Why down to 800 cc?

[keithaba]

I was trying to find out why (if my research is correct) moto gp went down from 900 cc to 800 cc as the max engine size?

Does anyone have a link or know why the engines went smaller? Just curious, I'm just getting into motogp and trying to understand more about it.

 

[ionbeam]

They have reduced displacement to try to slow speeds. There are some tracks where speeds have reached as much as 210 mph, with many running 200 +. The 800cc limit will be in force for at least five-years, to give manufacturers some assurance that they will get return on investment for the engineering investment needed.

The bad news is that the bikes will become much less user friendly because the power band will have to become more peaky, with higher rev limits.

 

[charismaticmegafauna]

<snip>...bikes will become much less user friendly*

Interesting term* -- if any Moto-GP (Formula 1) world-class race-bike can be thought of that way. Yet, with all the electronic/computer controls currently in vogue, they may become....'pussycats'? :blink:

Of note: in last week's WSBK race, one of the racers (apparently?) turned off the traction control (late in the race) to allow some wheel-spin and tire-smoking....

I think, the reasons for the 800cc formula may be more complicated than just max speed -- although, I agree, that's part of it.

 

[keithaba]

I guess that makes sense. Most of those tracks were probably designed back in the 500CC days.

I found this too, which emphasizes that speed was definatley a part of the decision.

clicky

Sounds like the bikes may have lost a little top end, but ultimately require more (or different) rider skill and handle a bit better.

 

[GunMD]

And actually they came down from 990cc to 800cc. Quite a drop, indeed. Despite the lower displacement and seemingly slower top speeds the lap times that some riders are turning are actually faster than on the 990s. It is my understanding that the faster lap times are in part due to the fact that the 800s are lighter and can carry more speed during cornering.

So let's recap.

The bikes were running too fast on the straights so they lowered the displacement.

Now the bikes are lighter and carry more speed in the corners**.

Hmmm. How many bikes have you seen eat shit on a straight-away? (Don't ask Shinya, he holds the unofficial record for fastest MotoGP get-off...which happened to be on a straight-away).

EDIT:

** I just read that they have kept the same minimum weight limit as they had in place during the 990 era. So much for my "lighter = faster" theory. :dntknw:

 

[tstaff]

I guess that makes sense. Most of those tracks were probably designed back in the 500CC days.

Those 500's were just slow pussycat's. :lol:

 

[keithaba]

I guess that makes sense. Most of those tracks were probably designed back in the 500CC days.

Those 500's were just slow pussycat's. :lol:

I didn't say they were slow, but they sure as hell didn't do 210mph! (At least I can't find any evidence that they did in a race).

Even though the minimum weight didn't change, I don't think many, if any, of the 990 cc bikes were even close to the minimum weight.

 

[GunMD]

Even though the minimum weight didn't change, I don't think many, if any, of the 990 cc bikes were even close to the minimum weight.

Good point. As I continued to read I came across support for your theory on that, as well.

Maybe someday I'll learn to read the ENTIRE article before I post up about what I've read.

 

[charismaticmegafauna]

<snip>... but they sure as hell didn't do 210mph! (At least I can't find any evidence that they did in a race).

Circa 1993 (Mick Doohan): At Hockenheim his NSR (500) became the first GP bike to clock 200mph.

(Alternatively) This from Jeremy Burgess: "You only use top speed once a lap, you use acceleration every corner."

 

[tstaff]

500/990/800/250/even 125cc can all do this.

 

[charismaticmegafauna]

Another data point RE: top speed:

This from Mr. Jim Reed (talking about a 30 year old bike!):

"From 1974 to 1982, a (Yamaha) TZ-750, either factory or privately backed, won every Daytona 200! Add to this the number of World Championships and National championships worldwide, and the TZ-750 will surely go down as one of the greatest racers of all time.

Surely, today super bikes handle better, stop harder and are just plain-better race bikes. However, I have yet to witness a Superbike 200 that compares to the experience of seeing a master such as Roberts, Cecotto or Baker, rocket around the banks approaching 190 mph. If you missed the nine-year reign of the TZ-750 at Daytona, you missed something very special in the history of motorcycle racing."

 

[wfooshee]

Keep in mind the 500s were 2-strokes when making the power/displacement comparisons!

 

[2WheelTiger]

.....and the #1 reason they wanted to bring down the top speed...... tires.

It had nothing to do with current crash rates on the straights. It had to do with the probability of crashes on the straights.

Remember Matt Mladin and Ben Spies on those things they call Dunlops?

 

[feejer222]

And actually they came down from 990cc to 800cc. Quite a drop, indeed. Despite the lower displacement and seemingly slower top speeds the lap times that some riders are turning are actually faster than on the 990s. It is my understanding that the faster lap times are in part due to the fact that the 800s are lighter and can carry more speed during cornering.
So let's recap.

The bikes were running too fast on the straights so they lowered the displacement.

Now the bikes are lighter and carry more speed in the corners**.

Hmmm. How many bikes have you seen eat shit on a straight-away? (Don't ask Shinya, he holds the unofficial record for fastest MotoGP get-off...which happened to be on a straight-away).

EDIT:

** I just read that they have kept the same minimum weight limit as they had in place during the 990 era. So much for my "lighter = faster" theory. :dntknw:

My understanding was that the bikes were too fast, can't think of another reason for them to reduce the power really. The Nakano crash was on the same straight that saw Loris Caparossi clock 215mph in practice. I can't just remember which circuit it is, (Valencia?)...Randy will tell me.

Click HERE for the Nakano crash. Watch how the marshalls take his helmet off after all that bouncing. Almost as scary as the crash. They would have been blasted for it here.

His back tyre broke up I seem to remember.

 

[GunMD]

I've been dying to watch that video all day, but I can't get to YouTube from...uhhh....ehem. From this computer.

I can't just remember which circuit it is, (Valencia?)...Randy will tell me.

I think it was Mugello, Italy.

 

[feejer222]

I've been dying to watch that video all day, but I can't get to YouTube from...uhhh....ehem. From this computer.

It's sat waiting for you when you get home Gun....now get some work done!

 

[keithaba]

500/990/800/250/even 125cc can all do this.

I'm not trying to say that I want the 990 back, I'm just curious why a switch. Racing anything takes skill let alone any motorcycle.

So far: decrease top speed and increased traction have the most evidence and reason.

Feejer: That crash looked rough... The helmet removal was a joke too, they definitely wouldn't do that now.

 

[charismaticmegafauna]

Keep in mind the 500s were 2-strokes when making the power/displacement comparisons!

True -- altho, (who knows?) there may be 2-stokes again. When MotoGP began, it took almost twice the size 4-stroke to be on par with the 2-strokes -- now it only takes an 800. Way back in 1957 the 500cc MotoGuzzi 4-stroke GrandPrix racer went 172mph and 2-strokes were hardly considered ('Deeks' excepted). In 1979 when Honda had the NR500 they (4-strokes and 2-strokes) were close to par (not quite). Maybe, with technology like BRP's ETEC, 2-strokes will be used again -- they're still valid in snowmobiles.

.....and the #1 reason they wanted to bring down the top speed...... tires.It had nothing to do with current crash rates on the straights. It had to do with the probability of crashes on the straights.

Remember Matt Mladin and Ben Spies on those things they call Dunlops?

And...Barry Sheene's crash at Dayton in '75 on his Suzuki at 178mph -- on a Dunlop.

Tires -- you're right about that. Part of the reason that the west banking isn't used anymore and the 200 is an FX race.

 

[feejer222]

500/990/800/250/even 125cc can all do this.

I'm not trying to say that I want the 990 back, I'm just curious why a switch. Racing anything takes skill let alone any motorcycle.

So far: decrease top speed and increased traction have the most evidence and reason.

Feejer: That crash looked rough... The helmet removal was a joke too, they definitely wouldn't do that now.

That was only 3 years ago at most.