MotoGP question

[DaveT319]

So why does it seem like the MotoGP and Moto2 bikes can lean much farther over than, say, the WSBK bikes? Something about the bikes? Something about the tires? Both? Something else?

Whatever it is, it's hugely impressive.

 

[cencalballer]

Tires, bikes and even mroe importantly the way they are ridden. A motogp bike has higher entry, exit speeds and to do that requires more lean. A superbike is a bit mroe point and squirt type of riding in comaprison.

 

[dtrides]

I believe Ben Spies said the GP tires had like 50 % more grip than what he had in WSBK. That just sounds amazing..
DT

 

[DannoXYZ]

Aren't MotoGP bikes lighter too?

MotoGP: 2-cyl = 297 lbs, 4-cyl = 330 lbs
WSBK: 363 lbs

That's a 10% difference and it appears the average weight of a MotoGP rider is lower as well. Kinda like power-to-weight, MotoGP has a superior tyre-grip to weight ratio. Thus faster cornering-speeds and more lean.

 

[Yo!Joe!!!]

I rode a (street version) Desmosedici RR once, and it was amazingly light and nimble...

 

[DaveT319]

But is there a different tire design for the GP bikes vs. the WSBK bikes? Because it never seems like the WSBKs aren't getting to the edge of the tire (no "chicken strips"). So where does that "extra" angle come from?

 

[BaCaRdIR1]

^^^^........1<2

 

[DannoXYZ]

But is there a different tire design for the GP bikes vs. the WSBK bikes? Because it never seems like the WSBKs aren't getting to the edge of the tire (no "chicken strips"). So where does that "extra" angle come from?

Counter-steering and physics. There's two equations involved. The first is lateral-acceleration based upon curve-radius and speed (or time around circle):

G = 1.22 [ (CircleRadius)/(LapTime^2) ]​

The second equation deals with lean-angle given any cornering-G:

Angle = ATAN(V^2/(R*G))*180/Pi​

Basically, in order to balance the centripedal force at a certain speed, you must counter-steer to lean... say 50-degrees from vertical. If you have tires and lighter weight such that you can corner even faster, you need to lean even more to balance the higher lateral-acceleration... so 60-degrees.

Imagine this photo as vector-additions. The lateral-G component is horizontal and gravity is vertical. The higher the lateral-G, the more horizontal the sum-vector (along axis of tyre).

 

[jraice]

Lighter weight, stiffer chassis (lots of interesting interviews from riders on the difference between coming into GP from liter bikes vs. the two strokes), better electronics and better tires.

 

[jraice]

Although I don't totally agree with you on your statement that WSBK's can't lean as much as GP bikes.

Ben seems to be doing alright on his R1.

http://www.pirate4x4.com/forum/attachment.php?attachmentid=608514&stc=1&d=1310648601

 

[the grinch]

...tires and lighter weight...

The 125 gp bikes lean over even further. You should see the lean angles that you can get on an 80cc motard.

 

[Burning1]

But is there a different tire design for the GP bikes vs. the WSBK bikes? Because it never seems like the WSBKs aren't getting to the edge of the tire (no "chicken strips"). So where does that "extra" angle come from?

Touching the edge of the tire to the ground is not the limits of traction by a very wide margin. In a lot of trackday photos, you can see that the rider is well past the point where they would have worn out their chicken strips. Likewise, I've seen a lot of scientific data showing what the contact patch looks like at extreme lean angles; the edge of the tire is very obvious.

With that said, the actual edge of the tire is very much a matter of tire profile, and a very tall pointy tire will lean much further before it's on the edge.

 

[DannoXYZ]

Although I don't totally agree with you on your statement that WSBK's can't lean as much as GP bikes.

Ben seems to be doing alright on his R1.

Pull out your protractors and measure them yourself. Here's your Spies pictures (rotated to level horizon):

WSBK:

MotoGP:

Pretty significant difference really. Notice how Spies has his arm stuck way out, while Lorenzo's arm is tucked in next to his body and it's still as close to rubbing the elbow.

But is there a different tire design for the GP bikes vs. the WSBK bikes? Because it never seems like the WSBKs aren't getting to the edge of the tire (no "chicken strips"). So where does that "extra" angle come from?

Don't get cause & effect mixed up. The higher lean doesn't cause higher cornering speeds or traction. It's the other way around, lighter-weight and grippier tyres causes higher cornering-speeds and lean-angles.

 

[Squidly McSmearstain]

While the pictures are interesting, you can't derive a conclusion from those.

Are those photos of the same corner? The riders are different. There's simply no way you can conclude a systematic lean angle difference between MototGP and WSBK based on those photos.

 

[DannoXYZ]

While the pictures are interesting, you can't derive a conclusion from those.

Are those photos of the same corner? The riders are different. There's simply no way you can conclude a systematic lean angle difference between MototGP and WSBK based on those photos.

Well, you can make a systematic comparison by analysing the entire series. Here's what you do:

1. find track where both MotoGP & WSBK runs... say... Donnington
2. find time-differences in laptimes... say.. 3-seconds
3. calculate speed-differences given those different laptimes
4. calculate speed-differences in the corners
5. calculate difference in cornering-G
6. calculate lean-angle given speed & cornering-G
7. plug into those equations I gave above.

You'll find the lean-angle differences are pretty much what's shown in those photos. Here's some more MotoGP photos:

Try as you might, you will NOT find as many WSBK photos with that much lean angle (if any). You want to look at LOTs of photos, analyse the laptimes and come up with some trends:

1. MotoGP bikes are faster than WSBK at every single track that they run in common

2. MotoGP 800cc bikes do not have a significant power-advantage over 1000cc WSBK

3. MotoGP bikes do not have significantly faster top-speed than WSBK

4. the faster MotoGP laptimes are made in the corners with higher cornering-speeds (all-out race-tyres are stickier than spec tyres)

5. MotoGP riders do not lean off the side of the bike as much, there's no room between the bike and the ground

6. MotoGp riders do not stick out their elbows, but keep them close to their bodies, again, because there's not much room between the bike and the ground.


BTW - I've been following MotoGP from way back when these guys were riding. Took these at Laguna:

 

[SM610]

Bottom pic...





Elflub?


Seems pretty specific, do they have special lube needs?

 

[TTTom]

Yet for all the better riders, stickier tires and lighter weight in MotoGP, comparing Q times at a favorite high speed track like Philips Island, a combined grid would have featured one superbike and two GP bikes on the front row and two superbikes, one GP bike on the second row. Both Q sessions held in decent weather.

Considering the cost difference and the fact that the 8 or 10 best riders in the world are in GP, there's not a lot of difference there.

 

[DannoXYZ]

Yeah, the gap is shrinking. Next year with semi-production based engines, limited numbers of engines for the season, and less electronic-aids in MotoGP, we should see them getting closer and closer in performance.

Although we need to also compare the riders. Spies was faster on MotoGP the season after his WSBK championship. Would be interesting to see how those guys at the front rows of WSBK would do when they jump ship to MotoGP.

 

[TTTom]

Yeah, the gap is shrinking. Next year with semi-production based engines, limited numbers of engines for the season, and less electronic-aids in MotoGP, we should see them getting closer and closer in performance.

Although we need to also compare the riders. Spies was faster on MotoGP the season after his WSBK championship. Would be interesting to see how those guys at the front rows of WSBK would do when they jump ship to MotoGP.

I think the faster guys in WorldSBK are equal to the slow half of the MotoGP grid. The aliens are the aliens and the next group (Dovi, Simo, Hayden & Spies) would still be the cream of the WorldSBK grid.

 

[Sane_Man]

Aren't the chassis's different between MotoGP and WSBK bike's?

If the MotoGP bike has a lower seat height for example, then that would allow the bike to lean over further because of the lower CG.