. rpm).

Further, with EFI engines (i.e. anything half-modern) there's always a computer there. So there's no point to getting rid of FBW really, as the cable doesn't get rid of the ECU. If there are people complaining about FBW, it's probably due to the feel of cables and their more pliant nature that smooths out any low-amplitude, high-frequency signals from the riders hand, due to aforementioned play and stretch. I.e. the cable basically provides a kind of band-stop filter. If there are engineers reading this whose riders complain about FBW, try adding such more such filtering to the processing of the throttle signal ;).

I don't have a problem with throttle by wire, and I do realize now that you must be technically correct. Somewhere in the software there must be a 1:1 function that tells the ECU the location of the throttle twist grip. Without this data input, the software couldn't filter the range.

Okay, what I'm saying then, technically speaking, is that I wish for the filters to be removed so that the 1:1 function directly determines the range.

If there's a "feel" issue with FBW, it's probably cause the FBW response is *less* filtered and *more* 1:1 than cable. Like I said, a cable is *not* 1:1 if you consider play and stretch. The effect of play/stretch is that small vibrations from the riders hand are "smoothed" out by the cable and don't really affect the throttle slides - the cable is a spring.

My guess is that, if there are feel issues, the FBW version *lacks* that smoothing filter function that are inherent to cables (and which the riders grew up with, from the lower classes) and is *too* direct. So they need to *add* more filtering to the FBW, is just my guess.

no way is fly by wire 1:1... the value that comes from the controller (throttle) goes through many functions before it effects actual fuel injection. along the way normalization/smoothing is surely applied whether implicitly or explicitly.

Which is why my '69 Triumph Bonneville cafe racer is still very beloved to me. How about: When you snap a clutch cable, you just pull over, get the spare out from under the seat, the tool kit from behind the side cover . . . . . . . . and twenty minutes later you're back on the road like nothing happened. Try that on a modern sport bike.

(Oops! This was intended to be a reply to Yikes! by nugget)

Now there's talk it may have been a cable problem.

I suspect Dovi's getting some feedback on it.

Fly-by-wire is the name for electronic joysticks with computer-controlled flight controls in airplanes, mostly made famous by the F16 fighter jet over 30 years ago. In cars it's called drive-by-wire, in bikes it's ride-by-wire - although I think Phoenix1's 'throttle-by-wire' as opposed to throttle-by-cable is maybe even better.
Apart from the name, I think it will be difficult to ban it from racing. More and more road bikes have it too, it's simply technological progress from which we all benefit. Still, it would definitely be good to ban them from a racing point of view, especially if that meant we would be getting rid of traction control.

gratuitous: was the throttle made by toyota? will there be a recall?

gutted to see the season end this way, gutted for dani who was really on an amazing roll and given what dovi did with that honda in QP today, i'm sure dani would have had a fantastic race.

as to the crash itself, it looked like he tried to slow down by downshifting. which is incredibly odd since it was not his brakes that failed... perhaps he was trying to get the bike under control rather than just tossing it away...