What if somebody built a faster lapping road car?

[beelsebob]

However the required lateral grip needed does increase linearly with weight hence more weight always means (except if you have grippier tyres...which is not the case for P1) less cornering speed.
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this is exactly right. Obviously if the vehicle weighs more, the tyre has to work harder to maintain the same level of lateral loads.

i think beelsebob is very confused.

Nope, you're just confused about what I'm asserting – I didn't assert that a truck could corner faster, only that it had more grip... But also required more grip in order to turn, and hence would corner slower.

although to be fair it is easy to get the concept of weight and downforce mixed up. actually im struggling now...i mean the extra 'weight' induced by downforce in an f1 car is slightly different to the standing weight of a truck...because its being physically pushed down by air.

Nope, no mix up here – weight *is* downforce. Downforce is simply force on the car, downwards. This includes both weight and negative lift created by aero surfaces.

This is not the same as a trucks weight bearing down on the tyres, theres nothing pushing the truck to the ground through the tyre.

Uh no, you're very confused here - force is force, there's no magical "aerodynamic" force that pushes down somehow magically more than gravity pushes down... Both weight and negative lift push an F1 car into the track. Only weight pushes a truck into the track.

Its just a heavy truck....sat on some tyres. It would therefore have a huge amount of inertia going into a corner, and therefore a truck would NOT be able to corner at the same speed as an F1 car, even if it had max grippy tyres.

No it wouldn't... But it would have more grip.

[Ogami musashi]

This is not to say a road legal car cannot be made to make F1 like numbers, the Caparo T1 is possibly the closest starting point.

Exactly, the Caparo T1 is the closest...and yet..look at the times... 1:10 around top gear track while the lotus T125 did put a 1:03 with similar power/weight ratio but otherwise much more downforce and grippy tires... and we're still 4 seconds left from the F1 records done on a damp track.

[Jersey Tom]

Couple things -

I believe whoever was saying a truck would create a lot of "grip" because it's heavy was speaking purely in terms of pounds of lateral force (which is true)... and did also mention it would have more mass to accelerate (also true)... and yes the end result is less acceleration capability.

In any event, as came up in another thread passenger car tires only last thousands of miles because of how they are driven. They aren't particularly durable in an absolute sense... if you took a generic sedan to a racetrack its tires would be obliterated pretty quickly.

I'd also be wary of saying F1 tires (construction wise) are "hard" or "stiff," though I suppose it depends on your definition. On the occasions you find a cutaway view of a tall sidewall race tire (there are a number floating around on the web and TV broadcasts so it's public domain information) you'll see that the sidewall is generally just a very thin layer of fabric. Not really any "mechanical stiffness" to it. I believe there was a photo of some unmounted Bridgestone F1 tires somewhere which showed them crumpled up like dishrags, to that point.

In general I hate talking about tires having "stiff" or "soft" sidewalls.

[Tim.Wright]

Until someone builds a tyre for this, it will never be possible.

There are basically two obstacles to overcome (as Greg has alluded to);

1. Power to weight ratio needs to be about the same as an F1 car
2. Tyres needs to be able to support about 5G of acceleration

Point 1 is already possible using well established methods.

Point 2 has not yet been done on a road tyre. It is very unlikely anyone will ever bother to develop a tyre which will support a "sedan" at 5G.

As to the original question of what happens then? Who cares... I still manage to get out of bed each morning even though the Veyron can travel faster than an F1 car.

Tim

[dren]

It will become more of a reality as F1 rules keep tightening down. If F1 was open with little regulation, there wouldn't be anything that could come close.

[Phil]

I find this discussion highly interesting. On the topic of grip and truck, DMotor, a german car-programm very similar to TopGear had a challenge between a race-truck and a Ferrari 360 CS.

Here's the video:

[youtube]http://www.youtube.com/watch?v=6p7FnPycXsE[/youtube]

Just goes to show what a truck with sticky tyres and a low CoG can do. Just thought this might be of interest given it's partly relevant to the discussion on grip somewhat.

[beelsebob]

The video is cool, but it doesn't really show what the confusion is about. People here seem to think that "grip" is the difference between the frictional force on the road, and the force required to make the vehicle turn. It's not, it's simply the frictional force on the road. In a vehicle that weighs more (and hence requires more force for the same acceleration into a turn), you need more grip. The lorry certainly will be creating more grip, purely by the fact that there's a lot of weight pushing it down into the tarmac... But it also requires more force to accelerate it at the same rate.

[Jersey Tom]

2. Tyres needs to be able to support about 5G of acceleration

Not necessarily impossible. The tires don't care how many "G" they are producing (a vehicle parameter) as much as just how many pounds of lateral demand for how many pounds of vertical load.

It's not entirely that F1 tires are particularly "grippy" ... hillclimb or FSAE tires are probably more tractive in a sense, F1 car can just produce the aero download required. Not to mention there are consumer cars out there which are massively "over-tired" as it is. Corvette comes to mind.

I still think it's possible you could make a road legal car with active suspension and powered aero (fans) which would give a GP car a run for its money.

But still, to your point and what I said initially.. who cares? F1 isn't about making the fastest possible cars.

[Tim.Wright]

Not necessarily impossible. The tires don't care how many "G" they are producing (a vehicle parameter) as much as just how many pounds of lateral demand for how many pounds of vertical load.

Yea, thats why I mentioned the word "sedan". Because a tyre that can support a sedan cornering at 5G (with 2-3G of downforce) doesn't exist.

Tim.

[Ogami musashi]

The video is cool, but it doesn't really show what the confusion is about. People here seem to think that "grip" is the difference between the frictional force on the road, and the force required to make the vehicle turn. It's not, it's simply the frictional force on the road. In a vehicle that weighs more (and hence requires more force for the same acceleration into a turn), you need more grip. The lorry certainly will be creating more grip, purely by the fact that there's a lot of weight pushing it down into the tarmac... But it also requires more force to accelerate it at the same rate.

Please stop playing on words....If you want to be picky the adhesion are the forceS at the tyre/road interface; And it is obvious for everyone here that "grip" defines the cornering capacities. Don't try to make it like you never implied the P1 would have as much grip as a F1 car at taking corners.



Tom:

I disagree about the purpose of recent F1 cars. Yes of course you have regulations, but many technicals details down to the regulations are made to be sure the cars are the fastest around a track.

[beelsebob]

The video is cool, but it doesn't really show what the confusion is about. People here seem to think that "grip" is the difference between the frictional force on the road, and the force required to make the vehicle turn. It's not, it's simply the frictional force on the road. In a vehicle that weighs more (and hence requires more force for the same acceleration into a turn), you need more grip. The lorry certainly will be creating more grip, purely by the fact that there's a lot of weight pushing it down into the tarmac... But it also requires more force to accelerate it at the same rate.

I didn't – I implied^Wsaid, directly that a lorry would have more grip, but less cornering ability.

[markp]

To corner at f1 speeds you would need race spec tyres and these would be useless on the road most obviously slicks would be illegal. A tyre that can be used in all road conditions and provide the ride quality for road use would fall apart at f1 speeds. A point I badly tried to make earlier. Plus McLaren p1 willlikely be slower than a radical etc so if any car can do it it's not been invented or is even in the pipeline. Might have a shot at a moto gp bike but I doubt it.

[Greg Locock]

No current or likely road car would be a good starting point, because you'd have to start from scratch. You don't need a monster engine, F1s are very powerful, but need that power to generate the downforce via inefficient airfoils instead of efficent suction. Various people have made various open wheelers road legal in various jurisdictions, I don't think that side of the job is necessarily that hard.

Whoever was talking about friction circles was on the money. A VGG diagram will tell you a lot.

[Just_a_fan]

To corner at f1 speeds you would need race spec tyres and these would be useless on the road most obviously slicks would be illegal. A tyre that can be used in all road conditions and provide the ride quality for road use would fall apart at f1 speeds. A point I badly tried to make earlier. Plus McLaren p1 willlikely be slower than a radical etc so if any car can do it it's not been invented or is even in the pipeline. Might have a shot at a moto gp bike but I doubt it.

You could probably use an F1 rain tyre on the road in all conditions if you could get Pirelli to homologate it for road use. No reason why this hypothetical road car can't use an F1-capable tyre / wheel combination. Sure, it wouldn't last long but then no one said the tyres had to be durable. Actually, no one said the car has to be usable in in all conditions - never seen an F1 car race in snow for example. Indeed there are a number of road-legal semi-slick tyres around these days. Making one that would carry the downforce loads shouldn't be impossible.

I think a road-legal car capable of lapping at F1 pace isn't that difficult. Expensive? Oh yes, very expensive! You'd basically be looking at building a quicker version of an LMP1 which would be trivially easy because there are no performance limiting rules to apply. Give the thing driver adjustable suspension (track and road settings for example) and you could make ground effect work on track and still be able to cross speed humps on the road.

But you're going to need an F1-style budget to build and run the thing!

[aussiegman]

To corner at f1 speeds you would need race spec tyres and these would be useless on the road most obviously slicks would be illegal. A tyre that can be used in all road conditions and provide the ride quality for road use would fall apart at f1 speeds.

I still disagree with this assumption as per my previous post. There are definitively road legal r-compound tyres that produce large amounts of grip if only last 250kms such as the Yokohama A050 soft / super soft compound, Hankook Ventus TD, Hoosier R6 etc. All DOT approved road legal tyres and so could be and in some cases are used as road tyres.

Again I would offer the example of the WTAC Team Nemo Evo which ran road legal Yokohama A050 tyre's of 295-30-18 size and managed to hold flat throttle at 260kph through turn 1 where it pulled 2.92G's at Eastern Creek (Sydney Motorsport Park) from the on board telemetry.

A point I badly tried to make earlier. Plus McLaren p1 willlikely be slower than a radical etc so if any car can do it it's not been invented or is even in the pipeline. Might have a shot at a moto gp bike but I doubt it.

Bikes are generally slower around a track, but faster in a sprint. The smaller contact patch of the tyres used negatively affects braking and corner speeds as does the lack or aero and aero stability.