"Cans" Vs Bikes

[RiderInBlack]

Does anyone know if the fact a car is wider than a bike means it can't "straighten" the corners so much, means the bikes should have a higher entry/exit speed or is that just a "theory"?
'Course a bike doesn't handle the "ripple-strip" the same!

Was thinking of the width factor today, which may explain the faster bike times on our narrow tracks.

I also was curious as to the angles of forces being applied to the tyres as a bike is cornering. As you lean the bike over you shift it's centre of gravity to the inside edge of the corner. The centrifical force is trying to throw the bike of the outside of the corner. Would not the act of these 2 forces increase the weight pushing the tyres onto the track, and thereby increase traction?
Wouldn't you get this effect on the outside tyres of a "can", but loose it on the inside tyres (just got thought of this as my old ute pitched and roll as I rounded the corner )?
Anyone here good at Bike Physics?

[Lou Girardin]

I don't know physics, but I do know that it's centrifugal force (weight) that eventually makes any tyre let go. Which is why heavy cars don't corner as fast as light ones, given equal rubber.
Lou

[Drunken Monkey]

Does anyone know if the fact a car is wider than a bike means it can't "straighten" the corners so much, means the bikes should have a higher entry/exit speed or is that just a "theory"?
'Course a bike doesn't handle the "ripple-strip" the same!

This is offset by the physics of all single track vehicles = under braking and acceleration, a single track vehicle (ie motorbike) tends to want to stand up. Strictly speaking, a car can be braking until the tightest point of the corner, then accelerate as it opens. A bike has to brake, pass through the apex at constant speed, then accelerate out. Not entirely true in practice -try putting the brakes on in a heavy car while in a corner - oops! But we all know it's even worse pulling on those front discs while you're dragging your knee!
Ultimately the reason has been covered: more rubber = more grip.

[Drunken Monkey]

I don't know physics, but I do know that it's centrifugal force (weight) that eventually makes any tyre let go. Which is why heavy cars don't corner as fast as light ones, given equal rubber.
Lou

Yes, you don't know physics There's no such thing as 'centrigual force' = its a layman's term used to describe things to kids. The correct term is centripedal acceleration, but let's not go into that. (where are those 'pedantic bastard' html tags when you need them??)

*ahem*

Terminology aside, you hit it right on the nose. Any given mass that moves has momentum (cf a stationary mass = inertia). The more momentum an object has, the harder it is to enact a force on it, in this case, acceleration (yes, turning is an acceleration - a 'vector quantitiy') in another direction.

And I thought I forgot all my high school physics...

[Grumpy]

Years ago now I was involvedin Superkart racing. We ran Rotax 250cc engines, no suspension but awesome brakes.

We raced at Cemetry curcuit a couple of times and around the tight circuit the top lap time from the karts smashed the bike Formula 1 lap record and it was a few years before the bikes got near it.

Another time I was practicing at Baypark....when there was a Bayprk that is...and the Tuaranga bike club were there too. I was out on the track with a racebike, a 1100 something. I can't remember what. I could practically run around the outside of it around the sweeper and leave it for dead out of the corners but it would get me down the straights although I would nail it under brakes.

The lack of weight and good traction were a huge advantage.

I have to say though, after racing at cemetry I gained a hell of a respect for the guys doing it on bikes. It was hard enough doing it on 4 wheels let alone 2 and I have to say the bikes sure looked more exciting than the Karts.

[FzerozeroT]

top gear did this between an R1 and a Porche Carrera 4, the Carrera won by a second, and they complained that "being a four wheel drive will make it slower in the dry" - never mind the fact that you could by ten R1's for the price.

[RiderInBlack]

Ultimately the reason has been covered: more rubber = more grip.

OK, given that more rubber = more grip, trikes & sidecars should hold better on corners than bikes. Do they:spudwhat:

[Motu]

Pushing us a bit here eh? Still comes down to contact patch - the side car will still only have the one front wheel for braking and one rear for drive,with more weight to stop and push,so they are slower for a given capacity,but they can use aerodynamics - a sidecar brake if used is only used to set up corners and keep the bike straight under braking.

A trike may have more traction on the drive wheels,but still only one front wheel for the extra weight.In the 60s some guys pushed the sidecar rules when they used a Mini powerplant with one rear wheel,rider and passenger sitting side by side.Of course they cleaned up and were promptly banned.

[RiderInBlack]

Pushing us a bit here eh?----
In the 60s some guys pushed the sidecar rules when they used a Mini powerplant with one rear wheel,rider and passenger sitting side by side.Of course they cleaned up and were promptly banned.

Yep But look at the good info I am getting out of you dudes

Racing rules alway amuse me. On one side we use it to develope our machines, but if someone comes up with something really good, we make a rule against it to make things "sporting" (or to favour a group). This slows down (or stops) improvements in the area. Think of the advances we would have in windpower if they had less rules governing say the America's Cup! F1 would real have got the ground effect down pat!
With bikes, 4's (or more) would get better without the breather restriction. OK, just shit-stiring again.

[wkid_one]

I don't know physics, but I do know that it's centrifugal force (weight) that eventually makes any tyre let go. Which is why heavy cars don't corner as fast as light ones, given equal rubber.
Lou

Biggest differentiating factor is the aero package the cars are running - this will make any car corner well - at the expense of increase drag however.

Race teams spend more money and time on setting the cars/bikes up than anything else - they have the luxury of hundreds of hours of testing and hundreds of gigabytes of telemetry - telling everything that the car/bike is doing.

The unfortunate thing is for bike - whilst part of it is a rubber on the road issue - their biggest downfall is the complete and utter inability to use aerodynamics in corners. And in fact - their complete disregard for aerodynamics full stop. Bikes create next to no downforce - therefore don't use air to create any traction advantage what-so-ever. Also - next to Truck Racing - they are some of the most inefficient aerodynamic vehicles racing on the planet today.

The flip side is that they can accelerate quicker as they don't need to overcome the friction of downforce. Don't be fooled in to thinking a bike is quicker in a straight line than an F1 Car - it is only because, in race trim, the F1 Car is having to overcome over 1 tonne of downward pressure acting as friction on the road. However - this is offset somewhat by the bikes incredibly brick like aerodynamics.

[Motu]

The dust bin full coverage fairing was banned in the late 50s,early 60s - I wonder how far down the aerodynamic road bikes be be now if they had been allowd to develope further?

[wkid_one]

I think they would probablt resemble what you see at Bonneville

[Big Dog]

Just to stick my oar in.....
If you make it a ratio of dollars spent per kmph the R1 is 10 times faster, given it is a tenth of the cost and only seconds slower..... and that is cost price not development cost.

Also the largest limiting factor on a bike tends to be the skill of the rider, in a car it tends to be the size of their balls.

[Lou Girardin]

Granted, bikes CD figures are not great, but their CDa (co-efficient of drag x area is better than most cars. Thats why a Hyabusa only needs 180 hp to hit 300km/h, compared to a 550 Maranello's 550.

[wkid_one]

My exact point Lou - the car is utilising downforce - which in turn creates friction - BUT - means it can wickedly out corner a motorcycle.

A car has to overcome both forward friction against the air - and downward friction against the road - whereas - a bike only has to overcome forward friction (for which it has a smaller frontal area). Bikes don't utilise downforce.