Car vs bike - cornering speeds

Car vs bike - cornering speeds

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Discussion

stackmonkey

Original Poster:

5,077 posts

256 months

Tuesday 22nd July 2008
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After a 'discussion' last night with a friend, I need a definitive answer backed up with the physics.
I was maintaining that, for a given genre (commuter, sports etc) a car will always be able to corner at a higher G force and that the only reason a bike could go round any corner quicker was by more effectively straight-lining the road.
He reckons that the cornering lean on a bike and lack of weight will mean that a bike will corner quicker.
I still believe that for a given line on a corner, a car would be quicker, or that for a given speed, a car can take a tighter line.

This arose after the discussion on straight line speed. My 5.0 Chimaera vs his SuzukiSV 650? which we agreed would be close, but neither of us could call on.

siscar

6,887 posts

224 months

Tuesday 22nd July 2008
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The car has much more grip, bikes will win on the straights but the car wins in the corners.

wee_andy

3 posts

196 months

Tuesday 22nd July 2008
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now I aint a biker, but having been n the back of my pals bike many a times, and in races with younger boy racers. a bike would clearly F**k a car round corners

sniff petrol

13,112 posts

219 months

Tuesday 22nd July 2008
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siscar said:
The car has much more grip, bikes will win on the straights but the car wins in the corners.
And under heavy braking.

cg360

611 posts

244 months

Tuesday 22nd July 2008
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On-road, you have too many variables in each corner to say that a car will always be faster, but on a track, car cornering speeds are higher due to larger contact area. Bikes accelerate faster, cars brake better and have higher cornering ability.

stackmonkey

Original Poster:

5,077 posts

256 months

Tuesday 22nd July 2008
quotequote all
cg360 said:
On-road, you have too many variables in each corner to say that a car will always be faster, but on a track, car cornering speeds are higher due to larger contact area. Bikes accelerate faster, cars brake better and have higher cornering ability.
This is what I told him, but he won't accept it, which is why I need the physics behind it.

kambites

68,437 posts

228 months

Tuesday 22nd July 2008
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There are two different question here really:



Mechanical grip:
The absolute maximum G-forces available are similar because contact patch per unit weight is broadly similar between the two types of vehicle. However, cars will always be faster on the road because:

1) You can commit much more in a car. Correcting mild under-steer in a car is part of everyday driving. Correcting any kind of slide on a bike is extremely difficult and dangerous. Plus if you do crash on a bike, it hurts more.

2) Bikes typically have a much higher ratio of unsprung to sprung mass so they can't deal with bumps as well as cars.



Aero grip:
Certain high-end cars use aerodynamics to generate greater grip though down-force. A bike cannot do this (because it leans through corners) so the very fastest cars (formula one cars for example) have far greater grip levels than the fastest bikes.



ETA: In reality though, it usually comes down to which of the pilots is more of an idiot.

Edited by kambites on Tuesday 22 July 09:08

sniff petrol

13,112 posts

219 months

Tuesday 22nd July 2008
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Have a look at some Youtube videos from trackdays for an idea of a hard ridden bike Vs car.

BlueEyedBoy

1,921 posts

203 months

Tuesday 22nd July 2008
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f1 vs moto gp, look at lap times, cars are faster round a track.

ettore

4,322 posts

259 months

Tuesday 22nd July 2008
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stackmonkey said:
cg360 said:
On-road, you have too many variables in each corner to say that a car will always be faster, but on a track, car cornering speeds are higher due to larger contact area. Bikes accelerate faster, cars brake better and have higher cornering ability.
This is what I told him, but he won't accept it, which is why I need the physics behind it.
Just look at the lap times for any circuit used by both cars and bikes. There is a very clear differential.

RobCrezz

7,892 posts

215 months

Tuesday 22nd July 2008
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sniff petrol said:
siscar said:
The car has much more grip, bikes will win on the straights but the car wins in the corners.
And under heavy braking.
Depends on the car. Caterhams and the like, will corner and brake faster than the bike, not acceleration isnt a million mile away.


This has been done to the death anyway.
Atom Vs Honda CBR 600-RR
http://www.youtube.com/watch?v=kUegrUQ4d3I

300bhp/ton

41,030 posts

197 months

Tuesday 22nd July 2008
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Didn't Clarkson try and settle this years back in one of his vids. A AWD Porsche with Jason Plato at the wheel and a superbike with someone I can't remember (ex Champ of some sort, think it was GP or somthing).

Anyhow on track the Porshce won from a standing start on a single flying lap.


Having said that, on the road (wide open A roads or Big B roads) a well ridden bike will be very very quick no matter the car you are in. In the bends, my experience tells me a well driven car can give many bikes something to think about.


If you want a straight line race then depending on the bike there are many cars fast enough to out run them. But BIG bhp is generally required.

sniff petrol

13,112 posts

219 months

Tuesday 22nd July 2008
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BlueEyedBoy said:
f1 vs moto gp, look at lap times, cars are faster round a track.
BTCC Vs BSB lap times might be a fairer comparison in relevance to road cars and bikes.

RobCrezz

7,892 posts

215 months

Tuesday 22nd July 2008
quotequote all
sniff petrol said:
BlueEyedBoy said:
f1 vs moto gp, look at lap times, cars are faster round a track.
BTCC Vs BSB lap times might be a fairer comparison in relevance to road cars and bikes.
I see where your coming from, but I think touring cars isnt fair against superbikes.

Maybe GT3 cars?

B(Route)

1,965 posts

211 months

Tuesday 22nd July 2008
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End of the day its almost entirely down to the rider/driver.

A well riden bike will destroy the average driver in any car.

A well riden bike will get a shock from a good driver in a good car.

The very sad fact is the vast majority of bikers are weekend warriors/summer riders, and they frankly cant go around corners for toffee.

I have been on the A54/A537 in a 1.2 clio and been held up by bikers who are scared of corners but do 140+ down the first straight.

At the same time I have had serious amounts of fun with a very well driven CSL on the A537

Sitting talking about G force and ultimate cornering speed is utter balls.....you need to talk real world on the road/track

Edited by B(Route) on Tuesday 22 July 09:24

300bhp/ton

41,030 posts

197 months

Tuesday 22nd July 2008
quotequote all
sniff petrol said:
BlueEyedBoy said:
f1 vs moto gp, look at lap times, cars are faster round a track.
BTCC Vs BSB lap times might be a fairer comparison in relevance to road cars and bikes.
Except a modern BTCC car shares nothing with a road car, not even the badge.

RobM77

35,349 posts

241 months

Tuesday 22nd July 2008
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There's not normally much in it when fast bikes are compared with fast cars on lap times. EVO compared an R1 with an R500 a while ago and the car won (by over a second on a twisty track), but then later on they compared an SR3 with a GSXR race bike and the bike won (on a fast track with a tight chicane). So it usually comes down to the circuit. Now, to answer the OP's question, in both those cases the bike can take a shallower line and it accelerates quicker, so I can logically deduce that a car must brake and corner better. Certainly at the Nurburgring and on roundabouts I've never come across a bike out cornering me in my car, even if the rider is really trying.

Dave^

7,515 posts

260 months

Tuesday 22nd July 2008
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[quote=B(Route)]End of the day its almost entirely down to the rider/driver.

A well riden bike will destroy the average driver in any car.

A well riden bike will get a shock from a good driver in a good car.

The very sad fact is the vast majority of bikers are weekend warriors/summer riders, and they frankly cant go around corners for toffee.

I have been on the A54/A537 in a 1.2 clio and been held up by bikers who are scared of corners but do 140+ down the first straight.

At the same time I have had serious amounts of fun with a very well driven CSL on the A537

Sitting talking about G force and ultimate cornering speed is utter balls.....you need to talk real world on the road/track

Edited by B(Route) on Tuesday 22 July 09:24

[/quote]


Exactly, cast your mind back when Sabine overtook a motorcycle round the Nurb' in a transit.....

stackmonkey

Original Poster:

5,077 posts

256 months

Tuesday 22nd July 2008
quotequote all
[quote=B(Route)]
Sitting talking about G force and ultimate cornering speed is utter balls.....

[/quote]

No, we need this to eliminate all the stuff above about how good the riders/drivers are, and specific road conditions.
If necessary use the specific bike and car mentioned in my OP.

Edited by stackmonkey on Tuesday 22 July 10:02

jon-

16,525 posts

223 months

Tuesday 22nd July 2008
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Just to annoy you further on my favourite hooning road I can comfortably hold similar apex speeds in both my 350z and Daytona 675. The car is easier to push right to the limit but ultimately no faster, and A-B on the road I'd put money on me being faster on the bike due to the straight line advantage and braking advantage (yep, 350z might have brembos and big discs but it's 1600kgs, the bike is 165kgs with race callipers and stupidly soft tyres). The only area the car is quicker in is corner turn in as I have to set the bike up were as I can throw the car in.

Edited by jon- on Tuesday 22 July 09:45