Does tyre wear affect top speed?

[hollus]

OK, I am risking looking a bit ridiculous here, but I'll ask anyways, one learns from errors.
With the current cars having an RPM limit, the car can only go as fast as the longest gear will allow, and we see current F1 cars hitting this rev limiter all the time, and I think then hitting top speed. Many slipstreams seem to be aborted simply for this reason.
So, for so many engine RPMs, the gear makes sure that the wheel makes so many revolutions (per minute, per second, per hour, whatever), and this many revolutions times the circumference of the tyre translates into so many meters (meters per second of kilometers per hour, same same).
Logically it would follow that a worn out tire, with less rubber, also has less circumference, and the the top speed would be reduced accordingly.
This sounds weird, though...
Am I right? Am I completely wrong? Why?

[Jersey Tom]

I haven't heard a F1 car banging off the rev limiter in top gear. Top speed is drag limited rather than gear limited... or at least very close to the edge of both.

Plus.. I'm guessing these tires have a roughly 13" effective radius. Haven't seen a F1 tire down to cords.. guessing they usually wear on the order of 0.050" .. so around 0.4% change. Going from a 49 to 50 tooth gear is a 5x larger difference.

In any event, when you wear those tires down they will run cooler.. all sorts of other crap doing on.. you wouldn't be able to pull out the circumference component from everything else.

[hollus]

Yes, of course. It is complex and they are not perfect circumferences.
So you sat 0.4% change? That would be about 1.2Km/H. Really difficult to notice.

I don't know about slicks, but rain tyres seem to wear down by significantly more than 1mm or 0.05".

[Jersey Tom]

Rain tires would have tread thickness to begin with, yes.

[ISLAMATRON]

With worn tires you wont be able to come off the corner as fast and so you wont get as high a top speed before you have to brake for the next corner.

Usually the cars dont hit the rev limiter in top gear... so the top speed is dictated by how well they come off the corner... and if they get a tow.

[Pandamasque]

From simracing experience - we usually set the top gear just a bit longer than necessary to hit the limiter in a good slipstream and low fuel only.

Also I agree with what ISLAMATRON mentioned, the compromised corner exit on worn tires will influence your top speed far more than than the slight change of radius.

[bidong]

i think given that you have a never ending drag strip, it will not compromise top speed.
But definitely during a race, a loose corner exit, because of worn tires, will affect top speed on the end of the straight. also braking earlier because of worn tires will affect top speed.

[Ciro Pabón]

This is a fallacy. Top speed is not related to RPM. Nobody is as fool as to use a top gear that limits top speed. As soon as this happens (if it has happened), then you would change that particular gear.

Top speed is limited by aerodynamic drag.

[speedsense]

OK, I am risking looking a bit ridiculous here, but I'll ask anyways, one learns from errors.
With the current cars having an RPM limit, the car can only go as fast as the longest gear will allow, and we see current F1 cars hitting this rev limiter all the time, and I think then hitting top speed. Many slipstreams seem to be aborted simply for this reason.
So, for so many engine RPMs, the gear makes sure that the wheel makes so many revolutions (per minute, per second, per hour, whatever), and this many revolutions times the circumference of the tyre translates into so many meters (meters per second of kilometers per hour, same same).
Logically it would follow that a worn out tire, with less rubber, also has less circumference, and the the top speed would be reduced accordingly.
This sounds weird, though...
Am I right? Am I completely wrong? Why?

No, you are not wrong and it is a worthy thought. Tires do wear, however as a race progresses, so does the heat in the tire, as it wears the heat also rises. This increases the tire pressure (which is already known through testing the tire). The increase in pressure makes the tire grow (with radials,not much growth but increases the side wall spring rate. Which effects the rolling distance of the tire)
Teams,through experience with the tire and data, already know what gearing will A)manage a slipstream b)hit max revs on a wearing tire and C) how long they can go before the cords give up and the rubber's gone...

[xpensive]

This is a fallacy. Top speed is not related to RPM. Nobody is as fool as to use a top gear that limits top speed. As soon as this happens (if it has happened), then you would change that particular gear.

Top speed is limited by aerodynamic drag.

Moderator is correct, top-speed is always balanced by wheel power, when power is in principle aerodynamic resistance times speed.

Wheel power (W) = Aerodynamic resistance (N) * Speed (m/s)

[hollus]

Thanks guys. And not a word out of tone, thanks again.
I should have asked about the top speed of a Ferrari or the top speed of a Mclaren or of a Mercedes. Then we would have had an interesting debate!

[autogyro]

Top speed is limited by having to match the rpm difference between seven stepped sequential ratios so as to match the power delivery available to the particular circuit being raced on.
It is easily possible to gear an F1 car to achieve much higher top speeds but to do so would compromise all the other speed gearing requirements.
There is a big down side with the regulation limited 18000 rpm here. It means that another tuning restriction is established resulting in a forced reduction in high speed overtaking. This adds to the huge problem of turbulent wake that is the primary cause, killing overtaking and F1 itself.
Aerodynamics may be the 'God' of F1 and its main downside but the aerodynamic drag created on an F1 car is much to low to reduce top speed on its own.

[xpensive]

But at the end of the day, in this Newtonian world, this will always be the universal rule:

Wheel power (Watt) = Aerodynamic resistance (Newton) * Topspeed (meters per second)

Wheel power, as well as engine power for that matter, is of course Torque (Newtonmeters) times angular velocity (radians per second),
but that is really beside the point here.

[kilcoo316]

Aerodynamics may be the 'God' of F1 and its main downside but the aerodynamic drag created on an F1 car is much to low to reduce top speed on its own.

The aerodynamic drag on an F1 car is almost entirely responsible for defining what the top speed is (there are some frictional losses in the drivetrain and the wheel bearings, but its absolutely negligible in comparison).

[autogyro]

Aerodynamics may be the 'God' of F1 and its main downside but the aerodynamic drag created on an F1 car is much to low to reduce top speed on its own.

The aerodynamic drag on an F1 car is almost entirely responsible for defining what the top speed is (there are some frictional losses in the drivetrain and the wheel bearings, but its absolutely negligible in comparison).

Top speed is restricted by gearing and rpm limit.
Aero drag is not the defining force.
So all bow to the god of downforce is incorrect in this case.